Thrombocytopenia

Question 1

What are thrombocytes?

Answer 1

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

Question 2

Etiology of thrombocytopenia?

Answer 2

Decreased platelet production, increased platelet destruction, hypersplenic sequestration

Question 3

What is the lab value for thrombocytopenia?

Answer 3

less than 150,00

Question 4

Some results you might see on blood smear?

Answer 4

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

Question 5

What is heparin induced thrombocytopenia associated with?

Answer 5

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

Question 6

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

Answer 6

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.

Question 7

What is idiopathic thrombocytopenic purpura (ITP)?

Answer 7

AUTOIMMUNE disorder caused by circulating antiplatelet autoantibodies (IgG)

Question 8

Workup for ITP?

Answer 8

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

Question 9

Clinical manifestation of ITP?

Answer 9

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

Question 10

Lab test for TTP?

Answer 10

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

Question 11

What is thrombotic thrombocytopenia purpura?

Answer 11

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

Question 12

Clinical presentation of TTP?

Answer 12

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

Question 13

Lab test for TTP?

Answer 13

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

Question 14

Treatment for chronic TTP?

Answer 14

Relapsing TTP- PLEX, rituximab or cyclophosphamide, splenectomy

Question 15

Laboratory test run if suspected thrombocytopenia?

Answer 15

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

Question 16

Workup for HIT?

Answer 16

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

Question 17

Treatment of HIT?

Answer 17

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

Question 18

Treatment of ITP?

Answer 18

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)

Question 19

Treatment of acute TTP?

Answer 19

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