Management of HIT type II

HIT type II can be recognised by a rapid fall in platelets occurring 5 to 14 days after starting heparin, and/or by the presence of thrombotic events occurring during this period. Thrombocytopenia can be caused by a number of diseases and conditions as well as by drugs, and other possible causes have to be excluded. Diagnosis is usually based on clinical assessment because of time delays in obtaining laboratory confirmation.

It is important when there is a strong clinical suspicion that a patient has HIT type II, heparin is discontinued immediately to stop the immune response. The serious risk of thrombosis frequently associated with this condition means that the use of alternative non-heparin parenteral anticoagulants is recommended. Suitable anticoagulants should rapidly obtain therapeutic levels and not induce or react with HIT antibodies. Left untreated the evidence suggests that patients have about a 50% risk of developing thrombosis.