Categories
Ailmemts & Remedies

Macular Degeneration (AMD OR ARMD)

Definition:
Macular degeneration is a medical condition usually of older adults which results in a loss of vision in the center of the visual field (the macula) because of damage to the retina. It occurs in “dry” and “wet” forms. It is a major cause of blindness in the elderly (>50 years). Macular degeneration can make it difficult or impossible to read or recognize faces, although enough peripheral vision remains to allow other activities of daily life.

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Human eye cross section view

Macular degeneration doesn’t cause total blindness, but it worsens your quality of life by blurring or causing a blind spot in your central vision. Clear central vision is necessary for reading, driving, recognizing faces and doing detail work.

The deterioration occurs in the macula (MAK-u-luh), which is in the center of the retina — the layer of tissue on the inside back wall of your eyeball.

The inner layer of the eye is the retina, which contains nerves that communicate sight, and behind the retina is the choroid, which contains the blood supply to the retina. In the dry (nonexudative) form, cellular debris called drusen accumulate between the retina and the choroid, and the retina can become detached. In the wet (exudative) form, which is more severe, blood vessels grow up from the choroid behind the retina, and the retina can also become detached. It can be treated with laser coagulation, and with medication that stops and sometimes reverses the growth of blood vessels.

Although some macular dystrophies affecting younger individuals are sometimes referred to as macular degeneration, the term generally refers to age-related macular degeneration (AMD or ARMD).

Signs:
Drusen
Pigmentary alterations
Exudative changes: hemorrhages in the eye, hard exudates, subretinal/sub-RPE/intraretinal fluid
Atrophy: incipient and geographic
Visual acuity drastically decreasing (two levels or more) ex: 20/20 to 20/80.

Symptoms:
Dry macular degeneration usually develops gradually and painlessly. You may notice these vision changes:

* The need for increasingly bright light when reading or doing close work
* Increasing difficulty adapting to low light levels, such as when entering a dimly lit restaurant
* Increasing blurriness of printed words
* A decrease in the intensity or brightness of colors
* Difficulty recognizing faces
* Gradual increase in the haziness of your overall vision
* Blurred or blind spot in the center of your visual field combined with a profound drop in the sharpness (acuity) of your central vision
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Normal Vision.……………………………...Vision with AMD

Your vision may falter in one eye while the other eye remains fine for years. You may not notice any or much change because your good eye compensates for the weak one. Your vision and lifestyle begin to be dramatically affected when this condition develops in both eyes.

Hallucinations

Additionally, some people with macular degeneration may experience visual hallucinations as their vision loss becomes more severe. These hallucinations may include unusual patterns, geometric figures, animals or even faces. You might be afraid to discuss these symptoms with your doctors or friends and family for fear you’ll be considered crazy. However, such hallucinations aren’t a sign of mental illness. In fact, they’re so common that there’s a name for this phenomenon — Charles Bonnet syndrome.

The Amsler Grid Test is one of the simplest and most effective methods for patients to monitor the health of the macula. The Amsler Grid is essentially a pattern of intersecting lines (identical to graph paper) with a black dot in the middle. The central black dot is used for fixation (a place for the eye to stare at). With normal vision, all lines surrounding the black dot will look straight and evenly spaced with no missing or odd looking areas when fixating on the grid’s central black dot. When there is disease affecting the macula, as in macular degeneration, the lines can look bent, distorted and/or missing. See a video on how to use an Amsler grid here:  and watch an animation showing the Amsler grid with macular degeneration here: .

Macular degeneration by itself will not lead to total blindness. For that matter, only a very small number of people with visual impairment are totally blind. In almost all cases, some vision remains. Other complicating conditions may possibly lead to such an acute condition (severe stroke or trauma, untreated glaucoma, etc.), but few macular degeneration patients experience total visual loss. The area of the macula comprises about 5% of the retina and is responsible for about 35% of the visual field. The remaining 65% (the peripheral field) remains unaffected by the disease

The loss of central vision profoundly affects visual functioning. It is not possible, for example, to read without central vision. Pictures which attempt to depict the central visual loss of macular degeneration with a black spot do not really do justice to the devastating nature of the visual loss. This can be demonstrated by printing letters 6 inches high on a piece of paper and attempting to identify them while looking straight ahead and holding the paper slightly to the side. Most people find this surprisingly difficult to do.

There is a loss off contrast sensitivity, so that contours, shadows and color vision are less vivid. The loss in contrast sensitivity can be quickly and easily measured by a contrast sensitivity test performed either at home or by an eye specialist.

Similar symptoms with a very different etiology and different treatment can be caused by Epiretinal membrane or macular pucker or leaking blood vessels in the eye..

When to see a doctor
See your eye doctor — particularly after age 50 — if:

* You notice changes in your central vision
* Your ability to see colors and fine detail becomes impaired

One way to monitor your eyes to determine if you may need to visit your eye doctor is to check your vision regularly using an Amsler grid. This simple test may help you detect changes in your sight that you otherwise may not notice.

Here’s how to perform the test:

* Hold the grid 14 inches (about 36 centimeters) in front of you in good light. Use your corrective glasses or reading glasses if you normally wear them.
* Cover one eye.
* Look directly at the center dot with your uncovered eye.
* While looking at this dot, determine whether all of the lines of the grid appear straight, uninterrupted and have the same contrast.
* Repeat the above steps with your other eye.
* If any part of the grid is missing or looks wavy, blurred or dark, contact your eye doctor immediately.

Causes:
The exact cause of dry macular degeneration is unknown, but the condition develops as the eye ages. The initial site of change is not in the light-sensitive cells of the macula, but in the retinal pigment epithelium (RPE), a single layer of cells located just behind the retina close to the back wall of your eye.

Your macula is an area about two-tenths of an inch (5 millimeters) in diameter at the center of your retina. This small part of your eye is responsible for clear vision, particularly in your direct line of sight.

The macula consists of millions of densely packed light-sensitive cells called cones and rods. Cones and rods have two segments: An inner segment controls cell functions and produces proteins responsive to light, and an outer segment stores and makes use of these proteins.

As they absorb light, outer segment proteins become degraded and eventually are shed as waste. Meanwhile, the inner segments continuously provide replacements for the outer segments. One function of the cells of the RPE is to remove the outer segments that are shed.

As the eye ages, cells in the RPE begin to deteriorate (atrophy) and lose their pigment. As a consequence, the RPE becomes less efficient in removing outer segment waste. When that happens, the normally uniform reddish color of the macula (as seen with an ophthalmoscope) takes on a mottled appearance. Drusen — yellow, fat-like deposits — begin to appear under the cones and rods. As the drusen and mottled pigmentation continue to develop, your vision gradually deteriorates.

Based on this progression, dry macular degeneration is categorized in three stages:

* Early stage. Several small drusen or a few medium-sized drusen are detected on the macula in one or both eyes. Generally, there’s no vision loss in the earliest stage.
* Intermediate stage. Many medium-sized drusen or one or more large drusen are detected in one or both eyes. At this stage, your central vision may start to blur and you may need extra light for reading or doing detail work.
* Advanced stage. Several large drusen, as well as extensive breakdown of light-sensitive cells in the macula, are detected. These features cause a well-defined spot of blurring in your central vision. The blurred area may become larger and more opaque over time.

Macular degeneration almost always starts out as the dry form. Dry macular degeneration may initially affect only one eye but, in most cases, both eyes eventually become involved.

Risk factors:
Contributing factors for development of macular degeneration include:

* Age. In the United States, macular degeneration is the leading cause of severe vision loss in people age 60 and older.
* Family history of macular degeneration. If someone in your family had macular degeneration, your odds of developing macular degeneration are higher. In recent years, researchers have identified some of the genes associated with macular degeneration. In the future, genetic screening tests may be helpful for assessing early risk of the disease.
* Race. Macular degeneration is more common in whites than it is in other groups, especially after age 75.
* Sex. Women are more likely than men to develop macular degeneration, and because they tend to live longer, women are more likely to experience the effects of severe vision loss from the disease.
* Cigarette smoking. Exposure to cigarette smoke doubles your risk of macular degeneration. Cigarette smoking is the single most preventable cause of macular degeneration.
*Stargardt’s disease (STGD, also known as Juvenile Macular Degeneration) is an autosomal recessive retinal disorder characterized by a juvenile-onset macular dystrophy, alterations of the peripheral retina, and subretinal deposition of lipofuscin-like material. A gene encoding an ATP-binding cassette (ABC) transporter was mapped to the 2-cM (centiMorgan) interval at 1p13-p21 previously shown by linkage analysis to harbor the STGD gene. This gene, ABCR, is expressed exclusively and at high levels in the retina, in rod but not cone photoreceptors, as detected by in situ hybridization. Mutational analysis of ABCR in STGD families revealed a total of 19 different mutations including homozygous mutations in two families with consanguineous parentage. These data indicate that ABCR is the causal gene of STGD/FFM.
*Drusen CMSD studies indicate that drusen are similar in molecular composition to plaques and deposits in other age-related diseases such as Alzheimer’s disease and atherosclerosis.
While there is a tendency for drusen to be blamed for the progressive loss of vision, drusen deposits can, however, be present in the retina without vision loss. Some patients with large deposits of drusen have normal visual acuity. If normal retinal reception and image transmission are sometimes possible in a retina when high concentrations of drusen are present, then even if drusen can be implicated in the loss of visual function, there must be at least one other factor that accounts for the loss of vision. Retinitis Pigmentosa (RP) is a genetically linked dysfunction of the retina and is related to mutation of the ATP Synthase Gene 63.
* Obesity. Being severely overweight increases the chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
* Light-colored eyes. People with light-colored eyes appear to be at greater risk than do those with darker eyes.
* Exposure to sunlight. Although the retina is more sensitive to shorter wavelengths of light, including ultraviolet (UV) light, only a small percentage of ultraviolet light actually reaches the retina. Most ultraviolet light is filtered by the transparent outer surface of your eye (cornea) and the natural crystalline lens in your eye. Some experts believe that long-term exposure to ultraviolet light may increase your risk of developing macular degeneration, but this risk has not been proved and remains controversial.
* Low levels of nutrients. This includes low blood levels of minerals, such as zinc, and of antioxidant vitamins, such as A, C and E. Antioxidants may protect your cells from oxygen damage (oxidation), which may partially be responsible for the effects of aging and for the development of certain diseases such as macular degeneration.
* Cardiovascular diseases. These include high blood pressure, stroke, heart attack and coronary artery disease with chest pain (angina).
*High fat intake is associated with an increased risk of macular degeneration in both women and men. Fat provides about 42% of the food energy in the average American diet. A diet that derives closer to 20-25% of total food energy from fat is probably healthier. Reducing fat intake to this level means cutting down greatly on consumption of red meats and high-fat dairy products such as whole milk, cheese, and butter. Eating more cold-water fish (at least twice weekly), rather than red meats, and eating any type of nuts may help macular degeneration patients.
*Oxidative stress: It has been proposed that age related accumulation of low molecular weight, phototoxic, pro-oxidant melanin oligomers within lysosomes in the retinal pigment epithelium may be partly responsible for decreasing the digestive rate of photoreceptor outer rod segments (POS) by the RPE. A decrease in the digestive rate of POS has been shown to be associated with lipofuscin formation – a classic sign associated with macular degeneration.
*Fibulin-5 mutation Rare forms of the disease are caused by geneic defects in fibulin-5, in an autosomal dominant manner. In 2004 Stone et al. performed a screen on 402 AMD patients and revealed a statistically significant correlation between mutations in Fibulin-5 and incidence of the disease. Furthermore the point mutants were found in the Calcium binding sites of the cbEGF domains of the protein. there is no structural basis for the effects of the mutations.

Diagnosis:
Diagnostic tests for macular degeneration may include:

*An eye examination. One of the things your eye doctor looks for while examining the inside of your eye is the presence of drusen and mottled pigmentation in the macula. The eye examination includes a simple test of your central vision and may include testing with an Amsler grid. If you have macular degeneration, when you look at the grid some of the straight lines may seem faded, broken or distorted. By noting where the break or distortion occurs — usually on or near the center of the grid — your eye doctor can better determine the location and extent of your macular damage.

Regular screening examinations can detect early signs of macular degeneration before the disease leads to vision loss.
*Angiography. To evaluate the extent of the damage from macular degeneration, your eye doctor may use fluorescein angiography. In this procedure, fluorescein dye is injected into a vein in your arm and photographs are taken of the back of the eye as the dye passes through blood vessels in your retina and choroid. Your doctor then uses these photographs to detect changes in macular pigmentation or to identify small macular blood vessels.

Your doctor may also suggest a similar procedure called indocyanine green angiography. Instead of fluorescein, a dye called indocyanine green is used. This test provides information that complements the findings obtained through fluorescein angiography.
* Optical coherence tomography. This noninvasive imaging test helps identify and display areas of retinal thickening or thinning. Such changes are associated with macular degeneration. This test can also reveal the presence of abnormal fluid in and under the retina or the RPE. It’s often used to help monitor the response of the retina to macular degeneration treatments.

Treatment:
There’s no treatment available to reverse dry macular degeneration. But this doesn’t mean you’ll eventually lose all of your sight. Dry macular degeneration usually progresses slowly, and many people with the condition are able to live relatively normal, productive lives, especially if only one eye is affected. Dry macular degeneration can, however, develop into the more rapidly progressive wet type of macular degeneration at any time.

Taking a high-dose formulation of antioxidants and zinc may reduce progression of dry macular degeneration to advanced macular degeneration. The National Eye Institute-sponsored Age-Related Eye Disease Study (AREDS) showed that a daily supplement of 500 milligrams (mg) of vitamin C, 400 international units (IU) of vitamin E, 15 mg of beta carotene (often as vitamin A — up to 25,000 IU), 80 mg of zinc (as zinc oxide) and 2 mg of copper (as cupric oxide) reduced the risk of progressing to moderate or severe vision loss by up to 25 percent.

Life Style & Home Remedies:
Macular degeneration doesn’t affect your side (peripheral) vision and usually doesn’t cause total blindness. But it can rob you of your central vision — which is important for driving, reading and recognizing people’s faces. A low-vision center may be able to assess your visual capabilities and suggest certain optical and household devices that can be helpful for some near-vision tasks. Ask your eye doctor if there are any low-vision centers in your area.

There are ways to cope with impaired vision. Below are a few suggestions:

* Use caution when driving. First, check with your doctor to see if driving is still safe based on your current visual acuity. When you do drive, there are certain situations to avoid. For example, don’t drive at night, in heavy traffic or in bad weather.
* Seek help traveling. Use public transportation or ask family members to help, especially with night driving.
* Travel with others. Contact your local area agency on aging for a list of vans and shuttles, volunteer driving networks or ride shares.
* Get good glasses. Optimize the vision you have with the right glasses, and keep an extra pair in the car.
* Use magnifiers. Large-print books and magazines can help you read more easily.
* View with large type on the Internet. Look for Web sites that use large-sized type fonts, or change the font size on your display.
* Obtain specialized appliances. Some clocks, radios, telephones and other appliances have extra-large numbers.
* Have proper light in your home. This will help with reading and other activities.
* Remove home hazards. Eliminate throw rugs and other possible tripping hazards in your home.
* Ask friends and family members for help. Tell them about your vision problems so that they can help you perform certain tasks and help you recognize people.
* Don’t become socially isolated. A common frustration of people with macular degeneration is the inability to recognize other people and greet them by name. If this happens to you, try asking people you know to say hi and tell you their names when you meet them on the street or in other situations so that you can greet them back.
* Take advantage of online networks. The Internet is a good source for support groups and resources for people with macular degeneration.

Alternative Medicine:
Some people have turned to complementary or alternative therapies, such as bilberry, ginkgo and shark cartilage, in the belief that they can help prevent the progression of macular degeneration.

However, there’s no conclusive evidence that any of these products are effective for macular degeneration, and some may interact with other medications you’re taking. Check with your doctor before taking any dietary or herbal supplement.

Prevention
The Age-Related Eye Disease Study showed that a combination of high-dose beta-carotene, vitamin C, vitamin E, and zinc can reduce the risk of progressing from early to advanced AMD by about 25 percent.  Studies are underway with the goal of reducing lipofuscin accumulation.

Studies have found that Lutein and zeaxanthin (Carotenoid nutrients found in green vegetables such as Kale, Spinach, Collards, spices such as Saffron, and egg yolk) protect against and possibly reverse macular degeneration and Retinitis pigmentosa.  Studies found that antioxidants disrupt the link of two processes that cause macular degeneration and extend the lifetime of irreplaceable photoreceptors and other retinal cells (Lutein is known to have antioxidant properties).

Eating spinach or collard greens five times a week decreases the risk of AMD by 43%

Studies reported in the British Journal of Ophthalmology suggest that while beneficial for those in advanced stages, antioxidant supplements can be counterproductive for people with early stages of AMD as antioxidants can potentially negate the beneficial effects of Omega-3 fats. It has been found that Omega-3 fatty acids can prevent or even halt the progress of degeneration. However, moderation of oily fishes in patients’ diets is suggested as they can lead to a build up of pollutants such fishes may contain.

The following measures may help you avoid macular degeneration:
*Eat foods containing antioxidants.
*Take antioxidant and zinc supplements.
* Eat fish.
*Stop smoking.
*Manage your other diseases.
*Get regular eye exams.
*Screen your vision regularly.

If you have some vision loss because of macular degeneration, your eye doctor can prescribe optical devices called low-vision aids that will help you see better for close-up work. Or your doctor may refer you to a low-vision specialist. In addition, a wide variety of support services and rehabilitation programs are available that may help you adjust your lifestyle.
Impact:
Macular degeneration can advance to legal blindness and inability to drive. It can also result in difficulty or inability to read or see faces.

Adaptive devices can help people read. These include magnifying glasses, special eyeglass lenses, desktop and portable electronic devices, and computer screen readers such as JAWS for Windows.

Composer Josef Tal checks a manuscript (2006)Accessible publishing also aims to provide a variety of fonts and formats for published books to make reading easier. This includes much larger fonts for printed books, patterns to make tracking easier, audiobooks and DAISY books with both text and audio.

Because the peripheral vision is not affected, people with macular degeneration can learn to use their remaining vision to continue most activities. Assistance and resources are available in every country and every state in the U.S. Classes for “independent living” are given and some technology can be obtained from a state department of rehabilitation. You can also search for macular degeneration on the internet and contact one of the non-profit organizations for assistance.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
Resources:
http://www.mayoclinic.com/health/macular-degeneration/DS00284
http://en.wikipedia.org/wiki/Macular_degeneration

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Categories
Diagnonistic Test

Chorionic Villus Sampling

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Definition
Chorionic villi are small structures in the placenta that act like blood vessels. These structures contain cells from the developing fetus. A test that removes a sample of these cells through a needle is called chorionic villus sampling (CVS).Chorionic villus sampling (CVS) is the removal of a small piece of placenta tissue (chorionic villi) from the uterus during early pregnancy to screen the baby for genetic defects
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CVS answers many of the same questions as amniocentesis about diseases that the baby might have. Diseases that can be diagnosed with CVS include Tay-Sachs, sickle cell anemia, cystic fibrosis, thalassemia, and Down syndrome. (Rh incompatibility and neural tube defects, however, can be diagnosed only through amniocentesis.) CVS can be done earlier in pregnancy than amniocentesis and can be done when there is not enough amniotic fluid to allow amniocentesis. However, it has some extra risks when compared with amniocentesis.

Why the Test is Performed
The test is a way of detecting genetic disorders. The sample is used to study the DNA, chromosomes, and enzymes of the fetus. It can be done sooner than amniocentesis, about 10 to 12 weeks after your last menstrual period. Test results take about 1 to 2 weeks, whereas amniocentesis results may take longer.

Chorionic villus sampling does not detect neural tube defects. If neural tube defects or Rh incompatibility are a concern, an amniocentesis will be performed.

This test can usually not diagnose problems in the way the body forms.

How the Test is Performed
CVS can be done through the cervix (transcervical) or through the abdomen (transabdominal). The techniques are equally safe when done by a provider with experience, although miscarriage rates are slightly higher when done through the cervix. The health care provider will use ultrasound to pick the safest approach and as a guide during sampling.

An abdominal ultrasound is performed to determine the position of the uterus, the size of the gestational sac, and the position of the placenta within the uterus. Your vulva, vagina, cervix, and abdomen are cleaned with an antiseptic such as Betadine.

The transcervical procedure is performed by inserting a thin plastic tube through the vagina and cervix to reach the placenta. The provider uses ultrasound images to help guide the tube into the appropriate area and then removes a small sample of chorionic villus tissue.

The transabdominal procedure is performed by inserting a needle through the abdomen and uterus and into the placenta. Ultrasound is used to help guide the needle, and a small amount of tissue is drawn into the syringe.

The sample is placed in a dish and evaluated in a laboratory.

What happens when the test is performed.
There are two ways that your doctor can perform CVS. Some patients have the sampling done through the vagina and cervix. Most patients have the sampling done through the abdominal wall. For both types of sampling, you lie on your back on an examination table and the doctor uses ultrasound to locate the fetus and the placenta.

If the sampling is to be done through the vagina and cervix, you place your feet in footrests and bend your knees up, as you would for a pelvic examination. A speculum (a device that looks like a duck-bill that can be opened and closed) is used to open the vagina so that your doctor can see inside. A long tube, much narrower than a straw, is inserted through the cervix and moved forward while your doctor watches on the ultrasound until it is next to the fetal side of the placenta. A small sample of the lining around the fetus is then pulled into the tube for testing.

If the sampling is to be done through the abdominal wall, your lower abdomen is cleaned with an antibacterial soap. In some cases, the doctor uses a small needle to inject a numbing medicine just under the skin, so that you do not feel the sampling needle. (Because the sampling needle does not cause much more stinging than the numbing medicine itself, not every doctor includes this step.) A hollow needle several inches long is inserted through the skin and muscle of the abdomen and through the wall of the uterus, to the edge of the placenta. This needle is held in place as a guide needle. A narrower needle is then inserted through the first needle and is rotated and moved inward and outward a number of times while a sample is collected into an attached syringe.

The fetal heart tones and the mother’s blood pressure and heart rate are checked at the beginning and end of the procedure. The whole procedure takes close to 30 minutes.

How to Prepare for the Test.
CVS can be done between the 10th and 13th weeks of pregnancy. Tell your doctor ahead of time if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist’s office.

Your health care provider will explain the procedure, its risks, and alternative procedures such as amniocentesis. Genetic counseling is recommended prior to the procedure. This will allow you to make an unhurried, informed decision regarding options for prenatal diagnosis.

You will be asked to sign a consent form before this procedure, and you may be asked to wear a hospital gown.

The morning of the procedure you may be asked to drink fluids and refrain from urinating to fill your bladder, which allows adequate visualization so the sample may be taken.

How the Test Will Feel
The ultrasound doesn’t hurt. A clear, water-based conducting gel is applied to the skin to help with the transmission of the sound waves. A handheld probe called a transducer is then moved over the area. In addition, your health care provider may apply pressure on your abdomen to find the position of your uterus.

The antiseptic cleansing solution will feel cold at first nd may irritate your skin if not washed off after the procedure. Some people are allergic to Betadine. Notify your health care provider if you are allergic to Betadine or if you have any other allergies.

Some women say the vaginal approach feels like a Pap smear with some discomfort and a feeling of pressure. There may be a small amount of vaginal bleeding following the procedure.

An obstetrician can perform this procedure in about 5 minutes, after the preparation

Risk Factors:

The risks of CVS are only slightly higher than those of an amniocentesis.

Possible complications include:

* Bleeding
* Infection
* Miscarriage
* Rh incompatibility in the mother
* Rupture of membranes

Signs of complications include:

* Excessive bleeding
* Excessive vaginal discharge
* Fever

The risk of miscarriage and other complications from CVS is slightly higher than the risk from amniocentesis, although some parents feel that it is worth the extra risk to be able to makedecisions earlier in the pregnancy if the results show the baby has a health problem. There have also been some reports that suggest there is a very small risk of birth defects (abnormal limbs) in the fetus.

One particular difficulty with this test is that due to variability in the cells of the placenta (called mosaicism), occasionally you can have an abnormal test result even if the baby is normal and healthy. This might lead you to make decisions about pregnancy termination that you would not have made if you had better information.

Some women have vaginal bleeding after the procedure. Infection is uncommon.

Report any signs of complications to your health care provider.

CVS may also cause limb problems in the fetus. This risk appears to be very low (1 in 3,000) when CVS is performed after 10 weeks gestational ag

Time to know the  result of the test
Chromosome analysis of the sample takes two weeks or more. The results of some tests may be available sooner.

RESULTS:-

Normal Results
A normal result means there are no signs of any genetic defects. However the test could miss some genetic defects.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

An abnormal result may be a sign of more than 200 disorders, including:

* Down syndrome
* Hemoglobinopathies
* Tay-Sachs disease

Considerations
If your blood is Rh negative, you may receive RhoGAM to prevent Rh incompatibility.
You will receive a follow-up ultrasound 2 to 4 days after the procedure to make sure the pregnancy is proceeding normally.

Resources:
https://www.health.harvard.edu/fhg/diagnostics/chorionic-villus-sampling.shtml
http://www.nlm.nih.gov/medlineplus/ency/article/003406.htm

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Categories
Diagnonistic Test

Amniocentesis

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Definition:
Amniocentesis (also referred to as amniotic fluid test or AFT), is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is extracted from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities
Tests of fetal cells found in this fluid can reveal the presence of Down syndrome or other chromosome problems in the baby. Amniocentesis can also show whether the lungs of the baby are mature enough to allow it to survive if it were elivered right away.

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Amniocentesis is often recommended for pregnant women over age 35, women who have an abnormal “triple screen” blood test during pregnancy, or women who have (or whose husbands have) a family history of certain diseases or birth defects.

How do you prepare for the test?

You should have a serious discussion with your obstetrician regarding whether to have amniocentesis. Amniocentesis may be done anytime between the 14th and 20th weeks of pregnancy to test for fetal abnormalities. To check on fetal lung development, the test may be done late in the third trimester.

Tell your doctor ahead of time if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist’s office.

Just before the test, you should empty your bladder.

How the test is performed ?
Before the actual procedure, a local anesthetic is sometimes given to relieve the pain when inserting the needle used to withdraw the fluid. A needle is usually inserted through the mother’s abdominal wall through the wall of the uterus into the amniotic sac. With the aid of ultrasound-guidance, a physician aims towards an area of the sac that is away from the fetus and extracts approximately 20ml of amniotic fluid for testing. The puncture heals, and the amniotic sac replenishes the liquid over a day or so. After the amniotic fluid is extracted, the fetal cells are separated from it. The cells are grown in a culture medium, then fixed and stained. Under a microscope the chromosomes are examined for abnormalities. The most common abnormalities detected are Down syndrome, Edward syndrome [Trisomy 18] and Turner syndrome [Monosomy X]. Amniocentesis is most safely performed after the 14th-16th week of pregnancy, does not need to be done before then due to risk it can to to the babys limbs. Usually genetic counseling is offered prior to amniocentesis.

What happens when the test is performed?
You wear a hospital gown and lie on your back on a table. An ultrasound is done to show the location of the fetus and placenta. Your lower abdomen is cleaned with an antibacterial soap. In some cases, the doctor uses a small needle to inject a numbing medicine just under the skin, so you do not feel the amniocentesis sampling needle later. (Because the sampling needle does not cause much more stinging than the numbing medicine itself, not every doctor includes this step.)

The hollow sampling needle is several inches long and is inserted through the skin and abdominal muscle and then through the wall of the uterus. A syringe attached to the needle is used to collect a sample of fluid.

The baby’s heart tones and the mother’s blood pressure and heart rate are checked at the beginning and end of the procedure. The whole procedure takes close to 30 minutes.

Risk Factors:
Although the procedure is routine, possible complications include infection of the amniotic sac from the needle, and failure of the puncture to heal properly, which can result in leakage or infection. Serious complications can result in miscarriage. Other possible complications include preterm labor and delivery, respiratory distress, postural deformities, fetal trauma and alloimmunisation (rhesus disease). Studies from the 1970s originally estimated the risk of amniocentesis-related miscarriage at around 1 in 200 (0.5%). A more recent study (2006) has indicated this may actually be much lower, perhaps as low as 1 in 1,600 (0.06%). In contrast, the risk of miscarriage from chorionic villus sampling (CVS) is believed to be approximately 1 in 100, although CVS may be done up to four weeks earlier, and may be preferable if the possibility of genetic defects is thought to be higher

Most women experience a few hours of mild pelvic cramping, and a few will have slight vaginal bleeding. About 1 in 100 women will have a temporary leak of amniotic fluid through the vagina; this usually causes no problem.

There is a small risk of miscarriage associated with amniocentesis; this occurs in about 1 in every 200 to 400 cases, depending in part on the timing of the test and the experience level of the physician performing it. Other risks (such as infection or injury to the fetus that does not cause miscarriage) are extremely rare.

What must you do after the test is over?
If the test confirms that you are Rh incompatible with the fetus, you will need to receive an injection of a medicine called Rh immune globulin (Rhogam) to protect the baby from complications.

Let your doctor know immediately if you are having any vaginal bleeding, fluid leakage, or strong abdominal pain.

Time to know the result:
Chromosome analysis of the fluid sample takes two weeks or more. The results of some tests may be available sooner.

Amniocentesis and stem cells:
Recent studies discovered that in amniotic fluid there are a lot of multipotent stem cell, mesenchymal, hematopoietic, neural,epithelial and endothelial stem cell[1][2][3]. Amniotic stem cells don’t have ethical problem. In fact, in harvesting embryonic stem cells, a human embryo is destroyed, and so it’s considered it immoral. Another potential benefit of using amniotic stem cells over those obtained from embryos is that they side-step ethical concerns among pro-life activists by obtaining pluripotent lines of undifferentiated cells without harm to a fetus or destruction of an embryo.

Artificial heart valves, working tracheas, as well as muscle, fat, bone, heart, neural and liver cells have all been engineered through use of amniotic stem cells [4]. Tissues obtained from amniotic cell lines show enormous promise for patients suffering from congenital diseases/malformations of the heart, liver, lungs, kidneys, and cerebral tissue

You may click to see:->HOW TO – Isolate amniotic stem cells from a placenta, at home

Resources:
https://www.health.harvard.edu/fhg/diagnostics/amniosentesis.shtml
http://en.wikipedia.org/wiki/Amniocentesis

http://healthlibrary.epnet.com/GetContent.aspx?token=7e9094f4-c284-4b3a-8f7c-867fd12b36ee&chunkiid=14762

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Categories
Diagnonistic Test

Percutaneous Transhepatic Cholangiography (PTCA)

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Definition:

Percutaneous transhepatic cholangiography (PTHC or PTC) is a radiologic technique used to visualize the anatomy of the biliary tract. A contrast medium is injected into a bile duct in the liver, after which X-rays are taken. It allows access to the biliary tree in cases where endoscopic retrograde cholangiopancreatography (ERCP) has been unsuccessful. Initially reported in 1937, the procedure became popular after a 1952 report in the English-language literature.

CLICK & SEE
It is an x-ray test that can help show whether there is a blockage in the liver or the bile ducts that drain it. Since the liver and its drainage system do not normally show up on x-rays, the doctor doing the x-ray needs to inject a special dye directly into the drainage system of the liver. This dye, which is visible on x-rays, should then spread out to fill the whole drainage system. If it does not, that means there is a blockage. This type of blockage might result from a gallstone or a cancer in the liver.

It is predominatly now performed as a therapeutic technique. There are less invasive means of imaging the biliary tree including transabdominal ultrasound, MRCP, computed tomography and endoscopic ultrasound. If the biliary system is obstructed, PTC may be used to drain bile until a more permanent solution for the obstruction is performed (e.g. surgery). Additionally, self expanding metal stents can be placed across malignant biliary strictures to allow palliative drainage. Percutaneous placement of metal stents can be utilised when therapeutic ERCP has been unsuccessful, anatomy is altered precluding endoscopic access to the duodenum, or where there has been separation of the segmental biliary drainage of the liver, allowing more selective placement of metal stents. It is generally accepted that percutanous biliary procedures have higher complication rates than therapeutic ERCP. Complications encountered include infection, bleeding and bile leaks.
Why the test is performed?
Bile is a by-product of protein metabolism. It is created in the liver and excreted into the intestines via the bile ducts. If bile cannot be removed from the body, it collects in the blood and is seen as a yellow discoloration of the skin and eyes (jaundice).

Also, the pancreas creates digestive fluids which drain via a common bile duct into the intestine, and thus obstruction can prevent the drainage of the fluids and may cause pancreatitis (inflammation of the pancreas).

A PTCA test can help identify whether a blockage is causing the jaundice and pancreatitis.

How do you prepare for the test?
Tell your doctor if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist’s office. Also tell your doctor if you could be pregnant. If you have diabetes and take insulin, discuss this with your doctor before the test.

Most people need to have a blood test done some time before the procedure, to make sure they are not at high risk for bleeding complications. If you take aspirin, nonsteroidal anti-inflammatory drugs, or other medicines that affect blood clotting, talk with your doctor. It may be necessary to stop or adjust the dose of these medicines before your test.

You will be told not to eat anything on the morning of the test so that your stomach is empty. This is a safety measure in the unlikely case you have a complication, such as bleeding, that might require repair surgery.

What happens when the test is performed?
You lie on a table wearing a hospital gown. An IV (intravenous) line is inserted into a vein in case you need medicines or fluid during the procedure. An area over your right ribcage is cleaned with an antibacterial soap. Then the radiologist may take a picture of your abdomen with an overhead camera. Medicine is injected through a small needle to numb the skin and the tissue underneath the skin in the area where the dye is to be injected. You may feel some brief stinging from the numbing medicine.

A separate needle is then inserted between two of your ribs on your right side. A small amount of xray dye is injected, and some pictures are taken that are visible on a video screen. Your doctor adjusts the placement of the needle until it is clear that the dye is flowing easily through the ducts (drainage tubes) inside your liver.

Because taking the x-ray pictures sometimes requires a significant amount of time, the doctor replaces the needle with a softer plastic tube. First, the syringe holding the dye is detached from the top of the needle, leaving the needle in place. The doctor then gently pushes a thin wire through the needle and into the duct where the needle has been sitting. Next the needle is pulled out, sliding over the outside end of the wire. The wire is left with one end inside the liver to hold the position where the needle had been. A thin plastic tube similar to an IV line is slid along the wire, like a long bead on a string, until it is in the same place where the needle was. The wire is then pulled out, and the dye syringe is attached to the tube.

More dye is injected through the plastic tube, and pictures are taken with the video camera as the dye spreads inside the liver. If there is no blockage, the dye drains out of the liver through the bile ducts and begins to show up on the x-ray in the area of your small intestine. Once all of the needed pictures have been taken, the plastic tube is pulled out, and a small bandage is placed over your side. The whole test usually takes less than an hour.

Risk Factors:
It is possible to have serious bleeding from this test. In some cases, blood leaks to the outside surface of the liver and causes a buildup of blood there. In other cases, blood can leak directly into the liver’s drainage system, in which case it might start showing up in your intestine, causing a bloody bowel movement. It is less likely that you could develop an infection after the test. The only soreness you are likely to have is at the skin surface where the needle went in. This should last for only a day or two.

In rare cases, the dye used in the test can damage your kidneys. This kidney effect is almost always temporary, but some people have permanent damage.

As with all x-rays, there is a small exposure to radiation. In large amounts, exposure to radiation can cause cancers or (in pregnant women) birth defects. The amount of radiation from the video x-ray in this test is very small-too small to be likely to cause any harm. (The people performing the test on you will wear lead shields, since they would otherwise be exposed to this radiation over and over, which could be more of a danger.)

Must you do anything special after the test is over?
Call your doctor right away if you have pain in your right abdomen or shoulder, fever, dizziness, or a change in your stool color to black or red.

How long is it before the result of the test is known?
You may be told a few early results of your test as soon as the test is done. It takes a day or two for the radiologist to review the x-rays more thoroughly and to give your doctor a full report.

RESULTS:-

Normal Result:-The bile ducts are normal in size and appearance for the age of the patient.

Abnormal Results:-The results may show that the ducts are enlarged, which may indicate the ducts are blocked. The blockage may be caused by infection, scarring, or stones. It may also indicate cancer in the bile ducts, liver, pancreas, or region of the gallbladder.

You may click & See:
*Blocked bile ducts
*Cholangitis (infection in common bile duct)
Special considerations:-
A PTCA may be done if an endoscopic retrograde cholangiopancreatography ( ERCP) cannot be performed or has failed in the past.

An MRCP (magnetic resonance cholangiopancreatography) is a newer, non-invasive imaging method, based on MRI, which provides similar views of the bile ducts.

Resources:
https://www.health.harvard.edu/fhg/diagnostics/percutaneous-transhepatic-cholangiography.shtml
http://en.wikipedia.org/wiki/Percutaneous_transhepatic_cholangiography
http://www.healthline.com/adamcontent/percutaneous-transhepatic-cholangiogram

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