What is the approach to diagnosing and treating a patient presenting with a new onset headache?

Approach to Headache

Begin by immediately ruling out life-threatening secondary causes using red flag criteria, then systematically differentiate between primary headache disorders through targeted history and examination.

Initial Assessment: Red Flag Screening

The first priority when evaluating any new headache is identifying red flags that suggest dangerous secondary causes requiring urgent intervention 1, 2:

Critical Red Flags Requiring Immediate Evaluation

• Thunderclap headache (sudden, severe onset) suggests subarachnoid hemorrhage 1, 2, 3
• New-onset headache after age 50 raises concern for temporal arteritis, mass lesion, or other secondary causes 1, 2, 3
• Progressive worsening headache suggests intracranial space-occupying lesion 1
• Headache with fever and neck stiffness indicates possible meningitis or subarachnoid hemorrhage 1, 3
• Focal neurological symptoms or signs suggest stroke, mass lesion, or other structural pathology 1, 2, 3
• Recent head or neck trauma raises concern for subdural hematoma 1, 4
• Headache provoked by Valsalva, cough, exertion, or postural changes suggests intracranial hypertension/hypotension or structural lesion 1, 2, 4
• Headache with altered consciousness, memory changes, personality changes, or weight loss indicates secondary pathology 1

Immediate Diagnostic Testing for Red Flags

For emergent presentations with red flags, obtain non-contrast CT head immediately to exclude acute hemorrhage or mass effect 2, 3. If CT is normal but subarachnoid hemorrhage is suspected, lumbar puncture is mandatory 3. For subacute presentations without immediate life threat, MRI brain with and without contrast is preferred, offering superior resolution without radiation 2.

Systematic History Taking for Primary Headache Diagnosis

Once secondary causes are excluded, obtain specific details to classify the primary headache disorder 1:

Temporal Pattern Classification

Categorize headaches into four groups 5:

• Recent onset thunderclap (seconds to minutes)
• Recent onset progressive (days to weeks)
• Episodic with headache-free periods (migraine, cluster headache)
• Chronic daily headache (≥15 days/month for >3 months)

Essential Headache Characteristics

Document the following specific features 1, 6, 7:

Duration:

• 4-72 hours suggests migraine 8, 6
• 15-180 minutes suggests cluster headache 2
• 30 minutes to 7 days suggests tension-type headache 8

Location:

• Unilateral suggests migraine or cluster headache 8, 6
• Bilateral suggests tension-type headache 8, 2
• Strictly unilateral orbital/periorbital/temporal suggests cluster headache 2

Quality:

• Pulsating suggests migraine 8, 6
• Pressing/tightening suggests tension-type headache 8, 2

Intensity:

• Moderate-to-severe with aggravation by routine activity suggests migraine 8, 6
• Mild-to-moderate without aggravation by activity suggests tension-type headache 2

Associated symptoms:

• Nausea/vomiting, photophobia, and phonophobia suggest migraine 8, 6, 7
• Ipsilateral autonomic features (lacrimation, rhinorrhea, ptosis) suggest cluster headache 2

Use of Headache Diary

Ask patients: "Do you feel like you have a headache of some type on 15 or more days per month?" 1. This simple question helps identify chronic migraine, as patients often underreport milder headache days 1. A prospective headache diary is essential for accurate diagnosis and reduces recall bias 6, 2.

Diagnostic Criteria for Common Primary Headaches

Migraine Without Aura

Requires at least 5 lifetime attacks meeting all of the following 8, 6:

• Duration: 4-72 hours (untreated)
• At least 2 of: unilateral location, pulsating quality, moderate-to-severe intensity, aggravation by routine activity
• At least 1 of: nausea/vomiting OR both photophobia and phonophobia

Chronic Migraine

Diagnosed when 1, 8, 6:

• Headache occurs ≥15 days/month for >3 months
• On ≥8 days/month, headache meets migraine criteria OR responds to triptan/ergot derivative
• Patient has history of at least 5 attacks meeting migraine without aura criteria

Common pitfall: Only 20% of patients meeting chronic migraine criteria are correctly diagnosed 1. Actively screen for this disabling condition.

Tension-Type Headache

Characterized by 8, 2:

• Bilateral location
• Pressing/tightening (non-pulsating) quality
• Mild-to-moderate intensity
• NOT aggravated by routine physical activity
• Absence of nausea or vomiting

Medication-Overuse Headache

Suspect when 8:

• Headache ≥15 days/month in patient with pre-existing headache disorder
• Regular overuse of acute medication for >3 months:
  • Non-opioid analgesics ≥15 days/month, OR
  • Triptans, ergots, opioids, or combination analgesics ≥10 days/month

Diagnostic Testing Indications

When Neuroimaging is NOT Needed

Primary headache disorders meeting diagnostic criteria with normal neurological examination do not require neuroimaging 3. The yield is extremely low: brain tumors 0.8%, AVMs 0.2%, aneurysms 0.1% in patients with normal exams 9.

When Neuroimaging IS Needed

Obtain imaging when 2, 4, 3:

• Any red flag present
• Abnormal neurological examination
• Atypical features not fitting primary headache pattern
• Change in established headache pattern
• Inadequate response to appropriate treatment

Treatment Approach

Acute Treatment for Migraine

First-line: NSAIDs (aspirin, ibuprofen, or diclofenac potassium) used early in the headache phase 1

Second-line: Triptans for patients not responding to NSAIDs 1, 7. Triptans eliminate pain in 20-30% of patients by 2 hours but cause transient flushing, tightness, or tingling in 25% 7. Avoid in patients with cardiovascular disease due to vasoconstrictive properties 7.

Third-line: Gepants (rimegepant, ubrogepant) or ditans (lasmiditan) 1, 7. Gepants eliminate headache in 20% at 2 hours with nausea/dry mouth in 1-4% 7. Lasmiditan is safe in cardiovascular disease but requires 8-hour driving restriction 1.

Adjunct: Prokinetic antiemetics (domperidone or metoclopramide) for nausea/vomiting 1

Avoid: Oral ergot alkaloids (poorly effective, toxic), opioids, and barbiturates (questionable efficacy, dependency risk) 1

Preventive Treatment Indications

Consider preventive therapy when 1:

• Quality of life remains impaired despite optimized acute therapy
• Patients adversely affected ≥2 days/month (not absolute rule)
• Severe or prolonged attacks
• Medication overuse present

For chronic migraine specifically, prophylactic treatment should be initiated 1. Evidence-based options include topiramate (only agent proven effective in randomized trials for chronic migraine), gabapentin, tizanidine, fluoxetine, amitriptyline, and valproate 1.

Assess efficacy only after adequate trial: 2-3 months for oral medications, 3-6 months for CGRP monoclonal antibodies, 6-9 months for onabotulinumtoxinA 1.

Referral Criteria

Consider neurology referral when 1:

• Diagnostic uncertainty persists
• Red flags present requiring specialist evaluation
• Inadequate response to first-line preventive treatments
• Chronic migraine requiring specialized management
• Patient unable to self-care