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Rapidly Progressive Glomerulonephritis

Glomerulonephritis subacuta

For medical students2 min readUpdated 2026-10-10

Rapidly progressive glomerulonephritis (RPGN), or crescentic glomerulonephritis, is a severe renal syndrome characterized by a rapid and swift decline in kidney function. The condition quickly leads to renal failure and has a key morphological hallmark: the formation of epithelial crescents.

Key FindingEpithelial crescents in glomeruli

RPGN CategoriesDivided into 3 main groups

Electron MicroscopyGlomerular basement membrane ruptures

PrognosisDevelopment of renal failure within weeks

Pathology and Classification

The condition manifests with a sharp drop in renal blood flow, glomerular filtration rate (GFR), and urine output. Clinically, the process is accompanied by severe oliguria or anuria. Within weeks or months, the disease progresses to irreversible acute or chronic renal failure.

Depending on the origin and clinical course, RPGN is divided into 3 groups:

Post-infectious (post-streptococcal) variant.
Associated with systemic diseases (e.g., systemic lupus erythematosus).
Idiopathic (primary) variant, accounting for about half of all cases.

Pathogenesis and Forms

There is no single mechanism for all variants of the disease; the pathogenesis directly depends on the specific form:

Immune-complex mechanism: characteristic of post-streptococcal forms and systemic lupus erythematosus.
Anti-GBM antibody mechanism: a prime example is Goodpasture syndrome. Circulating antibodies against the glomerular basement membrane are detected in the blood (>95% of cases), which cross-react with alveolar basement membranes, causing pulmonary hemorrhage. Immunohistochemistry reveals linear IgG and C3 complement deposits along the basement membranes.
Idiopathic RPGN: can be triggered by various pathways (immune complexes, anti-GBM antibodies, or ANCA), often demonstrating the most severe glomerular damage.

Pathological Anatomy: Gross and Microscopic Findings

At autopsy or renal biopsy in RPGN, the kidneys are enlarged and pale, with petechial hemorrhages visible on their surface.

Microscopic examination reveals focal necroses (including fibrinoid necrosis), as well as endothelial and mesangial cell proliferation. The main diagnostic criterion is the formation of cellular crescents:

They form in Bowman's space due to the proliferation of parietal epithelial cells and the migration of monocytes and macrophages.
Distinct strands of fibrin are identified between the layers of cells.
As they enlarge, the crescents compress the glomerulus and completely obliterate the capsular space.
Electron microscopy consistently records disruptions of the glomerular basement membrane, and in some patients, subepithelial deposits. Subsequently, most crescents undergo sclerosis.

Mnemonic

RPGN = Rapidly Progressive Glomerular Necrosis + Crescent formation.

Frequently asked questions

What immunohistochemical pattern (fluorescence type) is characteristic of the immune-complex variant of RPGN?

The immune-complex variant of rapidly progressive glomerulonephritis is characterized by a granular fluorescence pattern on immunofluorescence microscopy. This immunohistochemical pattern results from the deposition of preformed circulating immune complexes (or their formation in situ) within the mesangium and glomerular capillary walls. This type of injury is associated with conditions such as acute post-streptococcal glomerulonephritis, systemic lupus erythematosus, IgA nephropathy, Henoch-Schönlein purpura, cryoglobulinemia, and subacute infective endocarditis.

In which systemic diseases can secondary rapidly progressive glomerulonephritis develop?

Secondary rapidly progressive glomerulonephritis can develop in the setting of several rheumatic and systemic autoimmune disorders. These include:

Systemic lupus erythematosus — in severe lupus nephritis.
Vasculitis — presenting as focal segmental proliferative or extracapillary glomerulonephritis.
IgA nephropathy (Berger disease) — in severe courses with crescent formation.
Bacterial endocarditis — immune-complex glomerulonephritis.
Idiopathic mixed cryoglobulinemia — a systemic disorder.
Microscopic polyangiitis — a systemic necrotizing vasculitis.
Goodpasture syndrome — the anti-GBM antibody-mediated variant.

What types of antineutrophil cytoplasmic antibodies (ANCA) are detected in idiopathic RPGN?

Idiopathic rapidly progressive glomerulonephritis is associated with two main types of antineutrophil cytoplasmic antibodies, which occur with roughly equal frequency:

c-ANCA — antibodies against proteinase-3 (PR3);
p-ANCA — antibodies against myeloperoxidase (MPO).

These antibodies are characteristic of the pauci-immune variant of glomerular injury, in which immune deposits are absent or minimal.

What is the main morphological marker of rapidly progressive glomerulonephritis?

The main morphological marker is the formation of epithelial crescents in the majority of renal glomeruli.

What is the underlying mechanism of Goodpasture syndrome in RPGN?

It is driven by an antibody-mediated mechanism with circulating anti-glomerular basement membrane (anti-GBM) antibodies that cross-react with pulmonary alveoli, producing linear IgG deposits.

How do crescents form in the glomeruli?

They arise from the proliferation of parietal epithelial cells of Bowman's capsule and the migration of monocytes and macrophages into Bowman's space, leading to compression of the glomerulus.

Go deeper

Pathogenesis of immune-complex glomerulonephritis
Role of ANCA in idiopathic RPGN
Ultrastructural changes and the role of deposits
Differential diagnosis of extracapillary proliferation
Outcomes and glomerular crescent sclerosis