Patterns of glomerular injury
- Lesion
Glomeruli react to injury in only a few ways. Learning them, and the words for how much is hit, lets you read any kidney biopsy report.
What it is
Under the microscope a sick glomerulus can gain cells, thicken its capillary walls, collect glassy hyaline material or scar. These few reactions combine in each disease. The pathologist also says how widely they spread: in how many glomeruli (diffuse or focal) and in how much of each glomerulus (global or segmental). Light microscopy is always read together with immunofluorescence and electron microscopy.
Structure
- H&E and PAS show cellularity and matrix; silver (Jones) outlines basement membranes and spikes; trichrome shows deposits and scar.
- Immunofluorescence: granular (immune complexes) or linear (anti-GBM antibody) staining for IgG, IgA, IgM, C3, C1q, kappa and lambda.
- Electron microscopy: site of deposits (subepithelial, subendothelial, mesangial), basement membrane texture and foot process effacement.
- Crescents begin cellular, become fibrocellular and end fibrous, at which point they no longer recover.
Basic glomerular reactions and examples
| Reaction | What it means | Typical diseases |
|---|---|---|
| Mesangial hypercellularity | Mesangial cells and matrix increase | IgA nephropathy, mild lupus nephritis |
| Endocapillary hypercellularity | Capillaries filled with leukocytes and swollen cells | Postinfectious glomerulonephritis, lupus class IV |
| Crescents | Cells in Bowman space after capillary rupture | Anti-GBM disease, ANCA vasculitis, severe immune complex disease |
| Capillary wall thickening | Deposits or new basement membrane | Membranous nephropathy, MPGN, diabetes |
| Segmental sclerosis | Scar in part of the tuft | FSGS, healed injury of any cause |
| Global sclerosis | Whole tuft scarred | End-stage kidney, aging, nephrosclerosis |
Clinical notes
- The pattern predicts the clinical picture: proliferation and crescents give nephritic or rapidly progressive disease; wall and podocyte changes give nephrotic syndrome.
Test yourself
Think of the answer, then tap the question to see it.
What is the difference between focal and segmental?
Focal refers to the share of glomeruli involved (fewer than half); segmental to the part of a single glomerulus involved.
What triggers a crescent?
Rupture of glomerular capillaries lets fibrin and plasma into Bowman space, which drives proliferation of parietal epithelium and entry of macrophages.
Which stain outlines the glomerular basement membrane best?
A silver stain (Jones methenamine silver), with PAS as a second choice.
Elsewhere in DurgiPedia
- Glomerulus and the filtration barrier: podocytes, mesangium, JGA
- Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram
- Immunohistochemistry: the principle and the markers to know
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Glomerulonephritis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.