Encephalopathy refers to any disease of the brain that alters brain function or structure. Infections with bacteria, viruses or a protein called a prion that had become abnormal are among the many causes of this type of illness.

Specific forms of encephalopathy include:

• Hepatic encephalopathy. Occurs when the liver stops functioning properly and fails to metabolize or detoxify substances in the body.
  
  
• Transmissible spongiform encephalopathies (TSEs). These rare and deadly degenerative brain disorders are marked by tiny holes that make the brain appear “spongy.”

The main symptom of encephalopathy is an altered mental state. People may experience progressive memory loss and a decline in cognitive ability. They may become confused, disoriented and forgetful. Subtle personality changes may emerge, and patients may experience lethargy, seizures, inability to concentrate and progressive loss of consciousness.

In diagnosing encephalopathy, tests may be performed to help identify the specific underlying cause of the illness. These include blood tests, electroencephalograms (measures of brain’s electrical activity) and imaging studies such as magnetic resonance imaging (MRI).

Encephalopathy is a medical term used to describe any type of brain disease that alters brain function or structure. It has many causes, including infection with bacteria, viruses or a type of protein called a prion that is altered from its natural form. Infection with HIV can cause encephalopathy in some patients.

Encephalopathy can lead to serious complications that affect whole body systems. The complications include swelling of the brain (cerebral edema), irreversible neurological impairment and increased risk of certain medical conditions (e.g., respiratory failure, cardiovascular collapse, kidney failure). In some cases, patients may lapse into a coma that ends in death.

The forms of encephalopathy include:

• Hepatic encephalopathy. Occurs when the liver stops functioning properly and fails to metabolize or detoxify substances in the body. This allows toxic substances such as ammonia to build up in the bloodstream and to damage the central nervous system. There are many potential causes of hepatic encephalopathy, including infection and liver diseases such as cirrhosis.
  
  
• Transmissible spongiform encephalopathies (TSEs). These rare and deadly degenerative brain disorders are marked by tiny holes that make the brain appear “spongy.” They occur as a result of an abnormal version of a protein called a prion. Creutzfeldt-Jakob disease (CJD) is the best-known of the human TSEs. A newly recognized form is called variant Creutzfeldt-Jakob disease (vCJD). This is believed to result from consumption of beef contaminated with bovine spongiform encephalopathy (BSE), also known as mad cow disease. Other TSEs include kuru and Gerstmann Straussler Scheinker disease. People sometimes become infected with TSEs through contact with infected tissue, transplants (e.g., cornea), body fluids or contaminated medical instruments.

Many different factors can result in encephalopathy. Infection with a bacterium or virus may cause some forms of the condition. Some of the transmissible spongiform encephalopathies appear to be caused by sporadic mutations to proteins called prions in animals, specifically cattle, which are later eaten as meat. Despite the notoriety of these cases, only several hundred have occurred worldwide. Other causes include:

• Brain tumor or increased pressure in the skull
  
  
• Heredity (e.g., Gerstmann Straussler Scheinker disease)
  
  
• Lack of oxygen or blood flow to the brain
  
  
• Long-term exposure to toxic elements (e.g., drugs, industrial chemicals, radiation, etc.)
  
  
• Trauma
  
  
• Poor nutrition

The chief symptom of encephalopathy is an altered mental state. People may experience progressive memory loss and decline in cognitive ability. They may become confused, disoriented and forgetful. Subtle personality changes may emerge, and patients may experience lethargy, inability to concentrate and progressive loss of consciousness.

Other symptoms include:

• Dementia
• Loss of speech or swallowing ability
• Hallucinations
• Muscle atrophy and weakness
• Myoclonus (involuntary muscle twitching)
• Nystagmus (involuntary eye movement)
• Seizures
• Tremors

When these symptoms emerge, people are urged to seek immediate medical care.

In diagnosing encephalopathy, a physician will perform a complete physical examination and compile a thorough medical history.

Tests that may be performed to help identify the specific cause of a patient’s encephalopathy include blood tests, electroencephalograms (measures of brain’s electrical activity), sampling the cerebrospinal fluid surrounding the spinal cord (spinal tap), and imaging studies such as magnetic resonance imaging (MRI).

Treatment of encephalopathy often depends on the nature of patients’ symptoms and on the underlying condition that is causing the encephalopathy. For example, hospitalization usually is required for patients with hepatic encephalopathy to remove ammonia and other toxins from the body.

Medications such as anticonvulsants are prescribed to help control seizures. People with liver disorders that develop hepatic encephalopathy may require alterations to the diet (e.g., reducing excessive protein intake). Severe cases of encephalopathy that cause organ damage may result in the need for dialysis or transplant surgery to replace organs.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to encephalopathy:

1. How will I know if I have encephalopathy? Which signs should I watch for?
   
   
2. How will you diagnose encephalopathy?
   
   
3. What is the likely source of my encephalopathy?
   
   
4. What treatments do you recommend?
   
   
5. What is my prognosis?
   
   
6. Is it likely that I have permanent brain damage?
   
   
7. If my diagnosis is terminal, how quickly will my quality of life decline?
   
   
8. Are there certain activities I should I avoid during recovery?
   
   
9. How long will I need to rest?
   
   
10. What steps should I take to make sure I do not spread this illness to others?