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Balance & Mobility
Balance & Mobility Articles
Creutzfeldt-Jakob disease (CJD) is a rare, fatal brain disorder caused by prions. Prions are normal proteins that have changed their shape. Healthy proteins have a healthy shape, which allows them to function normally. The misshapen prion protein is unhealthy. Worse, the prion causes disease by making other proteins nearby change their healthy shape to the prion's unhealthy shape. In this way a prion makes more prions: it slowly turns healthy proteins into prions, too.
When symptoms eventually appear, CJD causes rapidly progressive dementia (mental decline) and involuntary jerking muscle movements called myoclonus. About 90% of people with CJD die within 1 year of diagnosis.
About 85-95% of cases of CJD are from sporadic mutations. The DNA in a brain cell is changed by the mutation, and makes an unhealthy prion protein. Less often, the mutation is hereditary (passed down from parent to child). Jewish people born in Czechoslovakia, Chile and Libya have a higher-than-average number of inherited cases of CJD. Inherited CJD does not cause symptoms until adulthood.
Prions also can be passed from an animal to a person, or from one person to another. Fortunately, it is hard to catch prion diseases. A type of CJD called "variant CJD" shows somewhat slower progression of brain injury and more psychiatric symptoms, and it tends to affect younger people. This type of CJD has been linked to eating beef from cattle with bovine spongiform encephalopathy (BSE), also called "mad cow disease." BSE is caused by prions.
In the 1990's, a small outbreak of variant CJD was described in the United Kingdom. It was caused by people eating beef infected with prions. Since then, changes in beef farming and processing practices have helped to limit the number of new cases.
It is extremely uncommon for CJD to spread from one person to another. However, in very rare cases CJD has been transmitted by a blood transfusion, by a medical procedure (because of contaminated equipment), by contaminated tissue (such as corneas that are used for transplant) or by injections of hormones extracted from human tissues.
Diabetic neuropathies are nerve disorders that affect people with diabetes. They occur more often in people with persistently high blood sugar levels.
There are several different diabetic neuropathies. They include:
Peripheral neuropathy. This is the most common type. It affects the longest nerves in the body. These nerves are part of the peripheral nervous system. This is the network of nerves that carry signals from your brain and spinal cord to the rest of your body and back.
The most common symptoms of peripheral neuropathy are numbness or pain in the feet and lower legs.
Autonomic neuropathy. This neuropathy damages collections of nerves that control your unconscious body functions. It may affect your digestion, your circulation and your sexual function.
Localized nerve failures (focal neuropathy). A nerve that controls a single muscle can lose its function. For example, focal neuropathy may cause problems with eye movement that result in double vision. Or it may cause drooping of one cheek.
Diabetic neuropathies occur in both type 1 and type 2 diabetes. They are most common in people whose blood glucose (blood sugar) levels are not well controlled.
Diabetic neuropathies can occur in people who have had diabetes for a short time. But they are most likely to affect those who have had the disease for more than a decade. It is also more common in people older than 40. Diabetics who smoke are especially at risk.
Diabetic neuropathy results from several changes in the nerves. But the specific cause of neuropathy is not completely understood. A persistently high concentration of blood sugar surrounding nerve cells definitely plays a role. The nerve cells must adjust their internal sugar content to be in balance with their surroundings. To do so, nerve cells make and store the sugar sorbitol. Sorbitol can gradually damage nerve cells.