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45 year old male presents with nausea, vomiting, profuse diarrhea, and abdominal cramping  occurring 6-7 hours after eating a meal he cooked containing wild mushrooms he picked the day before. What is you diagnosis?

Additional Information

Answer: 

Amanita containing mushroom ingestion. Amanita phalloides ( aka: death cap) contains a highly potent hepatotoxin responsible for 90% of mushroom fatalities worldwide.

Foraging and misidentification for edible is the primary source of exposure. Obtaining a history of mushroom ingestion, identifiying species, and early treatment are critical to improve outcomes.

Gastrointestinal symptoms occurring 6 hours or later after eating a wild or unknown mushrooms should be considered a serious life threatening emergency. Assume to due to an amatoxin containing mushroom and start treatment.

Amanita phalloides have white, greenish,or yellow tinted caps, broad gills free from stem, white spores, a ring or skirt of tissue near top of stem, and most importantly a bulbous base that sits in a cup-like sac.

Amatoxins are highly potent cyclopeptides with a fatal dose in adults of 0.1 mg /kg (approx.1/2  mushroom). Amatoxins are found in all parts of mushrooms and are markedly stable, resistant to cooking, freezing, drying, enzymes, or pH changes. Alpha-amantin, one of the most powerful amatoxins, is rapidly absorbed in the gut and transported into hepatocytes by an organic anion transporting polypeptide (OATP1B3 transporter) where it irreversibly binds RNA polymerase II, preventing protein synthesis and causing cell necrosis.

Triphasic toxicity:

1. Delayed GI phase (6-24 hours) : Initially no symptoms for 6-12 hours followed by nausea, vomiting, profuse diarrhea, and abdominal cramping 
2. Symptomatic recovery (24-36 hours) with false sense of recovery: subclinical rise liver transaminases
3. Hepatorenal phase ( 3-7 days) : Acute liver and renal failure

 November 2025-March 2026 after a late average to above average rainfall which resulted in super blooms of wild mushrooms there was an outbreak of 39 cases of amatoxin mushroom poisoning in northern California resulting in 3 liver transplantations and 4 deaths.

Comprehensive Treatment Approach: No single antidote or consensus on treatment protocol 

• Decontamination: single or multi dose activated charcoal to bind toxin and disrupt enterohepatic recirculation
• Aggressive IV hydration:  promotes amatoxin elimination by kidneys and corrects GI volume loss 
• N-acetylcysteine (NAC): antioxidant effects, 21 hour protocol
• Silibinin (milk thistle extract) : prevents uptake of amatoxin by hepatocytes cells by inhibition OATP transporter.  Oral available at health food stores. In US, intravenous (branded  Legalon SIL) not available in hospitals but is available by contacting the FDA emergency investigational new drug program and manufacturer. 5 mg/kg loading dose over 1 hour followed by continuous infusion 20 mg/kg/day 
• Octreotide infusion: minimize gallbladder contraction and slow enterohepatic recirculation. 50 mcg/hour IV
• HD Penicillin: Used historically can be used as alternative OATP inhibitor. 1 million units/kg divided qid
• Cyclosporine:  Promising highly potent OATP1B3. Readily available in IV  5 mg/kg IV over 4-6 hours every 24 hours
• CRRT/HD 
• Liver transplant

References

Amanita Species mushroom poisonings-Northern California, November 2025-March 2026. Brandecker KJ, Haymanc, et al. MMWR Morb Mortal Wkly Rep 2026;75:258-263. DOI: https://dx.doi.org/10.15585/mmwr.mm7520a2

Cyclosporine as a novel treatment for amatoxin-containing mushroom poisoning: a case series. Mackenzie, C. A., Austin, E., Thompson, et al. (2022). Toxicology Communications, 6(1), 23–27. https://doi.org/10.1080/24734306.2021.2006957