Fogo, Ch. 11 - Thrombotic MIcroangiopathies Flashcards Preview

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Flashcards in Fogo, Ch. 11 - Thrombotic MIcroangiopathies Deck (10)
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1
Q

Distinguish clinically between TTP and HUS.

A

TTP: Affects adults. Fever, bleeding, anemia, AKI, and neurologic impairment.

HUS: Affects children. Anemia, AKI, and thrombocytopenia.

2
Q

What are some mild findings in thrombotic microangiopathies?

A

Fibrin platelet thrombi in glomeruli and/or arterioles (more common in children)

Mesangiolysis and mesangial “unraveling”

3
Q

What are some severe findings in thrombotic microangiopathy?

A

Segmental cortical and arterial necrosis, RBC fragments.

4
Q

What are the LM findings that correlate to ischemic change?

A

GBM corrugation

Tuft retraction & collapse

5
Q

What are the IF/EM findings in TMAs?

A

Non-specific immunofluorescence (IgM/C3, fibrin/fibrinogen)

Swollen endothelium, fibrin tactoids, mesangiolysis, and GBM breakdown.

6
Q

What is the etiology of diarrhea-associated (D+) HUS?

A

Shiga-like or verotoxin from shigella or O157:H7 attaches to kidney Gb3 (via beta-subunit) and inactivates the 60S ribosomal subunit (via alpha-subunit)

7
Q

What is the etiology of non-diarrhea associated (D-) atypical HUS? How is it treated?

A

Probably related to defects in factor H, I, or membrane cofactor protein resulting in unregulated complement activation.

Treat with plasmapheresis, transplant, eculizumab.

8
Q

What are some familial and iatrogenic causes of TMA?

A

Familial: Deficiency of ADAMTS13 (results in long abnormal vWF multimers)

Drugs: Cyclosporine, mitomycin, anti-VEGF

9
Q

How can TTP be distinguished from HUS?

A

ADAMSTS13 is not severely reduced in (at least D+) HUS.

10
Q

Recall some prognostic factors in TMAs.

A

Children tend to do better.

Adults may suffer lasting renal injury (worse with segmental or cortical necrosis or PAI-1 abnormality).