OVERVIEW

• severe toxicity from mushrooms is rare in humans
• most symptomatic presentations are a self-limiting gastroenteritis requiring supportive care only
• lethal hepatotoxicity from Amanita mushrooms must be excluded
  — very rare in Australia
  — accounts for most mushroom related deaths worldwide
• mushroom identification is very difficult and often impossible (e.g. unavailable, decomposing, cooked, partially digested)

EXPOSURE

• usually when wild mushrooms are misidentified as an edible species
• may present as clusters with more than one person poisoned

ASSESSMENT

EARLY ONSET (<6 HOURS)

Gastrointestinal, e.g. many mushroom species

• toxic mechanisms uncertain
• GI symptoms with onset 30min-3h and resolution in 6-24h

Cholinergic, e.g. Citocybe and Inocybe species

• muscarine-mediated
• 30min-2h: cholinergic syndrome

Hallucinogenic, e.g. Psilocybin spp

• psilocybin-mediated
• onset in minutes: anxiety, mydriasis, ataxia, tacycardia, dyskinesia, hallucinations, delirium

Disulfram-like; e.g. Coprinus  spp

• coprine-mediated
• <2h of mushroom ingestion with prior ethanol consumption, lasts 6 hours: N&V, flushing, tachycardia, sweating, chest pain

Glutaminergic, e.g. Amanita muscaria and panterina

• 30min-2h: delirium, dysphoria, drowsiness, haullcinations, myoclonus, hyperreflexia, seizures

Epileptogenic, e.g. Gyromitra spp

• gyromitrin-mediated symptoms
• <6h: GI symptoms
• CNS symptoms: headache, ataxia, fatigue, nystagmus, tremor, bertigo, seizures (rare)
• 2-3 days: delayed hepatotoxicity (rare)
• 1-3 days after hepatotoxicity: hemolysis and methemoglobinaemia

Immunohaemolytic, e.g. Paxillus spp

• <3h: GI symptoms
• days: hemolytic anemia, immune-complex nephritis and renal failure

Pneumonic, e.g. inhalation of dried Lycoperdonosis spores

• <6h: N&V, rhinitis
• days: pneumonia

LATE ONSET (6-24 HOURS)

Hepatotoxic, e.g Amanita, Galerina and Lepiota spp

• hepatotoxic cyclopeptides: amatoxins, phallotoxins and virotoxins
• 6-24h: GI symptoms
• 18-36h: transient improvement, asymptomatic transaminitis
• 2-6d: severe gastroenteritis, hepatic failure and pancreatitis

Erythromelagia

• acromelic acids
• 24-72h onset, with resolution over 8 day sto 5 months: burining pain, redness and sweeling of hands and feet, exacerbated by heat and cold

VERY LATE ONSET (>24 HOURS)

Nephrotoxic, e.g. Cortinarius  and A. smithiana spp

• orellanine-mediated
• 24-36h: geadache, GI symptoms, flank pain progressing to interstitial nephritis and renal failure

Rhabdomyolysis, e.g. tricholoma  and  Russula  spp

• onset 24-72h: fatigue, myaligias, muscle weakness and myocarditis (very rare)

INVESTIGATIONS

• guided by clinical assessment
• check LFTs and renal function first if GI symptoms present >6 hours after exposure
• consider: FBC, UEC, CMP, LFTs, coags, CK, glucose, ECG, blood gas and lactate
• mycologist examination of mushroom samples

MANAGEMENT

Resuscitation

• rarely necessary
• life-threats include:
  — gastroenteritis and hypovolemic shock
  — seizures or coma
  — cholinergic crisis

Supportive care and monitoring, may include:

• neurological observations for seizures, coma and paralysis
• delirium management
• glucose monitoring
• cardiac monitoring
• rehydration and antiemetics
• monitor LFTs for 48 hours if suspected cyclopeptide hepatotoxin

Decontamination

• activated charcoal 50g (1g/kg in children) if onset of GI symptoms occurs >6 hours post-ingestion

Enhanced elimination

• consider multi-dose activated charcoal if suspected cyclopeptide hepatoxicity as alpha-amantin undergoes enterohepatic circulation

Antidotes

• cyclopeptide hepatoxicity (e.g. GI symptoms onset >6 hours or increasing transaminases)
  — N-acetylcysteine
  — penicilin 1 MU/kg/day
  — silibinin 5 mg/kg IB over 1 hour then 20 mg/kg/day for up to 3 days
• cholinergic syndrome — atropine
• seizures due to Gyromitra  mushrooms — pyridoxine (similar management to isonizid toxicity)

Disposition

• discharge home if risk assessment does not predict severe toxicity and:
  — asymptomatic, or
  — early onset GI symptoms are resolving and patient is clinically well (check LFTs and renal function first if lasts >6 hours)
• observe in hospital:
  — significant symptoms
  — risk assessment predicts potential for severe toxicity
• admit to HDU/ ICU:
  — coma or CNS dysfunction
  — liver or renal failure (may require transfer to a specialist center)

References and Links

• Bedry R, Baudrimont I, Deffieux G, Creppy EE, Pomies JP, Ragnaud JM, Dupon M, Neau D, Gabinski C, De Witte S, Chapalain JC, Godeau P, Beylot J. Wild-mushroom intoxication as a cause of rhabdomyolysis. N Engl J Med. 2001 Sep 13;345(11):798-802. PMID: 11556299.
• Diaz JH. Syndromic diagnosis and management of confirmed mushroom poisonings. Crit Care Med. 2005 Feb;33(2):427-36. PMID: 15699849.
• Lima AD, Costa Fortes R, Carvalho Garbi Novaes MR, Percário S. Poisonous mushrooms: a review of the most common intoxications. Nutr Hosp. 2012 Mar-Apr;27(2):402-8. PMID: 22732961.
• Roberts DM, Hall MJ, Falkland MM, Strasser SI, Buckley NA. Amanita phalloides poisoning and treatment with silibinin in the Australian Capital Territory and New South Wales. Med J Aust. 2013 Jan 21;198(1):43-7. PMID: 23330770.