Always look beyond the stones: hyperoxaluria overlooked

We report a case which demonstrates the disastrous consequences of late diagnosis of hyperoxaluria in a 24-year-old woman with nephrocalcinosis, a staghorn calculus and recurrent urinary tract infections. Her initial management at another hospital included multiple percutaneous nephrostomies and lithropsies. Metabolic screening was not undertaken. Hyperoxaluria was finally diagnosed by elevated urine oxalate (1.235 mmol/24 h) and renal biopsy, by which time there was already significant reduction of renal function. A diagnosis of hyperoxaluria type I was confirmed by liver biopsy. Despite starting pyridoxine and crystallization inhibitors, her renal function deteriorated, requiring hemodialysis and she was referred for combined liver-renal transplantation. Clinical clues of primary hyperoxaluria type I are a positive family history or presentation with severe renal stones at an unusually early age. Irrespective of the above, all patients with first presentation of renal calculi should undergo metabolic screening, including urine oxalate.