Thunderclap headaches can be caused by a variety of conditions, including:
- Subarachnoid hemorrhage (SAH) – bleeding in the brain
- Reversible cerebral vasoconstriction syndrome (RCVS) – a condition that causes the blood vessels in the brain to constrict and then dilate, leading to headaches and other symptoms
- Cerebral venous sinus thrombosis (CVST) – blood clot in the blood vessels of brain
- Pituitary apoplexy – a condition in which a pituitary gland tumor ruptures and bleeds into the brain
- Ischemic stroke – a type of stroke caused by a blood clot blocking blood flow to the brain