Heparin-induced thrombocytopenia syndrome

Hemorrhage is the main complication that can arise from heparin therapy. Other side effects include Heparin-Induced Thrombocytopenia Syndrome (HITS), local irritation, hypersensitivity reactions and with long-term use, alopecia, hypoaldoster-onism, and osteoporosis. 

Kikta MJ, Keller MR Humphrey PV, et al. Can low molecular weight heparins and heparinoids be safely given to patients with heparin-induced thrombocytopenia syndrome Surgery 1993 114 705-710. 

UFH has the disadvantages of a variable anticoagulant effect, sensitivity to platelet factor 4, a relative inability to inhibit clot-bound thrombin, and the potential to cause thrombocytopenia and/or heparin-induced thrombocytopenia syndrome (28). Low molecular weight hep-arins (LMWHs) and direct thrombin inhibitors are the antithrombins... 

Warkentin TE (2004) An overview of the heparin-induced thrombocytopenia syndrome. 

Heparin-induced thrombocytopenia A clinical syndrome of IgG antibody production against the heparin-platelet factor 4 complex occurring in approximately 1% to 5% of patients exposed to either heparin or low-molecular-weight heparin. Heparin-induced thrombocytopenia results in excess production of thrombin, platelet aggregation, and thrombocytopenia (due to platelet clumping), often leading to venous and arterial thrombosis, amputation of extremities, and death. 

Initial dosage in HIT or heparin-induced thrombocytopenia and thrombosis syndrome (HITTS) Before administering argatroban, discontinue heparin therapy and obtain a baseline activated partial thromboplastin time (aPTT). The recommended initial dose of argatroban for adults without hepatic impairment is 2 mcg/kg/min administered as a continuous infusion (see table). 

Matsuo T Tomaru T Kario K, et al. Incidence of heparin-PF4 complex antibody formation and heparin-induced thrombocytopenia in acute coronary syndrome. Thromb Res 2005 ... 

Thrombotic thrombocytopenic purpura is a rare acute or subacute disease in adults, rather similar to the hemolytic uremic syndrome in children, in which there is systemic malaise, fever, skin purpura, renal failure, hematuria and proteinuria. Hemorrhagic infarcts caused by platelet microthrombi occur in many organs in the brain they may cause stroke-like episodes (Matijevic and Wu 2006) although more commonly there is global encephalopathy. The blood film shows thrombocytopenia, hemolytic anemia and fragmented red cells. The differential diagnosis includes infective endocarditis, idiopathic thrombocytopenia, heparin-induced thrombocytopenia with thrombosis, systemic lupus erythematosus, non-bacterial thrombotic endocarditis and disseminated intravascular coagulation. 

Magnani HN. Orgaran (danaparoid sodium) use in the syndrome of heparin-induced thrombocytopenia. Platelets 1997 8 74. 

Patients with heparin-induced thrombocytopenia have a reported mortality of 25-30% and amputation rates of up to 25% (54). The development of the syndrome is not related to the dose of heparin in the therapeutic range (that is it is a hypersusceptibility reaction). This has been confirmed by the fact that thrombocytopenia with thromboembolic complications sometimes occurs after the limited exposure that is involved in flushing with heparin and saline to maintain the patency of venous catheters (55). 

Warkentin TE. Heparin-induced thrombocytopenia A clinicopathologic syndrome. Thromb Haemost 1999 82 439-447. 

Thrombocytopenia. Abnormal decrease in the number of thrombocytes below normal values. Frequently detected in patients with autoimmune diseases (e.g. systemic lupus erythematosus, -Sjogren syndrome, mixed connective tissue disease, antiphospholipid syndrome). Primary forms may be drug induced ( - heparin-induced thrombocytopenia) or mediated by antiplatelet antibodies ( - idiopathic thrombocytopenic purpura). 

Toxicity Bleeding, osteoporosis, heparin-induced thrombocytopenia (HIT), hypersensitivity Bleeding, skin necrosis (if low protein C), purple toe syndrome, drug interactions, teratogenic (bone dysmorpho-genesis)... 

Pauzner R, Greinacher A, Selleng K, Althaus K, Shenkman B, Seligsohn U. False-positive tests for heparin-induced thrombocytopenia in patients with antiphospholipid syndrome and systemic lupus erythematosus. J Thromb Haemost 2009 7(7) 1070-4. 

Kramer R, Oberg-Higgins P, Russo L, Braxton JH. Heparin-induced thrombocytopenia with thrombosis syndrome managed with plasmapheresis. Interact Cardiovasc Thorac Surg 2009 8(4) 439-41. 

White clot syndrome - Rarely, patients may develop new thrombus formation in association with thrombocytopenia resulting from irreversible aggregation of platelets induced by heparin, the so-called white clot syndrome. The process may lead to severe thromboembolic complications. Monitor platelet counts before and during therapy. If significant thrombocytopenia occurs, immediately... 

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