Clinical findings and kidney morphology in chronic kidney disease of unknown cause in India.

Abstract

Chronic kidney disease of unknown cause (CKDu) is an emerging health problem in India and other countries worldwide. However, clinical descriptions, including kidney pathology, are scarce. This is a descriptive case series of patients with CKDu from an endemic region in India, with a focus on clinical and biochemical characteristics, kidney biopsy findings, and environmental exposure. Patients with suspected CKDu, aged 20-65, and eGFR 30-80 mL/min/1.73 m² from rural areas with endemic prevalence of CKDu were included. The exclusion criteria were diabetes mellitus, uncontrolled hypertension, proteinuria >1 g/24 h, or other known kidney diseases. The participants underwent kidney biopsies, and blood and urine samples were collected. Fourteen participants (3 females, 11 males) with a mean eGFR of 53 (range 29-78) mL/min/1.73 m² were included. Kidney biopsies showed a combination of chronic tubulointerstitial damage, glomerulosclerosis, and glomerular hypertrophy, with varying degrees of interstitial inflammation. Eight participants had polyuria (diuresis ≥ 3 L/day). The urinary sediments were bland, with no haematuria. Serum potassium and sodium levels were, in most cases, normal but within the lower reference interval. The kidney morphology and clinical characteristics in patients with CKDu in India were similar to those described for CKDu in Central America and Sri Lanka.