Hyperuricemia-Induced Acute Kidney Injury in the Context of Chronic Kidney Disease: A Case Report

Abstract

Hyperuricemia is an independent risk factor for acute kidney injury and chronic kidney disease. Hyperuricemia-induced acute kidney injury most commonly occurs in patients who experience tumor lysis syndrome. Herein, we report an unusual case of hyperu-ricemia-induced acute kidney injury via a crystal-dependent mechanism in a patient with chronic kidney disease. A 30-year-old Asian male patient was transferred to our hospital presenting with acute kidney injury and elevated blood uric acid level. The patient had a 5-year history of gout and 2-year history of chronic kidney disease. The pathological results of renal biopsy supported the diagnosis of focal proliferative immunoglobulin A nephropathy and subacute tubulointerstitial nephritis due to urate crystal deposition. After supportive treatment with prednisone acetate and febuxostat, the patient's proteinuria, serum creatinine, and uric acid levels decreased rapidly in the subsequent 2 months. Urate crystallization-induced acute kidney injury in patients with preexisting chronic kidney disease is unusually detectable in the clinic unless there are timely renal biopsy findings. In this case, the patient's condition improved and his renal function and serum uric acid levels recovered rapidly with prednisone acetate and febuxostat treatment. Early identification and close monitoring of uric acid levels and renal function are highly recommended for patients with chronic kidney disease. Renal biopsies should also be performed in a timely manner to identify the cause and initiate targeted therapy. We also briefly review the pathophysiology of acute kidney injury caused by hyperuricemia.