POS-415 ELECTRON MICROSCOPY: THE GOLDEN WEAPON FOR GLOMERULAR DISORDERS

Abstract

Worldwide glomerular disorders (GD) constitute one of the major causes of end-stage renal disease (ESRD). Its spectrum varies in comparison to developing countries compared to developed countries. The definitive diagnosis of requires histopathological evaluation of renal biopsy by light microscopy (LM), immunofluorescence (IF), and electron microscopy (EM). Nowadays, EM has become the standard of care practice for the evaluation of GD. The objective of this study was to analyze the role of EM for an accurate diagnosis. This was a cross-sectional study conducted in patients of age group 18-65 years presenting at a tertiary care center in North India from August 2018 to January 2020. A total of 200 consecutive renal biopsies were performed and were subjected to LM, IF, and EM. IF was performed in 100% cases and EM done in 75.5% cases. The most common indication of kidney biopsy was nephrotic syndrome (44%). Primary glomerular disorder (PGD) observed in 62% of cases. The most common PGD was IgA nephropathy [IgAN (18.5%)], followed by focal segmental glomerulosclerosis [FSGS (16%)], membranous nephropathy [MN (10%)], minimal change disease [MCD (5%)], membranoproliferative glomerulonephritis [MPGN I (2.5%)], C3 glomerulonephritis [C3GN (4%)], Crescentic GN (2.5%), diffuse proliferative GN [DPGN (2%)], IgM nephropathy [IgMN (0.5%)] and miscellaneous (1%). Secondary glomerular disorders (SGD) accounted for 21% of cases. Lupus nephritis was the most common SGD. Vascular (5.5%), tubulointerstitial disorders (9%), and ESRD (5%) were less prevalent. MCD was the most common GD in patients less than 20 years, while IgAN was most common in patients 21-50 years, followed by FSGS. Above 51 years, FSGS was the most common GD, followed by MN. In 62% of cases, the diagnosis of glomerular disease was based on LM and IF findings alone. Discrepant IF findings were obtained in 5.5% cases. In 9% of cases, EM contributed to the diagnosis. EM was essential for the final diagnosis in 23.5% of the cases. Table 1: Case series evaluation based on EM Tabled 1CategoriesLM + IFDiscrepant IFUseful EMEssential EMTotal(A). PGD124MCD2-810FSGS18111232MN1323220DPGN1-214MPGN (MPGN I / C3GN/ DDD)2/2/-1/-/--/2/-2/4/-5/8/0CresGN5---5IgAN2362637IgMN1---1Miscellaneous1--12(B). SGD42LN812415DN8-2414AA10-1-11MM2---2HSP----0(C). Vascular Nephropathy11HUS----0TMA1-214HN1-124CAN3---3(D). Tubulo-interstitial nephritis (TIN)18Acute TIN10---10Chronic TIN5---5ATN3---3(E). ESRD5---5TOTAL (%)124 (62%)11 (5.5%)18 (9%)47 (23.5%)200 Open table in a new tab The incidence of IgAN and FSGS has increased significantly over the last decade, especially in developing countries. This study has provided comprehensive information about the changing spectrum of GD in adults with a focus on EM as a routine standard of care practice.