Hepatic encephalopathy is brain and nervous system damage that occurs as a complication of liver disorders. It causes different nervous system symptoms including changes in reflexes, changes in consciousness, and behavior changes that can range from mild to severe.

Hepatic encephalopathy is caused by disorders affecting the liver. These include disorders that reduce liver function (such as cirrhosis or hepatitis) and conditions where blood circulation does not enter the liver. The exact cause of hepatic encephalopathy is unknown.

However, when the liver cannot properly metabolize and and turn poisons into harmless substances in the body, these poisons build up in the bloodstream. One substance believed to be particularly harmful to the central nervous system is ammonia, which is produced by the body when proteins are digested. Ammonia is normally made harmless by the liver. Many other substances may also accumulate in the body if the liver is not working well. They add to the damage done to the nervous system.

In people with otherwise stable liver disorders, hepatic encephalopathy may be triggered by gastrointestinal bleeding, eating too much protein, infections, renal disease, procedures that bypass blood past the liver, and electrolyte abnormalities (especially a decrease in potassium). A potassium decrease may result from vomiting, or treatments such as paracentesis or taking diuretics ("water pills").

Hepatic encephalopathy may also be triggered by any condition that results in alkalosis, low oxygen levels in the body, use of medications that suppress the central nervous system (such as barbiturates or benzodiazepine tranquilizers), surgery, and sometimes by co-occurring illness.

Disorders that mimic or mask symptoms of hepatic encephalopathy include alcohol intoxication, sedative overdose, complicated alcohol withdrawal, Wernicke-Korsakoff syndrome, subdural hematoma, meningitis, and metabolic abnormalities such as low blood glucose.

Hepatic encephalopathy may occur as an acute, potentially reversible disorder or as a chronic, progressive disorder associated with chronic liver disease.

• Changes in mental state, consciousness, behavior, personality
  • Forgetfulness
  • Confusion, disorientation
  • Delirium
  • Dementia
  • Changes in mood
  • Decreased alertness, daytime sleepiness
  • Decreased responsiveness
  • Coma
• Decreased self-care ability
• Deterioration of handwriting or loss of other small hand movements
• Muscle tremors
• Muscle stiffness
• Seizures (rare)
• Speech impairment
• Uncontrollable movement
• Dysfunctional movement
• Agitation

Neurological symptoms may change. Coarse, "flapping" muscle tremor may be observed during voluntary movement, such as when the person attempts to hold the arms out in front of the body .

Mental status examination will be abnormal, particularly cognitive (thinking) tasks such as connecting numbers with lines.

Liver disease may be known or may be suspected, and signs of liver disease such as jaundice (yellow skin and eyes) and ascites (fluid collection in the abdomen) may be noted. Occasionally, there is a characteristic musty odor to the breath and the urine.

Blood tests may be nonspecific, or may show liver failure.

• Blood chemistry may show low albumin, high bilirubin, or other abnormalities.
• Serum ammonia levels are usually high.
• Prothrombin time may be prolonged and not correctable with Vitamin K.
• CT scan of the head may be normal, or may show general atrophy (loss of tissue).
• EEG (a reading of electrical activity in the brain) shows abnormalities.

Hepatic encephalopathy is an acute medical condition that may become a medical emergency. Hospitalization is required.

The goals of treatment include life support, elimination or treatment of the causes, and removal or neutralization of ammonia and other toxins. Life support may include support of breathing or blood circulation, particularly if coma develops. The brain may swell, which can be life-threatening.

Causes must be identified and treated. Gastrointestinal bleeding must be stopped. The intestines must be emptied of blood. Blood breaks down into protein parts that are converted to ammonia. Treatment of infections, kidney failure, and electrolyte abnormalities (especially potassium) is important.

In patients with severe, repeated cases of encephalopathy, the patient may be told to reduce protein in the diet to lower ammonia production. However, dietary counseling is important, as too little protein in the diet can contribute to malnutrition. Specially formulated intravenous or tube feedings may be necessary for critically ill patients.

Lactulose may be given to prevent intestinal bacteria from creating ammonia, and as a laxative to evacuate blood from the intestines. Neomycin may also be used to reduce ammonia production by intestinal bacteria. Rifaximin, a new antibiotic, is also effective in hepatic encephalopathy.

Sedatives, tranquilizers, and any other medications that are broken down or released by the liver should be avoided if possible. Medications containing ammonium (including certain antacids) should also be avoided. Other medications and treatments may be recommended, with variable results.

Acute hepatic encephalopathy may be correctable, while chronic forms of the disorder often keep getting worse. Both forms may result in irreversible coma and death. Approximately 80% ( 8 out of 10 patients) die if coma develops. Recovery and the risk of repeated cases are variable.

• Brain swelling
• Brain herniation
• Progressive, irreversible coma
• Permanent nervous system damage (to movement, sensation, or mental state)
• Increased risk of:
  • Sepsis
  • Respiratory failure
  • Cardiovascular collapse
  • Kidney failure
• Side effects of medications (see the specific medication)

Call your health care provider if any change in mental state or other neurological problem occurs, particularly if there is a known or suspected liver disorder. Hepatic encephalopathy can rapidly get worse and become an emergency condition!

Treating liver disorders may prevent some cases of hepatic encephalopathy. Avoiding heavy drinking and intravenous drug use can prevent many liver disorders.

If there are any neurological symptoms in a person with known or suspected liver disease, call for immediate medical attention.