Amatoxin poisoning from ingestion of Japanese Galerina mushrooms.

BACKGROUND: Although some Japanese Galerina species poisonings manifest as gastrointestinal symptoms followed by late-onset hepatorenal failure (phalloides syndrome), the toxin responsible for this has not been determined. CASE REPORT: We report a 6-year-old boy who developed characteristic cholera-like diarrhea and late-onset severe hepatic deterioration after eating mushrooms, later identified as a Galerina species, most likely Galerina fasciculata. A residual mushroom revealed alpha-amanitin. This account is the first known reported case of poisoning by Japanese Galerina species where an amatoxin was demonstrated to be responsible for the toxicity.