Lecture 8: Platelet Disorders Flashcards
ITP may be part of a broader disease affecting immune regulation such as what?
- HIV infection
- SLE
- Lymphoproliferative malignancy, especially in older pt’s
All pt’s with ITP should be screened for what infection; recent research has also linked ITP to what other infective agent?
- All pt’s should be screened for HIV
- Recent reports have linked ITP to H. pylori infection
What will blood smear of someone with ITP show?
Decreased platelets and occasional large platelets (megathrombocytes)
ITP can be triggered by almost any drug, but is most commonly seen in association with what?
Quinine or Quinidine
What are 2 effective therapies for ITP with severe thrombocytopenia or active bleeding is present?
Glucocorticoids and IVIG
Which 2nd line immunosuppressive agent will lead to doubling of the platelet count in 40% of pt’s with ITP?
Rituximab
Is splenectomy indicated for ITP?
Rarely, only in those w/ significant bleeding unresponsive to immunosuppressive medications
What should a CBC of pt with ITP show in terms of platelets, Hgb, Hct, and leukocytes?
- Low platelet count
- Normal Hgb, Hct, and leukocyte count
Although pt’s with heparin induced thrombocytopnia do not bleed excessively they have a dramatic risk what complications?
- DVT’sandPE’s
- Unusual clotting problems i.e., portal vein thrombosis or acute arterial occlusion
Which type of heparin is more likely to lead to HIT and which is less likely?
- Unfractionated heparin = more likely
- Incidence is 2-3x lower in pt’s receiving LMW heparin
What is the “4T Score” used clinically to determine the likelihood of HIT?
- Degree of Thrombocytopenia
- Timing of platelet count fall
- Thrombosis or other sequelae
- Other causes for Thrombocytopenia present
Describe the degree of thrombocytopenia associated with 2, 1, or 0 points using the “4T Score” in assessing HIT risk?
- 2 points = platelet count >50% fall and nadir ≥20,000/uL
- 1 point = platelet count 30-50% fall or nadir 10,000-19,000/uL
- 0 points = platelet count <30% fall or nadir <10,000/uL
Describe the timing of platelet count fall associated with 2, 1, or 0 points using the “4T Score” in assessing HIT risk?
- 2 points: clear onset btw days 5 and 10 or platelet count decrease at ≤1 day if prior heparin exposure within last 30 days
- 1 point: onset after day 10 or timing unclear, or ≤ day 1 if heparin exposure within past 30-100 days
- 0 points: platelet count fall <4 days without recent exposure
Describe the thrombosis or other sequelae category associated with 2, 1, or 0 points using the “4T Score” in assessing HIT risk?
- 2 points: confirmed nw thrombosis, skin necrosis, or acute systemic rxn after IV unfractionated heparin bolus
- 1 point: progressive or recurrent thrombosis, nonnecrotizing (erythematous) skin lesions, or suspected thrombosis not proven
- 0 points: no thrombosis or sequelae
Which findings for the category “other causes of thrombosis” are associated with 2, 1, or 0 points using the “4T Score” in assessing HIT risk?
- 2 points = no other cause apparent
- 1 point = another cause is possible
- 0 points = definite other cause