Skill Checkup: A 56-Year-Old Man With Primary IgA Nephropathy and Fatigue, Abdominal Pain, and Frothy Urine

A. Brent Alper, Jr, MD, MPH


May 01, 2023

A patient with IgA nephropathy who also has persistent polyuria usually has minimal-change light microscopic findings but does have IgA deposition with diffuse proliferative glomerular lesions apparent on immunofluorescence microscopy. Pathology generally shows mesangial and endocapillary hypercellularity, segmental sclerosis, and/or cellular crescents as well as presence of interstitial fibrosis and/or tubular atrophy.

In Alport syndrome, the glomerular basement membrane is irregularly thickened, and the central lamina densa is split and splintered into a heterogeneous network of strands, which enclose electron-lucent areas that may contain microgranulations. The epithelial aspect of the capillary wall is irregular, and epithelial foot processes are fused.

Thin basement membrane nephropathy biopsy results demonstrate cystic dilatation of the Bowman's capsule and atrophy of the glomerular tuft, with a thin glomerular basement membrane.

Renal biopsy in pyelonephritis often shows polymorphonuclear neutrophils in the tubules but may show focal glomerulosclerosis in advanced reflux nephropathy. In addition, xanthogranulomatous pyelonephritis must be distinguished from renal malakoplakia based on the presence of inclusions called Michaelis-Gutmann bodies in the latter.


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