Liver Necrosis Caused by Mushroom Poisoning in Dogs

Abstract

Mushrooms in Category A cause hepatic and renal damage after a prolonged latent period and are the most common cause of fatal mushroom poisonings in human beings. Category A is subdivided into 2 groups on the basis of the type of toxin produced. The genera Amanita and Galerina produce cyclopeptide toxins (Group I), and Gyromitra produces monomethylhydrazine toxins (Group II). Several Amanita species contain 3 kinds of cyclopeptide toxins: phallolysin, phallotoxins, and amanitins. 9 Of these toxins, only the amanitins play a significant role in poisonings. Mushrooms in categories B, C, and D have a rapid onset of clinical signs and effect the autonomic nervous system, central nervous system, and gastrointestinal tracts, respectively. Only one of the reported cases of mushroom poisoning in the dog was associated with a mushroom in Category A in which several animals were poisoned by ingesting Amanita phalloides. 6 Other mushrooms in this genus and category that have either been associated with human poisonings or contain amanitins are Amanita verna, Amanita virosa, Amanita bisporigera, and Amanita ocreata. 8 The purpose of this report is to describe the clinical and laboratory findings in 2 cases of canine mushroom poisoning. A 7-week-old male golden retriever had a sudden onset of extreme listlessness, ataxia, and petit mal seizures. The owner had observed the animal eating mushrooms on the day prior to onset of clinical signs. The puppy did not respond to intravenous Lactated Ringer’s solution and Valium and died within 6 hr of onset of clinical signs. Fresh and formalinfixed tissue, stomach contents, urine, clotted blood, and a mushroom were submitted to the diagnostic laboratory for evaluation. Strychnine was not detected in urine or stomach contents. The mushroom was identified as A. verna by a mycologist. The owner of the second case owned a small kennel and observed a sudden onset of yelping and a tense abdomen in a 12-week-old female Labrador retriever. The puppy became