Encephalopathy is a container term for various conditions affecting the brain. Generally, it affects large parts of the brain (or the whole organ), instead of leading to identifiable focal changes.

There are numerous different forms of encephalopathy. A commonly occurring form is hepatic encephalopathy, which occurs in severe cirrhosis of the liver. A form of encephalopathy that has recently received a lot of coverage is bovine spongiform encephalopathy (BSE, "mad cow disease").

Symptoms and causes

Encephalopathy alters brain function and/or structure. It may be caused by infectious agent (bacteria, virus, or prion), metabolic or mitochondrial dysfunction, brain tumor or increased intracranial pressure, prolonged exposure to toxic elements (including solvents, drugs, radiation, paints, industrial chemicals, and certain metals), chronic progressive trauma, poor nutrition, or lack of oxygen or blood flow to the brain.

The hallmark of encephalopathy is an altered mental state. Depending on the type and severity of encephalopathy, common neurological symptoms are progressive loss of memory and cognitive ability, subtle personality changes, inability to concentrate, lethargy, and progressive loss of consciousness. Other neurological symptoms may include myoclonus (involuntary twitching of a muscle or group of muscles), nystagmus (rapid, involuntary eye movement), tremor, muscle atrophy and weakness, dementia, seizures, and loss of ability to swallow or speak.

Diagnosis

Blood tests, spinal fluid examination by lumbar puncture, imaging studies, electroencephalograms and similar diagnostic studies may be used to differentiate the various causes of encephalopathy.

Therapy

Treatment is symptomatic and varies, according to the type and severity of the encephalopathy. Anticonvulsants may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some patients. In severe cases, dialysis or organ replacement surgery may be needed.

Prognosis

Treating the underlying cause of the disorder may improve symptoms. However, the encephalopathy may cause permanent structural changes and irreversible damage to the brain. Some encephalopathies can be fatal.

Refence

• Adapted from http://www.ninds.nih.gov/health_and_medical/disorders/encephalopathy.htm