Headache
at the bedside
- airway, breathing, circulation; full vitals, GCS, glucose
- BP and temperature → hypertensive emergency, infection
- the one question → worst or first headache of their life, and how fast it peaked
escalate now if
- systemic → fever, meningism, myalgias
- neoplasm → history of cancer
- onset → sudden / thunderclap
- older age → > 50 years (consider temporal arteritis)
- positional → worse lying / standing (ICP issues)
- precipitated → exertion, Valsalva, coughing
- papilledema → suggests ↑ ICP
- pattern → progressive or atypical
- pregnancy → pregnancy / postpartum (pre-eclampsia/eclampsia, CVST, PRES)
- painful eye → autonomic features (cluster, glaucoma)
- pathology / immune → HIV, immunosuppression
- any of these → CT first, then the specific scenario
differentials
secondary, must not miss
- subarachnoid hemorrhage → thunderclap, peaks in seconds to a minute, neck stiffness, collapse
- meningitis, encephalitis → fever, neck stiffness, photophobia, rash, confusion or seizure
- raised intracranial pressure → worse lying flat, morning vomiting, papilledema, cancer or shunt
- hypertensive emergency, PRES, eclampsia → very high BP, visual change, seizure, pregnancy → hypertension
- temporal arteritis → over 50, jaw claudication, scalp tenderness, visual symptoms
- venous sinus thrombosis → pregnancy, OCP, dehydration, progressive or positional headache, seizure
- angle-closure glaucoma, carotid dissection → painful red eye with halos; neck pain with Horner syndrome or deficit
primary
calculator Ottawa SAH rule · MDCalc ↗︎
focused check
- acute vs chronic; character, location, duration
- location clues (correlate with the full picture, not the site alone)
- occipital → cerebellar lesion, cervicogenic, cervical radiculopathy
- orbital → optic neuritis, cavernous sinus thrombosis
- facial → sinusitis, carotid artery dissection
- ask → fever, photophobia, N/V; trauma; meds (OCPs, anticoagulants, analgesic overuse); PMH (cancer, pregnancy, autoimmune)
- examine → neuro exam + GCS; meningeal signs; fundoscopy → papilledema; CN + visual fields; temporal artery (> 50 yrs)
send now
- CT brain → first-line for red flags; normal CT within 6 h of thunderclap onset effectively excludes SAH (LP if later or CT negative)
- consider CTA head/neck → head or neck trauma; focal neurological deficit; suspected cervical artery dissection or other vascular pathology
- consider CTV if cerebral venous sinus thrombosis suspected
- thunderclap, progressive, or positional headache resistant to usual analgesia; new seizure; focal deficit; papilledema
- risk factors → pregnancy / postpartum, hypercoagulable state, OCP, mastoiditis / local infection
treat
no red flags, likely primary
- paracetamol 1 g PO/IV q6h, max 4 g/day
- NSAID if none of the cautions below → ibuprofen 400 mg PO TDS (max 2.4 g/day) or ketorolac 10–30 mg IV/IM (max 90 mg/day; 60 mg if over 65 or under 50 kg); ketorolac course max 5 days in total, IV plus oral → analgesia
- no NSAID, oral or IV → AKI or CKD, GI bleed or ulcer history, heart failure, anticoagulants or bleeding risk, pregnancy from 20 weeks, aspirin or another NSAID already given
- migraine → antiemetic (metoclopramide 10 mg IV or prochlorperazine 12.5 mg IV/IM) ± triptan (sumatriptan 50–100 mg PO / 6 mg SC)
- no triptans in IHD or uncontrolled HTN
red flags present
- CT brain first
- if CT normal + meningitis suspected → LP
specific scenarios
- hypertensive emergency → hypertension
- suspected SAH → CT now (6-h rule in imaging above); late or CT negative → LP; neurosurgery once confirmed
- raised-ICP signs → urgent imaging, head-up 30°, neurosurgery
- suspected bacterial meningitis → antibiotics now, do not delay
- ceftriaxone 2 g IV q12h + vancomycin 15–20 mg/kg IV q12h
- add ampicillin 2 g IV q4h if >50 y or immunocompromised (Listeria cover)
- dexamethasone 10 mg IV (≈0.15 mg/kg) with / just before the first antibiotic dose, then q6h ×4 days
- full regimens and alternatives: Empiric Antibiotics
- suspected HSV encephalitis / meningoencephalitis → add acyclovir 10 mg/kg IV q8h empirically alongside bacterial cover while CSF HSV PCR and MRI are pending
- especially with altered mental status, seizures, or a focal / temporal-lobe picture
- do not wait for confirmation: missed HSV encephalitis carries major morbidity
- suspected temporal arteritis (age > 50, new headache, jaw claudication, visual symptoms, tender / thickened temporal artery, raised ESR/CRP) → prednisolone 40–60 mg daily now, do not wait for biopsy
- visual symptoms or impending visual loss: high-dose IV methylprednisolone 500–1000 mg daily × 3 days, then oral
- urgent Ophthalmology + Rheumatology
- acute angle-closure glaucoma (painful red eye, halos, fixed mid-dilated pupil, raised intraocular pressure) → urgent Ophthalmology; do not dilate the pupil
- hand over → red flags present or not, imaging result, analgesia given, review time
evidence
| source | type |
|---|---|
| Ottawa SAH Rule · Perry et al, BMJ 2013 ↗︎ | clinical decision rule |
| IDSA 2004 · Bacterial meningitis (empiric treatment) | specialty-society guidance |
| BSR/BHPR 2020 · Giant cell arteritis management | specialty-society guideline |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
free the on-call checklist covers the whole shift on one printable page.
studying for the IM exam? the IM Rapid Review covers headache red flags in the same format. see the sample chapter.
reviewed Jun 2026updated Oct 2026file complaint/headache