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Flashcards in Nephritic Syndrome Deck (40):
1

What disorder is caused by subendothelial immune complex deposits?

Membranoproliferative GN

2

What disorder is caused by mesangial immune complex deposits?

IgA nephropathy

3

Acute nephritic syndrome is characterized by the acute onset of: (6)

1. Hematuria (Microscopic or macroscopic, RBC casts)
2. Hypertension
3. Oliguria
4. Edema –usually moderate
5. Mild to moderate proteinuria
6. Azotemia

4

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)

5

3 Causes of endothelial cell injury:

1. Deposition of immune complexes in the subendothelial space
2. Thrombotic microangiopathies
3. Entrapment of paraproteins (in B-cell lymphoproliferative disorders, Plasma cell dyscrasias, Multiple myeloma)

6

Endothelial damage results in:
(How does this manifest clinically?)

a local inflammatory response
1. Cytokines + autacoids are released
2. Cytokines, autocoids + activated complement upregulate adhesion molecules on endothelial and circulating immune cells

Hematuria

7

What pathophysiological findings are characteristic of Membranoproliferative glomerulonephritis type I?

1. Hypercellularity of the glomerular tuft
2. Increased mononuclear cells within expanded mesangium + capillary lumens
3. Double-contour/duplication of glomerular basement membrane (tram track)

8

What causes duplication of the basement membrane?

endothelium displaced by
1) immune deposits
2) infiltrating mesangial cells

9

What are possible presentations of MPGN type I? (5)

1. Microscopic hematuria
2. Non-nephrotic range proteinuria
3. Nephrotic syndrome
4. Acute nephritic syndrome
5. Rapidly progressive glomerulonephritis

10

MPGN type 1 is often associated with what infection?

hepatitis C

11

What lab value will be low in MPGN type 1 and 2?

C3

12

MPGN type I progresses (slowly/rapidly) to end stage renal disease.

slowly

13

What is present in 80% of patients with dense deposit disease (MPGN type 2)?

C3 nephritic factor

14

What conditions may be associated with dense deposit disease (MPGN type 2)?

1. macular deposits in the eyes
2. acquired partial lipodystrophy (loss of subcut fat in upper 1/2 of body)

15

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

16

Describe the Pathophysiology of immune-complex-mediated membranoproliferative
glomerulonephritis.

1. complement activated via classical pathway
2. leukocytes recruited
3. leukocytes release proteases, etc, that damage endothelium/BMem/epithelium
4. repair leads to formation of new BMem that incorporates debris

17

Describe the Pathophysiology of complement-mediated membranoproliferative
glomerulonephritis.

1. controls of complement activation are dysregulated
2. complement activated via alternative pathway
3. leukocytes recruited
4. leukocytes release proteases, etc, that damage endothelium/BMem/epithelium
5. repair leads to formation of new BMem that incorporates debris

18

Most common primary glomerulonephritis worldwide:

IgA nephropathy (IgAN)

19

What characterized IgA nephropathy (pathologically)?

deposition of IgA-containing immune complexes predominantly in the mesangium, which results in a mesangioproliferative pattern of injury

20

IgA nephropathy may occur secondary to what conditions? (7)

Henoch-Schonlein Purpura
Ankylosing spondylitis
Dermatitis herpetiformis
Celiac disease
Inflammatory bowel disease
Cirrhosis
Psoriasis

21

What triggers IgA nephropathy, and how does this progress to the disease state (pathogenesis)?

1. URI or GI tract infection
2. IgA are produced that are under galactosylated at O-linked glycans in the hinge region of IgA1
3. IgG or IgA1 antibodies recognize these O-linked glycans terminating with N-acetylgalactosamine instead of galactose
4. Circulating immune complexes (CICs) deposit in the mesangium
*may result in a proliferative and occasionally necrotizing glomerulitis

22

________ nephritic sediment occurs within 1-2 days of infection.

synpharyngitic

23

Possible presentations of IgA nephropathy:
*highly variable

1. Asymptomatic
2. Microscopic hematuria
3. Intermittent gross hematuria
4. Synpharyngitic hematuria
5. Proteinuria -- nephrotic or non-nephrotic
6. Acute glomerulonephritis
7. Rapidly progressive glomerulonephritis

24

How does IgA nephropathy present clinically?

hypertension (often)
50% have increased serum IgA levels
increased risk for loss of renal function

25

Risk factors for IgA nephropathy-associated loss of renal function:

Heavy proteinuria
Decreased GFR at onset
Older age at onset
Uncontrolled hypertension
Crescents and/or tubulointerstitial fibrosis/atrophy
Familial forms

26

What is the pathophysiology of anti-GBM disease?

1. autoantibodies form against a noncollagenous portion of the α-3 subunit of type IV collagen
2. antibodies (usually IgG) bind to the GBM in a linear + uniform manner
3. Rapidly progressive glomerulonephritis develops, leading to kidney failure rapidly develops (due to focal glomerular necrosis and crescent formation)

27

What symptoms may precede or coincide with onset of renal dysfunction in Goodpasture's disease?

Cough
dyspnea
crackles
hemoptysis

28

In Goodpasture's disease, what may exacerbate pulmonary hemorrhage?

tobacco smoke
influenza
volatile hydrocarbons

29

How does Goodpasture's disease present?

Rapidly progressive renal failure with azotemia (50-70%)
Anemia out of proportion to renal insufficiency
Arthritis/arthralgias common
Hypertension (~20%)

30

How is Goodpasture's disease treated?

corticosteroids, plasmapheresis, and cytotoxic agents

31

What are "crescents", and what do they result in?

accumulation and proliferation of cells outside the glomerular tuft

result in compression of the tuft with rapid progression to renal failure

32

____ crescentic glomerulonephritis is a condition characterized by >50% glomeruli affected (under light microscopy).

diffuse

33

What are the 4 progressive/worsening crescent appearances?
*sorry, couldn't figure out how to word this

1. segmental proliferative and necrotizing lesions
2. cellular crescents
3. fibrocellular crescents
4. fibrous crescents

34

Pathogenesis of crescents:

1. severe damage to capillary walls
2. damage causes tears and necrosis to GBM
3. RBC, WBC, fibrinogen and plasma constituents enter Bowman’s space
4. mononuclear cells and parietal epithelial cells proliferate
(antibody and cell-mediated processes may be involved)

35

Type II Crescentic Glomerulonephritis is associated with what pattern of immune deposits?

granular

36

Rapidly progressive glomerulonephritis (is/isn't) a medical emergency.

"not"--
but requires prompt dx and trx to prevent severe permanent renal damage/failure

37

How is Alport syndrome inherited, and what is defective?

defects in α-5 collagen type IV (COL4A5)

X-linked (but may be AR)

38

How do heterozygous females present with Alport syndrome? Heterozygous males?

females: hematuria + thin basement membranes
males: persistent hematuria, progressive proteinuria, ultimately ESRD (heterozygous=affected)

Both: sensorineural hearing loss, lens abnormalities, platelet defects, (rarely) esophageal leiomyomas

39

What would you see in a kidney biopsy from a patient with Alport syndrome?

abnormally thin basement membranes
splintering of lamina densa, “basket weave appearance”

40

What protein abnormality causes thin basement membrane disease, and how severe is it?

defects in α-3 or α-4 collagen type IV, which results in GBM that is uniformly reduced by half

Usually benign if heterozygous