Headache Differential

Headache assessment begins with safety: decide whether the pattern is a primary headache disorder or a symptom of another condition that needs urgent treatment. Primary headache disorders include migraine, tension-type headache, and cluster headache. A secondary headache is caused by another process, such as intracranial bleeding, infection, stroke, raised intracranial pressure, venous thrombosis, acute glaucoma, head injury, pregnancy-related disease, medication exposure, or giant cell arteritis. A previous diagnosis of migraine does not explain every later headache. Compare the current event with the patient's established pattern and treat a new feature as new information. A normal neurological examination supports a primary headache diagnosis only when the history is also typical and stable; it does not cancel abrupt onset, papilledema, systemic illness, pregnancy or puerperium, recent trauma, or a substantial pattern change. The assessment purpose is therefore to identify time-critical secondary causes first, then characterize the phenotype, disability, medication exposure, and patient goals. Before a routine interview, observe airway, breathing, circulation, level of consciousness, and ability to communicate. If the patient is unstable or has an emergency red flag, stop the routine...