Thrombocytopenia heparin-associated

J Heparin-associated thrombocytopenia is a benign, transient, and mild phenomenon that usually occurs within the first few days of treatment. Platelet counts rarely drop below 100,000/mm3 and recover with continued therapy. 

Thrombocytopenia Thrombocytopenia has occurred in patients receiving heparin. The incidence of heparin-associated thrombocytopenia is higher with bovine than with porcine heparin. The severity also appears to be related to heparin dose. 

Thrombocytopenia, heparin-induced For anticoagulation in patients with heparin-induced thrombocytopenia (HIT) and associated thromboembolic disease in order to prevent further thromboembolic complications. 

Heparin-induced thrombocytopenia and associated thromboembolic disease to prevent further thromboembolic complications IV, IV Infusion 0.2-0.4 mg/kg, IV slowly over 15-20 sec, followed by IV infusion of 0.1-0.15 mg/kg/hr for 2-10 days or longer. Dosaye in renal impairment Initial dose is decreased to 0.2 mg/kg, with infusion rate adjusted based on creatinine clearance. 

Anticoagulation in patients with heparin-induced thrombocytopenia and associated thromboembolic disease... 

For the past few decades, heparin has been widely used for the prevention of postoperative thiomboemboUsm (6,7). However, there are several adverse side-effects associated with the use of heparin such as bleeding, heparin induced thrombocytopenia, heparin induced thrombosis (8,9) and osteoporosis (10). In addition, the regimen of pioph actic heparin used in the prevention of deep venous thrombosis (DVT) is tedious, requiring 2 to 3 daily injections because of the limited bioavailability and short half-life of heparin when administered subcutaneously. 

Heparinoids. Danaparinoid sodium is a mixture of several types of non-heparin glycosaminoglycans extracted from pig intestinal mucosa (84% heparan sulphate). It is an effective anticoagulant for the treatment of deep vein thrombosis (DVT) prophylaxis in high-risk patients and treatment of patients with heparin-associated thrombocytopenia. 

Danaparoid is as effective as heparins in inhibiting the formation of thrombi. Its major advantage over low molecular weight heparins is its low rate of cross-reactivity with heparin-associated antibodies from patients with heparin-induced thrombocytopenia (1). It is therefore indicated in patients with heparin-associated thrombocytopenia who require further anticoagulation after withdrawal of heparin. However, it should not be used if there is in vitro cross-reactivity between heparin and danaparoid. Cross-reactivity is uncommon but can result in thrombotic comphcations, as reported in a case with a fatal outcome (2). 

Huhle G, Geberth M, Hoffmann U, Heene DL, Harenberg J. Management of heparin-associated thrombocytopenia in pregnancy with subcutaneous r-hirudin. Gynecol Obstet Invest 2000 49(l) 67-9. 

A third variety, so-called delayed-onset heparin-induced thrombocytopenia has also been described in several reports. In 12 patients, recruited from secondary and tertiary care hospitals, thrombocytopenia and associated thrombosis occurred at a mean of 9.2 (range 5-19) days after the withdrawal of heparin nine received additional heparin, with further falls in platelet counts (32). In a retrospective case series, 14 patients, seen over a 3-year period, developed thromboembolic complications a median of 14 days after treatment with heparin (33). The emboli were venous (n — 10), or arterial (n — 2), or both (n — 2) of the 12 patients with venous embolism, 7 had pulmonary embolism. Platelet counts were mildly reduced in all but two patients at the time of the second presentation. On readmission, 11 patients received therapeutic heparin, which worsened their clinical condition and further reduced the platelet count. 

Bell WR, Royall RM. Heparin-associated thrombocytopenia a comparison of three heparin preparations. N Engl J Med 1980 303(16) 902-7. 

Cipolle RJ, Rodvold KA, and Seifert R (1983) Heparin-associated thrombocytopenia A prospective evaluation of 211 patients. Therapeutic Drug Monitoring 5 205-211. 

Frame JN, Mulvey KP, and Phares JC (1989) Correction of severe heparin-associated thrombocytopenia with intravenous immunoglobulin. Annals of Internal Medicine 111 946-947. 

Two types of thrombocytopenia associated with heparin use have been described. " As many as of 25% of patients receiving heparin therapy develop a benign, mild reduction in platelet counts referred to as non-immune-mediated heparin-associated thrombocytopenia (HAT) or previously called HIT type 1. HAT produces a transient fall in platelet count that occurs early, typically between days 2 and 4, during the course of therapy. The degree of thrombocytopenia is usually mild, with platelet counts rarely going below 100,000/mm . It is not necessary to discontinue heparin therapy in these patients because platelet counts generally rebound to baseline values despite continued use. The exact mechanism of HAT is unknown, but it may be the result of platelet aggregation, a dilutional effect, or diminished platelet... 

Faster JL, Nichols WK, Silver D. Thrombocytopenia associated with heparin-coated catheters in patients with heparin-associated antiplatelet antibodies. Arch Intern Med 1989 149 2285-2287. 

King DJ, Kelton JG. Heparin-associated thrombocytopenia. Ann Intern Med 1984 100 535-540. 

Bailey RT, Ursick JA, Heim KL, et al. Heparin-associated thrombocytopenia A prospective comparison of bo vine lung heparin, manufactured by a new process, and porcine intestinal heparin. Drug Intell Qin Pharm 1986 20 374-378. 

Refludan (r hirudin) S. cerevisiae Hoechst Marion Roussel Beh-ringwerke Anticoagulation therapy for heparin-associated thrombocytopenia... 

Hirudin (lepirudin). Protein from the head and gullet rings of the medicinal leech (Hirudo medicinalis) (ca. 3 mg/leech). H is a heparinoid that delays blood coagulation (thrombin inhibitor). The Mr of H. is ca. 9060 (other reports 10800), it has a high content of acidic amino acid residues. H. is a colorless powder, soluble in water, insoluble in ethanol. The anticoagu-lati ve activity of H. is based on the formation of a compound with Aromhin, so that the latter cannot exert its catalytic effect Commercially available for use in the treatment of thrombosis, hematomas, etc. In Europe, recombinant H. (Refludan ) is marketed for heparin-associated thrombocytopenia. 

Heparin-induced thrombocytopenia (HIT) is a very serious adverse effect associated with UFH use. Platelet counts should be monitored every 2 to 3 days dining the course of UFH therapy.5 HIT should be suspected if the platelet count drops by more than 50% from baseline or to below 120,000. In patients with contraindications to anticoagulation therapy, UFH should not be administered (Table 7-7). 

Many drugs, especially quinidine and heparin, induce antibodies leading to thrombocytopenia. In most cases the antibodies are drug-dependent however, there are many examples in which the antibodies are autoimmune in nature [42], even for drugs, such as quinidine that are classically associated with drug-dependent antibodies [43], Gold therapy, in particular, is associated with autoimmune-thrombocytopenia [44],... 

Hypersensitivity to LMWHs, heparin, or pork products hypersensitivity to sulfites or benzyl alcohol (multidose vials) history of heparin-induced thrombocytopenia (tinzaparin) active major bleeding thrombocytopenia associated with positive in... 

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... 

Adverse reactions associated with heparin include hemorrhage, chills, fever, urticaria, and thrombocytopenia. 

B. Thrombocytopenia is a frequent side effect association with heparin. This reduction in the level of circulating platelets increases bleeding. Purple toes are encountered during warfarin therapy. Heparin may be administered to pregnant mothers without risk to the fetus. Heparin requires antithrombin III for its anticoagulant action, but does not increase the level of this protein in the blood. 

Contraindications Active major bleeding concurrent heparin therapy hypersensitivity to dalteparin, heparin, or pork products thrombocytopenia associated with positive in vitro test for antiplatelet antibody... 

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