What causes liver encephalopathy?
The mechanism and cause of liver encephalopathy is not known. However, several factors are believed to be important in the pathogenesis of this disease. The most important two factors are liver cell failure and portal hypertension. This results in intrahepatic and extrahepatic shunting of portal venous blood into the systemic circulation so that the liver is largely
bypassed. As a result of these processes, various toxic substances absorbed from the intestine are not detoxified by the liver and lead to metabolic abnormalities in the central nervous system (CNS).
Liver 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 bypasses the liver. The exact cause of the disorder is unknown.
The liver cannot properly metabolize and detoxify substances in the body. Accumulation of toxic substances causes metabolic abnormalities that lead to damage in the central nervous system (brain and spinal cord). One substance believed to be toxicis ammonia, which is produced by the body when proteins are digested, but normally is detoxified by the liver. Many other substances also accumulate in the body and damage the nervous system.
In people with otherwise stable liver disorders, liver encephalopathy may be triggered by episodes of gastrointestinal bleeding, excessive dietary protein, electrolyte abnormalities (especially decrease in potassium, which may result from vomiting or treatments such as diuretics or paracentesis), infections, renal disease, and procedures that shunt blood past the liver.
The disorder may also be triggered by any condition that results in alkalosis (alkaline blood pH), low oxygen levels in the body, use of medications that suppress the central nervous system (such as barbiturates or Benzodiazepine tranquilizers), surgery, or possibly a coincidental illness. |
