IM17.{1,3} | Headache Foundations — Summary & Reflection

KEY TAKEAWAYS

Headache classification follows the ICHD-3 three-part framework: primary (migraine, TTH, cluster/TACs, other primary) versus secondary (attributed to a vascular, infective, structural, or metabolic cause) versus cranial neuralgias. Over 90% of headaches are primary.

Migraine (14–15% prevalence; F:M 3:1) is characterised by 4–72-hour attacks of moderate-to-severe pulsating unilateral headache with nausea/photophobia/phonophobia, aggravated by activity. Migraine with aura ('classical') adds fully reversible focal neurological symptoms (typically visual scintillating scotoma) developing over 5–20 minutes before the headache. The key clinical distinction: migraine with aura is an absolute contraindication to combined oestrogen-containing contraceptives. Chronic migraine: headache ≥15 days/month with ≥8 migraine days. Medication-overuse headache (MOH): analgesics ≥15 days/month (triptans ≥10 days/month) for >3 months.

Tension-type headache (most prevalent; up to 70%): bilateral, pressing/tightening, mild-to-moderate, not aggravated by activity, no nausea — contrasts with migraine on all these features.

Cluster headache: severe unilateral periorbital pain, 15–180 min, ipsilateral cranial autonomic features, restlessness, periodic clustering. Hypothalamic generator.

Red flags (SNNOOP10): thunderclap onset, neurological deficit, fever, systemic symptoms, new onset >50 years, positional headache, post-exertional onset. Thunderclap headache = CT then LP ≥12 hours → SAH excluded only when BOTH are negative.

REFLECT

Recall Pankaj from the opening vignette — he described the worst headache of his life during straining. You now know that thunderclap onset mandates CT then lumbar puncture, regardless of how well he appears on arrival. How would you explain this diagnostic urgency to a patient who feels better by the time he reaches the emergency department and wants to go home? Migraine with aura carries a stroke risk multiplier with combined OCP — what is your responsibility to Rajesh's wife if she attends the same clinic for contraceptive advice and mentions she too has migraines with 'flashing lights before the pain'? Reflecting on these real scenarios: the ICHD-3 criteria and SNNOOP10 red-flag framework are not academic exercises — they are the instruments that separate the safe clinician from the dangerous one.