Hepatitis is defined as degenerative/ inflammatory processes of the liver. The clinical manifestations associated with hepatic dysfunctions results from impairment in the maintenance of sugar levels, formation of plasma proteins, formation and excretion of bile salts and excretion of bile pigments, formation of prothrombin and detoxification and excretion of toxic substances including photodynamic substances.
Etiology: Depending on the etiology, liver dysfunction may be termed toxic hepatitis, infectious hepatitis, nutritional hepatitis, congestive hepatitis and parasitic hepatitis. Toxic hepatitis is caused by inorganic poisons like copper, arsenic, phosphorus, and organic poisons like carbon tetrachloride, hexachlorethane and chloroform. Poisonous plants like Lantana camara, and fungi Aspergillus flavus also cause hepatitis. Infectious hepatitis is caused by Chlamydia sp., Histoplasma or Salmonella sp. Nutritional hepatitis occurs due to methionine deficiency but is not very common in farm animals. Vitamin E and selenium deficiency also lead to hepatitis. Cobalt deficiency is a common cause of hepatitis in sheep. Congestive hepatitis occurs due to the congestive heart failure. Parasitic hepatitis is caused by liver fluke infestation and migrating larvae of Ascaris sp.
Clinical signs: Hepatitis is manifested by depression or excitement, anorexia to inappetance, jaundice, diarrhoea or constipation, muscular weakness, abdominal pain, ascites, photosensitization, haemorrhagic diathesis and recumbency. Nervous signs include head pressing, dummy syndrome and arching of back.
Diagnosis: Hepatitis is diagnosed by palpation, percussion, biopsy, and liver function tests including estimation of bile pigment level in urine and serum. Galactose tolerance test is done to evaluate carbohydrate metabolism. Enzyme function tests include analysis of AST (alanine animotransferase), SDH (sorbitol dehydrogenase), LDH (lactose dehydrogenase), argnisase and ALP (alkaline phosphatase). Measurement of icterus index is done to ascertain the severity of jaundice. Organic anion dye clearance/ retention test, glucose tolerance test, measurement of protein profile, radiological and liver biopsy examinations are also useful in its diagnosis. In canines, it can be detected by measuring levels of uric acid and blood ammonia.
Treatment: Protein and protein hydrolysate should be avoided. Diet should be rich in carbohydrate and low in protein and fat. Neomycin, chlorotetracycline and calcium can be given orally. Liver tonics may be given continuously either by oral route or by intramuscular injection.