OnlineMedEd: Intern Content - "Platelets"

Question 1

Review primary hemostasis.

Answer 1

Injured endothelium binds to von Willebrand factor. Platelets bind to vWF. Platelets then activate and bind to each other as well as fibrinogen.

Question 2

DIC results from _________ clots.

Answer 2

fibrin

Question 3

The “DIC panel” includes which tests?

Answer 3

• Platelets
• PT/INR
• PTT
• D-dimer
• Fibrinogen
• Blood smear (looking for schistocytes)

Question 4

How do you treat DIC?

Answer 4

•First and foremost, treat the underlying cause (e.g., AML, infection, etc.) 
•Second, replace missing things: 
- Platelets
- Cryo (for low fibrinogen) 
- FFP (for elevated PT, PTT) 
- pRBCs (for low Hgb)

Question 5

TTP results from ____________ clots.

Answer 5

hyaline

Question 6

Describe why it is easy to confuse TTP and DIC.

Answer 6

• They both result in low platelets and schistocytes on smear.
• Difference: TTP results in hyaline clots, so fibrinogen, D-dimer, and PT/PTT will be normal in TTP.

Question 7

Discuss the two typical presentations of HIT.

Answer 7

• Asymptomatic platelet drop in a hospitalized patient

* Clot worsening after giving heparin for the clot

Question 8

Review the scoring system for HIT diagnosis.

Answer 8

•Timing:

• 2: 5-10 days
• 1: > 10 days
• 0: < 5 days

•Thrombosis:

• 2: new thrombus
• 1: extension of thrombus
• 0: no thrombus

•Thrombocytopenia:

• 2: >50% but not 100%
• 1: 30-50% drop
• 0: <30% drop

•Alternative diagnosis:

• 2: none
• 1: plausible alternative
• 0: clear diagnosis

Question 9

HIT is treated how?

Answer 9

Lepirudin or argatroban bridge to warfarin

Question 10

How is ITP treated?

Answer 10

• First-line: corticosteroids
• Second-line: IVIG, rituximab
• Third-line (refractory): splenectomy