Platelet Disorders

Question 1

Bernard-Soulier syndrome platelet count

Answer 1

-/decrease

Question 2

Bernard-Soulier syndrome bleeding time

Answer 2

increase

Question 3

defect in platelet plug formation ->

Answer 3

increase bleeding time

Question 4

platelet abnormalities ->

Answer 4

micro hemorrhage: mucus membrane bleeding, epistaxis, petechiae, purpura, increase bleeding time, possibly decreased platelet count

Question 5

Bernard-Soulier syndrome mechanism

Answer 5

defect in platelet plug formation

large platelets

Question 6

Bernard-soulier syndrome comments

Answer 6

decrease GpIb -> defect in platelet-to-vWF adhesion

abnormal ristocetin test that does not correct with mixing studies

Question 7

Glanzman thrombasthenia platelet count

Answer 7

–

Question 8

Glanzmann thrombasthenia bleeding time

Answer 8

increase

Question 9

Glanzmann thrombasthenia mechanism

Answer 9

defect in platelet intern αIIb ß3 (GpIIb/IIIa) -> defect in platelet-to-platelet aggregation, and therefore platelet plug formation

Question 10

Glanzmann thrombasthenia labs

Answer 10

blood smear shows no platelet clumping

Question 11

HUS platelet count

Answer 11

decrease

Question 12

HUS bleeding time

Answer 12

increase

Question 13

HUS characterized by

Answer 13

thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure

Question 14

HUS presentation

Answer 14

typical HUS seen in children, accompanied by diarrhea and commonly caused by Shira-like toxin of EHEC
HUS in adults does not present with diarrhea; EHEC infection not required

Question 15

immune thrombocytopenia platelet count

Answer 15

decrease

Question 16

immune thrombocytopenia bleeding time

Answer 16

increase

Question 17

immune thrombocytopenia mechanism

Answer 17

anti-GpIIb/IIIa antibodies -> splenic macrophage consumption of platelet-antibody complex
may be primary or secondary to autoimmune disorder, viral illness, malignancy, or drug reaction

Question 18

immune thrombocytopenia labs

Answer 18

increase megakaryocytic on bone marrow biopsy

Question 19

immune thrombocytopenia treatment

Answer 19

steroids, IVIG

rituximab or splenectomy for refractory ITP

Question 20

TTP platelet count

Answer 20

decrease

Question 21

TTP bleeding time

Answer 21

increase

Question 22

TTP mechanism

Answer 22

inhibition or deficiency of ADAMTS 13 (vWF metalloprotease) -> decrease degradation of vWF multimers

Question 23

TTP pathogenesis

Answer 23

increase large vWF multimers -> increase platelet adhesion -> increase platelet aggregation and thrombosis

Question 24

TTP labs

Answer 24

schistocytes, increase LDH, normal coagulation parameters

Question 25

TTP symptoms

Answer 25

FAT RN | pentad of Fever, microangiopathic hemolytic Anemia, Thrombocytopenia, Renal failure, Neurologic symptoms

Question 26

TTP treatment

Answer 26

plasmapheresis, steroids

Question 27

von willebrand disease platelet count

Answer 27

normal

Question 28

vWD bleeding time

Answer 28

increase

Question 29

vWD PT

Answer 29

normal

Question 30

vWD PTT

Answer 30

normal or increased

Question 31

vWD mechanism

Answer 31

intrinsic pathway coagulation defect: decrease vWF -> increase PTT (vWF acts to carry/protect factor VIII) defect in platelet plug formation: decrease vWF -> defect in platelet-to-vWF adhesion autosomal dominant

Question 32

vWD treatment

Answer 32

desmopressin, which releases vWF stored in endothelium

Question 33

DIC platelet count

Answer 33

decrease

Question 34

DIC bleeding time

Answer 34

increase

Question 35

DIC PT

Answer 35

increase

Question 36

DIC PTT

Answer 36

increase

Question 37

DIC mechanism

Answer 37

widespread activation of clotting -> deficiency in clotting factors -> bleeding state

Question 38

causes of DIC

Answer 38

Sepsis (gram negative), Trauma, Obstetric complications, acute Pancreatitis, Malignancy, Nephrotic syndrome, Transfusion (STOP Making New Thrombi)

Question 39

DIC labs

Answer 39

schistocytes, increase fibrin degradation products (D-Dimers), decrease fibrinogen, decreas factors V and VIII