Hepatic Encephalopathy

Hepatic encephalopathy is disruption of brain functions resulting from a liver failure. It is a common finding in patients with decompensated liver cirrhosis.

Causes

The liver is the main chemical factory of the body. It creates a variety of substances necessary for proper function of internal environment, blood clotting, immune system and nutrition. In addition, the liver is essential for processing, detoxification and removal of potentially harmful substances and metabolic products. Probably the most common cause of a liver failure is worsened liver cirrhosis, which can be caused by many factors, especially by chronic alcoholism. In such case, hepatic encephalopathy may combine with alcoholic dementia. Whatever is the cause of the liver failure, the consequences are similar. The body accumulates pollutants such as the nitrogen-containing waste products arising from the protein metabolism. The production of those waste products is significantly caused by metabolic activity of intestinal bacteria (intestinal microflora).

 

Note: Impairment of hepatic encephalopathy may be also caused by TIPS, which is a special tube put in the liver tissue allowing good flow of blood through the cirrhotic liver. Its use is indicated in portal hypertension with bleeding from esophageal varices or with ascites that does not respond to conservative therapy. The TIPS solves the portal hypertension, but by bypassing the liver tissue, any waste products absorbed from the intestines flow directly to the brain without contact with the liver tissue.

Symptoms

Nitrogenous waste products (such as ammonia) circulate in the blood and penetrate the brain damaging its cells. The deterioration of brain functions is usually gradual and inconspicuous. At first it may manifests with a mild confusion and forgetfulness, another typical symptom is disruption of the diurnal cycle (i.e. sleeping during the day and waking at night). The patient often suffers from a special type of hand tremor known as the flapping tremor. The consciousness deteriorates, there may be epileptic seizures and the process may end with coma and death. In acute hepatic failure, the symptoms may occur suddenly and worsen rapidly.

Diagnosis

Medical history should focus on the patient's symptoms. Liver damage may be confirmed by blood tests (elevated liver tests) and imaging methods (ultrasound). It is advisable to evaluate level of ammonium in the patient’s blood as it usually corresponds with symptoms of encephalopathy. A simple clinical test for evaluation of severity of encephalopathy is drawing simple pictures that make the patients more or less troubles. Computed tomography of brain may serve to exclude any other organic disease of the brain (such as subdural hematoma that is typical for chronic alcoholics).

Treatment

The hepatic encephalopathy is usually related to severe insufficiency of liver functions. The patient usually requires hospitalization and intensive therapy. It is essential to prevent constipation. When the stool stays in the digestive tract for a too long time, the intestinal bacteria have more time to metabolize its protein components to harmful nitrogen-containing waste products. We administer laxatives to achieve several thin stools per day. For the same reason, we may use some antibiotics that kill the intestinal microflora – we prefer antibiotics that do not absorb and have maximal effect right in the intestines. We usually prescribe hepatoprotective drugs that should protect the liver tissue but their effects are somehow controversial. In addition to the therapy of hepatic encephalopathy itself, we should focus on treating the liver failure and its causes.