Idiopathic Hepatic Fibrosis
Hepatic fibrosis in young dogs that is not associated with any underlying inflammatory conditions is referred to as idiopathic hepatic fibrosis.
Affected dogs are usually <2 yr of age, but older dogs have been diagnosed with this disease. Three different categories have been described, based on the location of fibrosis. Excessive fibrosis around the centrilobular veins is referred to as central perivenous fibrosis, and German Shepherds appear to be predisposed. When fibrosis is intralobular, surrounding the hepatocytes, the condition is termed diffuse pericellular fibrosis. Again, German Shepherds are affected more commonly than other breeds. Periportal fibrosis is characterized as fibrosis in the portal areas. There appears to be no breed predisposition to periportal fibrosis.
Clinical signs are similar for all 3 forms and include ascites and hepatic encephalopathy due to portal hypertension and portosystemic shunting. Jaundice is uncommon, but may be present in dogs with diffuse pericellular fibrosis. Other signs include weight loss, vomiting, and diarrhea. Microcytic anemia, elevated AP and ALT, hypoalbuminemia, and markedly increased postprandial bile acids are common laboratory findings. Microhepatica is noted on radiographs, and portosystemic shunts can be identified by ultrasonography.
Symptomatic treatment for management of hepatic encephalopathy and ascites is recommended. The effect of antifibrotic therapy has not been thoroughly evaluated. Prognosis is guarded.