Heparin-induced thrombocytopenia with acute aortic and renal thrombosis in a patient treated with low-molecular-weight heparin.

Heparin-induced thrombocytopenia is a rare but serious complication of heparin therapy. Most of cases are related to unfractionated heparin, but a few are due to low molecular weight heparin sometimes associated with unfractionated heparin. A patient with pulmonary contusions after chest injury developed a catheter related subclavian vein thrombosis on day 16. He was treated by increasing doses of low molecular weight heparin. Aortic and renal thromboses occurred on day 21. Surgical thrombectomy, performed after starting alternative anticoagulation treatment led to complete arterial recovery. In case of suspicion of heparin-induced thrombocytopenia, with unfractionated or low-molecular-weight heparin, heparin treatment must be discontinued before the results of biological tests become available. Arterial and/or venous thrombosis is a serious complication of heparin-induced thrombocytopenia. The treatment has two aims: first, to restore arterial patency by clot removal by thrombectomy, bypass or thrombolysis, and second, to avoid new thrombosis formation by substitutive anticoagulation treatment: danaparoid may have cross-reaction with heparin, or lepirudin has anaphylactic risks and needs biological follow-up. Heparin-induced thrombocytopenia and thrombosis can be complicated by death or disabilities such as amputations, stroke, renal or bowel infarction. Once HIT has been diagnosed heparin should never be given again, but if cardiopulmonary bypass is required, it might be reintroduced during operation only if serum antibodies have disappeared.