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Infection-related glomerulonephritis (IRGN) is an immune complex-mediated acute glomerulonephritis that involves both in situ and circulating immune complexes associated with many non-renal infections with heterogeneous set of infectious foci. There has been a paradigm shift in the epidemiology of IRGN over the decades. From being a disease involving children with a good prognosis, it is now increasingly seen in adults where the majority of patients progress to CKD and ESRD. Studies from the Indian Subcontinent are few and retrospective in nature. We did a prospective study of biopsy-proven adults with IRGN to analyze the clinicopathological profile, outcome, and predictors of prognosis in our population.
It is a prospective observational study done between January 2023 to October 2023. The calculated sample size was 25 Biopsy-proven IRGN patients who were >18 years of age. Pregnant patients and those who had persistent hypocomplementemia for more than 3 months were excluded from the study.
The presence of underlying comorbid conditions such as DM, hypertension, CAD, alcoholism, and smoking were noted. All patients had the following investigations: CBC, RFT, LFT, Urine routine, C3 & C4. A thorough search for any active foci of infection was done in all patients.
All patients were followed up after 3 months and outcomes were measured as any one of the following ; (1) Normalisation of renal function - Complete Recovery
(2) Persistent renal dysfunction without dialysis dependency (3) Hemodialysis dependent.
Demographics:
Out of 25 patients, 18(72%) were more than 40 years of age. Mean age was 45 years. 16(64%) were males. Among comorbidities ,15(60%) had hypertension, 13(52%) had diabetes, 15(60%)were smokers, 9(36%)were alcoholic and 8(32%) had CAD
Clinical profile:
All 25(100%) patients presented with edema and proteinuria, 20(80%) had hematuria and 8(32%) had oliguria. 15(60%) presented with nephritic syndrome, 6(24%)with nephrotic syndrome, and 4(16%) patients with RPGN. Regarding foci of infection, 9(36%) had skin infection,4(16%) had LRTI,3(12%) had URI, 3(12%) had dental sepsis,2(8%) had UTI and in 4(16%) no foci could be identified.
Biopsy Findings:
All 25(100%) patients had endocapillary proliferation, and IF staining of IgG and C3. 8(32%) had IFTA of >25%. 8(32%) patients had underlying Diabetic Nephropathy. 6(24%) had crescents on biopsy.
Lab Findings at Presentation:
Among 25 patients,22(88%) had renal failure. Low C3 was seen in 22(88%) Low C4 was seen in 2(8%) 9(36%)had anemia and 6(24%) had hypoalbuminemia. Dialysis was given in 8(32%)
Outcomes at 3 months:
Complete recovery was seen in 16(64%) patients, Persistent renal dysfunction not requiring dialysis was seen in 4(16%) patients, and dialysis dependency was seen in 5(20%) patients
Risk factors predicting failure to achieve complete remission. Refer table 1
In our study, we have shown the varied clinicopathological manifestations of IRGN in our population subgroup and found that older age, diabetes mellitus, smoking, oliguria, RPGN, crescents, IFTA>25% with underlying diabetic nephropathy on biopsy, low hemoglobin, low serum albumin, and dialysis given at presentation were all associated with failure to attain complete recovery. A thorough evaluation for infective foci along with identifying patients at high risk of progression to CKD is vital to its management.