Thrombocytopenia Flashcards Preview

Clinical Medicine- Heme/Onc > Thrombocytopenia > Flashcards

Flashcards in Thrombocytopenia Deck (19)
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1

What are thrombocytes?

Platelets, provide first line defense against bleeding, form a platelet adhesive plug in traumatized capillaries and small arterioles

2

Etiology of thrombocytopenia?

Decreased platelet production, increased platelet destruction, hypersplenic sequestration

3

What is the lab value for thrombocytopenia?

less than 150,00

4

Some results you might see on blood smear?

Abnormalities of other cell lines suggest marrow/production etiology, isolated T-penia means peripheral destruction, elevated MPV (mean platelet volume) indicates increased thrombopoiesis

5

What is heparin induced thrombocytopenia associated with?

Arterial and venous thrombosis. Will have low platelet count and clotting

6

What is the pathophysiology of heparin induced thrombocytopenia (HIT)?

Platelets secrete protein PF4 that bind to heparin. IgG antibodies bind to the complex. This activates more platelet and antibody production. Platelets aggregate and undergo premature removal from circulation. This can lead to increased risk of thrombosis.

7

What is idiopathic thrombocytopenic purpura (ITP)?

AUTOIMMUNE disorder caused by circulating antiplatelet autoantibodies (IgG)

8

Workup for ITP?

Acute- decreased platelet (10-20,000), eosinophilia, mild lymphocytosis. Chronic- plt count 25-75,000, mild anemia, may be megakaryocytes on smear

9

Clinical manifestation of ITP?

Acute- abrupt onset of petechiae and purpura of skin and mucous membrane. Chronic- usually asx, may develop petechiae and purpura. Excessive mucoid bleeding. Examine/look for epistaxis, gingivial bleeding, easy bruising, hematuria, melena, hematochezia, menorrhagia, subconjunctival hemorrhage, retinal hemorrhage

10

Lab test for TTP?

CBC (severe anemia and T-penia), peri blood smear (numerous RBC fragments), elevated BUN/creatinine, evidence of hemolysis (increased retic ct, indirect bili, LDH), urinalysis, no evidence of DIC

11

What is thrombotic thrombocytopenia purpura?

Rare, often fatal, platelet consumption d/o associated with hemolytic anemia.

12

Clinical presentation of TTP?

Often begins like flu. C/o of non-specific constitutional sxs, purpura secondary to T-penia, jaundice, pallor, mucosal bleeding, fever, flucuating lvls of consciousness, renal failure and neurological events are often end stage

13

Lab test for TTP?

CBC (severe anemia and T-penia), peri blood smear (numerous RBC fragments), elevated BUN/creatinine, evidence of hemolysis (increased retic ct, indirect bili, LDH), urinalysis, no evidence of DIC

14

Treatment for chronic TTP?

Relapsing TTP- PLEX, rituximab or cyclophosphamide, splenectomy

15

Laboratory test run if suspected thrombocytopenia?

CBC, peripheral blood smear, (PT (INR), PTT- indicated in ill, hospitalized or postsurgical patients)

16

Workup for HIT?

Confirmed with lab testing. 4 T's, T-penia, timing of onset, thrombosis, oTher causes. Can also do Heparin antibody test, ELISA, Functional serotonin release assay (gold standard), doppler US

17

Treatment of HIT?

D/C heparin. Begin alternate anticoagulant. Direct thombin inhibitors (Argotroban, lepirudin, bivalirudin) then initiate Warfarin when count normalizes.

18

Treatment of ITP?

Treat symptoms and platelet count. Corticosteroids (high dose prednisone or dexamethasone 4-6 cycles. ISA (IVIG, anti DIG, rituximab), splenectomy for refractory pt. Thrombopoietin (Eltrombopag, romiplastim)

19

Treatment of acute TTP?

Emergency large volume plasmapheresis. Plasma exchange (PLEX) for atleast 2 days until count normal. Plasma infusion if unable to start PLEX. Prednisone, Rituximab, platelet transfusions, splenectomy