Objective:

Unusual clinical course

Background:

Multiple vaccines have been developed against COVID-19 as a collaborative worldwide effort. On March 18, 2021 the European Medicines Agency reported a serious and rare adverse effect of thrombosis with thrombocytopenia syndrome (TTS) after receiving the ChAdOx1 nCoV-19 vaccine; most of these cases were associated with cerebral venous sinus thrombosis (CVST). To date, there are no cases of TTS-related CVST reported after receipt of either of the 2 mRNA COVID-19 vaccines authorized for use in the United States. We report a case of CVST with the Moderna mRNA vaccine.

Case Report:

A healthy 45-year-old male patient without any risk factors presented with new-onset seizures 8 days after the receipt of the 2 nd dose of Moderna (mRNA-1273), with concomitant SAH as a complication. One day prior to admission, he noted headaches and neck pain unrelieved by over-the-counter analgesics. Computed tomography (CT) scan brain without contrast revealed a left frontal lobe intracerebral hemorrhage (ICH) along with subarachnoid hemorrhage (SAH). A subsequent contrast-enhanced magnetic resonance imaging (MRI) brain confirmed the CT findings as well as anterior superior sagittal sinus thrombosis. He had normal platelet count with a negative thrombophilia work-up and cancer screening. He was successfully anticoagulated with heparin and discharged on warfarin without neurological sequelae or further seizures. The case was reported to the US Vaccine Surveillance System.

Conclusions:

mRNA vaccine-related CVST is an extremely rare phenomenon. More data are needed to establish causality and understand the role of vaccine-related immune response resulting in thrombotic events with or without TTS.