The 'mushroom worker's lung' from Amanita phalloides poisoning is primarily caused by which toxin class, and what is the mechanism of death?
- A Amatoxins (alpha-amanitin) — RNA polymerase II inhibitors causing hepatorenal failure with delayed onset (6–24 hours) ✓
- B Muscarine — a nicotinic receptor agonist causing paralysis and apnoea
- C Ibotenic acid — a NMDA receptor agonist causing immediate seizures and death within 1 hour
- D Phallotoxins — actin polymerisation inhibitors causing immediate cardiac arrest
Explanation
Amanita phalloides ('death cap') contains amatoxins (primarily alpha-amanitin), which are heat-stable bicyclic octapeptides that specifically inhibit RNA polymerase II. This blocks transcription and therefore protein synthesis in all dividing cells, causing a characteristically delayed hepatorenal syndrome: GI symptoms start at 6–24 hours, followed by apparent improvement ('honeymoon phase'), then fulminant hepatic and renal failure at 48–96 hours. Muscarine causes cholinergic symptoms but is not the lethal component. Phallotoxins are poorly absorbed and not primarily responsible for systemic toxicity.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.