Spontaneous Subarachnoid Haemorrhage After COVID-19 Vaccination; a Rare Case Report

Introduction: Cerebrovascular incidents are considered uncommon but important complications of vaccination against coronavirus disease-2019 (COVID-19). Subarachnoid hemorrhages (SAH) usually occur due to an underlying cerebral aneurysm. In this study, we have reported a subarachnoid hemorrhage incidence in a patient shortly after receiving the COVID-19 vaccine (ChAdOx1- AstraZeneca). Case Presentation: A 69-year-old male with no remarkable risk factors referred to the emergency room with complaints of headache, nausea, and vomiting. The patient had received his first dose of vaccine against COVID-19 four days before symptoms started. An aggravated headache, nausea, elevated blood pressure (180/100), and drowsiness occurred on the second day of admission. Imaging implied on acute hydrocephalus and increased intracranial pressure (ICP) caused by subarachnoid hemorrhage. The condition was treated by inserting an external ventricular drain (EVD). We found no underlying vascular abnormality in primary and follow-up cerebral angiographies. Conclusions: Reported cerebral haemorrhages caused by COVID-19 vaccination are mostly intra-parenchymal. Our study observed a type of cerebrovascular event that has not been reported frequently. Vaccine-associated cerebrovascular events, however rarely, are critical. It is important to demonstrate possible risks and complications, as vaccination programs against COVID-19 have become an essential part of health care in most countries.