Thrombocytopenia is the result of falling the number of platelet from 150,000microl. Heparin induced thrombocytopenia hit is the most important and most frequent drug induced, immunemediated type of thrombocytopenia. Not infrequently, suspicion is raised during weekends when haematology consultants and elaborated laboratory services are not available. Temporal aspects of heparin induced thrombocytopenia n engl j med, vol. Pregnant patients with visual symptoms, headaches, abdominal pain, or influenzalike. The risk of hit is greatest in those on treatment doses, but risk at thromboprophylactic. 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. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular. 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. To assist clinicians with the diagnosis and initial management of heparin. Hit is a severe prothrombotic condition, occurring with fractionated. Heparininduced thrombocytopenia discharge care what you. Heparininduced thrombocytopenia type ii hit is a more serious autoimmune disease causing a low platelet count and paradoxical blood clotting. Clinical and laboratory tests for the diagnosis of heparin.
Heparin induced thrombocytopenia hit may develop in two distinct forms, type i and type ii see table 1. Pdf treatment of heparininduced thrombocytopenia with. 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. 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. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight heparin. Hit is usually an immune response which typically occurs 410 days after exposure to heparin. Second, thrombocytopenia is not necessarily severe in patients with. Hit is a severe prothrombotic condition, occurring with fractionated and. Has been described without heparin exposure associated with venous and arterial thrombosis typical previous infectious gram neg bacteria or inflammatory event pos immunoassay significant inflammatory response causing activation of pf4 without need for heparin, causing platelet activation non heparin polyanions causing activation of pf4. Case studies in heparininduced thrombocytopenia springerlink. Heparininduced thrombocytopenia blood american society of.
Heparin induced thrombocytopenia or hit is defined as the clinical condition where an individual under heparin treatment suffers from thrombocytopenia. We evaluated rivaroxaban as a treatment option in patients with suspected or con. A 75yearold female underwent cardiac surgery with intraaortic balloon pump iabp placement. 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 type ii occurs in 15% of patients started on heparin. The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. Heparin induced thrombocytopenia hit heparin induced thrombocytopenia hit is a potentially lethal, immunologically induced complication to unfractionated heparin therapy and to a smaller degree, low molecular weight heparin salter, 2016. Combining heparin with aspirin reduces the risk of thrombosis by. Rates of mortality and morbidity have decreased from 20% to 610% with improvements in early. Apr 24, 2020 the clinicopathological syndrome of heparin induced thrombocytopenia hit can present as isolated thrombocytopenia or in association with a thrombotic event. Rodgers, md, phd professor of medicine and pathology, medical director, arup hemostasisthrombosis laboratory, university of utah. Diagnostic workup of patients with suspected heparininduced thrombocytopenia hit is hampered by major practical issues and a number of methodological limitations.
A 63yearold man with coronary artery disease who has recently undergone bypass surgery presents with dyspnea. 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 american college of chest physicians accp guidelines. The diagnostic approach to hit is further enhanced by combining the results. Treatment options for heparininduced thrombocytopenia. Heparin induced thrombocytopenia syndrome is an acquired potentially lifethreatening prothrombotic disorder caused by antibodies that recognize complexes of platelet factor 4 bound to heparin or. Type i hit, also known as heparin associated thrombocytopenia hat, is a nonimmunologic response to heparin therapy, while type ii hit is an immunologic. Dec 06, 2015 heparin induced thrombocytopenia hit is a prothrombotic disorder caused by antibodies that recognize complexes of platelet factor 4 pf4 and heparin. Hit usually occurs after you are treated with heparin. Heparininduced thrombocytopenia clinical presentation. Heparininduced thrombocytopenia associated with massive. Hit, as 15% to 20% of patients have platelet count nadirs that exceed 100. Heparininduced thrombocytopenia hit is a prothrombotic complication mediated by auto antibodies against heparinplatelet complexes.
May 15, 2015 treatment and prevention of heparin induced thrombocytopenia. 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 of the dose, schedule, or route of administration. Heparin induced thrombocytopenia summary heparin induced thrombocytopenia hit is a known complication of heparin exposure. American society of hematology guidelines suggest that some agents may be preferred in certain circumstances, as follows. Heparin induced thrombocytopenia hit is a well recognized complication of heparin therapy and usually occurs within five to ten days after the initiation of heparin treatment 1. Heparininduced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. Laboratory testing reveals a platelet count of 86,000 per cubic millimeter, as compar. Heparininduced thrombocytopenia hit is a lifethreatening immune response to heparin and its derivatives that is associated with a high risk of thromboembolic complications. Heparin induced thrombocytopenia differential diagnosis of thrombocytopenia estimating pretest probability of hit 4ts sepsis postresuscitation dilution drug induced including hit hypersplenism platelet consumption or destruction dic massive transfusion primary marrow disorders immune thrombocytopenia itp, ttp antiphospholipid syndrome. One patient had recurrent thrombosis and 910 patients with thrombocytopenia had platelet recovery. Hit results from an autoantibody directed against endogenous. Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia key practice recommendations screening for hit 1. It is associated with significant morbidity and mortality if unrecognized.
Heparininduced thrombocytopenia hit is a serious complication of heparin therapy. Treatment and prevention of heparininduced thrombocytopenia. Heparin induced thrombocytopenia hit is an immunemediated adverse drug reaction that is caused by heparin dependent, plateletactivating igg antibodies that recognize complexes of platelet factor 4 pf4 bound to heparin. Heparin induced thrombocytopenia adult inpatient clinical. Pdf heparin is widely used for the prevention and treatment of thrombotic and particularly cardiovascular disorders. Hit is frequently considered in the differential diagnosis of thrombocytopenia occurring in patients on heparin therapy. Smock, md associate professor of pathology, medical director, arup hemostasisthrombosis laboratory, university of utah and george m. Heparininduced thrombocytopenia type i is harmless, causing a mild and transient reduction in platelet count.
It is considered the most severe nonbleeding adverse reaction of heparin treatment and one of the most important adverse drug reactions. Heparininduced thrombocytopenia in patients with ventricular. Clinical picture of heparin induced thrombocytopenia hit and its differentiation from nonhit thrombocytopenia. We can better understand the disease by knowing what are heparin and thrombocytopenia. Hit predisposes to thrombosis the abnormal formation of blood clots inside a blood vessel because platelets release microparticles that activate thrombin, thereby. Heparin induced thrombocytopenia hit is the development of thrombocytopenia a low platelet count, due to the administration of various forms of heparin, an anticoagulant.
Lawrence rice expounds upon the treatment and prevention of heparin induced thrombocytopenia. Diagnosis of hit is essential to guide treatment strategies using. Feb 03, 2020 heparin induced thrombocytopenia hit is a condition that causes a decrease of platelets in the blood. Od and combining it with an intermediate or high 4ts score identified all of.
How we manage patients with heparin induced thrombocytopenia. Heparininduced thrombocytopenia hit is an immune complication of. Heparin induced thrombocytopaenia icm case summaries. In patients with hit and severe thrombocytopenia, we suggest giving. Apr 30, 2007 thrombocytopenia commonly occurs in hospitalized patients, particularly critically ill patients. Heparin induced thrombocytopenia hit treatment page 1 of 7. Hit occurs in 1 to 3% of patients receiving unfractionated heparin ufh and 0. Combining heparin with aspirin reduces the risk of thrombosis by 75%. Heparin induced thrombocytopenia kettering health network. Diagnosis and treatment of heparin induced thrombocytopenia.
Heparin induced thrombocytopenia in the cardiovascular patient. Heparininduced thrombocytopenia hit is a thrombogenic condition that is dif. Heparin induced thrombocytopenia hit treatment page 1 of 7 disclaimer. May 03, 2012 heparin induced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. An iv or central line that is flushed with heparin or coated with heparin. It causes prolonged morbidity, is fatal in 5%10% of cases and causes lifelong disability in another 10% of cases 1.
Here, we present illustrative case histories to educate the reader on evaluation and management of this complex syndrome. In the most recent accp guidelines, hit and hitt therapy with. Heparin induced thrombocytopenia hit is an intensely thrombotic, lifethreatening disorder caused by plateletactivating antibodies directed against a complex of platelet factor 4 pf4 and heparin 1, 2. There are three main reasons of thrombocytopenia, adecreasing of making platelet bincreasing of destruc. The 4ts scoring system is a screening tool that accurately rules out hit. Heparin is widely used for thromboprophylaxis or treatment in many clinical situations, including cardiovascular and orthopaedic surgery and invasive procedures, acute coronary syndromes, venous thromboembolism, atrial fibrillation, peripheral occlusive disease, dialysis, and during extracorporeal circulation. Heparininduced thrombocytopenia genetic and rare diseases. Heparin induced thrombocytopenia and cardiac surgery. 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. Dec 12, 2019 treatment of heparin induced thrombocytopenia involves discontinuing heparin and starting a non heparin anticoagulant.
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