Lecture 7: Bleeding Disorders Flashcards
What two things in the history help determine bleeding disorder etiology?
- Bleeding site
- Underlying bleeding tendency that is enhanced by: other med conditions, intro of meds, or dietary supplements
why are age and sex important
severe inherited bleeding disorders often manifest in infancy or early childhood.
What does a mucocutaneous bleed suggest?
Qualitative/quantitative platelet disorder
What does a joint or soft tissue bleed suggest?
Coag factor disorder
What should an initial panel of lab tests include to help determine bleeding disorder etiology?
CBC
Peripheral blood smear
Coag panel (INR/PTT/PT)
CMP
Additional:
Bleeding time
PFA-100
What is a PFA for?
Whole blood flows through a capillary coated with platelet agonists.
platelets aggregate and stop the flow in the capillary
closure time is measured.
This assesses platelet function with greater sensitivity and reproducibility than the bleeding time.
What AC is measured with aPTT? Why?
UFH, because aPTT measures intrinsic pathway, which has thrombin.
What AC is measured with PT? Why?
Warfarin, because PT measures extrinsic pathway, which is more Vit-K dependent.
What other disease can PT monitor?
Liver, bc Vit K
What is INR?
International normalized ratio.
It is the ratio of PT to a standard sample.
What does high INR indicate?
Higher risk of bleeding.
What is the mnemonic for PTT and PT?
PTT = play table tennis (inside)
PT = play tennis (outside)
How are coag factors measured?
PT and aPTT can be compared in a sample plasma to a commercial plasma deficient in certain factors.
When do I use aPTT and PT tests together?
To monitor the transition between heparin and warfarin
What does a primary hemostasis disorder affect?
Mucous membrane bleeding, epistaxis, and petechiae.
Affects bleeding time and platelet counts.
What does a secondary hemostasis disorder affect?
Hemarthrosis, intracerebral hemorrhage, and deep tissue hematomas.
Affects PT and PTT.
What is hemophilia A?
Congenital deficiency of Factor 8. (vWF related)
What is hemophilia B?
Congenital deficiency of Factor 9
What kind of inheritance is hemophilia A?
X-linked recessive
1 in 5000 male live births
What kind of inheritance is hemophilia B? how many male live births
X-linked recessive
1 in 25000 male live births
How do female carriers of hemophilia present?
Asymptomatic.
How does severe hemophilia present commonly?
Early childhood spontaneous bleeds into joints or soft tissues.
How does mild hemophilia present commonly?
Excess bleeding post hemostatic challenge like surgery.
What is the secondary concern in patients with hemophilia?
They can develop inhibitors to the factors they are deficient in.
30% in A
5% in B