[Primary liver disease in the horse].

The clinical signs of liver disease are highly variable and non-specific. Irrespective of the cause or the duration of liver disease, more specific clinical signs, e.g. hepatic encephalopathy, become apparent in the advanced stages of the disease. Due to the non-specific clinical signs, the possible diagnosis of liver disease is frequently not taken into consideration. However, measurement of the plasma or serum concentrations of total bile acids and gamma glutamyl transferase (gamma GT) may provide valuable diagnostic information. The specific diagnosis can be confirmed by ultrasound examination of the liver and histological examination of a liver biopsy specimen. The most frequently documented liver diseases are acute hepatic necrosis, chronic hepatitis caused by pyrrolizidine alkaloids, cholelithiasis, and haemochromatosis. Immediate treatment with antibiotics and polyionic fluids, in association with supportive nutritional care, is usually necessary to maintain the horse until sufficient liver regeneration occurs to provide adequate function. The use of corticosteroids is contraindicated, except for patients with chronic active hepatitis. In some cases, e.g. portosystemic shunts or cholelithiasis, surgical intervention is indicated. Liver disease may be more common than is currently appreciated since little accurate information on the prevalence or incidence is available.