Hematology Flashcards
Ddx for Microcytic anemia (MCV <100)
Iron Deficiency Thalassemia Anemic or Chronic disease (low normal MCV) Sideroblasic anemia Lead poisoning
DDX Macrocytic amenia (MCV >100)
Megaloblastic anemia:folic acid or Vit B12 def Liver diease Alcoholism Reticulocytosis Hypothyroidism Myelodysplastic syndrome Antiretrovirals (AZT)
What is the onset and peak effect of vitamin k? IV and PO
IV 1-2 hours onset peak effect 6-12 hours
PO 6-12 hours onset peak effect 12-24 hours
What are the vitamin K sensitive clotting factors?
2,7,9,10
At what platelet count do you worry about spontaneous hemorrage?
<20
What are some common anti-platelet drugs?
- Aspirin (irreversible* cyclooxygenase inhibitor)
- Adenosine diphosphate (ADP) receptor inhibitors
- Clopidogrel (Plavix)
- Prasugrel (Effient)
- Ticagrelor (Brilinta)
- Ticlopidine (Ticlid) - Glycoprotein IIB/IIIA inhibitors (intravenous use only)
With low platelets or patients with platlet dysfunction, where do they normally bleed?
- Can bleed anywhere but may present with petechiae, have mucosal bleeding
- May have purpura - usu non palpable
What time course does HIT (heparin induced thrombocytopenia) appear?
5-7 days after starting heparin or LMWH. There is such thing as delayed onset hit usu up to 14 days post starting, but has been reported to occur 40 days after starting heparin
Other than low platelets itself what are other complications of HIT?
Patients can develop an arterial or venous thrombus.
What is the HUS triad?
Microangiopathic hemolytic anemia (MAHA)
Renal failure
Thrombocytopenia
What is the TTP pentad?
MAHA Renal Failure (less prominent feature) Thrombocytopenia Fever Neurologic symptoms - AMS - Stroke - Headaches - Bizarre behavior
Its not common to see this pentad..
If you suspect TTP what therapy should you avoid?
Transfusing platelets, may actually worsen condition causing additional thrombi in the micro-circulation.
- Consult Hematology
DDX incr INR (measures extrinsic pathway)
- Warfarin
- Vit K deficency
- Severe Liver disease
- Factor 7 def or inhibitor
DDX elevated PT/INR and PTT
- Deficencies of prothrombin, fibrinogen, Factors V and X
- Heparin + warfarin
- DIC *
- Liver Dx
DDX incr PTT (measures intrinsic pathway)
- Heparin
- Hemophilias
- vWF
Hemophilia A effects what factor?
8
Hemophilia B effects what factor?
9 aka. Christmas disease
In Hemophiliacs where do they most commonly bleed?
Joints, Deep muscle, urinary tract, Intracranial
In platelet disorders like vWF where do they commonly bleed?
Oral bleeding, epistaxis, menorragia,
GIB rare unless other cause - like ulcer etc.
What is in cryoprecipitate?
- Fibrinogen 150-250 mg with a half-life of 100-150 hours
- Factor VIII 80-150 U with a half-life of 12 hours
- von Willebrand factor 100-150 U with a half-life of 24 hours
- Factor XIII 50-75 U with a half-life of 150-300 hours.
What is in FFP?
All the blood clotting components, even the liable ones (5,8) but you have to give early after thawing.
What is the INR of FFP?
1.5
What is a d-dimer?
D-dimers are cross-linked fibrin degradation products
- it is a product of plasmin mediated fibrinoyltic degradation
- They are an excellent marker of fibrinolytic activity
What non-pathologic conditions are assoc with an elevated D-dimer? (5)
Non-pathological conditions associated with elevated D-dimer titres include:
- Age (healthy elderly people)
- Cigarette smoking
- Functional impairment
- Post-operatively
- Pregnancy
- Race (e.g. African Americans)
When can D-dimer be used to r/o VTE?
In a patient with low pre-test probability of having a VTE
- Need to use Wells criteria for PE or DVT.
