What are the red flags of migraine that require immediate medical attention?

Red Flags of Migraine Requiring Immediate Medical Attention

Patients with headache should be urgently evaluated when presenting with red flags that suggest potentially life-threatening secondary causes, including thunderclap headache (sudden, severe "worst headache of life"), which may indicate subarachnoid hemorrhage. 1

Key Red Flags Requiring Immediate Medical Attention

Patient History Red Flags

• Thunderclap headache - Sudden onset, severe intensity reaching maximum within minutes (suggests subarachnoid hemorrhage) 2, 1
• Atypical aura - Unusual presentation or duration (may indicate TIA, stroke, epilepsy, or arteriovenous malformations) 2
• Head trauma history - Recent head injury (suggests subdural hematoma) 2
• Progressive headache pattern - Worsening over time (may indicate intracranial space-occupying lesion) 2
• Positional aggravation - Headache worsens with certain positions (suggests intracranial hypertension or hypotension) 2, 1
• Valsalva-induced headache - Triggered by coughing, sneezing, or exertion (may indicate intracranial space-occupying lesion) 2, 1
• Associated systemic symptoms - Weight loss and/or changes in memory or personality (suggests secondary headache) 2, 1
• New onset after age 50 - Late-onset headaches (consider temporal arteritis or secondary causes) 2, 1
• Abrupt change in established headache pattern - Different characteristics from usual headaches 1

Physical Examination Red Flags

• Unexplained fever - May indicate meningitis 2
• Neck stiffness - Suggests meningitis or subarachnoid hemorrhage 2
• Focal neurological deficits - Any abnormal neurological findings (suggests secondary headache) 2, 1
• Altered mental status - Changes in consciousness or personality 2
• Papilledema - Swelling of the optic disc (indicates increased intracranial pressure) 1, 3

Diagnostic Approach for Red Flag Headaches

When red flags are present, a systematic approach is essential:

1. Immediate neuroimaging - For sudden severe headache, an immediate non-contrast CT scan is recommended to evaluate for subarachnoid hemorrhage 1

   • If CT is negative but clinical suspicion remains high, proceed to lumbar puncture

2. Comprehensive neurological examination - To detect subtle neurological deficits 1

3. Laboratory testing - As indicated by specific red flags (e.g., ESR/CRP for suspected temporal arteritis) 1

Common Pitfalls to Avoid

• Overlooking red flags in patients with known primary headache disorders - Patients with established migraine can still develop secondary headaches 1
• Confusing migraine aura with TIA - Migraine aura typically develops gradually over ≥5 minutes and resolves completely 2
• Missing medication overuse headache - Consider in patients using headache medication ≥15 days/month for NSAIDs or ≥10 days/month for triptans 1

Clinical Implications

The presence of red flags significantly increases the likelihood of a serious secondary cause of headache. While the combined sensitivity of red flag criteria is high (96.5%), their specificity is low (5.1%), meaning that many patients with red flags will not have serious pathology 4. Nevertheless, the potential consequences of missing a life-threatening cause of headache warrant thorough investigation when red flags are present.

Remember that even patients with established migraine diagnoses can develop secondary headaches. Any significant change in headache pattern or the emergence of new red flags should prompt immediate reevaluation.