Glomerulonephritis (GN): Pathological Spectrum
Glomerulonephritis encompasses a wide range of diseases involving immune-mediated glomerular damage. These are broadly categorized into Nephritic (inflammatory/proliferative) and Nephrotic (non-inflammatory/podocyte injury) syndromes.
1. The “Must-Distinguish” Histological Patterns
| Pattern | Key Pathological Features |
|---|---|
| Proliferative GN | Increased cellularity (mesangial, endothelial, epithelial). Usually Nephritic (e.g., PSGN, Lupus Nephritis Class III/IV). |
| Membranous GN | Diffuse capillary wall thickening without significant hypercellularity. Usually Nephrotic. |
| Crescentic (RPGN) | Crescents in >50% of glomeruli. Medical emergency. |
2. Exam “High-Yield” Associations
- Immunofluorescence (IF) Patterns:
- Linear: Anti-GBM disease (Goodpasture syndrome).
- Granular: Immune complex deposition (PSGN, SLE, IgA Nephropathy).
- Pauci-immune: ANCA-associated vasculitis (GPA, MPA).
- Lupus Nephritis: World Health Organization classification (I–VI) is essential. Class IV (Diffuse Proliferative) is the most common and severe.
Pathology Board Hint: For any GN question, always follow this algorithm: Clinical Presentation (Nephritic vs. Nephrotic) 