Progressive Renal Function Deterioration and Severe Nephrosclerosis in Two Hyperuricemic Patients Despite Favorable Blood Pressure Control

Abstract

Nephrosclerosis shows an increasing trend as a disease, leading to the initiation of dialysis. The main cause of nephrosclerosis is hypertension, but factors that promote arteriosclerosis, such as aging, are also involved. In addition, hyperuricemia-associated renal injury is known to show renal pathological features of nephrosclerosis. We examined renal biopsy specimens from two patients who presented with hyperuricemia and rapid renal decline without hypertension or glomerulonephritis. Case 1 was a 59-year-old man. Hypertension was well-controlled with medication. Case 2 was a 41-year-old woman. She was previously diagnosed with renal injury and hyperuricemia during pregnancy. Case 1 showed a decrease in eGFR of 17 mL/min/1.73 m² over 2 years, and case 2 showed a decrease in eGFR of 5 mL/min/1.73 m² over 1 year, indicating a progressive decline in the renal function. In these cases, blood pressure was normal or well-controlled, with scanty urine findings. Renal pathological findings showed glomerulosclerosis and glomerulomegaly. Interstitial fibrosis and tubular atrophy were noted around the glomerulosclerosis. No vascular lesions were seen. Glomerulomegaly suggested the presence of glomerular hyperfiltration, and hyperuricemia was suspected as a cause of nephrosclerosis. The family history of renal disease was unclear, and the involvement of autosomal dominant tubulointerstitial kidney disease could not be ruled out. Renal injury associated with hyperuricemia is characterized by vascular lesions, nephrosclerotic lesions, and tubulointerstitial injury, but the pathogenesis remains unclear. The management of asymptomatic hyperuricemia with renal injury requires further study.