From recurrent flank pain to systemic oxalosis: a case of primary hyperoxaluria type 1 requiring dual organ transplantation.

INTRODUCTION AND

IMPORTANCE

Primary hyperoxalurias (PH) are rare autosomal recessive inherited disorders that disrupt the metabolism of glyoxylate and oxalate. The most common type, primary hyperoxaluria type 1 (PH1), is caused by a deficiency in the liver enzyme alanine-glyoxylate aminotransferase (AGT), leading to the overproduction and excessive urinary excretion of oxalate.

CASE PRESENTATION: On routine evaluation, the patient presented with deranged renal function and echogenic kidneys. Imaging via KUB X-ray revealed radio-opaque kidney stones, small shrunken kidneys, and nephrocalcinosis, indicating progression to end-stage kidney disease (ESKD). Additional systemic manifestations included increased lumbar bone density and pulmonary fibrosis. Diagnosis was definitively confirmed through elevated 24-hour urinary oxalate levels and genetic screening showing an AGXT gene mutation. This necessitated combined liver-kidney transplantation (CLKT): the liver graft provides the missing AGT enzyme to stop oxalate production, while the kidney graft replaces damaged organs and discontinues chronic dialysis.

CLINICAL DISCUSSION: PH1 must be suspected in pediatric patients presenting with recurrent urolithiasis or nephrocalcinosis, especially in clinical cases of consanguinity. Early interventions - high fluid intake, crystallization inhibitors, and pyridoxine - can help preserve kidney function. For patients reaching ESKD, combined transplantation is the most effective approach to correct the underlying metabolic error and stop oxalate accumulation.

CONCLUSION

This case highlights the diagnostic challenge of PH1, where the initial presentation with flank pain and urinary symptoms may mimic a urinary tract infection, placing the patient at potential risk of urosepsis if misdiagnosed or untreated. CLKT remains the definitive treatment in advanced disease.