Headache Red Flags: The Symptoms That Mean Go to Hospital Now

Headache is the third most common reason for seeking medical attention globally and one of the most common symptoms in neurology clinics. 95% of headaches are primary — migraine, tension-type, or cluster headache — benign conditions that cause suffering but not danger. 5% of headaches are secondary — caused by an underlying condition that may be life-threatening. The stakes of missing this 5% are enormous. Every person with headache — and every doctor encountering headache patients — should know these red flags.

SNOOP2 — The Red Flag Mnemonic

S — Systemic symptoms or disease: Headache with fever (meningitis, encephalitis, brain abscess, temporal arteritis); headache with weight loss, night sweats (underlying malignancy or infection); headache in immunocompromised patient (HIV, organ transplant — higher risk of CNS opportunistic infections). N — Neurological signs: Any new neurological abnormality accompanying headache — limb weakness, facial asymmetry, speech difficulty, visual field loss, altered consciousness, papilloedema (optic disc swelling from raised ICP). O — Onset: thunderclap: Headache reaching maximum severity within 60 seconds — "the worst headache of my life." The classic presentation of subarachnoid haemorrhage from a ruptured cerebral aneurysm. 50% of SAH patients die or have permanent disability; early diagnosis and aneurysm securing prevents re-bleeding. CT head (emergency) + LP (if CT negative but clinical suspicion high). O — Older age (new headache above 50): Temporal arteritis (giant cell arteritis) — the most important diagnosis to consider. A new severe headache, scalp tenderness, jaw claudication (pain on chewing), visual symptoms, and ESR/CRP elevation in a patient over 50. Untreated → blindness. Treated with prednisolone urgently. P — Progressive headache changing pattern: New headache worsening over weeks; headache pattern changing in a previously well-characterised primary headache patient. P — Postural component: Headache dramatically worse on lying flat (raised ICP) or worse on standing and relieved lying down (CSF hypotension — "low pressure headache" after LP or spontaneous CSF leak).

If any red flag is present: go to emergency or call +91 90633 66983 — Sri Anand CNC, Chanda Nagar, Hyderabad.