Alphaamanitin

Alpha-amanitin is a potent toxin in the amatoxin family produced by some poisonous mushrooms, most notably Amanita phalloides (death cap) and related species such as Amanita virosa. It is one of the most lethal mushroom toxins and is responsible for many mushroom poisoning deaths worldwide. Alpha-amanitin is a small cyclic peptide that is resistant to heat and cooking.

The toxin acts by inhibiting RNA polymerase II in eukaryotic cells, effectively stopping mRNA synthesis and transcription. This mechanism leads to cell death, with the liver and kidneys being particularly affected due to high toxin uptake in hepatocytes and renal cells. The toxin is absorbed from the gastrointestinal tract and undergoes enterohepatic circulation, contributing to prolonged toxic effects.

Clinical features typically begin 6 to 24 hours after ingestion. Initial symptoms include nausea, vomiting, abdominal pain, and severe diarrhea, which may lead to dehydration. After a brief improvement during a latent phase, patients can develop signs of hepatic failure, including jaundice, coagulopathy, hypoglycemia, encephalopathy, and potential renal dysfunction, usually within 2 to 7 days. The course can be fatal without treatment, and liver transplantation may be required in fulminant cases.

Diagnosis is based on history of mushroom ingestion and laboratory evidence of liver injury, with detection of amatoxins in urine or blood by specialized analytical methods. Management is primarily supportive and time-sensitive, including aggressive fluid and electrolyte management, decontamination if early, and consideration of antidotal therapy such as intravenous silibinin in many centers. Penicillin G has historically been used, though evidence varies. Prognosis depends on the amount ingested and the speed of medical intervention. Prevention focuses on avoiding ingestion of wild mushrooms and proper identification.