01-09 PATH: Glomerular Dzs Flashcards

Alport syndrome mechanism

1
Q

charges on glomerulus

A

endothelium - neg charge from polyanionic GPs

podocyte - neg charged glycocalyx

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2
Q

major components of GBM

A

Type IV collagen
proteoglycans (esp. heparan sulfate)
laminin

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3
Q
  1. Anti-GBM nephritis
A

IN SITU IMM CMPLX DEPOSITION (like membranous GN)
Abs-against intrinsic BM Ags (alpha chain of Type IV collagen)
—IF: linear
—in Goodpasture’s synd, anti-GBM Abs cross-react with alveolar BMs in the lung.

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4
Q
  1. Membranous GN
A

IN SITU IMM CMPLX DEPOSITION (like anti-GBM)
—Abs against M-type phospholipase A2 receptor on foot processes of visc epithelial cells
—Ab binds —> activates complement —> sheds imm aggregates —> subendo deposits

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5
Q
  1. Circulating immune complex nephritis
A

CIRCULATING IMM CMPLX DEPOSITION
—Cmplxs not specific to nephron, just get stuck there
—depositions in the mesangium and subendoethelial areas in a GRANULAR pattern

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6
Q

terms to describe extent/regionality of renal damage?

A

@ kidney level: diffuse, focal

@ glomerular level: global, segmental

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7
Q

I.F. linear pattern ddx

A

– anti-GBM disease if intense (should be confirmed)
– light chain deposition disease
—membranoproliferative GN (MPGN) type II

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8
Q

I.F. granular pattern ddx

A

granular pattern = immune complexes
– mesangial: IgA and lupus nephropathy
– cap. wall: membranous
– combined: lupus, acute post-infectious GN

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9
Q

nephrotic syndrome

A

cytokines damage neg charge of BM —> leaks protein
—proteinuria >3.0g/d
—hyperlipidemia b/c liver make lipoprot to try and maintain oncotic pressure
—hypoalbuminemia
—peripheral edema (2° to hypoalb. and Na+ ret)
—hypercoag b/c anti-thrombin 3 peaces out

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10
Q

nephritic syndrome

A
neutrophils attack BM —> hematuria
—hematuria w/ red cell casts in the urine
—azotemia
—oliguria
—mild to moderate HTN
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11
Q

Most common nephrotic syndrome DDX

A
  1. minimal ∆dz
  2. FSGS: focal segmental glomerulosclerosis
  3. membranous GN
  4. amyloidosis
  5. DM
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12
Q

Most common nephritic syndrome DDX

A
  1. post-streptococcal GN
  2. MPGN: membranoproliferative GN
  3. lupus nephritis
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13
Q
  1. Minimal ∆ Dz
A
commonest NEPHROTIC syndrome in kids
—rapid onset
—90% 1°
—2° to NSAIDs, food rxn, bee stings, lymphoma
—normal light microscopy
—normal IF
—complete podocyte foot effacement on EM
—respond well to steroids
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14
Q
  1. FSGS
A

Focal Segmental Glomerulosclerosis
—Commonest NEPHROTIC syndrome in adults
—segmental cap collapse/scarring
—thickened BM, effacement of podocytes (but not as bad as MCD)
—bad news: progressive, poor tx response
—80% 1°; 20% 2° drugs, virus, genetics, small kidneys, obestity

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15
Q
  1. Membranous Glomerulopathy
A

• one of the commonest causes of NEPHROTIC syndrome in adults
• 1° and 2° forms (drugs, tumors, lupus, infections) • subepithelial immune deposits in capillary wall, which evolve over time
• may see spikes and holes in the GBM with special
stains
• IF: diffuse, granular pattern along the GBM (esp. IgG, C3)
• EM: subepithelial deposits with spike-like projections of the GBM between deposits

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16
Q
  1. Diabetes Mellitus
A

Causes a NEPHROTIC syndrome

EARLY Light micros
—glomerular hypertrophy
—thicker GBM
—wider mesangium
ADVANCED STAGE Light micr.:
—progressive thickening of GBM
—diffuse glomerulosclerosis
—nodular glomerulosclerosis (Kimmelstiel-Wilson
nodules) [can call this "KW Disease"]
—microaneurysms
—arteriolar hyalinization
IF: negative for deposits
EM: thick GBM, mesangial sclerosis
17
Q
  1. amyloidosis
A

Causes a NEPHROTIC syndrome

  • variable mesangial & GBM deposition of beta-pleated amyloid fibrils
  • Congo Red positive, with apple green birefringence under polarized light
  • EM: 8-12 nm random fibrils
  • most common amyloid proteins are light chains
  • other amyloid proteins include amyloid A, transthyretin, beta2-microglobulin, lysozyme, apolipoprotein AI or AII, others
18
Q
  1. acute post-infection GN
A

Causes a NEPHRITIC syndrome

• prototype: post-streptococcal (uncertain Ag)
• LIGHT: diffuse prolif. (i.e. exudative) GN
—diffuse endocap prolif w/ WBC —> swollen, hypercellular glomerulus
• IF: granular deposits along GBM (esp. C3)
• EM: classic subepithelial “hump-like” deposits

19
Q
  1. MPGN: Memebranoproliferative glomeulonephritis
A

Causes a NEPHRITIC syndrome

  • a general pattern of injury as well as a particular disease
  • 1° idiopathic forms but often 2° forms (the most common GN assoc w/ Hep B and C)
  • may present with nephrotic and/or nephritic syndrome
  • hypercellular glomeruli with leukocytes
  • glomeruli are often hyperlobulated
  • “tram-track” appearance due to duplication of GBMs, w/ subendothelial deposits, esp. C3
  • vast majority progress to ESRD regardless of Rx
20
Q
  1. lupus nephritis
A

Causes a NEPHRITIC syndrome

  • 60-70% of SLE pts get it, w/ wide spectrum of disease
  • WHO Classification: 6 classes
  • LIGHT: wire loops, hyaline thrombi, fibrinoid necrosis
  • IF: “full house” pattern of staining (everything stains positive, all 3 Ig’s, C3a, C1q and light chains)
  • EM: mesangial deposits in all subtypes + peripheral deposits
21
Q
  1. Alport syndrome
A

Causes a HEMATURIC Syndrome

  • nephritis w/ hematuria accomp. by nerve deafness & ocular abnormalities
  • caused by hetero group of mutations involved in collagen IV (α3 or α5) chain synth
  • EM: fragmentation & splitting of the GBM (“basketweave” pattern)
  • progresses to renal failure =(
22
Q
  1. Thin basement membrane dz
A

Causes a HEMATURIC Syndrome

a.k.a. Benign familial hematuria
• persistent or intermittent microhematuria (non-progressive)
• ? atypical or variant form of Alport syndrome (similar mutations in some cases)
• EM: generalized thinning of GBM

23
Q
  1. IgA Nephropathy (Berger’s)
A

Causes a HEMATURIC Syndrome

  • commonest cause of GN worldwide (esp. in Asians)
  • most pts present w/ gross or microscopic hematuria, buta few w/ nephrotic syndrome or renal failure
  • most classically, a mesangioproliferative appearance, but variable
  • IF & EM: IgA + deposits primarily in the mesangium
  • same renal pathology is seen in Henoch-Schönlein syndrome, a systemic vasculitic disease with GI, joint, and skin manifestations
24
Q
  1. Crescentic Glomerulonephritis
A

Causes a Rapidly-Progressing Renal Disease
—3 subtypes based on IF: granular, linear and pauci-immune
• crescent = sign of SEVERE glomerular injury
• cellular prolif along inside of B’s capsule and filling a part of B’s space.
– comprised of parietal epithelial cells, inflamm cells, and fibrin
– lesions evolve: cellular→fibrocellular→fibrous
• >50% glomerular involvement = “crescentic GN”
• fibrocellular or fibrous crescents indicate a probable poor response to Rx

25
Q

15a. Crescentic Glomerulonephritis w/ Linear IF

A

a. Linear = anti-GBM disease
• IF: linear deposits of IgG + C3
• anti-GBM Abs may cross-react w/ pulm
alve BM → hemorrhage (= Goodpasture’s)

26
Q

15b. Crescentic Glomerulonephritis w/ Granular IF

A

Granular = immune complex-mediated disease
• may be a complication of almost any of the immune complex nephritides
• IF: granular (“lumpy bumpy”) deposits

27
Q

15c. Crescentic Glomerulonephritis w/ Negative IF

A

IF negative = “pacui-immune”

a. ANCA-
b. ANCA+ (~80%)
• often associated with a systemic vasculitis, such as Wegener’s granulomatosis, Churg-Strauss, or
microscopic polyangiitis