Diet-induced hyperoxaluria: A case based mini-review

Oxalate nephropathy (ON) is a rare condition involving the precipitation of calcium oxalate crystals within the nephrons. Primary hyperoxaluria involves enzymatic defects in the metabolism of glyoxylate, while secondary hyperoxaluria includes dietary and malabsorption-related etiologies.

We discuss the case of a White male in his 80s who presented to the hospital with acute kidney injury on chronic kidney disease stage 4 in the setting of a new antibiotic prescription. Creatinine had increased to 4.2 mg/dL from a baseline of 2.2 mg/dL, with no etiology identified on urinalysis or renal ultrasound. Renal biopsy then revealed an acute tubular injury with intraluminal calcium oxalate crystals deposits, confirming a diagnosis of ON.

A detailed history revealed an excessive dietary intake of oxalate-rich foods, including nuts, and daily ingestion of 2 g of vitamin C. The patient was counselled on adjusting his diet and stopping vitamin C supplementation, which led his creatinine to return close to baseline 2 months post-discharge.

Thorough history-taking enables early recognition and timely interventions to possibly avoid hyperoxaluria from progressing to end-stage kidney disease (ESRD).