Hemo mehlman 4th 12-09 (1)

Question 1

Hemophilia A and B are …

Answer 1

XR

Question 2

If you get a difficult vignette where you’re not sure of the Dx, just remember you’ll never see ……. in girls

Answer 2

hemophilia A and B (XR)

Question 3

Skewed X-inactivation is called….

Answer 3

lyonization

Question 4

don’t read between the lines: unless the vignette specifically makes the Q about skewed X-inactivation, any XR disorder will always be only in a boy.

Answer 4

.

Question 5

vWD is …

Answer 5

AD

Question 6

vWD. In vignette what patient?

Answer 6

So you’ll often get a vignette with a girl.

USMLE will “reward” you sometimes with difficult vignettes. That is, if it’s a girl, you can instantaneously eliminate hemophilia.

Question 7

vWD is always a mix of a ….. problem.

Answer 7

vWD is always a mix of a platelet and a clotting factor problem.

Question 8

vWD platelet problem? CP

Answer 8

Platelet problem = epistaxis, petechiae, bruising; usually cutaneous

Question 9

vWD clotting factor problem problem?

Answer 9

Clotting factor problem = excessive bleeding after tooth extraction; menorrhagia (heavy periods)

Question 10

So vWD vignette you will get, e.g., epistaxis + heavy periods; or petechiae + lots of bleeding after tooth extraction; always a combo of the two

Answer 10

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Question 11

Platelet problem = increased …

Answer 11

increased bleeding time (BT); bleeding time has zero relation to clotting factors / clotting

Question 12

PT / aPTT = reflects clotting factors

Answer 12

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Question 13

In vWD, bleeding time 100% of the time is elevated.

Answer 13

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Question 14

vWF bridges ….. on platelets to ….

Answer 14

vWF bridges Gp1b on platelets to underlying collagen / vascular endothelium;

Question 15

vWF is necessary for …

Answer 15

necessary for platelet adhesion

Question 16

vWF does not affect …

Answer 16

does not affect aggregation (GpIIb/IIIa)

Question 17

vWF also has ancillary/secondary function of……

Answer 17

But vWF also has ancillary/secondary function of stabilizing factor VIII in plasma, meaning sometimes aPTT is elevated (normal is 25-40 SECONDS).

Question 18

1st important factor vWF: BT is always increased. aPTT is only elevated about half the time in questions.

Answer 18

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Question 19

2nd important factor vWF: If aPTT is increased, it’s not absurdly increased. Iow, normal aPTT might be 42 seconds. And if it is normal, it might be upper end of normal, like 38 seconds, which can still suggest to you it’s vWD.

Answer 19

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Question 20

vWD, what PT?

Answer 20

PT is always normal in vWD.

Question 21

Normal BT = 2-7 minutes.

Answer 21

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Question 22

Normal PT = 10-15 seconds

Answer 22

.

Question 23

Normal aPTT = 25-40 seconds

Answer 23

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Question 24

In hemophilia, because the issue is literally a deficiency of factor VIII in A, or IX in B – and in severe cases, antibodies against these factors – the aPTT ……..

Answer 24

aPTT WILL be absurdly elevated, like 90 seconds.

Question 25

Hemarthrosis is a clotting factor issue, in what disease?

Answer 25

classic for hemophilia vignettes, NOT vWD

Question 26

Why hemarthrosis in major clotting factor deficiency, ie hemophilia?

Answer 26

Implication being that it takes major clotting factor defect to precipitate full-blown hemarthrosis, whereas perhaps in vWD the effect isn’t salient enough to lead to the bleed in the joint.

Question 27

Hemophilia will be school boy with hemarthrosis, or if neonate, will be excessive bleeding with circumcision.

Answer 27

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Question 28

school boy + hemarthrosis = diagnose?

Answer 28

Hemophilia

Question 29

neonate + bleeding with circumcision = diagnose?

Answer 29

Hemophilia

Question 30

Question on the 2CK Free-120 had given a vWD question where they said girl had cut on her finger that took longer to stop than expected (they didn’t tell you bleeding time explicitly, but expected you to easily infer that); then they said in the labs, PT normal, aPTT normal. So remember, aPTT isn’t always elevated. They also say “platelet aggregation studies: normal.” Which makes sense because vWF is necessary for adhesion, not aggregation, as we said above.

Answer 30

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Question 31

viral infection in school-age kids causing low platelets, (about 80% of the time of Q) = diagnose?

Answer 31

Immune thrombocytopenia purpura (ITP)

Question 32

(20% of the time the vignette) will be a woman 30s-40s, without mention of viral infection, who just has random bruising, diagnose?

especially HY on USMLE 2CK.

Answer 32

Immune thrombocytopenia purpura (ITP)

Question 33

ITP is caused by autoantibodies against ….

Answer 33

GpIIb/IIIa (type II hypersensitivity

molecular mimicry most likely due to viral infection.

Question 34

Treatment of ITP, first?

Answer 34

steroids first

Question 35

Treatment of ITP, second?

Answer 35

steroids first, then IVIG

Question 36

Treatment of ITP, third?

Answer 36

steroids first, then IVIG, then splenectomy.

Question 37

ITP next best step in management?

Answer 37

STEROIDS

Question 38

ITP most effective management for reccurence?

Answer 38

Splenectomy = most effective at decreasing recurrence.

Question 39

Viral-induced neutropenia is similar to …

Answer 39

ITP

Question 40

Low neutrophils + fever =

Answer 40

neutropenic fever / febrile neutropenia

Question 41

Viral-induced neutropenia is similar to ITP, but instead of autoantibodies against platelets, they’re simply against ……

Answer 41

neutrophils

Question 42

neutropenic fever / febrile neutropenia =

Answer 42

infection without a way to control it via innate immunity =

Question 43

infection without a way to control it via innate immunity =

Answer 43

must give immediate broad-spectrum IV antibiotics

Question 44

what abs in febrile neutropenia?

Answer 44

generally third- or fourth-gen ceph + vancomycin; or pipericillin-tazobactam.

Question 45

Thrombotic thrombocytopenic purpura (TPP) is due to antibodies against

Answer 45

ADAMTS13 protein, which is normally responsible for cleaving vWF multimers, leading to decreased platelet-clumb breakdown.

Question 46

TPP. The clumps will shear RBCs flying past leading to …

Answer 46

schistocytosis

Question 47

Combination of thrombocytopenia + schistocytosis =

Answer 47

microangiopathic hemolytic anemia (MAHA)

Question 48

TTP you see a pentad of ?

Answer 48

1) thrombocytopenia,
2) hemolytic anemia with schistocytosis,
3) fever
4) renal insufficiency with red urine;
5) neurologic signs

Question 49

Hemolytic uremic syndrome (HUS) is just the triad of …?

Answer 49

thrombocytopenia;

hemolytic anemia with schistocytosis;

renal insufficiency with red urine

fever and neurologic signs not typically seen in HUS.

Question 50

what 2 symptoms seen in TTP, but not in HUS?

Answer 50

fever and neurologic signs not typically seen in HUS.

Question 51

HUS due to …2

Answer 51

EHEC O157:H7 shiga-like toxin (aka verotoxin),
or
Shigella’s shiga toxin.

Question 52

HUS: Toxin causes endothelial damage that leads to platelet consumption and “jagged edges” in the vessels that shear RBCs. Schistocytes are seen.

Answer 52

.

Question 53

Schistocytes = … in what diseases?

Answer 53

HUS, TTP, DIC, HELPP syndrome, prosthetic values (mechanical hemolysis).

Question 54

Vitamin K deficiency = PT, aPTT; bleeding time?

Answer 54

increased PT and aPTT; bleeding time is normal

Question 55

Vit K deficiency = BT is normal because platelets aren’t involved whatsoever. Issue is decreased gamma-carboxylation + activation of clotting factors II, VII, IX, X (and anti-clotting proteins C and S).

Answer 55

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Question 56

Vitamin K deficiency can be seen in …

Answer 56

Vitamin K deficiency can be seen in neonates with sterile bowels.

Question 57

vit K deficiency.
Although fat-soluble vitamin deficiencies can occur in small bowel malabsorptive disorders, i.e., with conditions like cystic fibrosis, Crohn disease, Celiac, chronic Giardiasis, etc., K deficiency is rare because of functional large bowel with normal flora in non-neonates

Answer 57

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Question 58

vit k deficiency.
A, D, and E would be deficient. E.g., cystic fibrosis kid with rickets (D deficiency).

Answer 58

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Question 59

USMLE wants you to know vitamin K deficiency can occur in patients who are on chronic broad-spectrum antibiotics. They’ll say patient on Abx is requiring a lower dose of warfarin to achieve same INR target range – why? → decrease in colonic normal flora.

Answer 59

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