What is the best diagnostic approach for a patient presenting with symptoms suggestive of migraine?

Best Diagnostic Test for Migraine

The medical history is the best and only necessary diagnostic test for migraine—no laboratory tests, imaging studies, or other investigations are required when the clinical presentation is typical and the neurological examination is normal. 1, 2

Why Medical History Alone Is Sufficient

Migraine is a clinical diagnosis that relies entirely on systematic application of the International Classification of Headache Disorders-3 (ICHD-3) criteria through a detailed history. 1, 2 The physical examination serves only as confirmation, and neuroimaging or other investigations are reserved exclusively for cases where secondary causes are suspected. 2

This approach is supported by evidence showing that neuroimaging in migraine patients with normal neurological examinations yields a clinically significant finding rate of only 0.2% (2/1086 patients)—no higher than the 0.4% rate in completely asymptomatic volunteers. 3

Essential Historical Elements to Obtain

Attack Characteristics (Required for Diagnosis)

For migraine without aura, you must document: 1, 2

• At least 5 lifetime attacks meeting all criteria
• Duration: 4-72 hours when untreated
• At least 2 pain characteristics: unilateral location, pulsating quality, moderate-to-severe intensity, or aggravation by routine physical activity
• At least 1 accompanying symptom: nausea/vomiting OR both photophobia and phonophobia

For migraine with aura, you must document: 1, 2

• At least 2 attacks meeting criteria
• Fully reversible aura symptoms: visual, sensory, speech/language, motor, brainstem, or retinal
• At least 3 aura characteristics: gradual spread over ≥5 minutes, two or more symptoms in succession, each symptom lasting 5-60 minutes, at least one unilateral symptom, at least one positive symptom, aura accompanied by or followed by headache within 60 minutes

Additional Critical History Points

• Age at onset: Migraine typically begins at or around puberty 1, 3
• Frequency: Distinguish episodic (<15 days/month) from chronic (≥15 days/month for >3 months) 1, 3
• Family history: Migraine has strong genetic component; positive family history strengthens diagnosis 1, 3
• Medication use: Document all acute and preventive medications to identify medication-overuse headache (≥15 days/month for non-opioid analgesics or ≥10 days/month for other acute medications for >3 months) 1, 3, 4

Validated Screening Tools to Enhance Diagnostic Accuracy

ID-Migraine questionnaire (3-item): Sensitivity 81%, specificity 75%, positive predictive value 93% 3, 2

Migraine Screen Questionnaire (5-item): Sensitivity 93%, specificity 81%, positive predictive value 83% 3, 2

Headache diary: Essential for reducing recall bias and increasing diagnostic accuracy; should document frequency, duration, character, triggers, accompanying symptoms, and medication use 3, 2

When Investigations ARE Indicated (Red Flags Only)

Neuroimaging and other tests are only appropriate when red flags suggest secondary causes: 3, 2, 5

• Thunderclap headache ("worst headache of life")
• New-onset headache after age 50
• Progressive worsening over weeks to months
• Headache awakening patient from sleep
• Headache with Valsalva, cough, or exertion
• Focal neurological symptoms or abnormal neurological examination
• Unexplained fever with neck stiffness
• Recent head or neck trauma
• Atypical aura (focal neurological symptoms or duration >60 minutes)

Imaging Selection When Red Flags Present

MRI brain with and without contrast: Preferred modality for subacute presentations or suspected tumor/inflammatory process; higher resolution without ionizing radiation 3

Non-contrast CT head: Only if presenting <6 hours from acute severe headache onset (subarachnoid hemorrhage); sensitivity 95% on day 0, declining to 74% on day 3 and 50% at 1 week 3

Common Pitfalls to Avoid

Do not order neuroimaging for typical migraine with normal examination. The American Academy of Neurology explicitly states that neuroimaging is not routinely indicated for migraine patients with normal neurological examinations, even after failed treatments. 3

Do not diagnose "sinus headache" without confirming sinusitis. Recurrent "sinus headaches" are actually migraine in most cases. 3

Do not miss medication-overuse headache. Any patient with ≥15 headache days/month requires careful medication history, as overuse perpetuates and worsens headaches. 1, 4

Do not rely on patient recall alone. Implement a headache diary prospectively, as recall bias significantly reduces diagnostic accuracy. 3, 2