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RAPIDLY PROGRESSIVE GLOMERULONEPHRITISCharacterized clinically by rapid and progressive loss of renal
function.Severe oilguria and signs of nephritic syndrome.If untreated ,death due to renal failure occurs from weeks to months.The most common histological picture is the presence of crescent in
most of the glomeruli hence called crescent glomerulonephritis.On the basis of immunological findings RPGN can be divide into
three groups: Type I - Anti GBM antibody-induced disease
Type II - Immune complex deposition
Type III- Pauci immune type
Anti-GBM antibody induced disease
Accounts for 20% of RPGN. Characterized by linear deposition of IgG.In some of these patients,the anti-GBM antibody cross reacts
with pulmonary alveolar basement membrane to produce the clinical picture of pulmonary hemorrhage associated with renal failure(Goodpasture syndrome).
The Goodpasture antigen is a peptide within the non-collagenous portion of the α-3 chain of collagen type IV
The majority of type I , disease however features anti-GBM antibody alone ,these cases are considered idiopathic.
Plasmapheresis to remove the pathogenic circulating antibodies is usually part of the treatment.
Immune complex depostition
Accounts for 25% of RPGN.It can be a complication of any of the immune complex
nephritides including : post infectious glomerulonephritis,lupus nephritis ,IgA nephropathy,Henoch-Schonlein purpura.
This type of RPGN frequently demonstrate cellular profusion within the glomerular tuft ,in addition to crescent formation.
These patients cannot usuly be helped by plasmapheresis.
Pauci-immune type
Accounts for 55% of RPGN.Defined by the lack of anti-GBM antibodies or immune complexesMost ptients with this type of RPGN have circulating antineutrophil
cytoplasmic antibodies (ANCAs). In some cases this type of RPGN is a component of a systemic vasculitis
such as :Wegener granulomatosis or microscopic polyangiitis. In many cases however,pauci-immune crescentric glomerulonephritis is
uisolated and hence idiopathic.More than 90% of such idiopathic cases have c-ANCAs or p-ANCAs in the
serum.The presence of circulating ANCAs in both idiopathic crescent
glomerulonephritis and cases of crescent glomerulonephritis that occur as a component of systemic vasculitis and the similar pathologic feature in either setting have led to the idea that these disorders are pathogenetically related.
The common denominator in all types of RPGN is severe glomerular injury and formation of crescent.
The common denominator in
all types of RPGN is severe
glomerular injury
SUMMARY OF CLASSIFICATION
MORPHOLOGY
The kidney are enlarged and pale often with petechial hemorrhages on the cortical surfaces.
Light microscopy can provide useful information to help distinguish which subclass (RPGN I, II, III) of crescentic glomerulonephritis is present.
RPGN type II have more segmental hypercellularity than types I and III.
Necrotizing changes of glomerular tufts are more common in RPGN types I and III. In particular, comparing RPGN Type I to RPGN type III, the pauci-immune disease is more often associated with necrotizing arteritis
Enlarged ,pale kidney with petechial hemorrhage on cortical surface
GROSS
Crescentric glomerulonephritis. Collapsed glomerular tuft and crescent-shaped mass of proliferating
parietal epithelial cells.
Glomeruli may show focal necrosis, diffuse or
focal endothelial
proliferation and
mesengial proliferation.
The histological picture is
dominated by distinctive crescents.
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS
LIGHT MICROSCOP
Y
Direct immunofluorescence shows smooth, linear staining of the glomerular capillary basement membranes for IgG. Similar staining pattern would also
be seen for C3.
•Anti GBM disease
•Good pasture syndrome
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS
Type I RPGN
IMMUNOFLUORESCENCE
Immunofluorescence reveals the granular pattern of staining characteristic of immune
complex deposition
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS
Type II RPGN
IMMUNOFLUORESCENCE
It has weak or no demonstrable immunoglobulin / complement deposition,
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS
Type III RPGN
IMMUNOFLUORESCENCE
Crescentric glomerulonephritis showing characteristic wrinkling of GBM with focal
disruptions (arrows)
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS
ELECTRON MICROSCOP
Y
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