Introduction & Glomerulonephritis

Question 1

Mention methods of injury in GN

Answer 1

1. By Abs & glomerular deposits of Igs, often various components of complement are found frequently in patient with GN
2. Abnormal activation & glomerular deposition of complement vy alternative pathway activation (may be sole pathogenesis in some forms of GN)
3. Cell-mediated immune mechanisms also may play a role in certain glomerular diseases

Question 2

Mention LM features of immunologically-mediated glomerular injury

Answer 2

1. Leukocytic infiltration into glomeruli
2. Hypercellularity due to proliferation of endothelial & mesangial cells
3. Crescent formation due to localized proliferation if parietal epithelial cells, probably due to escape of fibrin into space
4. Capillary wall thickening due to addition of material like immune complexes or mesangial extensions
5. Sclerosis due to collapsed glomerular capillary walls & capillary lumen obliteration due to deposition of inc mesangial matrix in mesangium & in areas of collapsed glomerular capillary walls.

Question 3

With regards immunofluorescence microscopy,……..gives a granular pattern, while ……..creates a linear pattern.

Answer 3

Immune complex deposition (circulating or in situ)
Antibodies against GBM in anti-GBM nephritis

Question 4

Mention possible finding EM study can reveal in glomerulonephritis

Answer 4

It reveals immune complexes as electron dense deposits or clumps in:
1. Mesangium
2. Between endothelial cells & GBM (subendothelial deposits)
3. Between outer surface of GBM & podocytes (subepithelial)

Question 5

Glomerular disease are mostly…..while tubular & interstitial disease are more likely…..

Answer 5

Immunologically mediated
Toxic or infectious agents

Question 6

GR: Severe golmerular disease affects tubules & vice versa

Answer 6

As severe glomerular disease impairs flow through the peritubular vascular system
Also tubukar diease leads to inc intraglomerular pressure & inducing cytokines and chemokines, may induce glomerular sclerosis

Question 7

Asymptamtic urinary abnormalities include…….
Manifestations of renal tubular defects include……

Answer 7

Proteinuria, hematuria, pyuria
Electrolyte imbalance, nocturia, polyuria, symptoms of osteodystrophy

Question 8

Mention mechanisms of antibody deposition in glomerulus

Answer 8

1. Deposition of circulating Ag-Ab complexes in the glomerular capillary wall or mesangium
2. Abs reacting in situ within the glomerulus either with fixed intrinsic glomerular Ags (GBM or podocyte) or with extrinsic molecules planted in glomerulus (endogenous as DNA or exogenous as microbial Ags)

Question 9

How do immune complexes & Abs cause injury?

Answer 9

By complement activation & leukocyte recruitment with release of various mediators and sometimes by direct podocyte damage with foot process changes.