Cerebral venous sinus thrombosis after ChAdOx1 vaccination: the first case of definite thrombosis with thrombocytopenia syndrome from India.

Cerebral venous sinus thrombosis (CVST) following novel coronavirus-2019 (nCoV-19) vaccination is a rare adverse effect. We report the first case of CVST associated with ChAdOx1 vaccination, with positive anti-platelet factor 4 (PF4) antibodies, from India. A 44-year-old woman developed a thunderclap headache 4 days after the first dose of the adenoviral vector vaccine ChAdOx1 (Covishield). Physical examination was unremarkable barring mild neck stiffness with no focal neurological deficits. MRI identified right transverse sinus thrombosis. Laboratory tests revealed raised D-dimer and thrombocytopenia; anti-PF4 antibodies were subsequently identified, consistent with thrombosis with thrombocytopenia syndrome (TTS). She was treated with non-heparin anticoagulation and intravenous immunoglobulin and made an uneventful recovery. Early recognition of adenoviral vector vaccine-related TTS, which resembles heparin-induced thrombocytopenia syndrome, is important as heparin and heparin analogues are best avoided in the treatment.