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Starfruit Nephrotoxicity Oxalate — ESENeph MCQ

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ModerateAcute Kidney InjuryStarfruit Nephrotoxicity OxalateESENeph

A 30-year-old man presents with acute kidney injury and haemolytic anaemia after eating large quantities of starfruit (Averrhoa carambola). His creatinine is 320 umol/L. What is the nephrotoxic mechanism?

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Correct answer: A — Starfruit contains high oxalate concentrations AND a neurotoxin (caramboxin); the combination causes acute oxalate nephropathy and neurotoxicity (seizures, encephalopathy) – risk is dramatically increased in pre-existing CKD

Starfruit (carambola) is highly nephrotoxic due to its extremely high oxalate content (causing acute oxalate nephropathy with intratubular calcium oxalate crystal deposition) and caramboxin (a neurotoxin normally cleared by the kidneys). In patients with normal kidney function, toxicity is rare but can occur with massive intake. In patients with pre-existing CKD, even moderate starfruit consumption can cause life-threatening intoxication. Neurotoxicity includes intractable hiccups, seizures, and coma. Management is supportive with haemodialysis for severe cases.

Reference: Neto et al 2003 – Starfruit Nephrotoxicity; KDIGO 2012 – AKI