Clinical features of type 2 heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a life—threatening complication of heparin therapy. Heparin induces a conformational change in a platelet surface protein (platelet factor 4), which exposes a neoantigen. In patients with HIT, HIT antibodies form in response to the neoantigen and bind to the surface of platelets, causing platelet aggregation, thrombocytopenia

Clinical signs 

Suspected with heparin exposure >5 days and  any of the following:

• Platelet count reduction >50% from baseline
• Arterial or venous thrombosis
• Necrotic skin lesions at heparin injection sites
• Acute systemic (anaphylactoid) reactions after heparin 

Diagnostic 

 Serotonin release assay: Gold standard confirmatory test evaluation a Start treatment in suspected cases prior to confirmatory tests

Treatment

Stop ALL heparin products a Start a direct thrombin inhibitor (eg, argatroban) orfondaparinux (synthetic pentasaccharide)