Elderberry The second, more important, category of mushrooms, which are responsible for 90% of mushroom-related deaths, are those typically associated with onset of symptoms that occur more than hours after ingestion The most important members of this group are those mushrooms that belong to the Amanita phalloides species With these mushrooms, after a latent period of many hours, GI upset appears Approximately 24 hours after ingestion, hepatic dysfunction appears, which may progress to fulminant hepatic failure Without liver transplantation, such patients generally die One other Amanita mushroom, A smithiana, causes symptom onset prior to hours, and then patients can develop renal failure more than 24 hours postingestion In areas where A smithiana can be found (the Pacific Northwest), risk stratification based on delayed onset of symptoms is not reliable Two compounds produce the toxic effects of A phalloides Phallotoxin acts first, causing nausea, vomiting, abdominal pain, and diarrhea Fever, tachycardia, and hyperglycemia may also occur during this stage The other toxin, amatoxin, causes renal tubular and hepatic necrosis Treatment of the gastroenteric phase includes fluid and electrolyte replacement If renal failure develops, dialysis may be necessary Hepatic damage after A phalloides ingestion may be attenuated by early use of repetitive activated charcoal, which appears to interrupt enterohepatic recirculation of amatoxin Additional therapies have shown mixed results in the treatment of A phalloides poisoning High-dose penicillin, Polymyxin B, cimetidine, N -acetylcysteine, thioctic acid, silibinin, prophylactic charcoal hemoperfusion, and other modalities await further investigation A regional poison control center may offer guidance with experimental therapies, but multiple-dose activated charcoal and vigorous attention to supportive care remain the standard For patients with poor prognosis, early referral for liver transplantation may be lifesaving SUBSTANCE USE CLINICAL PEARLS