Hit is an antibodymediated disorder of coagulation caused by exposure to heparin and associated with significant risk of thromboembolic complications and death 1,2,3. Heparin induced thrombocytopenia hit is caused by antibodies, elicited in response to heparin anticoagulant therapy, which can cause extreme platelet activation and result in a highly. Heparininduced thrombocytopenia hit is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 pf4 and heparin. Heparininduced thrombocytopenia shaikh n j emerg trauma shock. Pdf heparininduced thrombocytopenia occurs due to the formation of. Druginduced immune thrombocytopenia ditp is a challenging clinical problem that is underrecognized, difficult to diagnose and associated. Thrombocytopenia is a common problem in cardiovascular surgery patients. Heparin induced thrombocytopenia is the development of thrombocytopenia due to the administration of heparin. It is associated with significant morbidity and mortality if unrecognized. Heparininduced thrombocytopenia hit is a prothrombotic disorder caused by antibodies to complexes of platelet factor 4 pf4 and heparin. One third to onehalf of cases of hit are complicated by thrombosis, which may be limb or lifethreatening.
Because the platelet count normalizes even with continued heparin therapy, it is not associated with increased thrombotic risk. Differentiates patients with hit from those with other causes of thrombocytopenia. The pathophysiology of heparin induced thrombocytopenia includes an immunemediated reaction to heparin that activates platelets and results in an acquired hypercoagulability. This complication of heparin is often confusing because in hit, heparin. Heparin induced thrombocytopenia heparin induced thrombocytopenia hit can be defined as a decrease in platelet count that can occur during or shortly after exposure to heparin. Heparininduced thrombocytopenia history and exam bmj. Guidelines on the diagnosis and management of heparininduced thrombocytopenia. Pdf heparininduced thrombocytopenia hit is a potentially devastating immune. Heparininduced thrombocytopenia genetic and rare diseases. Heparininduced thrombocytopenia, however, is an exception to this general rule. 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. Heparin induced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis necessitating limb amputation, acute myocardial infarction, and stroke. The use of heparin to flush some vascular access devices makes hit a concern for infusion nurses.
Smock, md associate professor of pathology, medical director, arup hemostasisthrombosis laboratory. Hit is a transient, immunemediated adverse drug reaction in patients recently exposed to heparin that generally produces thrombocytopenia and often results in venous andor arterial thrombosis. Hit results from an interaction between negatively charged heparin and a. We evaluated rivaroxaban as a treatment option in patients with suspected or con. 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. 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.
Sysmex xe and xnseries analysers is higher in patients. Heparininduced thrombocytopenia hit is a clinicopathological syndrome that occurs when heparin dependent, igg antibodies bind to heparin platelet factor 4 pf4 complexes to activate platelets and. However, heparin induced thrombocytopenia hit is a rare but lifethreatening complication of prophylaxis or treatment. The classically taught heparin induced thrombocytopenia type 2 is very serious. The following guideline is intended to guide the diagnosis and management of heparin induced thrombocytopenia. 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 clinical presentation. The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. Heparin is widely used for the treatment and prophylaxis of thromboembolic diseases in medical and surgical patients.
Heparininduced thrombocytopenia investigations bmj best. Diagnosis of hit is based on both clinical thrombocytopenia or new thrombosis and laboratory findings. Do not send hit antibody testing elisa or serotonin release assay sra 4. Heparininduced thrombocytopenia hit is a lifethreatening immune response to heparin and its derivatives that is associated with a high risk of thromboembolic complications. One patient had recurrent thrombosis and 910 patients with thrombocytopenia. Heparin induced thrombocytopenia hit is a known complication of heparin exposure. 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. Hit is essentially a prothrombotic disorder mediated by an igg antiplatelet factor 4 heparin. This cardiology patient page focuses on heparin induced thrombocytopenia hit, a complication of heparin therapy. However, these patients are likely to require anticoagulation therapy at some point in the future. Laboratory testing for the antibodies that cause heparin induced thrombocytopenia. Hit is usually an immune response which typically occurs 410 days after exposure to heparin. Pdf diagnostic strategy in heparin induced thrombocytopenia. Heparin induced thrombocytopenia hit may develop in two distinct forms, type i and type ii see table 1.
Thrombocytopenia is any disorder in which there are not enough platelets. Hit predisposes to thrombosis and, when identified, the condition is then called heparin induced thrombocytopenia and thrombosis hitt. Heparininduced thrombocytopenia article nursingcenter. Heparin induced thrombocytopenia adult inpatient clinical.
Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia key practice recommendations screening for hit 1. Complications of hit are venousarterial thrombosis, skin gangrene, and acute platelet activation syndrome. Heparin induced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic. Consequently, heparin induced thrombocytopenia hit, an immune complication of heparin therapy, remains a highly relevant complication for the hematology practitioner to diagnose and manage. Hit results from an interaction between negatively charged heparin. Oct 12, 2010 heparin induced thrombocytopenia handout 1.
Heparin induced thrombocytopenia hit is an immunemediated hypercoagulable disorder caused by antibodies to platelet factor 4 pf4 and heparin. An iv or central line that is flushed with heparin or coated with heparin. Mar 22, 2011 heparin, a negatively charged glycosaminoglycan 3,00030,000 da, is an anticoagulant released by mast cells and basophils during the normal clotting process. List of heparininduced thrombocytopenia medications. Unlike other types of druginduced thrombocytopenia, hit promotes thrombosis rather than bleeding. Pathogenic antibodies to pf4 heparin bind and activate cellular fc. Heparin induced thrombocytopenia hit is a complication of heparin therapy and is characterized by two types. Heparininduced thrombocytopenia hit is a condition that causes a decrease of platelets in the blood. The most commonly used intravenous anticoagulant is heparin. Heparin induced thrombocytopenia hit is a thrombogenic condition that is dif. 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 hit is a condition that causes a decrease of platelets in the blood. Heparininduced thrombocytopenia rn continued education. Hit occurs in up to 5% of patients receiving unfractionated heparin. Nonheparin anticoagulants for heparininduced thrombocytopenia. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular. One of these is heparininduced thrombocytopenia hit, a common, serious and potentially lifethreatening condition 1,2, and one for which diagnosis can be dif. Laboratory testing reveals a platelet count of 86,000 per cubic millimeter, as compar. Approach to the diagnosis and management of druginduced. Heparin induced thrombocytopenia handout slideshare.
Druginduced thrombocytopenia for the hospitalist physician with a. Jul 14, 2017 heparininduced thrombocytopenia hit results in high rate of thrombosis 50% and mortality 1030% if untreated 1, 2. Guidelines on the diagnosis and management of heparin. Hit is something that needs to be closely watched for because consequences from it can include lifethreatening thrombosis. Clinical presentation and diagnosis of heparininduced. Hit usually occurs after you are treated with heparin. This complication of heparin is often confusing because in hit, heparin does the opposite of what it is supposed to do. Clinical features of heparin induced thrombocytopenia including risk factors for thrombosis.
Treatment and prevention of heparininduced thrombocytopenia. Guidelines from the american college of chest physicians accp suggest limiting platelet transfusions to patients with severe thrombocytopenia. Heparin induced thrombocytopenia mild to moderate thrombocytopenia or a 50 percent reduction after exposure to heparin or lowmolecularweight heparin arterial and venous thrombosis. Apixaban for treatment of confirmed heparininduced. Hit develops in temporal association with heparin therapy and manifests either as an unexplained thrombocytopenia or thrombocytopenia complicated by thrombosis. Sample case 64 yo woman with endocarditis platelet count decreases from 161k on day 7 to 60k on day 9 been receiving low molecular weight heparin. Because the platelet count normalizes even with continued heparin. Heparininduced thrombocytopenia heparininduced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count value after the start of heparin, an onset 5 to 10 days after the start of heparin, hypercoagulability, and the presence of heparindependent, plateletactivating igg. Heparininduced thrombocytopenia hit is the most important and most frequent drug induced, immunemediated type of 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.
Advances in the pathophysiology and treatment of heparin. Heparin induced thrombocytopenia hit treatment page 1 of 7. Sysmex white paper differential diagnosis of thrombocytopenia. Diagnosis of hit is based on both clinical thrombocytopenia. It is important as a healthcare worker to recognize the signs of heparin induced thrombocytopenia hit as treatment should begin before the laboratory confirms the diagnosis. This is the case with heparin induced thrombocytopenia, or hit.
Heparin induced thrombocytopenia hit is a prothrombotic adverse drug reaction. Heparininduced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. Thrombosis precedes thrombocytopenia in approximately 25% of patients with hit. Thrombocytopenia is a serious condition in which patients have a low platelet count. Heparin induced thrombocytopenia hit is considered the most common form of drug induced thrombocytopenia as well as one of the common causes of thrombocytopenia in hospitalized patients. However, not all thrombocytopenia is due to such system alterations. Hit may also be associated with low molecular weight heparin use. May 03, 2012 heparin induced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia.
Im going to reveal to you the secret method that allows you to get the equivalent exercise of 45 minutes at the gym, in just a few minutes per day. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular to md andersons specific patient population, services and structure, and clinical information. Hit is caused by formation of immunoglobulin g antibodies that recognize complexes of platelet factor 4 pf4 and heparin and activate platelets resulting in mild to moderate thrombocytopenia. Heparin induced thrombocytopenia hit is a syndrome of platelet activation, thrombocytopenia, and thrombosis that occurs in 15% of patients who receive heparin. This can occur due to certain disease processes such as alterations in the immune system or with leukemia. The 4ts scoring system is a screening tool that accurately rules out hit.
Heparininduced thrombocytopenia hit is caused by antibodies, elicited in response to heparin anticoagulant therapy, which can cause extreme platelet activation and result in a highly. Heparin induced anaphylactoid reaction associated with heparin induced thrombocytopenia in the ed. Heparininduced thrombocytopenia symptoms, diagnosis and. When drugs or medications are the causes of a low platelet count, it is called drug induced thrombocytope. Clinical picture of heparin induced thrombocytopenia hit and its differentiation from nonhit thrombocytopenia. Feb 03, 2020 what is heparin induced thrombocytopenia. Thrombocytopenia following heparin administration can be associated with an immune reaction, now referred to as heparininduced thrombocytopenia. Current guidelines recommend cessation of heparin for patients strongly suspected of having hit and prompt initiation of a nonheparin direct thrombin inhibitor for anticoagulation, such as argatroban or bivalirudin. Heparin induced thrombocytopenia hit is an immunemediated complication of heparin therapy.
Diagnosis of heparin induced thrombocytopenia karen a. Argatroban order set for heparininduced thrombocytopenia. Riia on platelets and monocytes to propagate a hypercoagulable state culminating in lifethreatening thrombosis. Nheparin induced thrombocytopenia hit is an immune. Heparin induced thrombocytopenia background heparin induced thrombocytopenia hit is a lifethreatening immune response to heparin and its derivatives that is associated with a high risk of thromboembolic complications. Diagnosis and treatment of heparin induced thrombocytopenia. Solidphase enzymeimmunoassays are an objective tool for ruling out hit, but a positive test requires platelet activation tests such as the serotonin.
Two clinical forms of hit are generally recognized. Hit occurs in up to 5% of patients receiving unfractionated heparin ufh, and in heparin induced thrombocytopenia with unfractionated and lowmolecularweight heparin thromboprophylaxis. The propensity for thrombosis distinguishes hit from other common drug induced. Heparin induced thrombocytopenia is a clinicopathologic syndrome that can be associated with severe complications and significant mortality. Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia. A 63yearold man with coronary artery disease who has recently undergone bypass surgery presents with dyspnea. Hit is considered to be the most important and most frequent drug induced type of thrombocytopenia. Uw health moderate quality of evidence, strong recommendation 2. Moser, md heparin induced thrombocytopenia hit is a complication seen in approximately 1%3% of patients treated with unfractionated heparin therapy.
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