Recent studies suggest that a thromboembolic disorder resembling heparin-induced thrombocytopenia (HIT), so-called spontaneous HIT syndrome, can occur in patients without any history of heparin exposure. It is likely due to anti-platelet factor 4 (PF4)/polyanion antibodies induced by other polyanions, such as bacterial surfaces and nucleic acids. We describe an atypical case of spontaneous HIT syndrome. A 70-year-old man suddenly presented with acute cerebral sinus thrombosis (CST). Soon after the initiation of unfractionated heparin (UFH) for the treatment of CST, his platelet count fell precipitously and he developed deep vein thrombosis, a clinical picture consistent with rapid-onset HIT but without any proximate episodes of heparin exposure, infection, trauma, surgery, or other acute illness. Antigen assays and a washed platelet activation assay indicated that the patient already possessed anti-PF4/heparin IgG antibodies with heparin-dependent platelet activation properties on admission. Cessation of UFH and initiation of argatroban resulted in prompt recovery of his platelet count without further thromboembolic events. We identified two similar cases in the literature. However, these patients do not meet the recently proposed criteria for spontaneous HIT syndrome. Even in atypical cases, however, inappropriate or delayed diagnosis of HIT appears to be associated with worse outcomes. We propose that these atypical cases should be included in the category of spontaneous HIT syndrome.

Oral aspirin is highly recommended for acute antithrombotic therapy and secondary prevention in ischemic stroke patients. Clopidogrel and cilostazol presented as good or better effectiveness in reducing the risk of recurrent stroke than aspirin. Dual antiplatelet agents may be used with the exception of aspirin plus dipyridamole, which is not generally recommended for secondary stroke prevention because of the associated high bleeding risk. The addition of dabigatran to warfarin therapy was approved for ischemic stroke prevention in patients with non valvular atrial fibrillation NVAF. In addition, novel oral anticoagulants e. g., factor Xa inhibitors rivaroxaban, apixaban have been tested in several ongoing large randomized trials. When administering anticoagulant agents for patients with NVAF, the estimation of the embolic and bleeding risks using CHADS 2 score, CHA 2 DS 2 VASc score and HASBLED score is recommended. In the Bleeding with Antithrombotic Therapy BAT Study group, the characteristics of bleeding complications in Japanese antithrombotic users were reported.