DIT Platelets

Question 1

2 functions of vWF?

Answer 1

complex with factor VIII (if deficiency increases PTT)

Platelet adhesion to vessel collagen wall and other platelets (Deficiency causes longer bleeding time)

Question 2

Platelets have thrombin. What does it do?

Answer 2

Fibrinogen to fibrin

Question 3

Side effect of aspirin in kids?

Answer 3

Reye syndrome. Hepatoencephalopathy

Liver poblems and encephalopathy and hypoglycemia (b/c bad liver)

Question 4

Platelet ADP receptors inhibitors?

How does it affect platelets

Answer 4

CLOPidogrel (has D and P in it)
TiCLOPidine
Ticagrelor
Prasugrel

No platelet aggregation b/c no aggregation b/c ADP receptor is what signals for GpIIbIIIa to be on cell surface

Question 5

Glycoprotein IIb/IIIa inhibitors

Answer 5

Abciximab, eptiFIBatide, and tiroFIBan

Can’t bind fibrinogen to crosslink platetes (fib in middle b/c mimics fibrinogen and interrupts binding site)

Question 6

Platelet lifespan?

Answer 6

8-10 days

Question 7

Symptoms of platelet disorders?

Answer 7

Microhemorrhages: bleeding from mucous membranes, epistaxis, petechiae (look like freckles), purpura

high bleeding time

Question 8

Platelet disorders. Only 4 of them, but they are 4 Star

Answer 8

4 star!

Question 9

Cause of immune thrombocytopenia?

Tx?

Labs?

Answer 9

Anti-GpIIb/IIIa antibodies: spelenic macrophage eat the platelets (virus can trigger it)

Labs: megakaryocytic increased in marrow b/c trying to get platelet count back up

Tx: steroids or IVIG or splenectomy (can’t store platelets in spleen so more in circulation)

Question 10

What is cause of TTP?

Answer 10

Thrombotic thrombocytopenic purpura:

Platelets excessively activated B/c ADAMTS13 is deficient so can’t break down vWF which causes large vWF which activates platelets.

Widespread thrombosis and results in thrombocytopenia. Results in purpura

Also: activation of coag cascade and excessive fibrin mesh: microangiopathic hemolytic anemia with schistocytes

Question 11

What is HUS? what is triad?

Answer 11

Think of as milder version of TTP

Hemolysis
Uremia (renal insifcciency)
Thrombocytopenia

Question 12

What is pentad of TTP? Mnemonic

Answer 12

Nasty FEVER Torched His KIDNEYS

Neurological symptoms (headache, confusion, seizure, coma)

Fever
Thrombocytopenia
Hemolysis
Kidney failure

Question 13

what is HUS associated with?

Answer 13

EHEC

Question 14

What is going on in Bernard Soulier syndrome?

Answer 14

Defect in Gp1b so can’t bind vWF. There is “1b” in bernard

Platelets are enlarged and removed from circulation so result is slightly low platelet count

Question 15

What is up in Glanzmann thrombasthenia?

Answer 15

GpIIb/IIa defect so no plaetelet aggregation.

Blood smear shows no platelet clumping

High BT, but normal PC

Question 16

Thrombocytopenia caused by things that are not wrong with platelets?

Answer 16

Heparin induced thrombocytopenia

Aplastic anemia

Question 17

What is going on in von Willebrand disease?

Tx? NEED TO KNOW

Answer 17

Decreased vWF so less of its two functions . 1: platelet adhesion and factor 8 stabilization

Higher BT AND higher PTT!!!

It is common

Tx is weird: DDAVP (desmopressin) b/c it releases stored vWF from endothelium

Question 18

What are causes of DIC? Mnemonic

Labs?

Answer 18

Labs: high fibrin split products, low fibrinogen, platelets and V and VIII (and really everything)

high BT, PT, PTT, Schistocytes

STOP Making New Thrombi

Sepsis
Trauma
Obstetric complication (abrupted placenta)
Pancreatitis
Malignancy
Transfusion