Bleeding Disorders - Ch. 14

Question 1

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

Answer 1

Bleeding due to abnormalities in vessel walls

Question 2

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

Answer 2

Meningococcemia (N. meningitidis)

Question 3

Ehlers-Danlos syndrome

Answer 3

Collagen defect –> microvascular bleeding

Question 4

Vitamin C deficiency, bleeding

Answer 4

Scurvy –> collagen defect, microvascular bleeding

Question 5

Cushing syndrome, bleeding

Answer 5

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

Question 6

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

Answer 6

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

Question 7

Henoch-Schonlein purpura

Answer 7

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

Question 8

4 general causes of thrombocytopenia

Answer 8

• Decreased production
• Decreased survival
• Sequestration
• Dilution

Question 9

Things that may selectively affect/inhibit megakaryotyes, causing thrombocytopenia

Answer 9

Cytotoxic drugs, thiazide drugs, alcohol, measles, HIV

Question 10

Things that may decrease platelet production due to BM failure

Answer 10

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

Question 11

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

Answer 11

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

Question 12

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

Answer 12

Heart valve can cause damage to both RBCs and platelets

Question 13

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

Answer 13

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

Question 14

Large spleen + thrombocytopenia

Answer 14

Spleen can sequester platelets, causing thrombocytopenia

Question 15

Autoantibody destruction of platelets, bleeding

Answer 15

Immune thrombocytopenic purpura

Question 16

3 causes of secondary chronic ITP

Answer 16

• SLE
• HIV
• B cell neoplasms (CLL)

Question 17

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

What antibody type?

Answer 17

Immune thrombocytopenic purpura

IgG

Question 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.

Answer 18

Idiopathic chronic ITP

Question 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.

Answer 19

Secondary chronic ITP - B-cell neoplasm

Question 20

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

Answer 20

Accelerated platelet destruction, causing increased thrombopoiesis

Question 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.

Answer 21

Acute ITP

Question 22

Drugs that cause thrombocytopenia via antibody recognition

Answer 22

Quinine, quinidine, vancomycin, heparin

Question 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

Answer 23

Heparin-induced thrombocytopenia (HIT) - Type 2

Question 24

CD4, CXCR4

Answer 24

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

Question 25

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

Answer 25

- 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

Question 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?

Answer 26

Thrombotic thrombocytopenic purpura (TTP) Anti-ADAMTS13 autoantibodies (acquired form) or mutation (inherited)

Question 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?

Answer 27

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

Question 28

Defect in complement factor H, CD46, or factor I

Answer 28

Atypical HUS

Question 29

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

Answer 29

Bernard-Soulier syndrome Defective platelet adhesion (vWF receptor deficit)

Question 30

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

Answer 30

Glanzmann thrombasthenia Impaired platelet aggregation (cannot form bridges via fibrinogen)

Question 31

Effect of uremia on platelets

Answer 31

Disrupts adhesion AND aggregation

Question 32

Storage pool disorders

Answer 32

Defective release of thromboxane and ADP from activated platelets

Question 33

Effect of aspirin on platelets

Answer 33

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

Question 34

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

Answer 34

Coagulation factor deficiencies

Question 35

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

Answer 35

Von Willebrand Disease

Question 36

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

Answer 36

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

Question 37

What is Ristocetin?

Answer 37

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

Question 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.

Answer 38

Hemophilia A (factor VIII deficiency)

Question 39

How to distinguish Hemophilia A from Hemophilia B?

Answer 39

ONLY from factor VIII and IX assays

Question 40

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

Answer 40

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

Question 41

Triggers of DIC

Answer 41

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

Question 42

Bilateral renal cortical necrosis

Answer 42

DIC

Question 43

Kasabach-Merritt syndrome

Answer 43

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

Question 44

Waterhouse-Friderichsen syndrome

Answer 44

DIC thrombi via meningococcemia causing massive adrenal hemorrhage and failure

Question 45

Read more about DIC

Answer 45

a

Question 46

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

Answer 46

DIC

Question 47

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

Answer 47

Obstetric complications; bleeding

Question 48

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

Answer 48

Cancers (adenocarcinomas, APL); thrombosis

Question 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?

Answer 49

Febrile nonhemolytic reaction (transfusion complication) Donor leukocytes secreting inflammatory mediators due to the foreign environment

Question 50

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

Answer 50

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

Question 51

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

Answer 51

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

Question 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

Answer 52

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

Question 53

Blood transfusion, low haptoglobin, high LDH, positive direct Coombs test, anti-Rh, anti-Kell, anti-Kid antibodies Antibody type? To what?

Answer 53

Delayed hemolytic transfusion reaction IgG - to foreign protein RBC antigens

Question 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?

Answer 54

Transfusion-related acute lung injury (TRALI) Lung neutrophil activation via antibodies from the transfused blood against MHC antigens A mother of multiple children

Question 55

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

Answer 55

Infectious spread via transfusion Start on prophylactic antibiotics while awaiting lab results