111 Disorders of Platelets and Vessel Wall Flashcards
Average lifespan of platelets (H20 C111 P823)
7-10 days
In vitro artifact resulting from platelet agglutination via antibodies when the calcium content is decreased by blood collection in EDTA (H20 C111 P823)
Peudothrombocytopenia
Patients with isolated thrombocytopenia who are at least this age should have their bone marrow examined (H20 C111 P823)
60 years
Clinical manifestation that is thought to denote an increased risk of life-threatening hemorrhage in the thrombocytopenic patient (H20 C111 P823)
Wet purpura
Most common cause of thrombocytopenia (H20 C111 P823)
Drugs
Drugs usually induce thrombocytopenia after a median length of 21 days. However, this drug class differs in that it can induce thrombocytopenia within 24 h of intial exposure. (H20 C111 P825)
Gp IIb/IIIa inhibitory drugs, e.g. abciximab
Nadir platelet counts in HIT are rarely below: (H20 C111 P825)
20,000/µL
Most patients develop HIT after exposure to heparin for how many days? (H20 C111 P825)
5-14 days
Most widely available test to detect HIT antibodies (H20 C111 P825)
ELISA with PF4/polyanion complex
An increased risk of thrombosis is present for at least how long after diagnosis of HIT (H20 C111 P825)
1 month
In addition to wet purpura, this sign may also herald life-threatening bleeding in ITP (H20 C111 P825)
Retinal hemorrhages
If anemia is present in a patient with ITP, this test should be done (H20 C111 P826)
Direct antiglobulin testing / Coombs test (to rule out Evans syndrome)
This platelet count is required to maintain vascular integrity (H20 C111 P823)
~5,000-10,000/µL
IVIgG has more efficacy than anti-Rh0(D) in these patients (H20 C111 P826)
Postsplenectomized patients
Oral TPO receptor agonist that is effective in raising platelet counts in patients with ITP (H20 C111 P826)
Elthrombopag
SC TPO receptor agonist that is effective in raising platelet counts in patients with ITP (H20 C111 P826)
Romiplostim
Common feature of the many forms of autosomal dominant thrombocytopenia (H20 C111 P826)
Large platelets
Functional platelet disorder due to absence of Gp Ib-IX-V (H20 C111 P826)
Bernard-Soulier syndrome
Inherited TTP (H20 C111 P826)
Upshaw-Shulman syndrome
Mainstay of treatment of TTP (H20 C111 P827)
Plasma exchange
Markedly elevated platelet counts above this value is a risk factor for bleeding (H20 C111 P827)
> 1.5 million/µL
Glanzmann thrombasthenia is an autosomal recessive disorder that is characterized by the absence of: (H20 C111 P827)
Platelet Gp IIb/IIIa receptor
Humanized monoclonal antibody against C5 that has efficacy in preserving renal function in HUS (H20 C111 P827)
Eculizumab
Inherited disorders of platelet dysfunction would require transfusion of: (H20 C111 P828)
HLA-matched leuko-depleted platelet concentrates
