DR Medhat MRCP

Investigations :
Routine SCr, eGFR , U&E , albumin , LFTs , uPCR (or uACR)
Urine R/M : proteinuria, hematuria (with dysmorhic RBCs) ,red cell casts.
Serology work up (for underlying cause)
- C3 , C4 , C3 nephritic factor (hypocomplementemia in all subtypes).
- Immunoglobulin assay.
- ANA , anti-ds DNA , ANCA,rheumatoid factor ,ESR
- Serum & urine protein electrophoresis (MM)
- Serum cryoglobulins
- Virology screen (esp. HCV).
Renal biopsy (LM ,EM,IF) :
see below.
Classification of MCGN :
Pathological (traditional) classification (according to the site of deposits) :
Causes
Features
Common
finding
Type 1 MCGN
Type 2 MCGN
'dense deposit disease'
(DDD)
Type 3 MCGN
90% of cases Less common Less common
Cryoglobulinaemia
(with Hepatitis C)
- Subendothelial
immune deposits of
electron dense
material .
- Classical pathway is
activated by immune
complexes normal/
C3 and C4)
Partial lipodystrophy
Factor H deficiency
- Intramembranous
deposites
- Alternate pathway is
activated C3,
normal C4.
- A stabilizing IgG binding
a C3 convertase (C3Bb)
occurs persistent
cleavage of C3,this is
called C3 nephritic
factor (Ab against
C3bBb), found in 70%
hepatitis B and
hepatitis C
- Immune
deposits, as in
type I, but
complete
disruption of the
GBM with
membranous
change
- Findings similar
to type II but
without the C3
nephritic factor
All subtypes have a characteristic` double contour` or ` GBM splitting` or
`Tram track sign`appearance of the GBM s to the interposition of
mesangial cell cytoplasm between the endothelium and GBM.
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