Heparin induced thrombocytopenia hit is an unusual immunemediated adverse drug reaction with the central paradox being its strong association with thrombosis, despite the role of an anticoagulant heparin in causing a fall in platelet count thrombocytopenia. Hit usually occurs after you are treated with heparin. The new england journal of medicine e382 n engl j med 382. Type ii heparininduced thrombocytopenia hit is an immunological disorder characterized by antibodies to heparinplatelet factor 4 complexes and a high risk of thrombotic complications. American society of hematology 2018 guidelines for management. While the treatment of hitt hit with thrombosis with anticoagulation is well established, the risks and treatment of isolated hit are unclear. Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia key practice recommendations screening for hit 1. By seshu introduction heparininduced thrombocytopenia hit without or with thrombosis hitt is the development of thrombocytopenia. Heparin induced thrombocytopenia adult inpatient clinical.
Although first reported in 1973, immune heparininduced thrombocytopenia hit remains one of the most frequent and devastating adverse drug reactions encountered by physicians. We present an exemplifying case of severe heparininduced thrombocytopenia hit in an. New guidelines for heparin induced thrombocytopenia on september 3, 20 uwmedicine laboratory services released a new reflexive panel for hit antibody testing. A 63yearold man with coronary artery disease who has recently undergone bypass surgery presents with dyspnea. Amiral j et al, pathogenicity of iga andor igm antibodies to heparin pf4 complexes in patients with heparin induced thrombocytopenia. Heparininduced thrombocytopenia hit is the development of thrombocytopenia a low platelet count, due to the administration of various forms of heparin, an anticoagulant. Heparin induced thrombocytopenia mild to moderate thrombocytopenia or a 50 percent reduction after exposure to heparin or lowmolecularweight heparin arterial and venous thrombosis. A retrospective evaluation of fondaparinux for confirmed. Heparininduced thrombocytopenia hit occurs following an immune reaction to the. This is a pdf file of an unedited manuscript that has. We present an exemplifying case of severe heparin induced thrombocytopenia hit in an effort to solidify its high priority in the differential diagnosis of thrombocytopenia.
Heparininduced thrombocytopenia hit is an unusual immunemediated adverse drug. Heparininduced thrombocytopenia hit is an antibodymediated adverse drug reac tion that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic. Here, we present illustrative case histories to educate the reader on evaluation and management of this complex syndrome. Mar 21, 2014 heparin is the most common anticoagulant used for prophylaxis of thrombotic events in left ventricular assist device patients as a transition to oral anticoagulants but carries the risk of heparin induced thrombocytopenia. Key clinical pointsheparin induced thrombocytopenia heparin induced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Heparininduced thrombocytopenia hit is a serious complication of heparin. Heparininduced thrombocytopenia is the most important of the immunemediated, druginduced thrombocytopenias. Highdose intravenous immunoglobulin for the treatment and. Recently, infection has been implicated in the development of hit.
Heparininduced thrombocytopenia hit is an adverse reaction to the drug. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight. Heparin induced thrombocytopenia hit is a potentially lifethreatening complication of heparin anticoagulation. Hit results from an autoantibody directed against endogenous. Heparin induced thrombocytopenia hit is a serious disorder caused by the development of antibodies against complexes formed by heparin and platelet factor 4. A case of heparininduced thrombocytopenia hit triggered by. Type ii heparin induced thrombocytopenia hit is an immunological disorder characterized by antibodies to heparin platelet factor 4 complexes and a high risk of thrombotic complications. Heparininduced thrombocytopenia develops in a 57yearold man who underwent kneereplacement surgery 7 days previously. Heparin induced thrombocytopenia hit is a clinicopathological syndrome that occurs when heparin dependent igg antibodies bind to heparin platelet factor 4 complexes to activate platelets and produce a hypercoagulable state. Recent data show that up to 8% of heparinized patients will develop the antibody associated with hit and that approximately 15% of patients on heparin will progress to develop hit with thrombocytopenia 11, 12, suffering from venous andor arterial thrombosis in at least one. A 67yearold female with diabetic nephropathy was admitted to our hospital with hypoxemia caused by volume overload. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight heparin. Heparininduced thrombocytopenia hit is a serious disorder caused by the development of antibodies against complexes formed by heparin and platelet factor 4.
The pocket guides are available as a mobile application for ios and android devices, as a mobilefriendly website, and as pdf. Heparin induced thrombocytopenia hit is a lifethreatening complication of exposure to heparin eg, unfractionated heparin, low molecular weight lmw heparin that occurs in a small percentage of patients exposed, regardless of the dose, schedule, or route of administration. The adverse drug effect known as heparininduced thrombocytopenia hit shows many similarities to a bacterial. Heparininduced thrombocytopenia blood american society. A case of heparininduced thrombocytopenia type 2 after repair of juxtarenal abdominal aortic aneurysm. Neutrophil activation and netosis are the major drivers of. Druginduced immune thrombocytopenia nejm journal watch. Key clinical pointsheparin induced thrombocytopenia heparininduced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Epidemiology of heparin induced thrombocytopenia hit general consensus of incidence heparin 1% due to treatment with porcine heparin heparin dose route of administration. Heparininduced thrombocytopenia is the most important of the immunemediated, drug induced thrombocytopenias. Epidemiology of heparininduced thrombocytopenia hit general consensus of incidence thrombocytopenia. Hit is usually an immune response which typically occurs 410 days after exposure to heparin.
Treatment and prevention of heparininduced thrombocytopenia. A case of heparin induced thrombocytopenia type 2 after repair of juxtarenal abdominal aortic aneurysm. Heparininduced thrombocytopenia hit is a lifethreatening complication of exposure to heparin ie, unfractionated heparin, low molecular weight lmw heparin that occurs in up to 5 percent of patients. Heparininduced thrombocytopenia hit is a potentially lifethreatening complication of heparin anticoagulation.
Isolated heparininduced thrombocytopenia is defined as a fall in platelet count associated with a positive heparin pf4 antibody test, in the absence of clinically overt thrombosis. Heparininduced thrombocytopenia what you need to know. However, in contrast to the agents identified in this study, heparin usually does not induce severe thrombocytopenia, and the main clinical effect of heparininduced thrombocytopenia is. Although first reported in 1973, immune heparin induced thrombocytopenia hit remains one of the most frequent and devastating adverse drug reactions encountered by physicians. Hit predisposes to thrombosis the abnormal formation of blood clots inside a blood vessel because platelets release microparticles that activate thrombin, thereby. Heparininduced thrombocytopenia type ii hit is a more serious autoimmune disease causing a low platelet count and paradoxical blood clotting. Heparininduced thrombocytopenia hit is a lifethreatening complication of exposure to heparin ie, unfractionated heparin, low molecular weight lmw heparin that occurs in up to 5 percent of patients exposed, regardless. Pathophysiology of heparininduced thrombocytopenia. Heparininduced thrombocytopenia genetic and rare diseases. All citations from each search strategy were downloaded into a reference. Heparininduced thrombocytopenia hit is an immunemediated hypercoagulable disorder caused by antibodies to platelet factor 4 pf4 and heparin.
This thoroughly updated fifth edition from international experts professors warkentin and greinacher is the gold standard for accurate diagnosis and management of this. Heparininduced thrombocytopenia retrospective analysis of. Thrombocytopenia commonly occurs in hospitalized patients, particularly critically ill patients. The propensity for thrombosis distinguishes hit from other common drug induced. Recent data show that up to 8% of heparinized patients will develop the. The most widely available diagnostic test for hit is the elisa which detects. Feb 03, 2020 heparin induced thrombocytopenia hit is a condition that causes a decrease of platelets in the blood. Heparin induced thrombocytopenia hit is the development of thrombocytopenia a low platelet count, due to the administration of various forms of heparin, an anticoagulant. Several agents are in clinical use for this condition, including parenteral. Dager, in chemistry and biology of heparin and heparan sulfate, 2005.
Heparin induced thrombocytopenia hit can be defined as any clinical event best explained by platelet factor 4 pf4. The cardinal manifestations of hit are declining platelet counts. Clinical picture of heparininduced thrombocytopenia hit and its differentiation from nonhit thrombocytopenia. Heparininduced thrombocytopenia hit is a lifethreatening complication of exposure to heparin eg, unfractionated heparin, low molecular weight lmw heparin that occurs in a small. This results in thrombocytopenia or thrombosis in temporal relation to a preceding heparin exposure. New guidelines for heparininduced thrombocytopenia on september 3, 20 uwmedicine laboratory services released a new reflexive panel for hit antibody testing.
The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to. Heparininduced thrombocytopenia hit is a condition that causes a decrease of platelets in the blood. Hit develops in temporal association with heparin therapy and manifests either as an unexplained thrombocytopenia or thrombocytopenia complicated by thrombosis. Heparin induced thrombocytopenia hit is an antibodymediated adverse drug reac tion that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis necessitating limb amputation, acute myocardial infarction, and stroke. New guidelines for heparininduced thrombocytopenia. A case of heparininduced thrombocytopenia hit triggered. Heparin induced thrombocytopenia hit is a lifethreatening complication of exposure to heparin ie, unfractionated heparin, low molecular weight lmw heparin that occurs in up to 5 percent of patients exposed, regardless of the dose, schedule, or route of administration. Heparininduced thrombocytopenia mild to moderate thrombocytopenia or a 50 percent reduction after exposure to heparin or lowmolecularweight heparin arterial and venous thrombosis.
This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular. The mechanism of heparininduced platelet aggregation jstage. Severe and persistent heparininduced thrombocytopenia. Heparininduced thrombocytopenia type ii occurs in 15% of patients started on heparin. Ticagrelor causes falsenegative functional tests for. Heparininduced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis. Heparin induced thrombocytopenia hit treatment page 1 of 7. Clinical picture of heparin induced thrombocytopenia hit and its differentiation from nonhit thrombocytopenia. Laboratory testing reveals a platelet count of 86,000 per cubic millimeter, as compar. Watanabe j, nishimura k, miyasaka s, morimoto k, hamasaki t, ishiguro s. A 75yearold female underwent cardiac surgery with intraaortic balloon pump iabp placement. Heparin induced thrombocytopenia hit is a clinicopathological syndrome that occurs when heparin dependent igg antibodies bind to heparinplatelet factor 4 complexes to activate.
Antigen tests for antipf4 heparin antibodies 6 have a. Key clinical pointsheparininduced thrombocytopenia heparininduced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Furthermore, thrombocytopenia is commonly associated with bleeding complications. Limited data is available for the treatment of heparin induced thrombocytopenia in this patient population. Pathogenic antibodies to pf4heparin bind and activate cellular fc. Solomon, andreas greinacher, heparininduced thrombocytopenia, new england journal of medicine, 2015, 373, 3, 252 crossref. Heparininduced thrombocytopenia type i is harmless, causing a mild and transient reduction in platelet count. Diagnosis and management of heparininduced thrombocytopenia. In conjunction with this change, new guidelines for management of suspected hit and management of confirmed hit have also been developed. Boushra al saoor, pharmd intern, al maarefa college 20 may 2015 2. It is associated with significant morbidity and mortality if unrecognized. Thrombotic events are a common complication of left ventricular assist device placement and warrant prophylactic anticoagulation. Nonheparin anticoagulants for heparininduced thrombocytopenia.
Hit results from an autoantibody directed against platelet factor 4. Heparininduced thrombocytopenia hit is a lifethreatening. Heparininduced thrombocytopenia type ii hit is a more serious autoimmune disease causing. A retrospective evaluation of fondaparinux for confirmed or. Riia on platelets and monocytes to propagate a hypercoagulable state culminating in lifethreatening thrombosis. Heparin induced thrombocytopenia hit is a serious adverse reaction that is caused by plateletactivating antiplatelet factor 4 pf4 heparin antibodies and leads to an increased risk for thrombosis 4. Downloaded from at norwegian institute of public health on september 6, 2019. The most widely used system for clinical diagnosis is the 4ts score 08 points. Experience to date suggests ivig deescalates hit and likely reduces thrombotic risk. An iv or central line that is flushed with heparin or coated with heparin. Heparin induced thrombocytopenia hit treatment page 2 of 7 disclaimer. The pocket guides are available as a mobile application for ios and android devices, as a mobilefriendly website, and as pdf downloads. Heparin induced thrombocytopenia hit is the most important and most frequent drug induced, immunemediated type of thrombocytopenia. May 03, 2012 heparin induced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia.
Bleeding complications are a primary safety concern with the use of heparin therapy. Incidence and outcomes of heparininduced thrombocytopenia in. Aug 10, 2010 isolated heparin induced thrombocytopenia is defined as a fall in platelet count associated with a positive heparin pf4 antibody test, in the absence of clinically overt thrombosis. The true incidence of hit remains low, occurring in 0. We herein present a case of hit diagnosed by a repeated functional assay. Heparininduced thrombocytopenia retrospective analysis. Incidence and outcomes of heparininduced thrombocytopenia. Heparin induced thrombocytopenia hit is an immunemediated hypercoagulable disorder caused by antibodies to platelet factor 4 pf4 and heparin.
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