Cases have been described highlighting atypical thrombosis associated with COVID-19 infection as well as with the ChAdOx1 nCoV-19 (AstraZeneca) vaccine and Johnson & Johnson vaccine
Neurological COVID-19 disease poses a considerable burden in terms of disease outcomes and use of hospital resources from prolonged intensive care and inpatient admission; preliminary data suggest these may differ according to WHO regions and country income levels. The different risk factors for encephalopathy and stroke suggest different disease mechanisms which may be amenable to intervention, especially in those who develop neurological symptoms after hospital admission 1)
Increased rates of thromboembolic events were identified in recipients, and, subsequently, a syndrome of vaccine-induced immune thrombotic thrombocytopenia (VITT) was described whereby recipients presented with cerebral venous sinus thrombosis, hemorrhagic infarctions, and - consequently - raised intracranial pressure.
Related cerebral venous sinus thrombosis and associated infarcts are rare complications of the AstraZeneca vaccine. Neurosurgical management involves treating intracranial hypertension however survival outcomes in a cohort were poor. In these series, decompression was performed in deteriorating patients however prophylactic decompression, in the presence of extensive venous sinus thrombosis, should be considered on a case-by-case basis. As vaccination programs accelerate across the world, neurosurgeons are likely to be increasingly involved in managing intracranial hypertension in patients with VITT-related sinus thromboses. 2).
Cerebral venous sinus thrombosis (CVT) prior to the COVID pandemic was rare, responsible for 0.5 of all strokes, at the onset of the pandemic on the East Coast, overall cross-sectional imaging volumes declined due to maintaining ventilation, high levels of care and limiting disease spread, although COVID-19 patients have a 30-60 times greater risk of CVT compared to the general population, and vaccination is currently the best option to mitigate severe disease. In early 2021, reports of adenoviral vector COVID vaccines causing CTV and Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT), led to a 39.65% increase in cross-sectional venography, however, in this study unvaccinated patients in 2021 had a higher incidence of CVT (10.1%), compared to the vaccinated patients (4.5%). Clinicians should be aware that VITT CVT may present with a headache 5-30 days post-vaccination with thrombosis best diagnosed on CTV or MRV. If thrombosis is present with thrombocytopenia, platelets <150 × 109, elevated D-Dimer >4000 FEU, and positive anti-PF4 ELISA assay, the diagnosis is definitive. VITT CVT resembles spontaneous autoimmune heparin-induced thrombocytopenia (HIT) and is postulated to occur from platelet factor 4 (PF4) binding to vaccine adenoviral vectors forming a novel antigen, anti-PF4 memory B-cells, and anti-PF4 (VITT) antibodies. 3).
A 65-year-old man who developed cognitive deficits and memory impairments following his first dose of Oxford AstraZeneca vaccine (Covishield). The onset of acute cognitive deficits and memory impairments could be another complication of COVID-19 vaccination that physicians and neurologists need to be warned of. Monitoring the safety of COVID-19 vaccines and describing the side effects associated with them is essential to improve safety profiles and enhance public trust 4).