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HOW I MANAGE THROMBOCYTOPENIA
Dr Li Huey Tan
Intensivist, Alfred Hospital
Clinical Lead Echocardiography, Epworth Hospital
Conflict of Interest - None
Dr Li Huey Tan
Intensivist, Alfred Hospital
Clinical Lead Echocardiography, Epworth Hospital
67 year old, Day 2 post CAG x 3 for TVDSinus rhythm, BP stable. ICC output15-20ml every 4 hours, due for ward discharge.Morning bloods showed Hb 9 g/dL, platelets 80 (150x109)
What would you do?
A. Transfuse 1 pool platelets as the patient still has drain output.
B. Repeat the FBC but probably just observe.
C. Withold the aspirin and Clexane.
D.Do a HITS screen. Duh..
E. Call Dr Yong…or haematology
Call Haematology?
Thrombocytopenia in ICU
• ~ 35-40% in intensive care patients. <150x 109/L. 5-20% Severe.• Bleeding risks (interventions- vascular catheters)• Delay in interventions, alteration in anticoagulation therapy
(aspirin, DVT prophylaxis), transfusions, concerns with heparin induced thrombocytopenia
What to do and when to do something?
EXPECTED
UNEXPECTED
ONSET (?count) & EVOLUTION
Common Causes (Hx, PE, Drugs)
DIAGNOSTIC(what to test)
THERAPEUTIC(what to do)
ONSET (?count) & EVOLUTION
Immunosuppresion Therapeutic Plasma Ex
Platelet Transfusion
FBC Blood film
Immunologic
Blood products Transfusion
Mechanisms of thrombocytopenia in ICU
patient. Greinacher, Selleng, ASH 2010
Mechanisms of thrombocytopenia in ICU
patient. Greinacher, Selleng, ASH 2010
Prognostic Marker
1. Marker for severity of illness
2. Higher MODS, APACHE score
3. Prolonged ICU stay
4. Increased mortality
What about the absolute count?
<20 x 109/L
• Marrow failure
• Severe coagulopathy (meningococcal sepsis, malaria)
• Immune mediated platelet consumption (ITP, TTP)
50-100 x109/L• Post-op (Bleeding or not
bleeding)• Bleeding• Medical, no bleeding
(sepsis, DIC <50x 109/L)• Chronic (bone marrow
dysplasia, liver disease, drugs, ITP, TTP, viral infection)
• Thromboembolic complications (APL Syndrome, HITs)
Uncommon cause (Need to know for ICU exam…)
Thrombotic Thrombocytopenic Purpura
• ADAMTS13 level low UL vWF
• life threatening thrombosis
• Rx-TPE (+ steroids)
MAHA
Fever TP
Renal failure
Neurologic
Uncommon cause (Need to know for ICU management)
Heparin Induced (Thrombotic) Thrombocytopenia Syndrome
When a patient is thrombocytopenic, would you order a HITS screen if you knew…
• It occurs in 0.3 – 0.5% ICU patients?
• Moderate TP was more likely a feature?
• Because it is an immune mediated response, the platelet count was only like to drop 4 to 5 days after heparin exposure?
• Very few do the 4Ts testing before deciding to order HITS screen?
• That just because HITS assay is + does not imply patient has HITS?
HIPA Postive
ELISA Postive 4 3
ELISA Equivocal 3 2
Positive10%
Equivocal7%
Negative83%
HITS Screen performed 2015 in ICU Melbourne Pathology
0
50
100
150
200
250
300
350
400
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
Series1
Bite Size HITS
ELISA (Enzyme Immunoassay) anti PF4/heparin Abs
Serotonin Release Assay (Functional)
Cheap(er)FastHigh sensitivityDetects IgM
CostlySlowHigh specificityDetects IgG
Bite Size HITS
The relationship among the clinical expression of HIT (thrombocytopenia with or without thrombosis), the type of heparin used, and the antibodies that cause HIT. This can be
conceptualized as an “iceberg.”
John G. Kelton, and Theodore E. Warkentin Blood 2008;112:2607-2616
©2008 by American Society of Hematology
Risk factors for developing HITS
1. Exposure to heparin• Therapeutic>
prophylactic
• UFH > LMWH
2. Degree of PF4 release
• Surgical, trauma> Medical
Referencezzz
• Thrombocytopenia in the intensive care unit patient. Greinacher A, SellengK. Hematology Am Soc Hematol Educ Program. 2010
• How I evaluate and treat thrombocytopenia in the intensive care unit patient. Andreas Greinacher and Sixten Selleng. Blood 2016 128:3032-3042
• Tsai HM. Pathophysiology of thrombotic thrombocytopenic purpura. Int J Hematol. 2010 Jan
• Heparin-induced thrombocytopenia: a historical perspective. John G. Kelton, and Theodore E. Warkentin. Blood 2008;112:2607-2616
• Changes in platelet count after cardiac surgery can effectively predict the development of pathogenic heparin-dependent antibodies. BJH. Pouplardet al. 2005
• Early-onset and persisting thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive. J of Thrombosis and Haemostasis. Selleng et al. 2009
• Temporal Aspects of Heparin-Induced Thrombocytopenia. Theodore E. Warkentin, M.D., and John G. Kelton, M.D. N Engl J Med 2001
Thanks!