Thrombocytopenia in medical-surgical critically ill patients: prevalence, incidence, and risk factors

Crowther, Mark; Cook, Deborah J.; Meade, Maureen O.; Griffith, Lauren; Guyatt, Gordon; Arnold, Donald M.; Rabbat, Christian G.; Geerts, William; Warkentin, Theodore E.

doi:10.1016/j.jcrc.2005.09.008

Cited by 216 publications

(216 citation statements)

References 21 publications

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“…The overall incidence of HIT in our series confirmed the findings of other studies (Verma et al, 2003;Crowther et al, 2005;Crowther et al 2010). HIT was most common (1AE35%) in patients who developed thrombocytopenia in ICU.…”

supporting

confidence: 91%

“…Despite high levels of exposure to heparin in ICU patients, it is perceived that HIT is uncommon with reported incidences of <1% (Verma et al, 2003;Crowther et al, 2005;Selleng et al, 2007). As the consequences of missing the diagnosis of HIT are so great (Warkentin & Kelton, 1996) and the pick up rate of indiscriminate testing so low (Verma et al, 2003;Crowther et al, 2005) it is clear that the use of clinical evaluation or a scoring system which discriminates between patients who are 'likely' or 'unlikely' to have this condition is required. The 4Ts scoring system has been developed to assess patients with suspected HIT (Lo et al, 2006).…”

mentioning

confidence: 99%

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Heparin‐induced thrombocytopenia and the utility of the 4Ts score in the Intensive Care Unit

Khan¹,

Noble

Watson³

2011

Br J Haematol

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supporting

confidence: 91%

mentioning

confidence: 99%

Heparin‐induced thrombocytopenia and the utility of the 4Ts score in the Intensive Care Unit

Khan¹,

Noble

Watson³

2011

Br J Haematol

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“…The endpoint used for detecting platelet activation can vary. Functional endpoints of light transmission (platelet aggregation or visualization of magnetic beads), release of radioactivity (platelets labeled with radioactive serotonin), or membrane activation markers (flow cytometry) are described in the literature.The functional assays, in particular the serotonin release assay (SRA), have high specificity (> 95%) 29 and a high positive predictive values (89-100%). 8 However, the sensitivity of these assays is largely dependent on the type of functional endpoint used (SRA > flow cytometry > light transmission; 62-100%) 30,31 and is heavily influenced by technical variables, including baseline platelet reactivity and complexity of assay.…”

mentioning

confidence: 99%

Heparin-Induced Thrombocytopenia

Arepally¹,

Cines²

2008

Diagnostic Criteria in Autoimmune Diseases

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Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder caused by antibodies that recognize complexes of platelet factor 4 (PF4) and heparin. HIT is frequently considered in the differential diagnosis of thrombocytopenia occurring in patients on heparin therapy. HIT is a challenging diagnosis because of routine heparin use in hospitalized patients, the common occurrence of thrombocytopenia, and high rates of anti-PF4/heparin seroconversions in patients treated with heparin. This chapter will summarize our diagnostic approach to HIT by underscoring critical elements of the clinical and laboratory evaluation. Keywordsplatelet factor 4; PF4; heparin; PF4/H complexes; HIT Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening immune complication which occurs after exposure to unfractionated heparin (UFH) or less commonly, to low-molecular weight heparins (LMWHs). 1 It is characterized by declining platelet counts beginning 5-14 days after heparin exposure occurring in isolation (isolated HIT) or concurrent with new arterial and venous thrombotic complications. 2 HIT is caused by antibodies directed against complexes formed by a platelet protein, platelet factor 4, and heparin (PF4/H). Circulating immune complexes containing IgG and PF4/H complexes bind to platelet and monocyte Fc receptors and promote cellular activation leading to procoagulant microparticle release and thrombin generation. 3,4 Historically, the challenge associated with HIT was lack of awareness of the syndrome and its pursuant complications; the challenge now is in over-diagnosis and treatment of HIT. With the widespread availability of screening immunoassays and the desire of clinicians to avoid the thrombotic consequences associated with true disease, many patients without HIT Correspondence to: Gowthami M. Arepally, arepa001@mc.duke.edu. now suffer needless morbidity due to bleeding complications from use of alternative anticoagulants. To avoid a reflexive diagnosis of HIT in the heparinized thrombocytopenic patient, clinicians must have a sound understanding of the clinical and laboratory diagnostic elements essential for a diagnosis of HIT. This paper reviews our diagnostic and management strategy in evaluating the common presentation of thrombocytopenia in a heparinized patient. NIH Public Access Diagnosing HIT: the clinical challengeHIT is a challenging clinical diagnosis. The increasing use of UFH/LMWH for thromboprophylaxis in hospitalized patients 5 coupled with the frequency of thrombocytopenia, particularly among critically ill patients, 6 results in a significant overlap of patients suspected of HIT. In a recent registry of ~1000 patients treated with thromboprophylactic dosed heparin, 19% (n = 190) met thrombocytopenia criteria compatible with a diagnosis of HIT (as defined by a platelet count < 150 × 10 9 /L or > 50% drop in platelet counts), but only 5% of patients were diagnosed with HIT. 6 This study and clinical experience suggest that other causes of thrombocytopenia, such as infection, medi...

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“…HIT is, therefore, a major concern in ICU patients. Nevertheless, thrombocytopenia is a common occur rence in 30-50% of ICU patients, so that diagnosis of HIT represents a major challenge [53]. Common reasons for thrombocytopenia in these patients include sepsis, adverse eff ects of drugs, transfusion reactions, and major surgical procedures [54].…”

Section: The Challenge Of Diagnosis and Treatment Of Hit In The Icumentioning

confidence: 99%

“…Th e development of thrombotic complications under heparin therapy is, there fore, a better indicator of a diagnosis of HIT than uncomplicated thrombocytopenia [3]. Repeated occlusion of hemodialysis fi lters and necrotic or erythematous skin lesions at the site of heparin injections may also be an important sign of HIT [3,53]. In this context, the use of HIT scores, such as the 4 T's score, may be helpful in establishing the diagnosis (vide supra).…”

Section: The Challenge Of Diagnosis and Treatment Of Hit In The Icumentioning

confidence: 99%

Heparin-induced Thrombocytopenia in the ICU: An Overview

Sakr¹

2011

Annual Update in Intensive Care and Emergency Medicine 2011

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Thrombocytopenia in medical-surgical critically ill patients: prevalence, incidence, and risk factors

Cited by 216 publications

References 21 publications

Heparin‐induced thrombocytopenia and the utility of the 4Ts score in the Intensive Care Unit

Heparin‐induced thrombocytopenia and the utility of the 4Ts score in the Intensive Care Unit

Heparin-Induced Thrombocytopenia

Heparin-induced Thrombocytopenia in the ICU: An Overview

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