Hepatic (liver) encephalopathy is a brain disorder caused by liver disease, including abnormal circulation. The liver plays a major role in food, vitamin, and hormone metabolism, which means it changes these substances into forms the body can use or into forms that allow easy removal to sustain normal body harmony. The word metabolism literally means change. The liver is like a chemical plant that continually changes numerous substances from one form into another that affects the body. The liver also contributes to various immune and blood-clotting activities, stores ingredients for future use, and plays a major role in digestion. Without the liver, the body would be fatally poisoned; the liver has the capacity to reduce many poisonous substances to harmless forms.
Normal circulation transports blood from the intestinal tract, through the liver, and into the large major vein, the caudal vena cava, which then carries blood toward the heart. Abnormal circulation transports blood from the intestinal tract (bypassing the liver) and carries unchanged poisonous substances directly into the caudal vena cava, through the heart, and distributes them to all parts of the body, including the brain. These bypasses are called shunts, and the portocaval shunt is one common type.
Some signs of hepatic encephalopathy include digestive and brain disorders, ranging from vomiting, diarrhea, loss of appetite, seizures, hypersensitivity, and excessive salivation (especially in cats).
Important Points in Treatment
1. Blood tests, radiographs (x-rays), blood contrast studies, such as angiography, and exploratory surgery are some of the procedures used to help diagnose hepatic encephalopathy.
2. Surgical treatment is more commonly used and has a higher success rate than non-surgical treatment. Surgical success varies, depending on the location of the shunt. There are intrahepatic (inside the liver) shunts and extrahepatic (outside the liver) shunts. The latter have a better prognosis (medical forecast) than intrahepatic shunts. Medical (non-surgical) management does have its purpose, especially in higher risk surgical patients.