[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Kidney](https://durgical.com/en/general-pathology/areas/kidney/) › Patterns of glomerular injury

# 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.

Updated Nov 12, 2026

## Key points

- Hypercellularity: proliferating mesangial or endothelial cells, infiltrating leukocytes, or crescents.
- Crescent: proliferating parietal epithelium plus macrophages in Bowman space, triggered by fibrin leaking through ruptured capillaries.
- Thick capillary walls: deposits (membranous), new basement membrane (spikes, double contours) or diabetic thickening.
- Hyalinosis: glassy plasma proteins in the wall; sclerosis: excess matrix and collapsed loops, the end of the road.
- Diffuse ≥ half of glomeruli, focal

## 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.

## Memory aid

Count, crowd, coat, crust, scar: more cells, cells in Bowman space, thicker walls, glassy hyaline, then scar.

## 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.

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## Elsewhere in DurgiPedia

- [Glomerulus and the filtration barrier: podocytes, mesangium, JGA](https://durgical.com/en/histology/glomerulus-and-the-filtration-barrier-podocytes-mesangium-jga/)
- [Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram](https://durgical.com/en/general-pathology/special-stains-in-diagnosis-congo-red-prussian-blue-pas-ziehl-neelsen-gram/)
- [Immunohistochemistry: the principle and the markers to know](https://durgical.com/en/general-pathology/immunohistochemistry-the-principle-and-the-markers-to-know/)

## Connections

## Related 4

- [Immune mechanisms of glomerular injury](https://durgical.com/en/general-pathology/immune-mechanisms-of-glomerular-injury/)
- [Glomerular diseases: comparison table](https://durgical.com/en/general-pathology/glomerular-diseases-comparison-table/)
- [Crescentic (rapidly progressive) glomerulonephritis](https://durgical.com/en/general-pathology/crescentic-glomerulonephritis/)
- [Biopsy: excisional, incisional, core needle, punch and fine-needle aspiration](https://durgical.com/en/general-pathology/biopsy-excisional-incisional-core-needle-punch-and-fine-needle-aspiration/)

## Related conditions 5

- [Nephrotic syndrome](https://durgical.com/en/conditions/nephrotic-syndrome/)
- [Rapidly progressive glomerulonephritis (anti-GBM, ANCA)](https://durgical.com/en/conditions/rapidly-progressive-glomerulonephritis/)
- [Diabetic kidney disease](https://durgical.com/en/conditions/diabetic-kidney-disease/)
- [Focal segmental glomerulosclerosis](https://durgical.com/en/conditions/focal-segmental-glomerulosclerosis/)
- [Membranoproliferative glomerulonephritis](https://durgical.com/en/conditions/membranoproliferative-glomerulonephritis/)

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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](https://medlineplus.gov/ency/article/000484.htm) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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