Mushroom Intoxication

By Sue E. Turnquist, DVM, MS, PhD, DACVP (TVDIL)

Two cases of mushroom toxicosis recently have been diagnosed at the TVDIL. The first case involved a 2 year-old mixed breed dog that died following a brief course of vomiting and bloody diarrhea. The second case involved a 12 week-old Labrador Retriever puppy with a history of vomiting with death occurring within 24 hours of the onset of clinical signs. The submitting veterinarian noted that the owners had seen the puppy eat a mushroom. Both dogs had submassive to massive hepatic necrosis which is very typical for mushroom poisoning.

The recent hot weather and rain have produced optimal growing conditions for mushrooms. There are a number of different toxic species of mushrooms, but Amanita mushrooms are most commonly associated with fatal mushroom poisoning in humans and dogs. Amanita species account for 95% of the mushroom-related fatalities in humans, and Amanita phalloides, the death cap mushroom, is responsible for >50% of the human fatalities and most of the dog fatalities. These mushrooms produce cyclopeptides including amatoxins, phallotoxins and virotoxins.

Cyclopeptide poisoning has three distinct phases:

  1. The initial phase which lasts around 24 hours is centered on the GI tract and is characterized by profuse bloody
    diarrhea, vomiting, abdominal pain, dehydration, electrolyte abnormalities, hyperthermia, tachycardia and hypergly-
  2. Phase 2 or the latent phase lasts 12 to 24 hours and the serum alanine transaminase (ALT) and aspartate transaminase
    (AST) begin to rise. The dog may appear to recover during this phase.
  3. The often terminal phase 3 occurs 3 to 4 days after ingestion and is considered the hepatorenal phase. This phase
    is characterized by severe hepatic dysfunction, severe renal failure, cerebral edema, icterus, elevated serum hepatic
    enzymes, hypoglycemia, coagulopathies, hemorrhage, azotemia, metabolic acidosis and sepsis. Hepatic encepha-
    lopathy and coma can also occur.

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