Vascular Arteriovenous malformation Aneurysm Moyamoya disease Fibromuscular dysplasia Cardiac Valvular heart disease (including endocarditis) Right-to-left shunts Atrial tumors Arrhythmia Cardiomyopathy Infectious Meningitis (especially tuberculous) Mycotic aneurysm Mastoiditis, otitis media, or sinusitis leading to venous sinus thrombosis Trauma Intracranial hemorrhage Cervical trauma with vertebral artery injury Intraoral trauma with carotid injury Brain tumor Drugs Cocaine Amphetamine Oral contraceptives Ergot poisoning Metabolic Homocystinuria Fabry disease Mitochondrial encephalopathies (MELAS syndrome) Organic acidemias Hyperlipidemias Hematologic/Autoimmune Sickle cell disease