Red-flag headache — SNNOOP10 and dangerous causes viva

SNNOOP framing. Older age >50 (O) and Progressive/new pattern (P) are positive. Jaw claudication and temporal tenderness point specifically to giant cell arteritis, not SAH. Visual dimming signals threatened anterior ischaemic optic neuropathy — this is sight-threatening today.^[3][1]

Immediate therapy. Do not wait for biopsy or imaging confirmation. Start systemic steroids immediately per the local protocol; if established visual loss, escalate per protocol. Urgent ophthalmology and rheumatology; arrange temporal artery biopsy or vascular imaging (ultrasound first-line per EULAR 2023)^[1] without delaying steroids. Check ESR and CRP (usually high; normal does not fully exclude).

Contrast with SAH pathway. Thunderclap maximal in seconds → immediate non-contrast CT (± LP if CT after 6 h or uncertain), neurosurgery, nimodipine — not steroids first.^[2] GCA is inflammatory large-vessel disease; SAH is vascular rupture. Mixing pathways (LP for classic GCA; steroids for classic thunderclap) fails the viva.

Pitfalls. Attributing visual change to migraine; waiting for biopsy; forgetting aspirin is adjunctive in some GCA pathways but steroids are the emergency therapy.^[1]