Diagnosis of Amanita toxicosis in a dog with acute hepatic necrosis.

Poisoning with amanitin-containing hepatotoxic mushrooms demands extensive efforts from clinicians, toxicologists, and pathologists. Presumptive diagnoses are established by positive identification of the suspect mushroom along with the occurrence of consistent clinical signs. If the animal dies, hepatic lesions may suggest exposure to amanitin-containing mushrooms; however, lesions are nonspecific. A 15-week-old female Dachshund was presented to the referring veterinarian for acute onset of lethargy that quickly progressed to sternal recumbency. Despite supportive care, the dog remained lethargic and died approximately 12 hours after initial presentation. A pale tan liver was noted at necropsy. Microscopically, the liver showed panlobular coagulative necrosis of hepatocytes. A presumptive diagnosis of amanitin poisoning was based on suspect history of exposure to mushrooms, clinical signs, and pathologic findings. Exposure to amanitin was confirmed through detection of alpha-amanitin in the liver by liquid chromatography/mass spectrometry. The objective of this case report is to illustrate the essential components to a successful diagnostic work-up of a suspect case of hepatotoxic mushroom poisoning. Although hepatotoxic mushroom poisoning has been documented in dogs before, confirmatory techniques for biologic specimens have not been used previously in diagnostic investigations.