Stethopedia | Approach

Approach to

Headache

Screen each headache for red flags and act on them first; then sort it as primary, vascular, infectious or inflammatory, or mass. In an alert, intact patient, a negative CT within 6 h of onset, read by a radiologist, excludes SAH.

  1. Headache that is new, changed, or unlike the usual pattern
  2. Onset, tempo, pattern vs usual; vitals, fundi, neuro exam, temporal arteries1,12
  3. Pregnant: BP (preeclampsia); red painful eye: glaucoma; housemates ill: CO level1
  4. Any red flag (SNNOOP10)?

Red flag: same-day workup; treat the emergency1,12

  • Sudden: peak ≤1 h, or on exertion
  • Fever, stiff neck, rash, confusion
  • Focal signs, seizure, papilledema
  • New after age 50; jaw claudication
  • Cancer, immunosupp., pregnancy
  • Positional, Valsalva, post-trauma

→ Meningitis or GCA: cultures/ESR, then treat before LP or biopsy7,11

Then: primary or secondary cause?

CausesCluesWorkupManagement

Primary

  • Migraine ± aura
  • Tension-type; medication overuse
  • Cluster, other autonomic types
  • POUND 4 of 5: migraine (LR 24)6
  • Band-like, mild, no nausea: tension
  • Brief orbital pain, tearing: cluster
  • Migraine/tension, normal exam: no scan6
  • New cluster-type: MRI (LR 10.7)6,12
  • Headache ≥8 d/mo: overuse risk; diary4
  • ED: IV prochlorperazine or GON block10
  • Ketorolac, metoclopramide; no opioids10
  • Acute drugs ≤2 d/wk; prevent if ≥4 bad d/mo4,12

Vascular

  • Subarachnoid hemorrhage
  • ICH, venous thrombosis, dissection
  • Pituitary apoplexy; also RCVS, PRES
  • Ottawa: ≥40 y, neck pain, witnessed LOC3
  • Exertion, instant peak, ↓neck flexion3
  • Horner: dissection; OCP, puerperium: CVT12
  • Alert, intact, CT ≤6 h negative: no SAH2
  • CT >6 h negative: LP or CTA2
  • CTA head/neck; CT or MR venography12
  • Neurosurgery; reverse anticoag; lower BP5,12
  • aSAH: oral nimodipine; secure aneurysm5
  • CVT: anticoagulate even if bleed12

Infection, inflammation

  • Bacterial meningitis
  • Encephalitis, brain abscess
  • Giant cell arteritis
  • Fever, neck stiffness, confusion11
  • Jaw claudication (LR 4.2), diplopia8
  • Normal ESR: GCA less likely (LR 0.2)8
  • Blood cultures, then LP11
  • CT 1st: focal, seizure, GCS <10, immunosupp.11
  • ESR, CRP; temporal artery US or biopsy9
  • Antibiotics + dexamethasone ± acyclovir11
  • GCA: prednisone 40–60 mg now; rheum ≤24 h7
  • GCA with vision loss: emergency7

Mass or pressure

  • Tumour, abscess, hydrocephalus
  • Idiopathic intracranial HTN
  • Low pressure: post-LP, CSF leak
  • Worse with Valsalva (LR 2.3)6
  • Worse lying down; morning vomiting1
  • Papilledema, diplopia, ↓LOC12
  • Abnormal exam: image (LR 5.3)6
  • MRI with gadolinium1
  • LP opening pressure after imaging
  • HOB 30–45°, osmotherapy, neurosurgery12
  • Tumour edema: dexamethasone12

Can't-miss cause Superscripts link to the references below.

References

  1. Do TP, Remmers A, Schytz HW, et al. Red and orange flags for secondary headaches in clinical practice: SNNOOP10 list. Neurology. 2019;92:134–144. PubMed 30587518
  2. American College of Emergency Physicians Clinical Policies Subcommittee on Acute Headache; Godwin SA, et al. Clinical policy: critical issues in adult patients presenting to the emergency department with acute headache. Ann Emerg Med. 2019;74:e41–e74. PubMed 31543134
  3. Perry JJ, Stiell IG, Sivilotti ML, et al. Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA. 2013;310:1248–1255. PubMed 24065011
  4. Medrea I, Cooper P, Lagman-Bartolome AM, et al. Updated Canadian Headache Society migraine prevention guideline with systematic review and meta-analysis. Can J Neurol Sci. 2024:1–23. doi:10.1017/cjn.2024.285 (corrigendum 2025). PubMed 39506371
  5. Hoh BL, Ko NU, Amin-Hanjani S, et al. 2023 guideline for the management of patients with aneurysmal subarachnoid hemorrhage: a guideline from the American Heart Association/American Stroke Association. Stroke. 2023;54:e314–e370. PubMed 37212182
  6. Detsky ME, McDonald DR, Baerlocher MO, et al. Does this patient with headache have a migraine or need neuroimaging? JAMA. 2006;296:1274–1283. PubMed 16968852
  7. Mukhtyar CB, Nikiphorou E, Bartoletti A, et al. 2025 EULAR recommendations for the management of polymyalgia rheumatica and primary large vessel vasculitis. Ann Rheum Dis. 2026. doi:10.1016/j.ard.2026.06.009. PubMed 42481270
  8. Smetana GW, Shmerling RH. Does this patient have temporal arteritis? JAMA. 2002;287:92–101. PubMed 11754714
  9. Dejaco C, Ramiro S, Bond M, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update. Ann Rheum Dis. 2024;83:741–751. PubMed 37550004
  10. Robblee J, Minen MT, Friedman BW, et al. 2025 guideline update to acute treatment of migraine for adults in the emergency department: the American Headache Society evidence assessment of parenteral pharmacotherapies. Headache. 2026;66:53–76. PubMed 41321235
  11. van de Beek D, Cabellos C, Dzupova O, et al. ESCMID guideline: diagnosis and treatment of acute bacterial meningitis. Clin Microbiol Infect. 2016;22 Suppl 3:S37–S62. PubMed 27062097
  12. Gay E, Levy N, eds. Headache & Vertigo; Stroke & TIA; CNS Emergencies. In: Department of Medicine Housestaff Manual, 30th ed. 2024:195, 197–198.

For education only; not a substitute for clinical judgment or local protocols. Where sources differ, the flowchart follows the current guideline.

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