Toxicology – Mushroom Poisoning

Source

Thousands of mushroom species exist, but only a relatively small number are known to be toxic. Most mushroom poisonings cause mild, self-limited gastrointestinal illness, although certain species can produce severe liver, kidney, neurological, or cholinergic toxicity.

Typical Presentation

A patient develops nausea, vomiting, abdominal discomfort, or other symptoms after eating wild-picked mushrooms. The timing of symptom onset is important: symptoms beginning within about 6 hours are generally associated with less dangerous exposures, whereas delayed symptoms may indicate potentially serious toxins such as amatoxins.

Clinical Features

Presentation varies according to the toxin involved:

• Allenic norleucine: Early GI illness followed by possible acute kidney failure.
• Amatoxins: Delayed gastrointestinal symptoms followed by severe liver injury and potentially fatal multiorgan failure.
• Coprine: Produces a disulfiram-like reaction when alcohol is consumed.
• GI irritants: Most common form; causes rapidly developing nausea, vomiting, abdominal cramps, and diarrhea.
• Gyromitrin: Delayed GI and neurological effects; seizures and liver or kidney injury may occur.
• Isoxazoles (muscimol/ibotenic acid): May cause agitation, unusual behavior, somnolence, or transient coma.
• Muscarine: Produces a cholinergic toxidrome with excessive secretions and other parasympathetic effects.
• Orellanine: Delayed gastrointestinal illness followed by kidney failure.
• Polyporic acid: Delayed neurological symptoms, weakness, and possible liver and kidney dysfunction.
• Psilocybin: Produces hallucinations and altered perception, usually with relatively rapid onset.

Mechanism of Action

There is no single mechanism because mushroom species contain different toxins. Effects may involve inhibition of cellular protein synthesis, cholinergic stimulation, neurotoxicity, or direct damage to the liver and kidneys.

Management

Treatment depends on the suspected toxin and is primarily supportive:

• Airway, circulation, fluid, and electrolyte management
• Activated charcoal may be considered after appropriate recent exposures
• Pyridoxine (vitamin B6) may be used for gyromitrin-associated seizures
• Atropine may be used for severe muscarinic/cholinergic symptoms
• N-acetylcysteine (NAC) and specialist-directed therapies such as silibinin may be considered in suspected amatoxin poisoning
• Severe liver or kidney failure may require advanced supportive care or transplantation evaluation

Key Points

• Most mushroom ingestions cause gastrointestinal symptoms only.
• Delayed onset of symptoms is more concerning than rapid onset.
• Amatoxin poisoning causes the majority of fatal mushroom poisonings.
• Amatoxins, orellanine, and allenic norleucine are particularly associated with delayed toxicity.