IM17.{2,4-5} | Headache Clinical Evaluation — Summary & Reflection

KEY TAKEAWAYS

The structured headache history covers: mode of onset (thunderclap = SAH first), site and radiation, character (pulsating → migraine; pressing → TTH; stabbing periorbital → cluster), severity, aura (elicit each type specifically: visual, sensory, motor, speech), associated symptoms (nausea/photophobia/phonophobia → migraine; autonomic features → cluster; fever/meningism → infection), precipitants, analgesic use frequency (MOH screen), impact on function, family history, and SNNOOP10 red-flag screen.

Neurological examination for headache includes: BP and temperature, higher mental functions, all cranial nerves (especially pupils + EOMs + fundoscopy for papilloedema), motor system (power, reflexes, plantars), cerebellar function, and meningeal signs:
- Nuchal rigidity: resistance to passive neck flexion
- Kernig's sign: resistance/pain when extending knee with hip flexed at 90°
- Brudzinski's sign: involuntary hip/knee flexion when neck is passively flexed
- Papilloedema: blurred disc margins, disc elevation, venous engorgement = raised ICP

Raised ICP features: morning headache, Valsalva aggravation, effortless vomiting, papilloedema, visual obscurations, CN VI palsy (non-localising), late: CN III palsy (blown pupil), Cushing triad (HTN + bradycardia + irregular breathing).

Differential diagnosis is generated in three steps: (1) pattern recognition against ICHD-3 for primary headaches, (2) exclusion of dangerous secondary diagnoses (SAH, meningitis, SOL, CVT, GCA), (3) documented clinical justification for each diagnosis and each exclusion.

REFLECT

Return to the opening vignette: you now have the tools to generate completely different differentials for the two patients from the history alone — before a single investigation is ordered. The 32-year-old woman with unilateral pulsating headache, nausea, and photophobia meets ICHD-3 criteria for migraine; a focused neurological examination to exclude papilloedema and focal deficit, combined with a negative SNNOOP10 screen, allows you to diagnose and treat without imaging. The 55-year-old man with progressive morning headache and effortless vomiting has a raised ICP pattern — and before you even perform fundoscopy, the history alone tells you that this is not a primary headache. How would you explain to the first patient why you are not ordering a brain scan, in a way that reassures rather than dismisses? And how would you explain to the second patient — who has been 'reassured' by his GP for three weeks — why urgent imaging is now necessary? The skill of clinical reasoning is inseparable from the skill of clinical communication.