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Headache

Thunderclap, worst-ever, or any red flag = imaging.

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Your objective: explain the approach, recognize important warning signs, then test your recall.

Abbreviations explained
ACS
Acute coronary syndrome
OMI
Occlusion myocardial infarction
ECG
Electrocardiogram
PE
Pulmonary embolism
POCUS
Point-of-care ultrasound
QTc
QT interval corrected for heart rate
LBBB
Left bundle branch block
RBBB
Right bundle branch block
hs-cTn
High-sensitivity cardiac troponin
CTA
Computed tomography angiography
ICU
Intensive care unit
Filter

The jobThunderclap, worst-ever, or any red flag = imaging.

  1. Thunderclap, worst-ever, or any red flag → image.
  2. A high-quality noncontrast CT within 6 h can exclude SAH in a neurologically intact adult under the ACEP pathway; persistent concern after a negative CT needs LP or CTA through shared decision-making.
  3. Do not delay antibiotics (and dexamethasone if pneumococcal likely) for CT when meningitis is possible.
  4. Age ≥50 with visual symptoms: treat GCA on suspicion — do not wait for ESR.

Primary headaches (migraine, tension, cluster) dominate ED volumes, but the task is to filter the ~1–5% with secondary catastrophes.

Thunderclap onset, fever with meningismus, papilledema, and new neuro deficits change everything.

Subarachnoid hemorrhage Critical

Key: Sudden worst-ever headache. High-quality noncontrast CT within 6 h with a normal neurologic exam can exclude SAH under the ACEP pathway. If residual risk remains, use LP or CTA with shared decision-making. Ottawa SAH applies only to alert, neurologically intact patients aged ≥16 with new nontraumatic severe headache peaking within 1 h; it does not exclude other secondary causes.

Intracranial hemorrhage Critical

Key: Focal deficits, anticoagulation, hypertension — non-contrast CT first.

Meningitis / encephalitis Critical

Key: Fever + meningismus ± altered mentation — antibiotics (and dexamethasone if pneumococcal likely) must not wait on CT; LP when safe.

Cerebral venous sinus thrombosis Critical

Key: Progressive headache, papilledema, hypercoagulable state, postpartum — CTV/MRV.

Arterial dissection (carotid/vertebral) Critical

Key: Head/neck pain + Horner syndrome or posterior-circulation symptoms after trauma or neck manipulation.

Acute angle-closure glaucoma Critical

Key: Painful red eye, halos, mid-dilated pupil, vision loss — ophthalmology now.

Giant cell arteritis (temporal arteritis) Emergent

Key: Age ≥50, jaw claudication, new headache, visual symptoms — start glucocorticoids immediately if cranial GCA/visual threat is suspected; do not wait for biopsy. ESR/CRP can be normal.

Migraine / tension / cluster Common

Key: Recurrent pattern without red flags; treat (prefer non-opioids) and arrange follow-up.

Tick what your patient has — the banner updates as you go.

Onset speed

thunderclap (<1 min to peak) = SAH until excluded

Worst-ever, first-ever, or atypical-for-this-patient headache

Fever, immunosuppression, malignancy, anticoagulation, pregnancy/postpartum

Positional (post-LP, intracranial hypotension), transient (RCVS), exertional or wake-up pattern

Associated

neck pain, photophobia, visual change, jaw claudication

Full neuro

focal deficits, gait, fundoscopy for papilledema

Meningismus

nuchal rigidity, Kernig/Brudzinski (insensitive — do not rely on them alone)

Temporal artery tenderness; scalp allodynia

Eye

acuity, pupils, red eye, corneal clouding

Skin

zoster, neurocutaneous stigmata

Bedside

  • Glucose, vitals including temperature, fundoscopy

Labs

  • ESR and CRP if GCA is possible (normal values do not exclude it)
  • Coagulation before LP
  • LP: opening pressure, cell count, xanthochromia (most reliable ≥12 h after onset; still perform LP after a late negative CT — RBCs in tube 4 also matter), microbiology as indicated

Imaging

  • Non-contrast CT for thunderclap/red flags (sufficient to rule out SAH if <6 h, neurologically intact, expert read)
  • CTV/MRV for CVT; CTA/MRA for dissection and aneurysm
  • MRI for posterior fossa or progressive headaches
Medication safety reminder

Use this as a first-pass prompt; verify all medications, doses, concentrations, contraindications, weight, pregnancy status, and local protocols before administration.

Check indication, allergy, route, renal/hepatic risk, interactions, monitoring, and local formulary.

Discharge

  • Clinically diagnosed migraine/tension with benign exam, effective non-opioid treatment, no red flags — return precautions and follow-up. A negative Ottawa SAH rule can avoid SAH testing only in its eligible population and without another reason to investigate.

Admit

  • Meningitis on therapy, CVT anticoagulation, GCA on glucocorticoids, refractory migraine/cluster infusions.

Neurosurgery / stroke unit / ICU

  • SAH (aneurysm securing), ICH per protocol, deteriorating meningitis, elevated ICP.

Use objective reassessment and the local pathway.

Before the next decision · reassess and hand over

Use these learning prompts with the presentation’s pathway. They are not discharge criteria.

  1. Reassess: compare symptoms, observations and examination with the initial assessment and response to treatment.
  2. Warning signs for Headache:
    • Thunderclap or “worst headache of my life”
    • Fever with meningismus or altered mentation
    • New focal deficit, seizure, or papilledema
    • First headache ≥50 y, in pregnancy/postpartum, cancer, or immunocompromise
    • Progressive or sleep-waking pattern over days
    • Painful red eye with visual loss
    • Trauma or anticoagulation with new headache
  3. Reconsider: check unresolved findings and alternative explanations, including the pitfalls below.
  4. Escalate: communicate deterioration, uncertainty or needs beyond the current setting.
  5. Plan the transition: identify outstanding results, responsibility for follow-up, patient understanding and specific return advice.
Review this presentation’s disposition pathway →Practice a handover →

Clinical Pearls

  • Third-generation CT within 6 h + a normal neuro exam rules out SAH (ACEP 2019). After 6 h: LP or CTA.
  • Ottawa SAH all-negative: you can skip imaging. Any single positive criterion means you cannot.
  • Start glucocorticoids immediately if cranial GCA with visual threat is suspected — do not wait for ESR or biopsy.
  • A first “migraine” after age 50 is a red flag, not a diagnosis.

Pitfalls

  • A normal third-generation CT within 6 h of onset, read by an experienced radiologist, rules out SAH in neurologically intact patients (ACEP Level B). After 6 h, CT is not sufficient — LP or CTA.
  • Sentinel “warning” headaches precede 10–40% of aneurysm ruptures.
  • Ottawa SAH Rule is highly sensitive but poorly specific — any single positive criterion means you cannot rule out SAH without testing.
  • GCA can present without a tender temporal artery and with a normal ESR.
  • Do not relabel a first “migraine” after age 50 without considering imaging.
  • Opioids are not first-line for primary headache in the ED (ACEP).
PRACTICE REFRESHER

Rapid recall

Test your first action and the dangerous diagnoses before revealing the answer.

01 · First move

Before you scroll, what needs to happen first?

02 · Immediate threats

Name at least two diagnoses that cannot wait.

PRIVATE TO THIS DEVICE

Your learning note

Capture a weak point, a teaching pearl, or a question to take to your next shift.

Review schedule starts when marked reviewed
Dizziness & VertigoRed Eye & Eye EmergenciesSeizuresAltered Mental StatusDiplopia

Selected guidance · source check 2026-09-07. These 2 source links support selected teaching points, not a complete review of this topic. Check population, setting and local protocol before applying a recommendation.

  • Rosen’s Emergency Medicine, 10th ed. (2023) — headache
  • ACEP 2019 Clinical Policy: Acute Headache (Ottawa SAH Rule; 6-hour CT rule; LP or CTA after negative CT)
  • AHA/ASA 2023 Guideline for Aneurysmal SAH
  • ACR/EULAR 2018 GCA classification; EULAR GCA management recommendations
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