Encephalopathy

Encephalopathy is a term used for any disorder of the brain that changes function or structure, according to the National Institute of Neurological Disorders and Stroke (NINDS). Encephalopathy may be caused by any number of reasons; the wide-ranging possibilities include:

• an infectious agent
• a brain tumor (Read about "Brain Tumors")
• pressure in the skull
• excessive exposure to toxic elements
• metabolic dysfunction
• a lack of blood flow or oxygen to the brain (Read about "Stroke")

Liver diseases and some digestive bleeding disorders can also result in encephalopathy. (Read about "The Liver") When the liver doesn't work the way it should to neutralize toxins in the body, those toxins can damage the brain. Liver and digestive conditions associated with encephalopathy include:

• cirrhosis (Read about "Cirrhosis")
• hepatitis (Read about "Hepatitis A" "Hepatitis B" "Hepatitis C" "Hepatitis D" "Hepatitis E")
• alcoholism (Read about "Alcoholism")
• gastrointestinal bleeding (Read about "Gastrointestinal Bleeding")

Liver disease may be suspected if there are other symptoms present, such as jaundice. (Read about "Jaundice")

Different tests can be used to help determine the cause of a patient's encephalopathy. These might include blood tests, imaging studies, spinal fluid examination and others. (Read about "Laboratory Testing" "Diagnostic Imaging")

The symptoms a patient suffers will depend on the type and severity of the encephalopathy. The main characteristic of any type of encephalopathy is an altered mental state, according to NINDS. Other common symptoms include:

• loss of memory and cognitive skills
• changes in personality
• lethargy
• loss of consciousness

Some patients may also suffer muscle twitching or jerking, seizures (Read about "Seizures"), tremors, weakness or dementia. (Read about "Dementia")

Treatment is aimed at controlling the symptoms, such as anticonvulsant medication to reduce seizures. When possible, treating the underlying cause of the disorder can also be successful. However, in some cases the changes and damage to the brain may be permanent. Some encephalopathies can even be fatal.

Transmissible spongiform encephalopathies

A dangerous type of encephalopathy includes the transmissible spongiform encephalopathies (TSEs). These rare disorders cause the brain to degenerate over time. They are characterized by microscopic holes that give the brain a "spongy" appearance. TSEs are also called prion diseases, because they are believed to be caused by abnormal versions of prion proteins. These proteins are found naturally in the body. In normal form, they are harmless. However, they can take on an abnormal infectious form, which causes disease.

There are three ways human TSEs can occur:

• sporadically (when some of the patient's normal prions spontaneously change into the infectious form)
• as hereditary diseases (Read about "Genetics")
• through transmission from an infected individual

This last way is unusual, as TSEs cannot be spread through the air or casual contact. Transmission would have to occur from contact with infected body fluids or tissue, or contaminated medical equipment.

The best known of the human TSEs is Creutzfeldt-Jakob disease (CJD). (Read about "Creutzfeldt-Jakob Disease") Even so, it is very rare, affecting only one person in a million every year. A new type of CJD, called variant CJD, was discovered in the mid-1990's and has been linked to "mad cow disease." (Read about "Mad Cow Disease") According to NINDS, researchers believe that variant CJD may have developed in humans from consumption of beef from cattle with an animal TSE called bovine spongiform encephalopathy, more commonly known as "mad cow disease."

The symptoms of TSEs are very much the same as other encephalopathies listed above, but may also include lack or coordination, insomnia, depression (Read about insomnia in "Sleep" "Depressive Illnesses") and confusion.

There is no cure for TSEs or even a treatment that can stop the progression of the diseases. They advance rapidly over a few months and sometimes years, and end with the patient's death. The only treatment is to help ease the symptoms and make the patient as comfortable as possible.