Bleeding Disorders - Ch. 14 Flashcards Preview

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Flashcards in Bleeding Disorders - Ch. 14 Deck (55):
1

Petechiae and purpura, normal PT and PTT, normal platelet count

Bleeding due to abnormalities in vessel walls

2

Major infection that can cause vasculitis, DIC, and abnormal bleeding

Meningococcemia (N. meningitidis)

3

Ehlers-Danlos syndrome

Collagen defect --> microvascular bleeding

4

Vitamin C deficiency, bleeding

Scurvy --> collagen defect, microvascular bleeding

5

Cushing syndrome, bleeding

Excessive corticosteroid production --> protein wasting --> loss of perivascular support tissue --> microvascular bleeding

6

***Hereditary hemorrhagic telangiectasia (W-O-R syndrome)

AD, mutations cause TGF-beta signaling abnormalities, causing dilated tortuous blood vessels that bleed easily (nose, tongue, mouth, eyes, GI tract)

7

Henoch-Schonlein purpura

Systemic immune IgA nephropathy/vasculitis disorder -- immune complex deposition --> rash/palpable purpura, colicky abdominal pain, polyarthralgia, acute glomerulonephritis

8

4 general causes of thrombocytopenia

- Decreased production
- Decreased survival
- Sequestration
- Dilution

9

Things that may selectively affect/inhibit megakaryotyes, causing thrombocytopenia

Cytotoxic drugs, thiazide drugs, alcohol, measles, HIV

10

Things that may decrease platelet production due to BM failure

B12 or folate deficiency, aplastic anemia, myelodysplastic syndrome, metastatic cancer, granulomatous disease, leukemia

11

A woman is pregnant, but the fetus has very few platelets. Cause?

Alloantibodies - the baby's platelets are destroyed by antibodies in the mother

12

A person with a mechanical heart valve has anemia and thrombocytopenia. Why?

Heart valve can cause damage to both RBCs and platelets

13

A patient receives a blood transfusion and develops thrombocytopenia. Why?

Platelets die over time in stored blood, so the patient's platelet concentration is diluted with transfusion

14

Large spleen + thrombocytopenia

Spleen can sequester platelets, causing thrombocytopenia

15

Autoantibody destruction of platelets, bleeding

Immune thrombocytopenic purpura

16

3 causes of secondary chronic ITP

- SLE
- HIV
- B cell neoplasms (CLL)

17

Antibodies against platelet glycoproteins 2b-3a or 1b-IX

What antibody type?

Immune thrombocytopenic purpura

IgG

18

Adult woman under 40, petechiae in skin and mouth, history of easy bruising, nose bleeds, and hemorrhaging after minor trauma. Menorrhagia and melena. Spleen appears normal, no LAD is noted.

Idiopathic chronic ITP

19

Adult woman under 40, petechiae in skin and mouth, history of easy bruising, nose bleeds, and hemorrhaging after minor trauma. Menorrhagia and melena. Splenomegaly and lymphadenopathy are notable.

Secondary chronic ITP - B-cell neoplasm

20

Thrombocytopenia, increased megakaryocytes in the marrow, large platelets in the blood, normal PT and PTT

Accelerated platelet destruction, causing increased thrombopoiesis

21

Child, recently had an upper respiratory viral illness, now presents with thrombocytopenia, petechiae, and purpura. PT and PTT are normal. Increased megakaryocytes in the marrow.

Acute ITP

22

Drugs that cause thrombocytopenia via antibody recognition

Quinine, quinidine, vancomycin, heparin

23

A patient is being treated for an acute MI with IV heparin in the hospital. About a week after treatment, signs of bleeding begin. She barely survives a pulmonary embolism. Blood work shows antibodies against platelet factor 4

Heparin-induced thrombocytopenia (HIT) - Type 2

24

CD4, CXCR4

Receptor and co-receptor for HIV infection, found on megakaryocytes

25

An HIV+ patient develops thrombocytopenia of no other known cause. Why? (2)

- HIV infects megakaryocytes via CD4/CXCR4 and causes apoptosis
- HIV infects plasma cells and causes autoantibody formation against platelet 2b-3 complexes, leading to phagocytosis

26

Adult female, petechiae/purpura, fever, pallor, weakness, fatigue, transient neurologic deficits. Labs show thrombocytopenia, normal PT and PTT. PB smear shows schistocytes or helmet cells. BM biopsy shows increased megakaryocytes.

Cause?

Thrombotic thrombocytopenic purpura (TTP)

Anti-ADAMTS13 autoantibodies (acquired form) or mutation (inherited)

27

Child started having bloody diarrhea, fever, and abdominal pain 3 days ago. Now presents to the ER w/ petechiae/purpura, oliguria, and hematuria. Labs show throbocytopenia, normal PT and PTT. PB shows schistocytes or helmet cells. BM biopsy shows increased megakaryocytes.

Cause?

Hemolytic-uremic syndrome (HUS)

EHEC (or other) infection/toxin, causing endothelial damage, platelet activation, micro-thrombi, and inflammation

28

Defect in complement factor H, CD46, or factor I

Atypical HUS

29

Petechiae/purpura, mild thrombocytopenia, enlarged platelets in blood, GP1b-IX deficiency/mutation

Inherent problem?

Bernard-Soulier syndrome

Defective platelet adhesion (vWF receptor deficit)

30

Petechiae/purpura/bleeding, normal platelet amount, IIb-IIIa deficiency/mutation

Inherent problem?

Glanzmann thrombasthenia

Impaired platelet aggregation (cannot form bridges via fibrinogen)

31

Effect of uremia on platelets

Disrupts adhesion AND aggregation

32

Storage pool disorders

Defective release of thromboxane and ADP from activated platelets

33

Effect of aspirin on platelets

Inhibits production of TxA2 and PGs, which are needed for proper platelet function

34

Post-traumatic ecchymoses, prolonged bleeding after surgeries, bleeding into GI tract, GU tract, and weight-bearing joints

Coagulation factor deficiencies

35

Patient has obvious bleeding issue. Labs show normal platelet amount, prolonged PTT, decreased factor VIII level. Ristocetin activity is reduced.

Von Willebrand Disease

36

Why is factor VIII decreased in vWD types 1 and 3?

vWF stabilizes factor VIII, thus deficient vWF causes decreased factor VIII

37

What is Ristocetin?

Causes platelet aggregation via vWF binding to GP1b. Reduced if vWF is deficient.

38

Male, history of easy bruising and progressive joint pain, presents to the ER due to massive hemorrhage after falling from a tree. Normal platelet amount, prolonged PTT, decreased factor VIII level or activity.

Hemophilia A (factor VIII deficiency)

39

How to distinguish Hemophilia A from Hemophilia B?

ONLY from factor VIII and IX assays

40

A chronic alcoholic presents with excessive bleeding following minor trauma. Labs show normal platelet amount. PT and PTT are prolonged.

Liver disease --> deficient coagulation factors and epoxide reductase (vitamin K activation)

41

Triggers of DIC

- Amniotic fluid tTP (pregnancy complication)
- Septic endotoxins (E. coli, meningococcemia)
- Mucinous adenocarcinoma
- APL primary granules
- Ag-Ab complexes (SLE)
- Heat stroke or burns

42

Bilateral renal cortical necrosis

DIC

43

Kasabach-Merritt syndrome

DIC thrombi w/in giant hemangiomas due to stasis and fragile BV trauma

44

Waterhouse-Friderichsen syndrome

DIC thrombi via meningococcemia causing massive adrenal hemorrhage and failure

45

Read more about DIC

a

46

Bleeding or thrombosis, thrombocytopenia, increased PT and PTT, decreased fibrinogen, D-dimer increase

DIC

47

Acute DIC is most often due to _____ and presents with _____

Obstetric complications; bleeding

48

Chronic DIC is most often due to _____ and presents with _____

Cancers (adenocarcinomas, APL); thrombosis

49

A patient is in the hospital and receives a transfusion of packed RBCs and/or platelets. Soon after, she develops a fever, chills, and dyspnea. She responds well to acetaminophen.

Cause?

Febrile nonhemolytic reaction (transfusion complication)

Donor leukocytes secreting inflammatory mediators due to the foreign environment

50

A patient receives a blood transfusion and develops a severe anaphylactic reaction. Explain

IgA deficiency --> IgG antibodies develop against the IgA in the donor blood --> allergic reaction

51

A patient receives a blood transfusion and develops hives all over his body. Explain

Allergen in the donor blood --> IgE reaction in the patient

52

A patient receives a blood transfusion and develops fever, shaking chills, and flank pain. Hemoglobinuria. A direct Coombs test is positive. May progress to severe symptoms. Explain

IgM reaction to inappropriate ABO blood type, causing complement-mediated hemolysis and inflammation

53

Blood transfusion, low haptoglobin, high LDH, positive direct Coombs test, anti-Rh, anti-Kell, anti-Kid antibodies

Antibody type? To what?

Delayed hemolytic transfusion reaction

IgG - to foreign protein RBC antigens

54

Patient w/ COPD, blood transfusion, sudden SOB, respiratory failure, b/l pulmonary infiltrates, fever, hypotension

Due to what?

The donor was most likely what?

Transfusion-related acute lung injury (TRALI)

Lung neutrophil activation via antibodies from the transfused blood against MHC antigens

A mother of multiple children

55

Blood transfusion, fever, hypotension, chills. Must be cautious of what?

Should do what?

Infectious spread via transfusion

Start on prophylactic antibiotics while awaiting lab results