Hepatic encephalopathy (HE) is a degenerative disease of the brain caused by severe hepatic insufficiency in advanced liver disease. It is characterized by abnormal mental status, an altered state of consciousness and impaired neurologic function.

The most common cause is a congenital abnormality present at birth called a portosystemic shunt. This is an anatomical defect that causes blood to be diverted around the liver instead of passing through the liver. The liver cannot detoxify the blood and the toxins reach the brain and cause the clinical syndrome. Patients with liver failure due to toxic or infectious causes can also exhibit signs of HE.

There is no age, sex, or breed predisposition for animals with toxic or infectious liver disease; however, animals with congenital portosystemic shunts are usually brought to the veterinarian within the first year of life.

What to Watch For

The clinical manifestations of HE can range from mild (unusual behavior) to severe (coma).

Hysteria

Unpredictable bouts of aggression

Staggering

Pacing

Compulsive circling

Pressing the head against a wall

Sudden apparent blindness

Tremors

Seizures

Coma-like state

These unusual behavior changes are often more pronounced a short time after a meal.

Also watch for:

Anorexia

Lethargy

Weight loss

Drinking a lot or urinating a lot

Nausea or hypersalivation (drooling)

Vomiting

Diarrhea