Nephritic Syndrome Flashcards
What disorder is caused by subendothelial immune complex deposits?
Membranoproliferative GN
What disorder is caused by mesangial immune complex deposits?
IgA nephropathy
Acute nephritic syndrome is characterized by the acute onset of: (6)
- Hematuria (Microscopic or macroscopic, RBC casts)
- Hypertension
- Oliguria
- Edema –usually moderate
- Mild to moderate proteinuria
- Azotemia
Diseases due to immune deposition are associated with circulating immune complexes that are planted at sites according to their:
size charge (and other affinity characteristics)
3 Causes of endothelial cell injury:
- Deposition of immune complexes in the subendothelial space
- Thrombotic microangiopathies
- Entrapment of paraproteins (in B-cell lymphoproliferative disorders, Plasma cell dyscrasias, Multiple myeloma)
Endothelial damage results in:
How does this manifest clinically?
a local inflammatory response
- Cytokines + autacoids are released
- Cytokines, autocoids + activated complement upregulate adhesion molecules on endothelial and circulating immune cells
Hematuria
What pathophysiological findings are characteristic of Membranoproliferative glomerulonephritis type I?
- Hypercellularity of the glomerular tuft
- Increased mononuclear cells within expanded mesangium + capillary lumens
- Double-contour/duplication of glomerular basement membrane (tram track)
What causes duplication of the basement membrane?
endothelium displaced by
1) immune deposits
2) infiltrating mesangial cells
What are possible presentations of MPGN type I? (5)
- Microscopic hematuria
- Non-nephrotic range proteinuria
- Nephrotic syndrome
- Acute nephritic syndrome
- Rapidly progressive glomerulonephritis
MPGN type 1 is often associated with what infection?
hepatitis C
What lab value will be low in MPGN type 1 and 2?
C3
MPGN type I progresses (slowly/rapidly) to end stage renal disease.
slowly
What is present in 80% of patients with dense deposit disease (MPGN type 2)?
C3 nephritic factor
What conditions may be associated with dense deposit disease (MPGN type 2)?
- macular deposits in the eyes
2. acquired partial lipodystrophy (loss of subcut fat in upper 1/2 of body)
In dense deposit disease (type II MPGN), what is seen on immunofluorescence? On Electron microscopy?
IF: C3, but no Ig
EM: characteristic electron-dense deposits in the GBM
Describe the Pathophysiology of immune-complex-mediated membranoproliferative
glomerulonephritis.
- complement activated via classical pathway
- leukocytes recruited
- leukocytes release proteases, etc, that damage endothelium/BMem/epithelium
- repair leads to formation of new BMem that incorporates debris