Those that are emergencies
Pain that peaks in under a minute is an emergency path: haemorrhage, cerebral venous thrombosis, dissection, and hypertensive crisis stay in play until appropriate imaging and tests are done. The label primary thunderclap is the end of that path, not the start.
Quieter but still important
Hypnic headache wakes older adults from sleep and must be separated from nocturnal hypertension, apnoea, and intracranial lesions. Ice-pick pain lasts seconds; if it is new and strictly fixed in one spot, imaging is sometimes needed. Helmet or band headache improves when the external pressure is removed.
These pages are written for health professionals. They do not replace a history, examination, or clinical judgment. Treatment is decided for each patient individually.