Cerebral venous sinus thrombosis after COVID-19 vaccination: a case report and literature review

"Introduction

... The most common side effects of COVID-19 vaccination include fatigue, headache and local pain around the injection site. However, there have been rare cases of cerebral venous sinus thrombosis (CVST) associated with either the Ad26.COV2.S vaccine or ChAdOx1 nCoV-19 vaccine. CVST can present with headache or seizures and may involve elevated intracranial pressure. When CVST follows a COVID-19 vaccination, it may be referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT). The proposed mechanism of VITT is similar to that of heparin-induced thrombotic thrombocytopenia (HITT) in terms of developing high levels of antibodies against the complexes of platelet factor 4 (PF4) and heparin with associated thrombocytopenia. However, the immune response is triggered by the vaccine and considered to be heparin independent. Medical literature discussed many VITT cases to date. Our report also offers a VITT–related CVST case in a young man with no prior history of thrombosis. We also provide a literature review on CVST associated with adenovirus vector-based vaccines, with discussion of proposed mechanisms and recent treatment guidelines...

Discussion 

... There are a few proposed pathophysiologic mechanisms implicated in CVST development. One of these is VITT which is similar to HITT in its pathophysiology. HITT results from the formation of immune complexes consisting of autoantibodies against PF4 and heparin. These immune complexes bind to the surface of platelets and monocytes, provoking their activation by cross-linking Fc γIIA receptors. In the case of VITT, it is believed that the leakage of DNA from the adenovirus infected cells binds to PF4 and triggers the production of autoantibodies. Our case tested positive for PF4 autoantibodies as in previously reported CVST cases associated with Ad26.COV2.S vaccine, which might indicate a high probability of VITT being the underlying pathophysiology of CVST in this patient. Another proposed mechanism of VITT may be independent of PF4 autoantibodies. Viral vector-based COVID-19 vaccines contain high amounts of viral particles, which may be distributed across different body tissues including the brain. The COVID-19 adenoviral vectors might trigger an immune response in the brain, leading to localized vascular thrombosis. According to the reported cases in Table 1, this mechanism could explain CVST in patients who tested negative for PF4 autoantibodies. Interestingly, those patients did not have any associated systemic thrombosis and were reported to have CVST secondary to ChAdOx1 nCoV-19 vaccine."