ACUTE OXALATE NEPHROTOXICITY SECONDARY TO STARFRUIT INGESTION

ABSTRACT

We present the case of a patient with acute kidney injury (AKI) associated with star fruit consumption, a very popular food in the tropics. A 69 year old male with a PMH of HTN, gout and stage 2 CKD presented to the Miami VA the day after visiting the Puerto Rico VA for hiccups and abdominal discomfort. He had been found to have an AKI but decided to seek care to the Miami VA instead of being admitted. He denied recent use of NSAIDs or antibiotics and had no changes in medication regimen. He had one self-limited episode of loose stools 2 days prior with no vomiting and had no urinary or neurologic complaints. His physical exam was normal for his age. Labs showed a Cr 4.5 (eGFR 13), a bland urinalysis, mild proteinuria, FeNa 4.1% (in context of chronic HCTZ use) and FeUrea 52.2%. Further testing showed negative SARS-CoV-2, hepatitis and HIV serologies, ANA(-), SPEP(-), UPEP(-), and normal complement levels. Imaging revealed normal appearance and size of kidneys, no hydronephrosis, and no urolithiasis. Given negative work-up, a kidney biopsy was performed revealing acute tubular injury with increased intratubular oxalate, mild to moderate interstitial fibrosis, moderate to marked arteriosclerosis, FSGS (likely secondary). Upon further questioning he reported consuming a large amount of star fruit the day before developing GI symptoms. He was discharged with close follow up, no renal replacement therapy was needed. Star fruit induced nephrotoxicity is a rare cause of AKI, however it should be suspected in patients with AKI and a recent consumption of large amounts of this fruit. Initial presentation includes nausea, vomiting, abdominal pain and hiccups. After ingestion, circulating free oxalates are filtered through the kidney where they can precipitate into calcium oxalate crystals and cause tubular obstruction. Demonstration of this through biopsy is diagnostic for this type of nephrotoxicity. Many patients need early renal replacement therapy, at least temporarily, but fortunately that wasn't the case in our patient. Oxalate nephrotoxicity should be suspected in patients presenting with AKI and recent consumption of starfruit.