MICA · FIRST-LINE LEARNING NOTES
Understand, prioritise and organise follow-up
A primary headache diagnosis requires a compatible history and appropriate examination after checking for features suggesting a secondary cause.
Look for warning features
Thunderclap headache, reaching maximum severity very rapidly, requires urgent assessment even when the neurological examination appears normal. Look for focal deficit, confusion, seizure, fever with neck stiffness, recent trauma and a marked change from previous headaches. A painful red eye with visual loss also suggests an emergency. Pregnancy, the postpartum period, immunosuppression and a history of cancer affect vigilance and referral.
[1][2][3][4]Characterise without anchoring
Clarify onset, time to maximum intensity, duration, location, associated symptoms and triggers. Distinguish a familiar episode from a first or different headache. Assess vital signs, alertness and neurological findings, adding eye or meningeal assessment as indicated. Ask about all analgesics, including non-prescription medicines, and frequency of use. Recurrent episodes with nausea, photophobia and functional impairment suggest migraine but do not negate a new warning feature.
[1][2]A normal neurological examination does not adequately reassure in thunderclap or clearly unusual headache. Ask about exertional onset, loss of consciousness and progression. New headache with visual or systemic features also needs attention. Investigation depends on the suspected cause, timing and expertise; negative imaging has different implications in different settings.
[1][2]Target investigations
Suspected subarachnoid haemorrhage requires immediate referral to a service able to arrange CT and specialist assessment. Interpretation of a negative CT depends on time since onset and reporting quality; it does not automatically end the investigation. Further testing belongs within that pathway. A well-characterised primary headache without warning features does not require imaging solely for reassurance. Suspected meningitis requires urgent care without avoidable treatment delay.
[2][1][3]Track course and medication use
For a primary headache, explain the diagnosis and agree on an individual care plan. A diary helps record frequency, duration, impact and medication use. Repeated analgesic use can perpetuate headache and should prompt supervised treatment review. Reassess a changing pattern, increasing disability or any unusual symptom. Instructions should clearly distinguish planned follow-up from immediate reassessment for a warning feature.
[1]A learning situation
FICTIONAL CASE · SELF-REFLECTION WITHOUT A SCORE
A man with a history of migraine describes a very severe headache during exertion, immediately different from his usual episodes. He has no weakness or fever. Rest partly reduces the pain.
Does his migraine history justify usual migraine care?
Read the reasoning
No. Rapid onset and a change from previous attacks require urgent assessment for a secondary cause, particularly vascular disease. No focal deficit and partial improvement are insufficient reassurance. Communicate exact onset time and time to peak intensity without delaying referral to test the response to an analgesic.
References and scope
- Headaches in over 12s — CG150: Recommendations (updated June 2025) ↗
- Subarachnoid haemorrhage caused by a ruptured aneurysm — NG228: Recommendations ↗
- Meningitis (bacterial) and meningococcal disease — NG240: Recommendations ↗
- ACR Appropriateness Criteria® Headache — Revised 2022 ↗
Original educational synthesis for adult first-line practice. International references must be interpreted with the clinical setting and local care pathways. Independent human scientific review remains to be confirmed.