[Thrombopenias induced by heparin: diagnostic and therapeutic innovations]

Heparin-induced thrombocytopenia (HIT) is a difficult immune-mediated phenomenon that physicians have to cope with. It is caused by platelet-activating, heparin-dependent IgG antibody and may be associated with venous and arterial thrombosis, potentially fatal. Simple tests are now available which can detect most antibodies implicated in HIT. The old term "white clot syndrome" suggested that HIT was mostly associated with arterial thromboembolic events, but more recent publications indicate that HIT is also an important risk factor for venous thromboembolism. In case of suspicion of HIT, treatment by heparin should imperatively be stopped and an alternative anticoagulant treatment should be started before any laboratory confirmation.