Cold-Induced Reversible Cerebral Vasoconstriction Syndrome Presenting With Intraventricular Hemorrhage in a Normotensive Patient.

Reversible cerebral vasoconstriction syndrome (RCVS) is a transient neurovascular disorder characterized by sudden, severe headaches and reversible multifocal cerebral artery narrowing. While it is often associated with vasoactive substances, emotional stress, or postpartum status, environmental triggers such as cold exposure are rarely reported. We describe the case of a 61-year-old normotensive female who developed a thunderclap headache and vomiting shortly after brief exposure to cold weather. Initial evaluation revealed hypothermia and metabolic acidosis; she was discharged without neuroimaging. Three days later, brain imaging revealed a subacute left caudate intracerebral hemorrhage with intraventricular extension. Her condition deteriorated following an acute hypertensive episode attributed to anxiety. CT angiography and digital subtraction angiography demonstrated multifocal cerebral vasospasm without aneurysm or arteriovenous malformation. A working diagnosis of RCVS was made, and the patient improved with calcium channel blocker therapy (nimodipine) and supportive care. This case emphasizes the importance of recognizing RCVS in hemorrhagic presentations, even in normotensive patients, and suggests a potential role of cold-induced autonomic dysregulation in its pathogenesis.