Morphological Spectrum and Novel Necrotizing Crescentic Pattern in Microfilaria-Induced Renal Injury: A Case Series

Microfilarial infection is endemic in tropical regions, but renal involvement remains rare and under-recognized. The spectrum of biopsy-proven lesions is diverse, and its clinicopathological correlates are incompletely understood. We retrospectively analyzed renal biopsies that demonstrated intraglomerular microfilariae over a 6-year period. There were a total of seven patients (four males/three females; median age: 32 years, range 15-55). The presentations included nephrotic syndrome (2), acute nephritic syndrome (1), chyluria ± hematuria (2), and rapidly progressive renal failure (1). The biopsy spectrum showed non-proliferative glomerulonephritis (3), membranous pattern (1), amyloidosis (1), and crescentic lesions (2). Microfilariae were identified in glomerular (6) and peritubular (3) capillaries. DIF was positive in 3 (IgG and/or C3). All received diethylcarbamazine; 3 additionally received steroids. Clinical response was complete (4) and partial (3). Microfilaria-induced renal injury exhibits a wider morphological spectrum than previously recognized, including aggressive necrotizing crescentic glomerulonephritis. Awareness of this entity in endemic regions and timely institution of antifilarial therapy, with or without immunomodulation, can preserve renal function and improve outcome.