Quantitative morphometry of glomerulonephritis with crescents. Diagnostic and predictive value.

Histologic patterns in the glomerular tufts in "Glomerulonephritis with many crescents" take three main forms: (1) compression and sclerosis of glomeruli, (2) necrotizing glomerulitis, and (3) proliferation with or without exudation. In the third group, histologic differentiation between patients with poststreptococcal glomerulonephritis with many crescents (AGN) and those with nonstreptococcal rapidly progressive glomerulonephritis (RPGN) may be impossible. In a retrospective study, quantitative morphometry of glomeruli effectively separated three patients with AGN from two patients with RPGN after the usual histologic and electron microscopic observations had failed. Parameters studied were areas of tufts and crescents and total number of cells and granulocytes in tufts and crescents. Surface areas of tufts and crescents were separately determined by photographing glomeruli, projecting and tracing outlines of tufts and crescents, and cutting out and weighing the tracings. The cell density of glomerular tufts (cell per 1000-sq. mum. area) was significantly greater in AGN than in RPGN when either total cell densities (17.64 plus or minus 0.41 versus 13.63 plus or minus 0.30) or total cells minus granulocytes (16.39 plus or minus 0.50 versus 12.99 plus or minus 0.52) were compared. The cell density in the tufts was 120 and 70 per cent greater than controls in AGN and RPGN, respectively. Exudation of inflammatory cells is contributory but not the major cause of hypercellularity in AGN. Follow-up studies with biopsies showed marked resolution in two of three patients with AGN, with normal blood urea nitrogen levels and focal scarring in the third, whereas the two patients with RPGN had either extensive scarring and reduced renal function or required chronic hemodialysis.