How to Care for Tracheostomy Patients at Home
A tracheostomy is a procedure in which an incision is made in the trachea. The objective of a tracheostomy is usually to allow the patient to breathe through the resulting opening, also known as a stoma. The stoma requires daily attention to prevent infection after the patient comes home, especially if the patient is on a ventilator.
Instructions
1.Fill a small cup with hydrogen peroxide solution. Fill a second cup with sterile water. Instruct the patient to lay face up and place a rolled towel under the patient's shoulders. This will cause the patient's neck to straighten and allow you to visualize the stoma more easily.
2.Wash your hands and place some cotton swabs in the cup of hydrogen peroxide solution. Clean the skin around the tracheostomy tube by using one cotton swab on each fourth of the circle around the stoma. Ensure that you don't allow the hydrogen peroxide solution into the stoma or tracheostomy tube.
3.Soak a cotton swab in sterile water. Swab the skin around the stoma with the moistened cotton swab. Dry the skin with a dry cotton swab or precut tracheostomy gauze. Change the tracheostomy ties if the skin under the ties appears irritated.
4.Inspect the dressing on a recent tracheostomy and replace it if it's moist. Fold a piece of precut tracheostomy gauze into a U shape and tuck it between the tracheostomy tube and the patient's skin. Be careful not to block the opening of the tracheostomy tube with the gauze.
5.Check the stoma of an older tracheostomy to ensure that it doesn't have any redness or rash. You don't necessarily need to change the dressing of a completely healed stoma if the skin is in good condition.
Selasa, 17 Ogos 2010
CHICKENPOX...
Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus (VZV).[1] It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and become itchy, raw pockmarks, which mostly heal without scarring.
Chicken pox is spread easily through coughs or sneezes of ill individuals or through direct contact with secretions from the rash. Following primary infection there is usually lifelong protective immunity from further episodes of chickenpox.
Chickenpox is rarely fatal, although it is generally more severe in adult males than in adult females or children. Pregnant women and those with a suppressed immune system are at highest risk of serious complications. Chicken pox is now believed to be the cause of one third of stroke cases in children.[2] The most common late complication of chicken pox is shingles, caused by reactivation of the varicella zoster virus decades after the initial episode of chickenpox.
Chickenpox has been observed in other primates, including chimpanzees[3] and gorillas.[4]
Signs and symptoms
Chickenpox is a highly infectious disease that spreads from person to person by direct contact or by air from an infected person's coughing or sneezing. Touching the fluid blister can also spread the disease. A person with chickenpox is infectious from one to five days before the rash appears.[5] The contagious period continues until all blisters have formed scabs, which may take 5 to 6 days at which point they are no longer contagious.[6] It takes from 10 to 21 days after contact with an infected person for someone to develop chickenpox. Chickenpox (varicella) is often heralded by a prodrome of anorexia, myalgia, nausea, fever, headache, sore throat, pain in both ears, complaints of pressure in head or swollen face, and malaise in adolescents and adults, while in children the first symptom is usually the development of a papular rash, followed by development of malaise, fever (a body temperature of 38 °C (100 °F), but may be as high as 42 °C (108 °F) in rare cases), and anorexia. Rarely cough, rhinitis, abdominal pain, and gastrointestinal distress has been reported in patients with varicella. Typically, the disease is more severe in adults.[7]
A single blister, typical during the early stages of the rash
The back of a 30-year-old male, taken on day 5 of the rash
Treatment
This section requires expansion.
Although there have been no formal clinical studies evaluating the effectiveness of topical application of calamine lotion, a topical barrier preparation containing zinc oxide and one of the most commonly used interventions, it has an excellent safety profile.[20] It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection.[21] Scratching may also increase the risk of secondary infection.[22] Addition of a small quantity of vinegar to the water is sometimes advocated. Painkillers could be taken to prevent feeling itchy [23]
To relieve the symptoms of chicken pox, people commonly use anti-itching creams and lotions. These lotions are not to be used on the face or close to the eyes. An oatmeal bath also might help ease discomfort.[24]
Varicella treatment mainly consists of easing the symptoms as there is no actual cure of the condition. Some treatments are however available for relieving the symptoms while the immune system clears the virus from the body. As a protective measure, patients are usually required to stay at home while they are infectious to avoid spreading the disease to others. Also, sufferers are frequently asked to cut their nails short or to wear gloves to prevent scratching and to minimize the risk of secondary infections.
The condition resolves by itself within a couple of weeks but meanwhile patients must pay attention to their personal hygiene.[25] The rash caused by varicella zoster virus may however last for up to one month, although the infectious stage does not take longer than a week or two.[26] Also, staying in a cold surrounding can help in easing the itching as heat and sweat makes it worse. Calamine lotion may be tried as it may relieve the symptoms because of its soothing, cooling effect on the skin.
Natural chicken pox remedies include pea water, baking soda, vitamin E oil, honey, herbal tea or carrot and coriander. It is believed that the irritation of the skin can be relieved to some extent with water in which fresh peas have been cooked.[27] A lotion made of baking soda with water can be sponged onto the skin of the patients to ease the itching. Also, rubbing vitamin E oil or honey on the skin is thought to have a healing effect on the marks that could remain after the infection has been cured. Some people claim that the mild sedative effect of green tea is effective in relieving the symptoms. It is not however known to what extent these home remedies can actually help the patients cope better with their symptoms.
A varicella vaccine is available for people who have been exposed to the virus, but have not experienced symptoms. The vaccine is more effective if administered within three days and up to five days after exposure. It has been shown that the chicken pox vaccine may prevent or reduce the symptoms in 90% of cases, if given within three days after exposure. People who have been exposed to the virus but who are contraindicated to receive the vaccine, there is a medication available, called varicella zoster immunoglobulin or VZIG which may prevent or reduce the symptoms after exposure. VZIG is primarily administered to individuals who are at risk of developing complications due to its high costs and temporary protection. This type of treatment is only recommended in newborns whose mothers have had chicken pox few days prior or after delivery, children with leukemia or lymphoma, people with a poor immune system or pregnant women. VZIG is recommended to be administered no later than 96 hours after exposure to the virus.
Chicken pox is spread easily through coughs or sneezes of ill individuals or through direct contact with secretions from the rash. Following primary infection there is usually lifelong protective immunity from further episodes of chickenpox.
Chickenpox is rarely fatal, although it is generally more severe in adult males than in adult females or children. Pregnant women and those with a suppressed immune system are at highest risk of serious complications. Chicken pox is now believed to be the cause of one third of stroke cases in children.[2] The most common late complication of chicken pox is shingles, caused by reactivation of the varicella zoster virus decades after the initial episode of chickenpox.
Chickenpox has been observed in other primates, including chimpanzees[3] and gorillas.[4]
Signs and symptoms
Chickenpox is a highly infectious disease that spreads from person to person by direct contact or by air from an infected person's coughing or sneezing. Touching the fluid blister can also spread the disease. A person with chickenpox is infectious from one to five days before the rash appears.[5] The contagious period continues until all blisters have formed scabs, which may take 5 to 6 days at which point they are no longer contagious.[6] It takes from 10 to 21 days after contact with an infected person for someone to develop chickenpox. Chickenpox (varicella) is often heralded by a prodrome of anorexia, myalgia, nausea, fever, headache, sore throat, pain in both ears, complaints of pressure in head or swollen face, and malaise in adolescents and adults, while in children the first symptom is usually the development of a papular rash, followed by development of malaise, fever (a body temperature of 38 °C (100 °F), but may be as high as 42 °C (108 °F) in rare cases), and anorexia. Rarely cough, rhinitis, abdominal pain, and gastrointestinal distress has been reported in patients with varicella. Typically, the disease is more severe in adults.[7]
A single blister, typical during the early stages of the rash
The back of a 30-year-old male, taken on day 5 of the rash
Treatment
This section requires expansion.
Although there have been no formal clinical studies evaluating the effectiveness of topical application of calamine lotion, a topical barrier preparation containing zinc oxide and one of the most commonly used interventions, it has an excellent safety profile.[20] It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection.[21] Scratching may also increase the risk of secondary infection.[22] Addition of a small quantity of vinegar to the water is sometimes advocated. Painkillers could be taken to prevent feeling itchy [23]
To relieve the symptoms of chicken pox, people commonly use anti-itching creams and lotions. These lotions are not to be used on the face or close to the eyes. An oatmeal bath also might help ease discomfort.[24]
Varicella treatment mainly consists of easing the symptoms as there is no actual cure of the condition. Some treatments are however available for relieving the symptoms while the immune system clears the virus from the body. As a protective measure, patients are usually required to stay at home while they are infectious to avoid spreading the disease to others. Also, sufferers are frequently asked to cut their nails short or to wear gloves to prevent scratching and to minimize the risk of secondary infections.
The condition resolves by itself within a couple of weeks but meanwhile patients must pay attention to their personal hygiene.[25] The rash caused by varicella zoster virus may however last for up to one month, although the infectious stage does not take longer than a week or two.[26] Also, staying in a cold surrounding can help in easing the itching as heat and sweat makes it worse. Calamine lotion may be tried as it may relieve the symptoms because of its soothing, cooling effect on the skin.
Natural chicken pox remedies include pea water, baking soda, vitamin E oil, honey, herbal tea or carrot and coriander. It is believed that the irritation of the skin can be relieved to some extent with water in which fresh peas have been cooked.[27] A lotion made of baking soda with water can be sponged onto the skin of the patients to ease the itching. Also, rubbing vitamin E oil or honey on the skin is thought to have a healing effect on the marks that could remain after the infection has been cured. Some people claim that the mild sedative effect of green tea is effective in relieving the symptoms. It is not however known to what extent these home remedies can actually help the patients cope better with their symptoms.
A varicella vaccine is available for people who have been exposed to the virus, but have not experienced symptoms. The vaccine is more effective if administered within three days and up to five days after exposure. It has been shown that the chicken pox vaccine may prevent or reduce the symptoms in 90% of cases, if given within three days after exposure. People who have been exposed to the virus but who are contraindicated to receive the vaccine, there is a medication available, called varicella zoster immunoglobulin or VZIG which may prevent or reduce the symptoms after exposure. VZIG is primarily administered to individuals who are at risk of developing complications due to its high costs and temporary protection. This type of treatment is only recommended in newborns whose mothers have had chicken pox few days prior or after delivery, children with leukemia or lymphoma, people with a poor immune system or pregnant women. VZIG is recommended to be administered no later than 96 hours after exposure to the virus.
What is syphilis??
Syphilis is a sexually transmitted disease caused by the spirochetal bacterium Treponema pallidum subspecies pallidum. The route of transmission of syphilis is almost always through sexual contact, although there are examples of congenital syphilis via transmission from mother to child in utero or at birth.
The signs and symptoms of syphilis are numerous; before the advent of serological testing, precise diagnosis was very difficult. In fact, the disease was dubbed the "Great Imitator" because it was often confused with other diseases, particularly in its tertiary stage. [1]
Syphilis can generally be treated with antibiotics, including penicillin. If left untreated, syphilis can damage the heart, aorta, brain, eyes, and bones. In some cases these effects can be fatal.
Signs and symptom
Primary syphilis
Primary chancre of syphilis on the hand. Unlike some kinds of sexually transmitted infections, syphilis infections are not limited to the genitals, and can be transmitted through non-sexual contact.
Primary syphilis is typically acquired via direct sexual contact with the infectious lesions of a person with syphilis.[2] Approximately 10–90 days after the initial exposure (average 21 days) a skin lesion appears at the point of contact, which is usually the genitalia, but can be anywhere on the body. This lesion, called a chancre, is a firm, painless skin ulceration localized at the point of initial exposure to the spirochete, often on the penis, vagina or rectum. In rare circumstances, there may be multiple lesions present, although it is typical that only one lesion is seen. The lesion may persist for 4 to 6 weeks and usually heals spontaneously. Local lymph node swelling can occur. During the initial incubation period, individuals are otherwise asymptomatic. As a result, many patients do not seek medical care immediately.
Secondary syphilis
Typical presentation of secondary syphilis rash on the palms of the hands and usually also seen on soles of feet.
Secondary syphilis in 52-year-old man with AIDS; the reddish papules and nodules—some pustular—extend over his face, chest, arms, and back
Intensely pruritic, papulonodular eruption of secondary syphilis in a 23-year-old man, extending over his arms and back.
Secondary syphilis occurs approximately 1–6 months (commonly 6 to 8 weeks)[citation needed] after the primary infection. There are many different manifestations of secondary disease. There may be a symmetrical reddish-pink non-itchy rash on the trunk and extremities.[3] The rash can involve the palms of the hands and the soles of the feet. In moist areas of the body (usually vulva or scrotum), the rash becomes flat, broad, whitish, wart-like lesions known as condyloma latum. Mucous patches may also appear on the genitals or in the mouth. All of these lesions are infectious and harbor active treponeme organisms. A patient with syphilis is most contagious when he or she has secondary syphilis.[specify] Other symptoms common at this stage include fever, sore throat,[citation needed] malaise, weight loss, headache, meningismus[citation needed] and enlarged lymph nodes. Rare manifestations include an acute meningitis that occurs in about 2% of patients, hepatitis, renal disease, hypertrophic gastritis[citation needed], patchy proctitis[citation needed], ulcerative colitis[citation needed], rectosigmoid mass[citation needed], arthritis, periostitis, optic neuritis, interstitial keratitis[citation needed], iritis[citation needed] and uveitis.
Latent syphilis
Latent syphilis is defined as having serologic proof of infection without signs or symptoms of disease.[2] Latent syphilis is further described as either early or late. Early latent syphilis is defined as having syphilis for two years or less[verification needed] from the time of initial infection without signs or symptoms of disease. Late latent syphilis is infection for greater than two years but without clinical evidence of disease. The distinction is important for both therapy and risk for transmission. In the real world, the timing of infection is often not known and should be presumed to be late for the purpose of therapy.[citation needed] Early latent syphilis may be treated with a single intramuscular injection of a long-acting penicillin. Late latent syphilis requires three weekly injections. For infectiousness late latent syphilis is not considered as contagious as early latent syphilis. Fifty percent of those infected with latent syphilis will progress into late stage (tertiary) syphilis, 25% will stay in the latent stage, and 25% will make a full recovery.[citation needed]
Tertiary syphilis
Model of the head of a patient with tertiary syphilis.
Tertiary syphilis usually occurs 1–10 years after the initial infection, however in some cases it can take up to 50 years. This stage is characterized by the formation of gummas, which are soft, tumor-like balls of inflammation known as granulomas. The granulomas are chronic and represent an inability of the immune system to completely clear the organism. They may appear almost anywhere in the body including in the skeleton. The gummas produce a chronic inflammatory state in the body with mass effects upon the local anatomy.[citation needed] Other characteristics of untreated tertiary syphilis include neuropathic joint disease, which is a degeneration of joint surfaces resulting from loss of sensation and fine position sense (proprioception).[citation needed] The more severe manifestations include neurosyphilis and cardiovascular syphilis. In a study of untreated syphilis, 10% of patients developed cardiovascular syphilis, 16% had gumma formation and 7% had neurosyphilis.[4][non-primary source needed]
Neurological complications at this stage can be diverse. In some patients manifestations include generalized paresis of the insane, which results in personality changes, changes in emotional affect, hyperactive reflexes and Argyll-Robertson pupil. This is a diagnostic sign in which the small and irregular pupils constrict in response to focusing the eyes, but not to light. Tabes dorsalis, also known as locomotor ataxia, a disorder of the spinal cord, often results in a characteristic shuffling gait. See below for more information about neurosyphilis.[citation needed]
Cardiovascular complications include syphilitic aortitis, aortic aneurysm, aneurysm of sinus of Valsalva and aortic regurgitation. Syphilis infects the ascending aorta causing aortic dilation and aortic regurgitation.[citation needed] This can be heard with a stethoscope as a heart murmur. Contraction of the tunica intima leads to a tree bark appearance that is wrinkly. The aortic valve dilation and subsequent insufficiency leads to diastolic regurgitation and causes massive hypertrophy of the left ventricle. The heart grows so large (over 1,000 grams) that the heart is termed cor bovinum (cow's heart). The course can be insidious and heart failure may be the presenting sign after years of disease. The infection can also occur in the coronary arteries and cause narrowing of the vessels. Syphilitic aortitis can cause de Musset's sign,[5] a characteristic bobbing of the head in synchrony with the heartbeat. The clinical course of these cardiovascular effects causes mediastinal encroachment and secondary respiratory difficulties (dyspnea), difficulty swallowing (dyphagia) and persistent cough because of pressure on the recurrent laryngeal nerve triggering the cough reflex. Pain can stem from erosion of the ribs or vertebrae. Also, the cor bovinum can lead to coronary ostia obstruction and ischemia. The aneurysm developed during the disease course may also rupture, leading to massive intrathoracic hemorrhage and likely death; although the most likely cause of death is the heart failure resulting from aortic regurgitation.
The signs and symptoms of syphilis are numerous; before the advent of serological testing, precise diagnosis was very difficult. In fact, the disease was dubbed the "Great Imitator" because it was often confused with other diseases, particularly in its tertiary stage. [1]
Syphilis can generally be treated with antibiotics, including penicillin. If left untreated, syphilis can damage the heart, aorta, brain, eyes, and bones. In some cases these effects can be fatal.
Signs and symptom
Primary syphilis
Primary chancre of syphilis on the hand. Unlike some kinds of sexually transmitted infections, syphilis infections are not limited to the genitals, and can be transmitted through non-sexual contact.
Primary syphilis is typically acquired via direct sexual contact with the infectious lesions of a person with syphilis.[2] Approximately 10–90 days after the initial exposure (average 21 days) a skin lesion appears at the point of contact, which is usually the genitalia, but can be anywhere on the body. This lesion, called a chancre, is a firm, painless skin ulceration localized at the point of initial exposure to the spirochete, often on the penis, vagina or rectum. In rare circumstances, there may be multiple lesions present, although it is typical that only one lesion is seen. The lesion may persist for 4 to 6 weeks and usually heals spontaneously. Local lymph node swelling can occur. During the initial incubation period, individuals are otherwise asymptomatic. As a result, many patients do not seek medical care immediately.
Secondary syphilis
Typical presentation of secondary syphilis rash on the palms of the hands and usually also seen on soles of feet.
Secondary syphilis in 52-year-old man with AIDS; the reddish papules and nodules—some pustular—extend over his face, chest, arms, and back
Intensely pruritic, papulonodular eruption of secondary syphilis in a 23-year-old man, extending over his arms and back.
Secondary syphilis occurs approximately 1–6 months (commonly 6 to 8 weeks)[citation needed] after the primary infection. There are many different manifestations of secondary disease. There may be a symmetrical reddish-pink non-itchy rash on the trunk and extremities.[3] The rash can involve the palms of the hands and the soles of the feet. In moist areas of the body (usually vulva or scrotum), the rash becomes flat, broad, whitish, wart-like lesions known as condyloma latum. Mucous patches may also appear on the genitals or in the mouth. All of these lesions are infectious and harbor active treponeme organisms. A patient with syphilis is most contagious when he or she has secondary syphilis.[specify] Other symptoms common at this stage include fever, sore throat,[citation needed] malaise, weight loss, headache, meningismus[citation needed] and enlarged lymph nodes. Rare manifestations include an acute meningitis that occurs in about 2% of patients, hepatitis, renal disease, hypertrophic gastritis[citation needed], patchy proctitis[citation needed], ulcerative colitis[citation needed], rectosigmoid mass[citation needed], arthritis, periostitis, optic neuritis, interstitial keratitis[citation needed], iritis[citation needed] and uveitis.
Latent syphilis
Latent syphilis is defined as having serologic proof of infection without signs or symptoms of disease.[2] Latent syphilis is further described as either early or late. Early latent syphilis is defined as having syphilis for two years or less[verification needed] from the time of initial infection without signs or symptoms of disease. Late latent syphilis is infection for greater than two years but without clinical evidence of disease. The distinction is important for both therapy and risk for transmission. In the real world, the timing of infection is often not known and should be presumed to be late for the purpose of therapy.[citation needed] Early latent syphilis may be treated with a single intramuscular injection of a long-acting penicillin. Late latent syphilis requires three weekly injections. For infectiousness late latent syphilis is not considered as contagious as early latent syphilis. Fifty percent of those infected with latent syphilis will progress into late stage (tertiary) syphilis, 25% will stay in the latent stage, and 25% will make a full recovery.[citation needed]
Tertiary syphilis
Model of the head of a patient with tertiary syphilis.
Tertiary syphilis usually occurs 1–10 years after the initial infection, however in some cases it can take up to 50 years. This stage is characterized by the formation of gummas, which are soft, tumor-like balls of inflammation known as granulomas. The granulomas are chronic and represent an inability of the immune system to completely clear the organism. They may appear almost anywhere in the body including in the skeleton. The gummas produce a chronic inflammatory state in the body with mass effects upon the local anatomy.[citation needed] Other characteristics of untreated tertiary syphilis include neuropathic joint disease, which is a degeneration of joint surfaces resulting from loss of sensation and fine position sense (proprioception).[citation needed] The more severe manifestations include neurosyphilis and cardiovascular syphilis. In a study of untreated syphilis, 10% of patients developed cardiovascular syphilis, 16% had gumma formation and 7% had neurosyphilis.[4][non-primary source needed]
Neurological complications at this stage can be diverse. In some patients manifestations include generalized paresis of the insane, which results in personality changes, changes in emotional affect, hyperactive reflexes and Argyll-Robertson pupil. This is a diagnostic sign in which the small and irregular pupils constrict in response to focusing the eyes, but not to light. Tabes dorsalis, also known as locomotor ataxia, a disorder of the spinal cord, often results in a characteristic shuffling gait. See below for more information about neurosyphilis.[citation needed]
Cardiovascular complications include syphilitic aortitis, aortic aneurysm, aneurysm of sinus of Valsalva and aortic regurgitation. Syphilis infects the ascending aorta causing aortic dilation and aortic regurgitation.[citation needed] This can be heard with a stethoscope as a heart murmur. Contraction of the tunica intima leads to a tree bark appearance that is wrinkly. The aortic valve dilation and subsequent insufficiency leads to diastolic regurgitation and causes massive hypertrophy of the left ventricle. The heart grows so large (over 1,000 grams) that the heart is termed cor bovinum (cow's heart). The course can be insidious and heart failure may be the presenting sign after years of disease. The infection can also occur in the coronary arteries and cause narrowing of the vessels. Syphilitic aortitis can cause de Musset's sign,[5] a characteristic bobbing of the head in synchrony with the heartbeat. The clinical course of these cardiovascular effects causes mediastinal encroachment and secondary respiratory difficulties (dyspnea), difficulty swallowing (dyphagia) and persistent cough because of pressure on the recurrent laryngeal nerve triggering the cough reflex. Pain can stem from erosion of the ribs or vertebrae. Also, the cor bovinum can lead to coronary ostia obstruction and ischemia. The aneurysm developed during the disease course may also rupture, leading to massive intrathoracic hemorrhage and likely death; although the most likely cause of death is the heart failure resulting from aortic regurgitation.
Astigmatism??
What is astigmatism?" is a question that eye doctors hear every day, but actually it's spelled "astigmatism." Although astigmatism is the most common vision problem, most people don't know what it is.
Astigmatism may accompany farsightedness or nearsightedness. Usually it is caused by an irregularly shaped cornea (called corneal astigmatism). But sometimes lenticular astigmatism results from an irregularly shaped lens, which is located behind the cornea.
Either kind of astigmatism can usually be corrected with eyeglasses, contact lenses, or refractive surgery.
Astigmatism Symptoms and Signs
You may not notice small amounts of astigmatism at all or have just slightly blurred vision. But sometimes uncorrected astigmatism can give you headaches or eye strain and distort or blur your vision at all distances.
Because not only adults can be astigmatic, you need to make sure you schedule an eye exam for your child.
Dr. Karla Zadnik, an optometrist at The Ohio State University School of Optometry, found in a recent study of 2,523 children that more than 28 percent of them had astigmatism. Children may be even more unaware of the condition than adults, and they are unlikely to complain about blurred or distorted vision.
But astigmatism can affect a child's ability to see well in school and during sports, which is why it's important that eye exams be scheduled at regular intervals to detect any astigmatism early on.
What Causes Astigmatism?
Astigmatism occurs when the cornea is shaped more like an oblong football than a spherical baseball, which is the normal shape. In most astigmatic eyes, the oblong or oval shape causes light rays to focus on two points in the back of your eye, rather than on just one. This is because, like a football, an astigmatic cornea has a steeper curve and a flatter one.
In regular astigmatism, the meridians in which the two different curves lie are located 90 degrees apart. In irregular astigmatism, the two meridians may be located at something other than 90 degrees apart; or there are more than two meridians.
Regular astigmatism is usually easy to correct (see treatments below), but irregular astigmatism can be complicated and more difficult to correct, depending on the extent of the irregularity and its cause.
Usually astigmatism is hereditary: many people are born with an oblong cornea, and the resulting vision problem may get worse over time.
But astigmatism may also result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus, a disease that causes a gradual thinning of the cornea.
Astigmatism Treatment
Unless it is extreme, astigmatism can be compensated for satisfactorily with eyeglasses or contact lenses.
If your eyeglass or contact lens prescription contains three parts rather than one, your eye care practitioner has found some astigmatism in one or both of your eyes. A prescription with three parts looks like this: -2.75 -1.25 x 90.
• The first part indicates your main spherical correction, meaning the amount of power (in diopters) required in a lens to sharpen your visual acuity to an acceptable level, usually 20/20. In this example, the person has myopia and requires a negative (concave) lens to correct it.
• Part two shows the extent of the astigmatism in diopters. Again, the minus sign means a concave lens is needed.
• Part three is the axis (in degrees) of the cylinder required to bend certain light rays to compensate for the cornea's oval shape.
Many people with astigmatism believe that they can't wear contact lenses or that only rigid contact lenses (RGPs, also called GP lenses) can correct astigmatism.
This was true many years ago, but now soft toric contact lenses can correct astigmatism. Toric lenses have a special correction built into them and may also contain a prescription for nearsightedness or farsightedness if you need it.
While soft torics work well for many people, if you have severe astigmatism, you'll likely do better with RGP contact lenses or eyeglasses. Your eye care practitioner will advise you.
Depending on the type and severity of your astigmatism, you may also be able to have it corrected with refractive surgery. Discuss with your eye doctor which procedure is best to correct your astigmatism, and review your options in our LASIK & Vision Surgery section
Astigmatism may accompany farsightedness or nearsightedness. Usually it is caused by an irregularly shaped cornea (called corneal astigmatism). But sometimes lenticular astigmatism results from an irregularly shaped lens, which is located behind the cornea.
Either kind of astigmatism can usually be corrected with eyeglasses, contact lenses, or refractive surgery.
Astigmatism Symptoms and Signs
You may not notice small amounts of astigmatism at all or have just slightly blurred vision. But sometimes uncorrected astigmatism can give you headaches or eye strain and distort or blur your vision at all distances.
Because not only adults can be astigmatic, you need to make sure you schedule an eye exam for your child.
Dr. Karla Zadnik, an optometrist at The Ohio State University School of Optometry, found in a recent study of 2,523 children that more than 28 percent of them had astigmatism. Children may be even more unaware of the condition than adults, and they are unlikely to complain about blurred or distorted vision.
But astigmatism can affect a child's ability to see well in school and during sports, which is why it's important that eye exams be scheduled at regular intervals to detect any astigmatism early on.
What Causes Astigmatism?
Astigmatism occurs when the cornea is shaped more like an oblong football than a spherical baseball, which is the normal shape. In most astigmatic eyes, the oblong or oval shape causes light rays to focus on two points in the back of your eye, rather than on just one. This is because, like a football, an astigmatic cornea has a steeper curve and a flatter one.
In regular astigmatism, the meridians in which the two different curves lie are located 90 degrees apart. In irregular astigmatism, the two meridians may be located at something other than 90 degrees apart; or there are more than two meridians.
Regular astigmatism is usually easy to correct (see treatments below), but irregular astigmatism can be complicated and more difficult to correct, depending on the extent of the irregularity and its cause.
Usually astigmatism is hereditary: many people are born with an oblong cornea, and the resulting vision problem may get worse over time.
But astigmatism may also result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus, a disease that causes a gradual thinning of the cornea.
Astigmatism Treatment
Unless it is extreme, astigmatism can be compensated for satisfactorily with eyeglasses or contact lenses.
If your eyeglass or contact lens prescription contains three parts rather than one, your eye care practitioner has found some astigmatism in one or both of your eyes. A prescription with three parts looks like this: -2.75 -1.25 x 90.
• The first part indicates your main spherical correction, meaning the amount of power (in diopters) required in a lens to sharpen your visual acuity to an acceptable level, usually 20/20. In this example, the person has myopia and requires a negative (concave) lens to correct it.
• Part two shows the extent of the astigmatism in diopters. Again, the minus sign means a concave lens is needed.
• Part three is the axis (in degrees) of the cylinder required to bend certain light rays to compensate for the cornea's oval shape.
Many people with astigmatism believe that they can't wear contact lenses or that only rigid contact lenses (RGPs, also called GP lenses) can correct astigmatism.
This was true many years ago, but now soft toric contact lenses can correct astigmatism. Toric lenses have a special correction built into them and may also contain a prescription for nearsightedness or farsightedness if you need it.
While soft torics work well for many people, if you have severe astigmatism, you'll likely do better with RGP contact lenses or eyeglasses. Your eye care practitioner will advise you.
Depending on the type and severity of your astigmatism, you may also be able to have it corrected with refractive surgery. Discuss with your eye doctor which procedure is best to correct your astigmatism, and review your options in our LASIK & Vision Surgery section
WHAT IS ALZHEIMER'S DISEASE??
DEFINITION..
Alzheimer's disease is the most common cause of dementia and accounts for 50% - 60% of all cases. Alzheimer's disease was first described by a German Physician Alois Alzheimer in 1906. This disease causes a heavy burden both emotionally and financially and the consequences can be quite devastating.
Alzheimer's disease is a condition in which nerve cells in the brain die, making it difficult for the brain's signals to be transmitted properly. A person with Alzheimer's disease has problems with memory, judgment, and thinking, which makes it hard for the person to work or take part in day-to-day life. The death of the nerve cells occurs gradually over a period of years.
During the course of Alzheimer's disease, nerve cells die in particular regions of the brain. The brain shrinks as gaps develop in the temporal lobe and hippocampus, which are responsible for storing and retrieving new information. This in turn affects people's ability to remember, speak, think and make decisions. The production of certain chemicals in the brain, such as acetylcholine is also affected. It is not known what causes nerve cells to die but there are characteristic appearances of the brain after death. In particular, 'tangles' and 'plaques' made from protein fragments are observed under the microscope in damaged areas of brain. This confirms the diagnosis of Alzheimer's disease.
Causes of Alzheimer’s disease
The cause of Alzheimer's dementia is not fully understood, but advancing age and a family history of Alzheimer's dementia increases one's risk of developing it. The number of persons with Alzheimer's dementia doubles every 5 years beyond the age of 65 and by the age of 85, one in 4 can develop this illness, which is about 25% of the population above the age of 85 years. Thus age plays a crucial part in policy and decision making for care of the elderly, this is an alarming figure more so as the baby boomers will be reaching this age soon.
Symptoms
Most patients' symptoms progress slowly over a number of years. Symptoms may not be noticed early on. Sometimes, it is only when family members look back that they realize when the changes started to occur.
Common symptoms of Alzheimer's disease include:
• Impaired memory and thinking. The person has difficulty remembering things or learning new information. In the later stages of the disease, long-term memory loss occurs, which means that the person can't remember personal information, such as his or her place of birth or occupation, or names of close family members.
• Disorientation and confusion. People with Alzheimer's disease may get lost when out on their own and may not be able to remember where they are or how they got there. They may not recognize previously familiar places and situations. They also may not recognize familiar faces or know what time of the day it is, or even what year it is.
• Misplacing things. The person forgets where he or she put things used every day, such as glasses, a hearing aid, keys, etc. The person may also put things in strange places, such as leaving their glasses in the refrigerator.
• Abstract thinking. People with Alzheimer's disease may find certain tasks -- such as balancing a checkbook -- more difficult than usual. For example, they might forget what the numbers mean and what needs to be done with them.
• Trouble performing familiar tasks. The person begins to have difficulty performing daily tasks, such as eating, dressing, and grooming. Planning for normal day-to-day tasks is also impaired.
• Changes in personality and behavior. The person becomes unusually angry, irritable, restless, or quiet. At times, people with Alzheimer's disease can become confused, paranoid, or fearful.
• Poor or decreased judgment. People with Alzheimer's disease may leave the house on a cold day without a coat or shoes, or could go to the store wearing their pajamas.
• Inability to follow directions. The person has difficulty understanding simple commands or directions. The person may get lost easily and begin to wander.
• Problems with language and communication. The person can't recall words, name objects (even ones that are very familiar to them -- like a pen), or understand the meaning of common words.
• Impaired visual and spatial skills. The person loses spatial abilities (the ability to judge shapes and sizes, and the relationship of objects in space) and can't arrange items in a certain order or recognize shapes.
• Loss of motivation or initiative. The person may become very passive and require prompting to become involved and interact with others.
• Loss of normal sleep patterns. The person may sleep during the day and be wide-awake at night.
Diagnosis
It is important to visit a doctor if you or a loved one experiences any of these symptoms so you can receive the proper evaluation and diagnosis. There are other conditions -- such as depression, a head injury, certain chemical imbalances, or the effects of some medications --that can produce symptoms that are similar to Alzheimer's disease. Many of these conditions are treatable.
Your doctor can only determine if the symptoms are probably due to Alzheimer's disease after a thorough medical, psychiatric, and neurological evaluation. He will evaluate other possible causes of dementia to rule out all other factors before settling on Alzheimer's disease as a diagnosis.
Currently, no definitive diagnostic test for Alzheimer's exists. A definite diagnosis of Alzheimer's disease is possible only after death, when a pathologist can more closely examine a patient's brain for the telltale changes associated with Alzheimer's disease.
Prognosis
The course of Alzheimer's disease varies widely from person to person. The duration of the illness could be short (2-3 years) or long (up to 20 years). Usually the parts of the brain that control memory and thinking are affected first, but over time, cells die in other areas of the brain.
Eventually, a person with Alzheimer's will need complete care. If the person has no other serious illnesses, the loss of brain function itself will eventually cause death.
Alzheimer's disease is the most common cause of dementia and accounts for 50% - 60% of all cases. Alzheimer's disease was first described by a German Physician Alois Alzheimer in 1906. This disease causes a heavy burden both emotionally and financially and the consequences can be quite devastating.
Alzheimer's disease is a condition in which nerve cells in the brain die, making it difficult for the brain's signals to be transmitted properly. A person with Alzheimer's disease has problems with memory, judgment, and thinking, which makes it hard for the person to work or take part in day-to-day life. The death of the nerve cells occurs gradually over a period of years.
During the course of Alzheimer's disease, nerve cells die in particular regions of the brain. The brain shrinks as gaps develop in the temporal lobe and hippocampus, which are responsible for storing and retrieving new information. This in turn affects people's ability to remember, speak, think and make decisions. The production of certain chemicals in the brain, such as acetylcholine is also affected. It is not known what causes nerve cells to die but there are characteristic appearances of the brain after death. In particular, 'tangles' and 'plaques' made from protein fragments are observed under the microscope in damaged areas of brain. This confirms the diagnosis of Alzheimer's disease.
Causes of Alzheimer’s disease
The cause of Alzheimer's dementia is not fully understood, but advancing age and a family history of Alzheimer's dementia increases one's risk of developing it. The number of persons with Alzheimer's dementia doubles every 5 years beyond the age of 65 and by the age of 85, one in 4 can develop this illness, which is about 25% of the population above the age of 85 years. Thus age plays a crucial part in policy and decision making for care of the elderly, this is an alarming figure more so as the baby boomers will be reaching this age soon.
Symptoms
Most patients' symptoms progress slowly over a number of years. Symptoms may not be noticed early on. Sometimes, it is only when family members look back that they realize when the changes started to occur.
Common symptoms of Alzheimer's disease include:
• Impaired memory and thinking. The person has difficulty remembering things or learning new information. In the later stages of the disease, long-term memory loss occurs, which means that the person can't remember personal information, such as his or her place of birth or occupation, or names of close family members.
• Disorientation and confusion. People with Alzheimer's disease may get lost when out on their own and may not be able to remember where they are or how they got there. They may not recognize previously familiar places and situations. They also may not recognize familiar faces or know what time of the day it is, or even what year it is.
• Misplacing things. The person forgets where he or she put things used every day, such as glasses, a hearing aid, keys, etc. The person may also put things in strange places, such as leaving their glasses in the refrigerator.
• Abstract thinking. People with Alzheimer's disease may find certain tasks -- such as balancing a checkbook -- more difficult than usual. For example, they might forget what the numbers mean and what needs to be done with them.
• Trouble performing familiar tasks. The person begins to have difficulty performing daily tasks, such as eating, dressing, and grooming. Planning for normal day-to-day tasks is also impaired.
• Changes in personality and behavior. The person becomes unusually angry, irritable, restless, or quiet. At times, people with Alzheimer's disease can become confused, paranoid, or fearful.
• Poor or decreased judgment. People with Alzheimer's disease may leave the house on a cold day without a coat or shoes, or could go to the store wearing their pajamas.
• Inability to follow directions. The person has difficulty understanding simple commands or directions. The person may get lost easily and begin to wander.
• Problems with language and communication. The person can't recall words, name objects (even ones that are very familiar to them -- like a pen), or understand the meaning of common words.
• Impaired visual and spatial skills. The person loses spatial abilities (the ability to judge shapes and sizes, and the relationship of objects in space) and can't arrange items in a certain order or recognize shapes.
• Loss of motivation or initiative. The person may become very passive and require prompting to become involved and interact with others.
• Loss of normal sleep patterns. The person may sleep during the day and be wide-awake at night.
Diagnosis
It is important to visit a doctor if you or a loved one experiences any of these symptoms so you can receive the proper evaluation and diagnosis. There are other conditions -- such as depression, a head injury, certain chemical imbalances, or the effects of some medications --that can produce symptoms that are similar to Alzheimer's disease. Many of these conditions are treatable.
Your doctor can only determine if the symptoms are probably due to Alzheimer's disease after a thorough medical, psychiatric, and neurological evaluation. He will evaluate other possible causes of dementia to rule out all other factors before settling on Alzheimer's disease as a diagnosis.
Currently, no definitive diagnostic test for Alzheimer's exists. A definite diagnosis of Alzheimer's disease is possible only after death, when a pathologist can more closely examine a patient's brain for the telltale changes associated with Alzheimer's disease.
Prognosis
The course of Alzheimer's disease varies widely from person to person. The duration of the illness could be short (2-3 years) or long (up to 20 years). Usually the parts of the brain that control memory and thinking are affected first, but over time, cells die in other areas of the brain.
Eventually, a person with Alzheimer's will need complete care. If the person has no other serious illnesses, the loss of brain function itself will eventually cause death.
Chlamydia...
What Is It?
Chlamydia is a sexually transmitted disease (STD) spread by having unprotected sex with someone infected with bacteria called Chlamydia trachomatis. These bacteria are found in the urine and genital secretions of infected people. Chlamydia can affect several areas of the reproductive system, causing urethritis, vaginitis, cervicitis and pelvic inflammatory disease (PID). Chlamydia also can cause eye infections and pneumonia in newborns delivered by mothers who have chlamydia.
Chlamydia is one of the most common sexually transmitted diseases in the United States, with an estimated 4 million new infections occurring each year. Infections occur most often in unmarried people under age 25 who have had two or more sex partners during the previous year. In women, chlamydia that is not treated can lead to infertility, chronic pelvic pain and tubal pregnancy, in which the fertilized egg implants and grows in the fallopian tube, rather than the uterus.
Symptoms
About 75% of women and 50% of men with chlamydia have no symptoms. This is why many infected people remain untreated and can continue to spread the infection to others.
In women, chlamydia can cause:
• A burning sensation when urinating
• An abnormal vaginal discharge
• Light vaginal bleeding (especially after intercourse)
• Pain in the pelvis or lower abdomen
In men, chlamydia can cause:
• An abnormal release of fluid that is not urine or semen (called penile discharge)
• A burning sensation when urinating
Diagnosis
Because chlamydia may not cause any symptoms, your doctor will gauge your risk of having the infection based on your sexual history. For example, your doctor will ask if you have had sex without using condoms. Your doctor can confirm whether you have chlamydia by using a urine test or a swab to collect fluid from the urethra or cervix. If you are at risk of chlamydia, you should be tested at least once a year, even if you have no symptoms
Expected Duration
If untreated, chlamydia can last for many months, and during this time, bacteria can be spread to others through unprotected sex.
Prevention
Because chlamydia is a disease that can be spread during sexual intercourse, you can prevent chlamydia by:
• Not having sex
• Having sex with only one, uninfected person
• Always using male latex condoms during sexual activity
To prevent complications of untreated chlamydia, including infertility and tubal pregnancy, sexually active women at risk of chlamydia should have a routine pelvic examination with a chlamydia-screening test every year. To prevent chlamydia eye infections and pneumonia in newborns, pregnant women at risk of chlamydia should be screened.
Prevention
Because chlamydia is a disease that can be spread during sexual intercourse, you can prevent chlamydia by:
• Not having sex
• Having sex with only one, uninfected person
• Always using male latex condoms during sexual activity
To prevent complications of untreated chlamydia, including infertility and tubal pregnancy, sexually active women at risk of chlamydia should have a routine pelvic examination with a chlamydia-screening test every year. To prevent chlamydia eye infections and pneumonia in newborns, pregnant women at risk of chlamydia should be screened.
Chlamydia is a sexually transmitted disease (STD) spread by having unprotected sex with someone infected with bacteria called Chlamydia trachomatis. These bacteria are found in the urine and genital secretions of infected people. Chlamydia can affect several areas of the reproductive system, causing urethritis, vaginitis, cervicitis and pelvic inflammatory disease (PID). Chlamydia also can cause eye infections and pneumonia in newborns delivered by mothers who have chlamydia.
Chlamydia is one of the most common sexually transmitted diseases in the United States, with an estimated 4 million new infections occurring each year. Infections occur most often in unmarried people under age 25 who have had two or more sex partners during the previous year. In women, chlamydia that is not treated can lead to infertility, chronic pelvic pain and tubal pregnancy, in which the fertilized egg implants and grows in the fallopian tube, rather than the uterus.
Symptoms
About 75% of women and 50% of men with chlamydia have no symptoms. This is why many infected people remain untreated and can continue to spread the infection to others.
In women, chlamydia can cause:
• A burning sensation when urinating
• An abnormal vaginal discharge
• Light vaginal bleeding (especially after intercourse)
• Pain in the pelvis or lower abdomen
In men, chlamydia can cause:
• An abnormal release of fluid that is not urine or semen (called penile discharge)
• A burning sensation when urinating
Diagnosis
Because chlamydia may not cause any symptoms, your doctor will gauge your risk of having the infection based on your sexual history. For example, your doctor will ask if you have had sex without using condoms. Your doctor can confirm whether you have chlamydia by using a urine test or a swab to collect fluid from the urethra or cervix. If you are at risk of chlamydia, you should be tested at least once a year, even if you have no symptoms
Expected Duration
If untreated, chlamydia can last for many months, and during this time, bacteria can be spread to others through unprotected sex.
Prevention
Because chlamydia is a disease that can be spread during sexual intercourse, you can prevent chlamydia by:
• Not having sex
• Having sex with only one, uninfected person
• Always using male latex condoms during sexual activity
To prevent complications of untreated chlamydia, including infertility and tubal pregnancy, sexually active women at risk of chlamydia should have a routine pelvic examination with a chlamydia-screening test every year. To prevent chlamydia eye infections and pneumonia in newborns, pregnant women at risk of chlamydia should be screened.
Prevention
Because chlamydia is a disease that can be spread during sexual intercourse, you can prevent chlamydia by:
• Not having sex
• Having sex with only one, uninfected person
• Always using male latex condoms during sexual activity
To prevent complications of untreated chlamydia, including infertility and tubal pregnancy, sexually active women at risk of chlamydia should have a routine pelvic examination with a chlamydia-screening test every year. To prevent chlamydia eye infections and pneumonia in newborns, pregnant women at risk of chlamydia should be screened.
Thalassemias
Definition
Thalassemia describes a group of inherited disorders characterized by reduced or absent amounts of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen throughout the body. There are two basic groups of thalassemia disorders: alpha thalassemias and beta thalassemias. These conditions cause varying degrees of anemia, which can range from insignificant to fatal.
Description
Thalassemia is a genetic disorder. It cannot be acquired from contact with other people or from the environment. In all types of thalassemia, the quantity of hemoglobin produced is reduced or absent. This circumstance affects the ability of the blood to carry oxygen to all parts of the body. Although both alpha and beta thalassemias affect hemoglobin, these diseases affect the body in distinctly different ways. Hemoglobin is made up of three components: alpha globin, beta globin, and heme. Thalassemias are classified according to the globin that is deficient.
Alpha Thalassemia
Individuals inherit from each parent a gene controlling alpha globin production. Two spots (called loci) on these genes control alpha globin production. Alpha thalassemias result from changes (mutations) in these genes. There are two main types of alpha thalassemia disease: hemoglobin H disease and alpha thalassemia major. The two diseases are quite different from beta thalassemia, as well as from one another.
Individuals with hemoglobin H disease have inherited one completely defective gene and one gene that has one rather than two functional loci. This circumstance substantially reduces the amount of alpha globin that the body produces. As a result, individuals with hemoglobin H disease can experience events of hemolytic anemia—anemia caused by the rapid breakdown of the red blood cells. These events are thought to be triggered by various environmental causes, such as infection and/or exposure to certain chemicals. Hemoglobin H disease is milder than alpha thalassemia and usually milder than beta thalassemia.
Individuals with alpha thalassemia major have inherited two completely defective genes, one from each parent. Alpha thalassemia major, sometimes called hemoglobin Barts or hydrops fetalis, is a fatal disease that results in severe anemia that begins even before birth. Most affected babies do not survive to be born or die shortly after birth.
Beta Thalassemia
Beta thalassemia, also called Cooley's anemia, is the most well known type of thalassemia. It is caused by a change in the gene for the beta globin component of hemoglobin. Beta thalassemia causes variable anemia that can range from moderate to severe, depending in part on the exact genetic change underlying the disease.
Beta thalassemia major causes severe anemia that usually occurs within three to six months after birth. If left untreated, severe anemia can result in stunted growth and development, as well as other characteristic physical complications that can lead to a dramatically decreased life expectancy. In developed countries, screening in the newborn period usually identifies beta thalassemia before symptoms have developed. Children who are identified early can be started on ongoing blood transfusion therapy as needed.
Beta thalassemia minor describes a disease where only one gene of the pair that control beta hemoglobin production is defective. There are few or mild events. However, the individual can pass the defective gene on to his or her offspring
Beta thalassemia intermedia is a clinical term that describes the disease in individuals who have moderate anemia that only requires blood transfusions intermittently.
Demographics
The thalassemias are among the most common genetic diseases worldwide. Both alpha and beta thalassemia have been described in individuals of almost every ancestry, but the conditions are more common among certain ethnic groups. Unaffected carriers of all types of thalassemia traits do not experience health problems.
Determining the prevalence for alpha thalassemia is difficult due to limitations in diagnostic testing. In the United States, up to 30 percent of African Americans are thought to be carriers for alpha thalassemia traits, meaning that they show no symptoms of the disorder but can pass the trait to their offspring. Despite this estimate, the number of babies born with hemoglobin H disease or alpha thalassemia major is very low. The highest frequency of alpha thalassemia diseases occurs in individuals of Southeast Asian and Chinese descent. Individuals of Greek, Middle Eastern, and North African descent also carry genes for the disease more frequently than individuals of Northern European descent. One study of 500 pregnant women in northern Thailand estimated a frequency of one in 500 pregnancies affected by alpha thalassemia major, for example. Prevalence of alpha thalassemia disease is significantly lower in the United States owing primarily to immigration patterns. However, at least one state, California, has observed growing hemoglobin H disease rates that are high enough to justify universal newborn screening for the condition.
Beta thalassemia trait is seen most commonly in people with the following ancestry: Mediterranean (including North African, and particularly Italian and Greek), Middle Eastern, Indian, African, Chinese, and Southeast Asian (including Vietnamese, Laotian, Thai, Singaporean, Filipino, Cambodian, Malaysian, Burmese, and Indonesian). It is difficult to obtain accurate prevalence figures for various types of thalassemia within different populations.
Two studies reflect prevalence figures that can be helpful counseling families and determining who to screen for beta thalassemia. Between the years of 1990 and 1996, the State of California screened over 3.1 million newborns for beta thalassemia. Approximately one in 114,000 infants had beta thalassemia major, with prevalence rates being highest among Asian Indians (about one in 4,000), Southeast Asians (about one in 10,000), and Middle Easterners (about one in 7,000). The pattern observed in California is expected to be different in other areas of the United States and the world. For example, Italians are underrepresented in this population when compared to the population of the East Coast of the United States.
Causes and Symptoms
Humans normally make several types of hemoglobin. An individual's stage in development determines whether he or she makes primarily embryonic, fetal, or adult hemoglobins. All types of hemoglobin are made of three components: heme, alpha globin, and beta globin. All types of thalassemia are caused by changes in either the alpha- or beta-globin gene. These changes cause little or no globin to be produced. All types of thalassemias are recessively inherited, meaning that a genetic change must be inherited from both the mother and the father to produce the disease in the child. The severity of the disease is influenced by the exact thalassemia mutations inherited, as well as other genetic and environmental factors. There are rare exceptions, notably with beta thalassemia, where globin gene mutations exhibit a dominant pattern of inheritance in which only one gene needs to be altered in order to see disease expression.
Alpha Thalassemia
Most individuals have four normal copies of the alpha globin gene, two copies on each chromosome 16. These genes make the alpha globin component of normal adult hemoglobin, which is called hemoglobin A. Alpha globin is also a component of fetal hemoglobin. Since there are four genes (instead of the usual two) to consider when looking at alpha globin gene inheritance, there are several alpha globin types that are possible.
Absence of one functioning alpha globin gene leads to a condition known as silent alpha thalassemia trait. This condition causes no health problems and can be detected only by special genetic testing. Alpha thalassemia trait occurs when two alpha globin genes are missing or not functioning. There are no associated health problems, although the trait status may be detected by more routine blood screening.
Hemoglobin H disease results from the deletion of three of the four alpha globin genes. Hemoglobin H symptoms can also be a part of a unique condition called alpha thalassemia mental retardation syndrome. This syndrome can be caused by a deletion of a significant amount of chromosome 16, affecting the alpha globin genes. This situation is usually not inherited, but rather occurs sporadically in the affected individual. Affected individuals have mild hemoglobin H disease, mild-to-moderate mental retardation, and characteristic facial features, as well as various other developmental processes that mimic hemoglobin H disease.
Alpha thalassemia major results from the deletion of all four alpha globin genes, such that there are no functioning alpha globin genes. In this situation, there is a 25 percent chance for alpha thalassemia major in each of such a couple's children.
Beta Thalassemia
Most individuals have two normal copies of the beta globin gene, which is located on chromosome 11 and makes the beta globin component of normal adult hemoglobin. There are approximately one hundred genetic mutations that have been described that cause beta thalassemia, designated as either beta0 or beta+ mutations. No beta globin is produced with a beta0 mutation, and only a small fraction of the normal amount of beta globin is produced with a beta+ mutation.
When an individual has one normal beta globin gene and one with a beta thalassemia mutation, he or she is said to carry the beta thalassemia trait. Carrying the trait is generally thought not to cause health problems, although some women with beta thalassemia trait may have an increased tendency toward anemia during pregnancy.
When both parents carry the beta thalassemia trait, there is a 25 percent chance that each of their children will inherit beta thalassemia disease by inheriting two beta thalassemia mutations, one from each parent. The clinical severity of the beta thalassemia disease depends largely on whether the mutations inherited are beta0 thalassemia or beta+ thalassemia mutations. Two beta0 mutations generally lead to beta thalassemia major, and two beta+ thalassemia mutations generally lead to beta thalassemia intermedia, a milder form of the disease. Inheritance of one beta0 and one beta+ thalassemia mutation tends to be less predictable.
Symptoms
Hemoglobin H Disease
Hemoglobin H disease is a relatively mild form of thalassemia that may go unrecognized. It is not generally considered a condition that will reduce one's life expectancy. Education is an important part of managing the health of an individual with hemoglobin H disease. It is important to be able to recognize the signs of severe anemia that require medical attention. It is also important to be aware of the medications, chemicals, and other exposures to avoid due to the theoretical risk they pose of precipitating a severe anemia event. When severe anemia occurs, it is treated with blood transfusion therapy. For many individuals with hemoglobin H disease, this is rarely required. For those with a more severe form of the disease, the need for transfusions may be intermittent or ongoing, perhaps on a monthly basis, and require desferoxamine treatment. This treatment removes excess iron from the body. Individuals with this more severe form of the disease may also have an increased chance of requiring removal of an enlarged and/or overactive spleen.
Alpha Thalassemia Major
Because alpha globin is a necessary component of hemoglobin, absence of all functioning alpha globin genes leads to serious medical consequences that begin even before birth. Affected fetuses develop severe anemia as early as the first trimester of pregnancy. The placenta, heart, liver, spleen, and adrenal glands may all become enlarged. Fluid can begin collecting throughout the body as early as the start of the second trimester, causing damage to developing tissues and organs. Growth retardation is also common. Affected fetuses usually miscarry or die shortly after birth. In addition, women carrying affected fetuses are at increased risk of developing complications of pregnancy and delivery. Up to 80 percent of such women develop toxemia, a disturbance of metabolism that can potentially lead to convulsions and coma. Other maternal complications include premature delivery and increased rates of delivery by cesarean section, as well as hemorrhage after delivery.
Beta thalassemia major is characterized by severe anemia that can begin several months after birth. In the United States and other developed countries beta thalassemia is identified and treated early and effectively. Therefore, the following discussion of symptoms applies primarily to affected individuals in the past and in some underdeveloped countries as of the early 2000s. If untreated, beta thalassemia major can lead to severe lethargy, paleness, and growth and developmental delay. The body attempts to compensate by producing more blood, which is made inside the bones in the marrow. However, this effort is ineffective without the needed genetic instructions to make enough functioning hemoglobin. Instead, obvious bone expansion and changes occur that cause characteristic facial and other changes in appearance, as well as increased risk of fractures. Severe anemia taxes other organs in the body such as the heart, spleen, and liver, which must work harder than usual. This stress can lead to heart failure, as well as enlargement and other problems of the liver and spleen. When untreated, beta thalassemia major generally results in childhood death, usually due to heart failure. In developed countries, diagnosis is usually made early, often before symptoms have begun. This factor allows for treatment with blood transfusion therapy, which can prevent most of the complications of the severe anemia caused by beta thalassemia major.
Individuals with beta thalassemia intermedia have a more moderate anemia that may only require treatment with transfusion intermittently, such as when infections stress the body. As a person with beta thalassemia intermedia gets older, however, the need for blood transfusions may increase to the point that they are required on a regular basis. When this occurs the disease becomes more similar to beta thalassemia major. Other genetic and environmental factors can influence the course of the disease as well. For example, co-inheritance of one or two alpha thalassemia mutations can tend to improve some of the symptoms of beta thalassemia disease, which results in part from an imbalance in the amount of alpha- and beta-globin present in the red blood cells.
When to Call the Doctor
Signs of thalassemia diseases are often noted by the doctor during newborn screening. Parents should contact their doctors if they suspect any developmental delays, especially if the parents belong to one of the ethnic groups at higher risk for the disease.
Diagnosis
Diagnosis of thalassemia can occur under various circumstances and at various ages. Several states offer thalassemia screening as part of the usual battery of blood tests done on newborns. This arrangement allows for early identification and treatment. Thalassemia can be identified before birth using prenatal diagnosis. Chorionic villus sampling (CVS) can be done as early as 10 weeks of pregnancy. It involves removing a sample of the placenta and testing the cells. CVS carries a risk of causing a miscarriage that is between 0.5 percent and 1 percent. Amniocentesis is generally done between 15 and 22 weeks of pregnancy but can sometimes be offered earlier. Two to three tablespoons of the fluid surrounding the baby are removed. This fluid contains fetal cells that can be tested. The risk of miscarriage associated with amniocentesis ranges from 0.33 to 0.5 percent.
Pregnant women and couples may choose prenatal testing in order to prepare for the birth of a baby that may have thalassemia. Alternately, knowing the diagnosis during pregnancy allows for the option of pregnancy termination. Preimplantation genetic diagnosis (PGD) is a relatively new technique that involves in-vitro fertilization followed by genetic testing of one cell from each developing embryo. Only the embryos unaffected by the disease are transferred back into the uterus.
Thalassemia may be suspected if an individual shows signs that are suggestive of the disease. In all cases, however, laboratory tests are essential to confirm the exact diagnosis and to allow for the provision of accurate genetic counseling about recurrence risks and testing options for parents and affected individuals. Screening is likewise recommended to determine trait status for individuals of high-risk ethnic groups.
The following tests are used to screen for thalassemia disease and/or trait:
• complete blood count
• hemoglobin electrophoresis
• free erythrocyte-protoporphyrin (or ferritin or other studies of serum iron levels)
A complete blood count will identify low levels of hemoglobin, small red blood cells, and other red blood cell abnormalities that are characteristic of a thalassemia diagnosis. Since thalassemia trait can sometimes be difficult to distinguish from iron deficiency, tests to evaluate iron levels are important.
Hemoglobin electrophoresis is a test that can help identify the types and quantities of hemoglobin made by an individual. This test uses an electric field applied across a slab of gel-like material. Hemoglobins migrate through this gel at various rates and to specific locations, depending on their size, shape, and electrical charge. Isoelectric focusing and high-performance liquid chromatography (HPLC) use similar principles to separate hemoglobins. They can be used instead of or in various combinations with hemoglobin electrophoresis to determine the types and quantities of hemoglobin present. Hemoglobin electrophoresis results are usually within the normal range for all types of alpha thalassemia. Hemoglobin electrophoresis can also detect structurally abnormal hemoglobins that may be co-inherited with a thalassemia trait. Sometimes DNA testing is needed in addition to the above screening tests. This test can be performed to help confirm the diagnosis and establish the exact genetic type of thalassemia.
Treatment
Because alpha thalassemia major is most often a fatal condition in the prenatal or newborn period, treatment has previously been focused on identifying affected pregnancies in order to provide appropriate management to reduce potential maternal complications. Pregnancy termination provides one form of management. Increased prenatal surveillance and early treatment of maternal complications is an approach that is appropriate for mothers who wish to continue their pregnancy with the knowledge that the baby will most likely not survive. In the last decade of the twentieth century and early 2000s, a handful of infants with this condition have survived long-term. Most of these infants received experimental treatment including transfusions before birth, early delivery, and bone marrow transplantation before birth, although the latter procedure had, as of 2004, not yet been successful. For those infants who survive to delivery, there seems to be an increased risk of developmental problems and physical effects, particularly heart and genital malformations. Otherwise, the medical outlook is similar to a child with beta thalassemia major, with the important exception that ongoing, lifelong blood transfusions begin at birth.
Beta Thalassemia
Individuals with beta thalassemia major receive regular blood transfusions, usually on a monthly basis. This helps prevent severe anemia and allow for growth and development that is more normal. Transfusion therapy does have limitations, however. Individuals can develop reactions to certain proteins in the blood, called a transfusion reaction. Such a reaction can make locating appropriately matched donor blood more difficult. Although blood supplies in the United States are very safe, there remains an increased risk of exposure to such blood-borne infections as hepatitis.
An additional side effect of repeated transfusions is that the body is unable to get rid of the excess iron that accompanies each transfusion. A medication called desferoxamine is administered, usually five nights per week over a period of several hours, using an automatic pump that can be used during sleep or taken anywhere the person goes. This medication is able to bind to the excess iron, which can then be eliminated through urine.
If desferoxamine is not used regularly or is unavailable, iron overload can develop and cause tissue damage and organ damage and failure. The heart, liver, and endocrine organs are particularly vulnerable. Desferoxamine itself may produce on rare occasions allergic or toxic side effects, including hearing damage. Signs of desferoxamine toxicity are screened for and generally develop in individuals who overuse the medication when body iron levels are sufficiently low. Overall, however, transfusion and desferoxamine therapy have increased the life expectancy of individuals with the most severe types of beta thalassemia major to the fourth or fifth decade.
As of 2004, new treatments including medications that target the production of red blood cells (e.g. erythropoeitin) or fetal hemoglobin (e.g. hydroxyurea and butyrate) and bone marrow transplantation may offer more effective treatment of beta thalassemia major. Other possible treatments may include gene therapy techniques aimed at increasing the amount of normal hemoglobin the body is able to make.
Prognosis
Prognosis, as noted above, depends on the type and severity of the disease. Individuals with severe disease may be stillborn or die shortly after birth. On the other hand, some individuals with mild disease have a relatively normal life expectancy.
Prevention
Thalassemias are inherited diseases that cannot be prevented. It is, however, possible to identify carriers of the disease and provide them with genetic counseling and appropriate information concerning the chance of their offspring having thalassemia disease.
Individuals with hemoglobin H disease can reduce the likelihood of symptoms by avoiding infections and certain environmental triggers.
Parental Concerns
If parents are thinking of having a child and believe they might be carriers of defective hemoglobin genes, they can be screened and receive genetic counseling so that they can assess their option.
Thalassemia describes a group of inherited disorders characterized by reduced or absent amounts of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen throughout the body. There are two basic groups of thalassemia disorders: alpha thalassemias and beta thalassemias. These conditions cause varying degrees of anemia, which can range from insignificant to fatal.
Description
Thalassemia is a genetic disorder. It cannot be acquired from contact with other people or from the environment. In all types of thalassemia, the quantity of hemoglobin produced is reduced or absent. This circumstance affects the ability of the blood to carry oxygen to all parts of the body. Although both alpha and beta thalassemias affect hemoglobin, these diseases affect the body in distinctly different ways. Hemoglobin is made up of three components: alpha globin, beta globin, and heme. Thalassemias are classified according to the globin that is deficient.
Alpha Thalassemia
Individuals inherit from each parent a gene controlling alpha globin production. Two spots (called loci) on these genes control alpha globin production. Alpha thalassemias result from changes (mutations) in these genes. There are two main types of alpha thalassemia disease: hemoglobin H disease and alpha thalassemia major. The two diseases are quite different from beta thalassemia, as well as from one another.
Individuals with hemoglobin H disease have inherited one completely defective gene and one gene that has one rather than two functional loci. This circumstance substantially reduces the amount of alpha globin that the body produces. As a result, individuals with hemoglobin H disease can experience events of hemolytic anemia—anemia caused by the rapid breakdown of the red blood cells. These events are thought to be triggered by various environmental causes, such as infection and/or exposure to certain chemicals. Hemoglobin H disease is milder than alpha thalassemia and usually milder than beta thalassemia.
Individuals with alpha thalassemia major have inherited two completely defective genes, one from each parent. Alpha thalassemia major, sometimes called hemoglobin Barts or hydrops fetalis, is a fatal disease that results in severe anemia that begins even before birth. Most affected babies do not survive to be born or die shortly after birth.
Beta Thalassemia
Beta thalassemia, also called Cooley's anemia, is the most well known type of thalassemia. It is caused by a change in the gene for the beta globin component of hemoglobin. Beta thalassemia causes variable anemia that can range from moderate to severe, depending in part on the exact genetic change underlying the disease.
Beta thalassemia major causes severe anemia that usually occurs within three to six months after birth. If left untreated, severe anemia can result in stunted growth and development, as well as other characteristic physical complications that can lead to a dramatically decreased life expectancy. In developed countries, screening in the newborn period usually identifies beta thalassemia before symptoms have developed. Children who are identified early can be started on ongoing blood transfusion therapy as needed.
Beta thalassemia minor describes a disease where only one gene of the pair that control beta hemoglobin production is defective. There are few or mild events. However, the individual can pass the defective gene on to his or her offspring
Beta thalassemia intermedia is a clinical term that describes the disease in individuals who have moderate anemia that only requires blood transfusions intermittently.
Demographics
The thalassemias are among the most common genetic diseases worldwide. Both alpha and beta thalassemia have been described in individuals of almost every ancestry, but the conditions are more common among certain ethnic groups. Unaffected carriers of all types of thalassemia traits do not experience health problems.
Determining the prevalence for alpha thalassemia is difficult due to limitations in diagnostic testing. In the United States, up to 30 percent of African Americans are thought to be carriers for alpha thalassemia traits, meaning that they show no symptoms of the disorder but can pass the trait to their offspring. Despite this estimate, the number of babies born with hemoglobin H disease or alpha thalassemia major is very low. The highest frequency of alpha thalassemia diseases occurs in individuals of Southeast Asian and Chinese descent. Individuals of Greek, Middle Eastern, and North African descent also carry genes for the disease more frequently than individuals of Northern European descent. One study of 500 pregnant women in northern Thailand estimated a frequency of one in 500 pregnancies affected by alpha thalassemia major, for example. Prevalence of alpha thalassemia disease is significantly lower in the United States owing primarily to immigration patterns. However, at least one state, California, has observed growing hemoglobin H disease rates that are high enough to justify universal newborn screening for the condition.
Beta thalassemia trait is seen most commonly in people with the following ancestry: Mediterranean (including North African, and particularly Italian and Greek), Middle Eastern, Indian, African, Chinese, and Southeast Asian (including Vietnamese, Laotian, Thai, Singaporean, Filipino, Cambodian, Malaysian, Burmese, and Indonesian). It is difficult to obtain accurate prevalence figures for various types of thalassemia within different populations.
Two studies reflect prevalence figures that can be helpful counseling families and determining who to screen for beta thalassemia. Between the years of 1990 and 1996, the State of California screened over 3.1 million newborns for beta thalassemia. Approximately one in 114,000 infants had beta thalassemia major, with prevalence rates being highest among Asian Indians (about one in 4,000), Southeast Asians (about one in 10,000), and Middle Easterners (about one in 7,000). The pattern observed in California is expected to be different in other areas of the United States and the world. For example, Italians are underrepresented in this population when compared to the population of the East Coast of the United States.
Causes and Symptoms
Humans normally make several types of hemoglobin. An individual's stage in development determines whether he or she makes primarily embryonic, fetal, or adult hemoglobins. All types of hemoglobin are made of three components: heme, alpha globin, and beta globin. All types of thalassemia are caused by changes in either the alpha- or beta-globin gene. These changes cause little or no globin to be produced. All types of thalassemias are recessively inherited, meaning that a genetic change must be inherited from both the mother and the father to produce the disease in the child. The severity of the disease is influenced by the exact thalassemia mutations inherited, as well as other genetic and environmental factors. There are rare exceptions, notably with beta thalassemia, where globin gene mutations exhibit a dominant pattern of inheritance in which only one gene needs to be altered in order to see disease expression.
Alpha Thalassemia
Most individuals have four normal copies of the alpha globin gene, two copies on each chromosome 16. These genes make the alpha globin component of normal adult hemoglobin, which is called hemoglobin A. Alpha globin is also a component of fetal hemoglobin. Since there are four genes (instead of the usual two) to consider when looking at alpha globin gene inheritance, there are several alpha globin types that are possible.
Absence of one functioning alpha globin gene leads to a condition known as silent alpha thalassemia trait. This condition causes no health problems and can be detected only by special genetic testing. Alpha thalassemia trait occurs when two alpha globin genes are missing or not functioning. There are no associated health problems, although the trait status may be detected by more routine blood screening.
Hemoglobin H disease results from the deletion of three of the four alpha globin genes. Hemoglobin H symptoms can also be a part of a unique condition called alpha thalassemia mental retardation syndrome. This syndrome can be caused by a deletion of a significant amount of chromosome 16, affecting the alpha globin genes. This situation is usually not inherited, but rather occurs sporadically in the affected individual. Affected individuals have mild hemoglobin H disease, mild-to-moderate mental retardation, and characteristic facial features, as well as various other developmental processes that mimic hemoglobin H disease.
Alpha thalassemia major results from the deletion of all four alpha globin genes, such that there are no functioning alpha globin genes. In this situation, there is a 25 percent chance for alpha thalassemia major in each of such a couple's children.
Beta Thalassemia
Most individuals have two normal copies of the beta globin gene, which is located on chromosome 11 and makes the beta globin component of normal adult hemoglobin. There are approximately one hundred genetic mutations that have been described that cause beta thalassemia, designated as either beta0 or beta+ mutations. No beta globin is produced with a beta0 mutation, and only a small fraction of the normal amount of beta globin is produced with a beta+ mutation.
When an individual has one normal beta globin gene and one with a beta thalassemia mutation, he or she is said to carry the beta thalassemia trait. Carrying the trait is generally thought not to cause health problems, although some women with beta thalassemia trait may have an increased tendency toward anemia during pregnancy.
When both parents carry the beta thalassemia trait, there is a 25 percent chance that each of their children will inherit beta thalassemia disease by inheriting two beta thalassemia mutations, one from each parent. The clinical severity of the beta thalassemia disease depends largely on whether the mutations inherited are beta0 thalassemia or beta+ thalassemia mutations. Two beta0 mutations generally lead to beta thalassemia major, and two beta+ thalassemia mutations generally lead to beta thalassemia intermedia, a milder form of the disease. Inheritance of one beta0 and one beta+ thalassemia mutation tends to be less predictable.
Symptoms
Hemoglobin H Disease
Hemoglobin H disease is a relatively mild form of thalassemia that may go unrecognized. It is not generally considered a condition that will reduce one's life expectancy. Education is an important part of managing the health of an individual with hemoglobin H disease. It is important to be able to recognize the signs of severe anemia that require medical attention. It is also important to be aware of the medications, chemicals, and other exposures to avoid due to the theoretical risk they pose of precipitating a severe anemia event. When severe anemia occurs, it is treated with blood transfusion therapy. For many individuals with hemoglobin H disease, this is rarely required. For those with a more severe form of the disease, the need for transfusions may be intermittent or ongoing, perhaps on a monthly basis, and require desferoxamine treatment. This treatment removes excess iron from the body. Individuals with this more severe form of the disease may also have an increased chance of requiring removal of an enlarged and/or overactive spleen.
Alpha Thalassemia Major
Because alpha globin is a necessary component of hemoglobin, absence of all functioning alpha globin genes leads to serious medical consequences that begin even before birth. Affected fetuses develop severe anemia as early as the first trimester of pregnancy. The placenta, heart, liver, spleen, and adrenal glands may all become enlarged. Fluid can begin collecting throughout the body as early as the start of the second trimester, causing damage to developing tissues and organs. Growth retardation is also common. Affected fetuses usually miscarry or die shortly after birth. In addition, women carrying affected fetuses are at increased risk of developing complications of pregnancy and delivery. Up to 80 percent of such women develop toxemia, a disturbance of metabolism that can potentially lead to convulsions and coma. Other maternal complications include premature delivery and increased rates of delivery by cesarean section, as well as hemorrhage after delivery.
Beta thalassemia major is characterized by severe anemia that can begin several months after birth. In the United States and other developed countries beta thalassemia is identified and treated early and effectively. Therefore, the following discussion of symptoms applies primarily to affected individuals in the past and in some underdeveloped countries as of the early 2000s. If untreated, beta thalassemia major can lead to severe lethargy, paleness, and growth and developmental delay. The body attempts to compensate by producing more blood, which is made inside the bones in the marrow. However, this effort is ineffective without the needed genetic instructions to make enough functioning hemoglobin. Instead, obvious bone expansion and changes occur that cause characteristic facial and other changes in appearance, as well as increased risk of fractures. Severe anemia taxes other organs in the body such as the heart, spleen, and liver, which must work harder than usual. This stress can lead to heart failure, as well as enlargement and other problems of the liver and spleen. When untreated, beta thalassemia major generally results in childhood death, usually due to heart failure. In developed countries, diagnosis is usually made early, often before symptoms have begun. This factor allows for treatment with blood transfusion therapy, which can prevent most of the complications of the severe anemia caused by beta thalassemia major.
Individuals with beta thalassemia intermedia have a more moderate anemia that may only require treatment with transfusion intermittently, such as when infections stress the body. As a person with beta thalassemia intermedia gets older, however, the need for blood transfusions may increase to the point that they are required on a regular basis. When this occurs the disease becomes more similar to beta thalassemia major. Other genetic and environmental factors can influence the course of the disease as well. For example, co-inheritance of one or two alpha thalassemia mutations can tend to improve some of the symptoms of beta thalassemia disease, which results in part from an imbalance in the amount of alpha- and beta-globin present in the red blood cells.
When to Call the Doctor
Signs of thalassemia diseases are often noted by the doctor during newborn screening. Parents should contact their doctors if they suspect any developmental delays, especially if the parents belong to one of the ethnic groups at higher risk for the disease.
Diagnosis
Diagnosis of thalassemia can occur under various circumstances and at various ages. Several states offer thalassemia screening as part of the usual battery of blood tests done on newborns. This arrangement allows for early identification and treatment. Thalassemia can be identified before birth using prenatal diagnosis. Chorionic villus sampling (CVS) can be done as early as 10 weeks of pregnancy. It involves removing a sample of the placenta and testing the cells. CVS carries a risk of causing a miscarriage that is between 0.5 percent and 1 percent. Amniocentesis is generally done between 15 and 22 weeks of pregnancy but can sometimes be offered earlier. Two to three tablespoons of the fluid surrounding the baby are removed. This fluid contains fetal cells that can be tested. The risk of miscarriage associated with amniocentesis ranges from 0.33 to 0.5 percent.
Pregnant women and couples may choose prenatal testing in order to prepare for the birth of a baby that may have thalassemia. Alternately, knowing the diagnosis during pregnancy allows for the option of pregnancy termination. Preimplantation genetic diagnosis (PGD) is a relatively new technique that involves in-vitro fertilization followed by genetic testing of one cell from each developing embryo. Only the embryos unaffected by the disease are transferred back into the uterus.
Thalassemia may be suspected if an individual shows signs that are suggestive of the disease. In all cases, however, laboratory tests are essential to confirm the exact diagnosis and to allow for the provision of accurate genetic counseling about recurrence risks and testing options for parents and affected individuals. Screening is likewise recommended to determine trait status for individuals of high-risk ethnic groups.
The following tests are used to screen for thalassemia disease and/or trait:
• complete blood count
• hemoglobin electrophoresis
• free erythrocyte-protoporphyrin (or ferritin or other studies of serum iron levels)
A complete blood count will identify low levels of hemoglobin, small red blood cells, and other red blood cell abnormalities that are characteristic of a thalassemia diagnosis. Since thalassemia trait can sometimes be difficult to distinguish from iron deficiency, tests to evaluate iron levels are important.
Hemoglobin electrophoresis is a test that can help identify the types and quantities of hemoglobin made by an individual. This test uses an electric field applied across a slab of gel-like material. Hemoglobins migrate through this gel at various rates and to specific locations, depending on their size, shape, and electrical charge. Isoelectric focusing and high-performance liquid chromatography (HPLC) use similar principles to separate hemoglobins. They can be used instead of or in various combinations with hemoglobin electrophoresis to determine the types and quantities of hemoglobin present. Hemoglobin electrophoresis results are usually within the normal range for all types of alpha thalassemia. Hemoglobin electrophoresis can also detect structurally abnormal hemoglobins that may be co-inherited with a thalassemia trait. Sometimes DNA testing is needed in addition to the above screening tests. This test can be performed to help confirm the diagnosis and establish the exact genetic type of thalassemia.
Treatment
Because alpha thalassemia major is most often a fatal condition in the prenatal or newborn period, treatment has previously been focused on identifying affected pregnancies in order to provide appropriate management to reduce potential maternal complications. Pregnancy termination provides one form of management. Increased prenatal surveillance and early treatment of maternal complications is an approach that is appropriate for mothers who wish to continue their pregnancy with the knowledge that the baby will most likely not survive. In the last decade of the twentieth century and early 2000s, a handful of infants with this condition have survived long-term. Most of these infants received experimental treatment including transfusions before birth, early delivery, and bone marrow transplantation before birth, although the latter procedure had, as of 2004, not yet been successful. For those infants who survive to delivery, there seems to be an increased risk of developmental problems and physical effects, particularly heart and genital malformations. Otherwise, the medical outlook is similar to a child with beta thalassemia major, with the important exception that ongoing, lifelong blood transfusions begin at birth.
Beta Thalassemia
Individuals with beta thalassemia major receive regular blood transfusions, usually on a monthly basis. This helps prevent severe anemia and allow for growth and development that is more normal. Transfusion therapy does have limitations, however. Individuals can develop reactions to certain proteins in the blood, called a transfusion reaction. Such a reaction can make locating appropriately matched donor blood more difficult. Although blood supplies in the United States are very safe, there remains an increased risk of exposure to such blood-borne infections as hepatitis.
An additional side effect of repeated transfusions is that the body is unable to get rid of the excess iron that accompanies each transfusion. A medication called desferoxamine is administered, usually five nights per week over a period of several hours, using an automatic pump that can be used during sleep or taken anywhere the person goes. This medication is able to bind to the excess iron, which can then be eliminated through urine.
If desferoxamine is not used regularly or is unavailable, iron overload can develop and cause tissue damage and organ damage and failure. The heart, liver, and endocrine organs are particularly vulnerable. Desferoxamine itself may produce on rare occasions allergic or toxic side effects, including hearing damage. Signs of desferoxamine toxicity are screened for and generally develop in individuals who overuse the medication when body iron levels are sufficiently low. Overall, however, transfusion and desferoxamine therapy have increased the life expectancy of individuals with the most severe types of beta thalassemia major to the fourth or fifth decade.
As of 2004, new treatments including medications that target the production of red blood cells (e.g. erythropoeitin) or fetal hemoglobin (e.g. hydroxyurea and butyrate) and bone marrow transplantation may offer more effective treatment of beta thalassemia major. Other possible treatments may include gene therapy techniques aimed at increasing the amount of normal hemoglobin the body is able to make.
Prognosis
Prognosis, as noted above, depends on the type and severity of the disease. Individuals with severe disease may be stillborn or die shortly after birth. On the other hand, some individuals with mild disease have a relatively normal life expectancy.
Prevention
Thalassemias are inherited diseases that cannot be prevented. It is, however, possible to identify carriers of the disease and provide them with genetic counseling and appropriate information concerning the chance of their offspring having thalassemia disease.
Individuals with hemoglobin H disease can reduce the likelihood of symptoms by avoiding infections and certain environmental triggers.
Parental Concerns
If parents are thinking of having a child and believe they might be carriers of defective hemoglobin genes, they can be screened and receive genetic counseling so that they can assess their option.
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