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Balints syndrome

Balints syndrome, originally described in 1909, is usually construed as the inability to see more than oneobject at the same time (simultanagnosia) and, therefore, as a deficit in visual attention. Balints originalcase report described two additional features: ocular apraxia, an inability to direct voluntary eyemovements; and optic ataxia, difficulty reaching for objects under visual guidance. Simultanagnosia

most commonly results from biparietal damage, but has also been reported with occipital and thalamiclesions.

Case history 6 An active, 60 year old retired maths teacher was having increasing trouble with herhobbies. She could no longer coordinate moves with her partner in country dancing, was unable to workout where to place the tiles in Scrabble, and kept missing lines when reading. She had difficulty placingthe cutlery correctly on the table and was unable to locate objects pointed out by her husband,although she felt there was nothing wrong with her eyesight. An MRI scan revealed bilateral, severe

atrophy of the parietal and occipital lobes.

Charles Bonnet syndrome

The Charles Bonnet syndrome is characterised by complex visual hallucinosis occurring in the context ofocular pathology, most commonly macular degeneration in the elderly. The patient typically sees vividimages of scenery, animals or people, often in the evening. Patients usually have full insight and are notgenerally distressed by the images. Many can stop their hallucinations by simple manoeuvres such asopening or closing the eyes. Functional imaging reveals activation of visual association cortices during

these hallucinations.8

Gamma-glutamyl transferase (GGT) is an enzyme that is found in many organs, such as the kidney, liver,gallbladder, spleen, and pancreas. Among these, the liver is the main source of GGT in the blood. Thistest measures the level of GGT in a blood sample.

GGT is increased in most diseases that cause damage to the liver or bile ducts. Normally, GGT is present

in low levels, but when the liver is injured, the GGT level can rise. GGT is usually the first liver enzyme torise in the blood when any of the bile ducts that carry bile from the liver to the intestines becomeobstructed, for example, by tumors or stones. This makes it the most sensitive liver enzyme test fordetecting bile duct problems.

However, the GGT test is not very specific and is not useful in differentiating between various causes ofliver damage because it can be elevated with many types of liver diseases, such as cancer and viralhepatitis as well as other non-hepatic conditions such as acute coronary syndrome.

For this reason, use of GGT is controversial, and guidelines published by the National Academy of ClinicalBiochemistry and the American Association for the Study of Liver Diseases do not recommend routine

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use of GGT. These guidelines do suggest, however, that it can be useful in determining the cause of ahigh alkaline phosphatase (ALP) level, another enzyme found in the liver.

Both GGT and ALP are increased in liver diseases, but only ALP will be increased with diseases affecting

bone tissue. Therefore, GGT can be used as a follow up to an elevated ALP to help determine if the highALP result is due to liver or bone disease.

GGT levels are sometimes increased with consumption of even small amounts of alcohol. Higher levelsare found more commonly in chronic heavy drinkers than in people who consume less than 2 to 3 drinksper day or who only drink heavily on occasion (binge drinkers). The GGT test may be used in evaluatingsomeone for acute or chronic alcohol abuse.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or evendifficult to manage, you might consider reading one or more of the following articles: Coping with TestPain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests,and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a bloodsample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

GGT levels fall after meals. You may be instructed to fast (have nothing to eat or drink except water) forat least 8 hours prior to the test. Alcohol and certain prescription medications can affect GGT levels, soyou may be asked to abstain from them prior to the test as well.

How is it used?

The gamma-glutamyl transferase (GGT) test may be used to determine the cause of elevated alkalinephosphatase (ALP). Both ALP and GGT are elevated in disease of the bile ducts and in some liverdiseases, but only ALP will be elevated in bone disease. Therefore, if the GGT level is normal in a personwith a high ALP, the cause of the elevated ALP is most likely bone disease.

The GGT test is sometimes used to help detect liver disease and bile duct obstructions. It is usually

ordered in conjunction with or as follow up to other liver tests such as ALT, AST, ALP, and bilirubin. Ingeneral, an increased GGT level indicates that a person's liver is being damaged but does not specificallypoint to a condition that may be causing the injury.

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A low or normal GGT test result indicates that it is unlikely that a person has liver disease or hasconsumed any alcohol.

A high GGT level can help rule out bone disease as the cause of an increased ALP level, but if GGT is low

or normal, then an increased ALP is more likely due to bone disease.

Is there anything else I should know?

Even small amounts of alcohol within 24 hours of a GGT test may cause a temporary increase inthe GGT

Smoking can also increase GGT.

Elevated GGT levels may be an indicator of cardiovascular disease and/or hypertension. Some studieshave shown that people with increased GGT levels have an elevated risk of dying from heart disease, butthe reason for this association is not yet known.

Drugs that may cause an elevated GGT level include phenytoin, carbamazepine, and barbiturates such asphenobarbital. Use of many other prescription and non-prescription drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs), lipid-lowering drugs, antibiotics, histamine receptor blockers (used totreat excess stomach acid production), antifungal agents, antidepressants, and hormones such as

testosterone, can increase GGT levels. Clofibrate and oral contraceptives can decrease GGT levels.

Levels of GGT increase with age in women, but not in men, and are always somewhat higher in menthan in women.

1. Can my GGT level be elevated if I don't have any symptoms?

Yes, GGT is very sensitive and can be increased when you don't have symptoms. This elevation may betemporary, perhaps due to medications that you are taking or alcohol ingested within 24 hours of the

test. If other liver enzymes are normal, your health practitioner may just wait and then repeat the GGTtest. If the GGT is very high and/or your other liver enzymes are elevated, it may be necessary to havemore extensive testing to identify the cause.

2. I am an alcoholic, but I have quit drinking. Will my GGT ever go back to normal?

Over time, your GGT level will fall from whatever level it was at when you stopped drinking alcohol towithin the normal range. This can take several weeks to more than a month. Abstaining from alcohol willdecrease your chances of further damaging your liver and should allow your liver function to improve.