Feline hepatic lipidosis is the most common feline liver disease in North America. It is characterized by the accumulation of fat in liver cells. The underlying causes and pathophysiologic mechanisms remain poorly understood. Various diseases have been concurrently associated with hepatic lipidosis, but in many cats an underlying cause is not found. Obesity does not appear to directly cause hepatic lipidosis in cats but seems to be a major predisposing factor in most cats with this disease. Hepatic lipidosis commonly affects obese, middle-aged cats. About 90% of affected cats were obese prior to onset of clinical signs and at presentation have lost 25-50% of their previous body weight. Usually, a behavioral or physical stress can be identified that caused the cat to stop eating for one to two weeks. Anorexia of several days to weeks is the most common clinical sign but lethargy, depression, jaundice, and vomiting are also common. Other symptoms include depression, salivation, and muscle wasting.

Clinical suspicion of liver disease is based on clinical signs and the results of blood tests. Diagnosis of hepatic lipidosis is confirmed by cytologic or histologic examination of a liver biopsy. The condition is reversible with aggressive nutritional support, but without treatment, hepatic lipidosis is fatal. Treatment requires intensive nutritional support for at least one month and many times longer. This involves the surgical placement of a feeding tube to provide adequate caloric requirements and administration of medications. Once the feeding tube is in place and vomiting is under control, most cats can be managed at home. The feeding tube is only removed once the cat is eating enough on his own to meet his daily energy requirements. About 65% of cats recover in 3-6 weeks. Some cats require intensive treatment for several months before spontaneous eating resumes and some patients succumb to underlying diseases. There does not appear to be permanent liver damage in cats that have recovered from hepatic lipidosis.

Idiopathic hepatic lipidosis is a common disease of cats characterized by triglyceride accumulation in liver cells, cholestasis, and liver failure. Prevention of obesity seems to be the best way to guard against hepatic lipidosis.