CLINICOPATHOLOGICAL SPECTRUM AND OUTCOMES OF INFECTION-RELATED GLOMERULONEPHRITIS IN PEDIATRIC AND ADULT POPULATIONS: A THREE-YEAR SINGLE-CENTER EXPERIENCE FROM SOUTH INDIA

Infection-related glomerulonephritis (IRGN) continues to be an important cause of acute nephritic syndrome, particularly in tropical regions where infectious triggers are abundant and varied. The disease, once thought to be a post-streptococcal relic of childhood, now increasingly affects adults and the elderly, often in association with diabetes or chronic infections. Despite this epidemiologic shift, comparative data between pediatric and adult IRGN remain sparse. This study aimed to delineate differences in clinical presentation, renal pathology, and short-term outcomes among children and adults with IRGN, diagnosed over a three-year period in a tertiary nephrology center in South India.

A retrospective observational analysis was conducted on 90 patients diagnosed with IRGN between January 2022 and June 2025. Institutional ethical committee approval was granted as per local policy. Demographic details, presenting symptoms, laboratory data, renal biopsy findings, treatment modalities, and outcomes were collected from institutional records. Patients were categorized as Pediatric (<18 years) and adult (≥18 years). Renal biopsy was performed in 56 cases with atypical or severe presentation. Histopathologic patterns were classified based on light microscopy, and immunofluorescence findings were noted when available. Outcomes were assessed at three months post-presentation and categorized as complete recovery, progression to CKD, or death.

The study included 53 pediatric (59%) and 37 adult (41%) patients. Mean ages were 9.1 ± 4.3 years and 43.5 ± 16.8 years, respectively. Males predominated in both groups (64% vs 57%). Infection sites include skin, urinary, tonsillar, respiratory and specific background infections (e.g., Varicella, Koch’s, leprosy, dengue).Fever (56%), dysuria (48%), and edema (45%) were common presentations, while skin or throat infections preceded renal symptoms in nearly one-third of cases. The median urine protein-creatinine ratio was 4.0 (IQR 2.6–5.4). C3 status distribution is significantly different between age groups (p = 0.00053).Among those biopsied, diffuse proliferative glomerulonephritis (DPGN) was the predominant pattern (~45% in both groups). Crescentic lesions were observed in 6 pediatric and 2 adult biopsies. C3-dominant deposits, occasionally accompanied by IgG or IgA, were the hallmark finding on immunofluorescence. Tubulointerstitial inflammation was common and occasionally severe.Renal replacement therapy (RRT) was required in 13 patients (14%), with a higher frequency among adults (11 vs 2 children, p<0.05). Notably, adults often presented with more pronounced azotemia and delayed recovery.At follow-up, 52 of 53 children (98%) achieved full recovery, while one succumbed to infection. In the adult group, 35 (95%) recovered, one developed CKD, and one was lost to follow-up.

Over a three-year period, IRGN in this South Indian cohort spanned all ages and maintained its male predominance. DPGN remained the commonest pattern, yet crescentic and tubulointerstitial variants signaled more severe disease. Prompt infection control and supportive renal care ensured excellent short-term recovery, particularly among children. Adults, however, warrant vigilant follow-up to monitor for residual dysfunction and CKD evolution.