Glomerulonephritis can be classified on the basis of (I) the
etiologic cause; (II) the histopathologic findings on examination of kidney
biopsy; (III) or according to the clinical presentation.
(I) Etiology of glomerulonephritis:
This could be either:
a) Primary (idiopathic) when the glomerular disease is not part of
systemic disease and the cause is unknown.
b) Secondary when glomerular disease is part of a systemic disease
(e.g. diabetes mellitus) or due to a known cause (e.g. post-
streptococcal glomerulonephritis).
Secondary glomerulonephritis may be the result of:
- Infection which may be bacterial (e.g. post-streptococcal), viral
(e.g. HBV, HCV, CMV), parasitic (e.g. Schistosoma mansoni,
malaria). - Collagen disease (e.g. SLE, polyarteritis nodosa, rheumatoid
arthritis). - Drug (e.g. Penicillamine, Paradione, Aspirin, Heroin).
- Metabolic disease (e.g. Diabetes mellitus, amyloidosis).
- Malignancy (e.g. lymphoma).
- Heredofamilial (e.g. Alport syndrome).
(II) Histopathologic classification of glomerulonephritis:
A paraffin section from a percutaneous needle biopsy of the kidney
of a patient with glomerulonephritis (whether primary or secondary), when
examined by light microscopy may show any of the following:
- Minimal change (Nil-change) disease (lipoid nephrosis) (Figure
3.1):