COVID-19 as a trigger of cerebral venous sinus thrombosis in a patient with autoimmune hyperthyroidism: a case report.

Background: Cerebral venous sinus thrombosis (CVST) composes an uncommon subtype of stroke caused by thrombotic occlusion of the cerebral venous system and tends to occur in hypercoagulable states. Albeit exceedingly rare, autoimmune hyperthyroidism and COVID-19 has been implicated as rare risk factors for CVST. As both conditions are capable of inducing degrees of inflammation and hypercoagulability, we postulate that COVID-19 could trigger CVST by superimposing endotheliitis and inflammation on the hypercoagulable and hypofibrinolytic state of hyperthyroidism. Case presentation: We report the case of an adult male with headache, fever, nausea, vomiting, and previously known autoimmune hyperthyroidism. Diagnostics revealed elevated inflammatory and hypercoagulability markers, free T4, low TSHs, and positive SARS-CoV-2 PCR. Neuroimaging demonstrated an acute intracerebral and subdural hemorrhage attributable to cerebral sinus thromboses. A diagnosis of CVST with associated COVID-19 and autoimmune hyperthyroidism was established, and anticoagulation therapy was initiated. Follow-up examination revealed complete symptomatic resolution and regression of thrombosis. Conclusions: Clinicians should be aware that even mild COVID-19 could precipitate CVST, especially in presence of other risk factors. Further studies should be conducted to evaluate the effects of mild COVID-19 on existing prothrombic states, including autoimmune hyperthyroidism. Furthermore, a high index of suspicion towards a secondary cause must be maintained for headaches in COVID-19, as it may indicate a serious etiology, including CVST.