Objective: The first cases of acute renal tubulopathy related to Amanita proxima poisoning were described in 1994; the mushroom contains a toxin responsible for the allenic-norleucine syndrome, characterised by a kidney damage that occur earlier than in Cortinarius orellanus poisoning and generally improve with complete resolution within ten days.
Case report: A 45 years old woman was admitted to the hospital because of nausea, vomiting, and heartburn started the day before. Symptoms occurred eight hours after eating a single big wild mushroom; three friends who had the same meal were all asymptomatic. Twelve hours after the admission the woman became anuric and blood tests showed an impaired renal function: creatinine 13 mg/dL urea 240 mg/dL, AST 240 U / L, ALT 350 U / l. The patient was transferred to the nephrology unit of the Hospital Di Venere of Bari and the PCC of Milan was consulted. The toxicologist supposed a nephrotoxic syndrome caused by the consumption of Amanita proxima and sent a picture of the mushroom ingested to a mycologist who identified the specie as Amanita proxima Dumé, Bull (typical volva reddish-orange, ivory white hat, scaly stalk) sometimes mistaken for Amanita ovoidea. Haemodialysis was performed for five days followed by supportive care. Urine output gradually increased, serum creatinine decreased and Ast - Alt normalized.
Conclusions: Amanita proxima contains an allenic-norleucine toxin (different from orellanine for the absence of inhibition of alkaline phosphatase), responsible for the reversible kidney damage, characterised by tubulointerstitial nephritis with acute tubular necrosis and renal failure. Occurrence and seriousness of symptoms seem to be variable and dependent on the amount ingested.