Histopathological Spectrum of Kidney Biopsies of Patients Presenting as Rapidly Progressive Renal Failure – A Retrospective Observational Study from Two Tertiary Care Centers

A BSTRACT Introduction: Rapidly progressive renal failure (RPRF) is a clinical diagnosis where a patient presents with rapid and progressive decline in the glomerular filtration rate (GFR) of at least 50% over a short period, ranging from days to weeks. The histopathological spectrum of various clinical presentations of renal dysfunction changes with time, age, and geographical factors. The main aim of this study was to understand the current histopathological spectrum of kidney biopsies of patients presenting as RPRF. Materials and Methods: This retrospective observational study was conducted at two tertiary care corporate hospitals situated in the northern part of India. All native kidney biopsies performed from July 1, 2022, to June 30, 2024, were reviewed for various variables. Results: 94 native kidney biopsies with a clinical history of RPRF were analyzed. The mean age of patients presenting as RPRF was 49.23 ± 1.72 years. The mean serum creatinine at the time of kidney biopsy was 5.82 ± 2.89 mg/dl. Seventy-five percent of patients had microscopic hematuria on presentation. The mean urinary protein–creatinine ratio was 1940 ± 1560 mg/g. Almost 45% of patients had hypertension as comorbidity, while only 19% had diabetes. The most frequent histological diagnosis was pauci-immune glomerulonephritis (26.6%) followed by both interstitial nephritis (20.2%) and IgA nephropathy (IgAN, 20.2%). Interestingly, one patient with collagenofibrotic glomerulopathy also had a rarely documented RPRF like presentation. Conclusions: This study provides information about the clinical and histopathological spectrum of RPRF, with pauci-immune glomerulonephritis being the commonest cause followed by IgA nephropathy. Kidney biopsy is an important tool for appropriate diagnosis and management in such cases.