The most dangerous type of mushrooms contain hepatotoxic cyclopeptides, including amatoxins (most toxic), phallotoxins, and virotoxins. These include Amanita phalloides (death cap or death angel), A ocreata (angel of death), Galerina spp, and Lepiota spp. This class of mushroom results in 95% of mushroom-related fatalities in humans and the most fatalities worldwide.5 When ingested, amatoxins are taken up by hepatocytes via the sodium-dependent transport system and inhibit nuclear RNA polymerase II, which results in decreased protein synthesis and secondary cell death.5 Three phases of toxicosis are seen: severe GI signs (hypersalivation, vomiting, diarrhea, abdominal pain) within 6–24 hours; a false recovery period (12–24 hours); and a hepatorenal phase (36–72 hours postexposure).5,6 Kidney failure can develop as a result of proximal and distal tubular necrosis several days later.5
Related Article: The Case: Suspected Amanita spp Mushroom Poisoning
Along with appropriate clinicopathologic monitoring and symptomatic supportive care, treatment includes early decontamination (emesis induction if appropriate, followed by multiple doses of activated charcoal); fluid therapy (crystalloids, colloids); GI support (antiemetics, antacids); treatment for coagulopathy if indicated (vitamin K1 therapy, plasma transfusions); treatment for hepatic encephalopathy (lactulose, neomycin, anticonvulsants); hepatoprotectants (silibinin, S-adenosyl methionine, N-acetylcysteine). Peritoneal dialysis5 and parenteral penicillin G benzathine2,3 have also been reported to yield sucessful results in humans. Acute hepatic failure is more commonly seen in dogs than acute kidney injury; once signs of severe organ injury develop, prognosis is poor to grave.