Laboratory confirmation of Amanita smithiana mushroom poisoning.

CONTEXT: Here we present a case of Amanita smithiana poisoning resulting in acute kidney injury requiring dialysis, and highlight laboratory methods used to confirm the diagnosis. Identification of Amanita smithiana toxin using thin-layer chromatography can provide greater diagnostic certainty than history and renal function tests alone. CASE DETAILS: A 63-year-old male presented to hospital with anuria and gastrointestinal symptoms, two days after consuming a soup of wild mushrooms he had picked. He was found to be in acute renal failure, requiring hemodialysis. After nine days of supportive treatment, he recovered renal function, and was discharged in good health 15 days post-ingestion. The patient provided a sample of leftover soup, and examination of cooked mushroom fragments by a mycologist provided preliminary identification of A. smithiana. Thin-layer chromatography revealed the presence of A. smithiana toxin in the soup, confirming this identification. DISCUSSION: A. smithiana is a nephrotoxic mushroom that can be easily mistaken for the edible and highly prized Pine mushroom (Tricholoma magnivelare). It causes initial gastrointestinal symptoms, followed by acute renal failure. Treatment includes dialysis and supportive care until the patient recovers renal function. The chemical structure of the A. smithiana toxin is unknown, but it can be identified as a characteristic spot on thin-layer chromatography.