Foraging and eating wild mushrooms can result in liver failure and even death because mistaking toxic mushrooms for edible varieties is common, illustrates a case published in CMAJ (Canadian Medical Association Journal)

"Distinguishing safe from harmful mushrooms is a challenge even for mycologists," writes Dr. Adina Weinerman, Division of General Internal Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, with coauthors.

The case focuses on a previously healthy 52-year-old immigrant woman of Asian descent who had foraged for wild mushrooms in a local park with her husband, who had foraging experience in his native land. The woman presented with severe abdominal pain and gastrointestinal distress, and eventually required a liver transplant. She had brought samples of the mushrooms -- the toxic species Aminata bisporigera -- she had eaten.

People with poisoning from toxic mushrooms go through three phases. Gastrointestinal symptoms including pain, nausea, vomiting and diarrhea (within 6-24 hours after ingestion), is followed by a false "recovery" period in which the patient appears to improve. The authors caution that this temporary phase can result in premature discharge from hospital or emergency department. In the final phase, occurring 48 hours after ingestion, the patient's liver begins to fail, leading to multiorgan failure and potentially death.

There is no antidote for mushroom toxicity. Physicians caring for patients with this condition should provide aggressive care to combat symptoms, monitor liver function, consult a poison control centre for additional treatments and investigate liver organ donation in case of liver failure. Although charcoal can absorb the toxin, the delayed development of symptoms and presentation to an emergency department limits its efficacy because it needs to be administered promptly.

Foraging is becoming increasingly popular, and people need to be aware of the associated risks of misidentifying mushrooms. Mushrooms of the Amanita genus, which includes over 600 types, cause most deaths from mushroom poisoning.

"Patients should be counselled that poisonous and edible mushrooms can be very similar in appearance and that wild mushrooms of uncertain identity should not be eaten. This information is especially important for immigrants who might mistake local poisonous mushrooms for familiar edible species from their native land," conclude the authors.

They recommend that public health authorities be informed in case of poisoning so that they can locate the source of toxic mushrooms to prevent further cases of poisoning.

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