Crescent formation in glomerulonephritis occur in? 1-Mesangium 2-Mesenchyme 3-Endothelium 4-Endothelium and mesangium
Reading File
Finding Sources
Reading File
Finding Sources
The textbook sources are very clear. Here is the complete answer:
Answer: None of the above - Crescents form in Bowman's Space
The correct answer to this question is none of the listed options. Crescents in glomerulonephritis form in Bowman's space (the urinary space), from proliferation of parietal epithelial cells (PECs) lining Bowman's capsule, along with infiltrating macrophages/monocytes and fibrin deposition.
Why the given options are wrong:
| Option | Structure | Correct? |
|---|---|---|
| Mesangium | Intraglomerular supporting cells | No |
| Mesenchyme | Embryonic connective tissue | No |
| Endothelium | Capillary lining cells | No |
| Endothelium + Mesangium | Both intraglomerular | No |
What actually happens (from authoritative sources):
According to Comprehensive Clinical Nephrology, 7th Ed.:
"Crescent formation represents a severe cellular response and is initiated by cytokine-driven proliferation, particularly of the parietal epithelial cells. Local breaks in the GBM or Bowman's capsule, mediated by activated leukocytes, are followed by macrophage infiltration, proliferation of parietal epithelial cells and podocytes, and local fibrin deposition."
According to Histology: A Text and Atlas (Junqueira):
"A cellular crescent is formed by deposition of fibrin infiltrated by macrophages and proliferated parietal cells of the Bowman capsule."
According to Goldman-Cecil Medicine:
"The kidney biopsy shows extensive extracapillary proliferation manifested as crescent formation in the Bowman space."
Mechanism Summary:
- Injury to the glomerular capillary wall (GBM breaks) from inflammation
- Fibrin leaks into Bowman's space
- Fibrin stimulates proliferation of parietal epithelial cells lining Bowman's capsule
- Monocytes/macrophages enter Bowman's space through GBM breaks
- Together, fibrin + proliferating parietal cells + macrophages form the crescent (so called because it compresses the glomerular tuft into a crescent shape when viewed on histology)
This is why the lesion is called extracapillary proliferation - the cellular proliferation happens outside the capillary tuft, within Bowman's space - not in the mesangium, endothelium, or mesenchyme.
Sources: Comprehensive Clinical Nephrology 7th Ed.; Histology: A Text and Atlas (Junqueira); Goldman-Cecil Medicine; Brenner & Rector's The Kidney
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