Diana Escobar Azusa Pacific University

Authors: Thiele, Thomas, Kathleen Selleng, Sixten Selleng, Andreas Greinacher, &Tamam Bakchoul July 2013 Source: International Seminar of Hematology Database: MEDLINE

 Thrombocytopenia (TCP) is commonly defined as a platelet count of <150,000 plts, some apply the cut-off at <100,000 plts, and even further to <50,000plts in patients ◦ Platelet number alone is not definitive  Compare to the patient’s baseline & nadir  Analyze timing of decrease & overall trend  Also analyze a lack of rise in plt ct.

Common Causes

1. Hemodilution 2. Increased platelet consumption ◦ Due to massive trauma, bleeding, sepsis, DIC 3. Decreased platelet production 4. Increased platelet sequestration 5. Platelet destruction by immune mechanisms  Pseudothombocytopenina: “Idiopathic” ◦ develops in 2.5% of pts taking grycoprotein Iib/IIIa antagonists: abciximab, integrilin, tirofiban  Dx: repeated blood counts in citrated or heparinized blood

 In order to correctly identify, nurses must be familiar with the “normal” platelet trends in ICU patients with differing conditions. ◦ i.e.: trauma, major/minor surgery, medical.  Postsurgical: Expected Plt ct. decline between D1-D4 ◦ Magnitude reflects the extent of tissue trauma/blood loss  Plt. Consumption ◦ Should reach pre-surgery level between D5-D7, peak at D14

 *Post-Trauma: Critically injured pts: almost normal Plt cts at admission w/ rapid Plt decrease during first hrs ◦ *Plt ct <50,000 &/or delay in Plt. Recovery  associated with high mortality  *Medical: Plt. ct depends on underlying disease ◦ Predisposing conditions: Sepsis, DIC, Renal Replacement Therapy, Extracorporeal circuits, Intravascular devices, Multi-organ Failure, & recent CPR  Recent study of 243 ICU Pts  In medical pts. Plt recovery expected w/in 5D (90%), with proper treatment of underlying disease  Higher morbidity/mortality is Plt recovery delayed >4D  Persistent TCP at D14  mortality rt of 66% vs. 16% with normal Plt ct. Median Plt increase expected in ICU pts of ~30 x 10 ∧ 9/ L/D in survivors

 Monitor closely the trends in Plt recovery and be alert for any sudden decrease after initial recovery  Acute TCP can result from: ◦ Sepsis, acute infection, acute leukemia, severe thromboembolism, intoxication: alcohol, drug side- effects  Be alert for: ◦ Rapid decrease w/in hrs after several days in ICU w/out reason  Dx: Plt trends, baseline, nadir, plt specifics

 Trauma: concomitant treatment for hemodilution, hypothermia, loss of clotting factors and platelets, hyperfibrinolysis ◦ Early Plt transfusions w/RBCs for major trauma  DIC: Manage underlying conditions and causes, platelet transfusions only given in cases w/high risk for bleeding  Sepsis: correlated with adverse outcomes, but not a cause, therefore Tx underlying infection  Intoxication: ◦ Chronic Alcohol abuse due to Plt sequestration in spleen (splenomegaly)

 Intoxication… ◦ Drugs (Non-Immune Pathogenesis): adverse drug reactions in 20% hospital pts. (effects on megakaryocytes)  Study of 3,496 pts finds:  Histamine H2 Antagonists  Nonsteroidal anti-inflammatory drugs  Unfractionated heparin  Acetaminophen (3.4% pts), valproate, carbamazepine, phenobartital, phenytoin (1%pts) ◦ Herbals: take detailed Hx ◦ Venoms: activate clotting cascade ◦ Treatment: charcoal ingestions, dialysis, antidote administration, d/c medications

 Immune: Plt ct fall to <5,000 w/in 24-48hrs w/bleeding symptoms or if Plt ct decreases 50%+ in 2 nd week of Tx ◦ Immune mediated Drug-Induced Thrombocytopenia (DITP)  Dx: Need lab tests of drug-dependent antibodies  Tx: D/C drugs immediately  Most Common Drugs:  Vancomycin, Penicillin, trimethoprim/sulfamethozazole, ceftriaxone, ibuprofen, meirtazapine

 Drug: Heparin Induced TCP (HIT) ◦ Drug-mediated, prothromboric disorder b/c immunization against Plt. Factor 4  S/S: Plt ct fall >50% from the highest value after start of Heparin Tx and/or a new thrombosis occurring 5-14D after Tx ◦ Incidence of HIT is low in ICU according to study  N= ICU pts w/ incidence confirmed in 0.5% pts  Dx depends on scoring results of: Thrombocytopenia, Timing, Thrombosis, & oThers (4Ts Test/HEP Test)  Tx: d/c heparin, use low molecular weight heparin delteparin, use non-heparin anticoagulants

 What are the 3 most common causes of TCP in ICU patients? A. HIT, sepsis, trauma B. Trauma, DIC, sepsis C. Trauma, surgery complications, sepsis D. Intoxication, trauma, Immune response

 What are the three most common causes of TCP in ICU patients? A. HIP, sepsis, trauma B. Trauma, DIC, sepsis C. Trauma, surgery complications, sepsis D. Intoxication, trauma, Immune response

 True or False: Platelet transfusion is the first line treatment for patients with Thrombocytopenia

 False, first line treatment should be to target and treat underlying disease, platelet transfusions are only indicated bleeding patients or invasive procedures

Thiele, T., Selleng, K., Selleng, S., Greinacher, A., & Bakchoul, T. (2013). Thrombocytopenia in the intensive care unit-diagnostic approach and management. Seminars In Hematology, 50(3), doi: /j.seminhematol