Idiopathic acute hepatic disease in horses: 12 cases (1982-1992).

Acute hepatic disease was diagnosed in 16 horses during the study period. Twelve of those cases were characterized as idiopathic acute hepatic disease (IAHD). In 9 of the 12 (75%) cases of IAHD, the horses were female, and 7 of the 9 females were lactating and had been treated with tetanus antitoxin at parturition. Diagnosis of IAHD was based on anamnesis, clinical signs, and results of serum biochemical analyses, hepatic biopsy, and postmortem examination. Within 1 year of the illness, 75% (9/12) of the horses had died or had been euthanatized. Not all horses had the typical fulminant signs associated with IAHD and in those horses, serum biochemical analyses were particularly helpful in diagnosis. Because tetanus antitoxin administration seemed to be associated with IAHD, use of tetanus antitoxin is not without risk, and routine administration of tetanus antitoxin, particularly to parturient mares, should be discouraged.