Headache: documentation that holds up

Most headaches are benign and your scribe will capture the story. This is the reasoning it can't hear — the red flags to ask about, the dangerous secondary causes to exclude on paper, and the language that shows you actively ruled out subarachnoid hemorrhage rather than assuming a migraine.

01What's at stake

Headache is ~2% of ED visits; only 1%–3% of those are subarachnoid hemorrhage — but missed SAH is one of the classic high-liability misses, with an initial-visit misdiagnosis rate reported as high as 5%. Of patients with sudden, severe (thunderclap) headache and a normal neurologic exam, 10%–16% have SAH, and the patient can look completely well. The chart has to show you considered the dangerous causes and why you judged them unlikely — not just the benign diagnosis you landed on.

The anchoring trap: "history of migraines, so I called it a migraine." Patients with a migraine history still get SAH, meningitis, and dissection. The defensible move is to document how this headache differs from their usual one.

02Can't-miss differential

• Subarachnoid hemorrhage — thunderclap / maximal-at-onset; the flagship miss.
• Bacterial meningitis — fever, neck stiffness, immunosuppression.
• Mass / tumor — progressive, positional, worse lying flat or with Valsalva; papilledema.
• Cervical artery dissection — neck pain, trauma, Horner syndrome, focal deficit.
• Cerebral venous sinus thrombosis — pregnancy/postpartum, OCPs, hypercoagulable state.
• Giant cell arteritis — age >50, jaw claudication, vision change, elevated ESR.
• Acute angle-closure glaucoma — eye pain/redness, fixed mid-range pupil, high IOP.
• Carbon monoxide poisoning — waxing/waning, clustered cases, the whole household sick.

03History — the red flags that change your decision

• Maximal intensity within seconds–minutes of onset (thunderclap)? → SAH
• Onset with exertion, cough, straining, or sexual activity? → SAH
• New headache after age 50, or distinctly different from prior headaches? → secondary cause
• Fever, neck pain/stiffness? → meningitis / SAH
• Syncope or transient loss of consciousness at onset? → SAH
• Vision change, jaw claudication (age >50)? → GCA / glaucoma
• Pregnant/postpartum, OCP, immunocompromise/HIV, malignancy, neurosurgery/shunt? → CVST / mass / lesion
• Progressive over weeks, worse lying flat? → mass / raised ICP

"Worst headache of life" raises pretest probability but is not decisive on its own — in the Perry cohort 93% of SAH patients reported it, but so did 77% of those without SAH. Document the onset and tempo, not just the severity.

04Exam & testing

• Focused neuro exam — a focal deficit carries the highest likelihood ratio for imaging-positive pathology. Document cranial nerves, visual fields, strength/sensation ×4, gait and coordination, and mental status.
• Targeted exam — temporal artery tenderness (GCA), nuchal rigidity (meningitis/SAH), fundoscopy/IOP (papilledema, glaucoma), CN III palsy with anisocoria (posterior communicating aneurysm).
• Non-contrast head CT for suspected SAH/mass — sensitivity for SAH is highly time-dependent; a CT within 6 hours of a thunderclap onset, on a modern scanner read by a qualified radiologist, approached 100% sensitivity in Perry's 2011 cohort.
• CT-then-LP — after a negative CT, a neurologically normal patient can still have up to a 7% chance of SAH; LP (RBC trend across tubes, opening pressure, xanthochromia) remains the AHA-endorsed rule-out, and also catches CVST, IIH, and meningitis. If the patient declines LP, document informed shared decision-making.
• Targeted tests — ESR for GCA, carboxyhemoglobin for CO, IOP for glaucoma, MRI/MRV for CVST.

05Risk tools & evidence

• Ottawa SAH rule — in alert patients ≥15y with new, severe, non-traumatic headache peaking within 1 hour (and no deficits, prior aneurysm/SAH, tumor, or chronic recurrent headache): age ≥40, neck pain/stiffness, witnessed LOC, onset during exertion, thunderclap, or limited neck flexion. Any one present → investigate. Sensitivity ~98.5%, specificity ~27.5%. Perry JJ, et al. JAMA. 2013.
• 6-hour CT — non-contrast CT within 6h of onset is highly sensitive for SAH; outside that window, sensitivity falls and LP gains value. Perry JJ, et al. BMJ. 2011.

06What to document

07Where charts fail

• Anchoring on a migraine history without documenting how this headache differs.
• Using response to analgesics/triptans to exclude SAH — pain relief does not rule out hemorrhage or tumor.
• Stopping at a negative CT without documenting the LP discussion (or the shared decision to defer it).
• No pertinent negatives for onset/tempo — the cheapest, most defensible lines to add.
• Forgetting to ask HIV/malignancy/pregnancy status, which lower the imaging threshold.

08Sources

• Singh A, Soares WE. Management strategies for acute headache in the emergency department. Emergency Medicine Practice (EB Medicine). 2012;14(6).
• Aisiku I, Edlow JA, Goldstein J, Thomas LE. An evidence-based approach to diagnosis and management of subarachnoid hemorrhage in the emergency department. Emergency Medicine Practice (EB Medicine). 2014;16(10).
• Perry JJ, Stiell IG, Sivilotti ML, et al. Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA. 2013;310(12):1248-1255.
• Perry JJ, Stiell IG, Sivilotti ML, et al. Sensitivity of CT performed within six hours of headache onset for subarachnoid haemorrhage. BMJ. 2011;343:d4277.
• Edlow JA, Panagos PD, Godwin SA, et al. Clinical policy: critical issues in the evaluation and management of adult patients with acute headache. Ann Emerg Med. 2008;52(4):407-436.
• Pope JV, Edlow JA. Favorable response to analgesics does not predict a benign etiology of headache. Headache. 2008;48:944-950.

© 2026 Kim Trinh, MD. All rights reserved. Educational only — synthesized from EB Medicine and primary literature. Synthetic examples. Not medical advice — apply local protocol and judgment.