What are red flag headache symptoms?

Red Flag Headache Symptoms

Red flag headache symptoms are warning signs that may indicate a potentially serious or life-threatening underlying cause of headache that requires urgent evaluation and neuroimaging. 1

Patient History Red Flags

• Thunderclap headache - sudden onset, reaching maximum intensity within seconds to minutes, suggesting possible subarachnoid hemorrhage 1
• Atypical aura - may indicate transient ischemic attack, stroke, epilepsy, or arteriovenous malformations 1
• Head trauma - headache following trauma may suggest subdural hematoma 1
• Progressive headache - worsening over time could indicate an intracranial space-occupying lesion 1
• Headache aggravated by postures or maneuvers that raise intracranial pressure - may suggest intracranial hypertension or hypotension 1
• Headache brought on by sneezing, coughing, or exercise - could indicate an intracranial space-occupying lesion 1
• Headache associated with weight loss and/or change in memory or personality - suggests secondary headache 1
• Headache onset after age 50 - suggests secondary headache; consider temporal arteritis 1, 2
• Abrupt onset of severe headache - described as "worst headache of life" may indicate serious vascular pathology 1, 2
• Marked change in headache pattern - significant change in previously stable headache characteristics 1, 3
• Persistent headache following head trauma - may indicate intracranial injury 1
• Headache that awakens patient from sleep - may indicate increased intracranial pressure 1

Physical Examination Red Flags

• Unexplained fever - may indicate meningitis 1
• Neck stiffness - possible meningitis or subarachnoid hemorrhage 1
• Focal neurological symptoms - suggests secondary headache 1, 4
• Weight loss - suggests secondary headache, possibly malignancy 1
• Impaired memory and/or altered consciousness or personality - suggests secondary headache 1
• Papilledema - indicates increased intracranial pressure 4, 5
• Uncoordination - may indicate cerebellar pathology 1

Clinical Significance and Approach

• Neuroimaging is indicated when red flags are present to rule out secondary causes of headache 1, 6
• MRI is preferred over CT due to higher resolution and absence of radiation exposure, except when acute intracranial hemorrhage is suspected (then CT without contrast is recommended) 1, 4
• The presence of multiple red flags increases the likelihood of a secondary headache 5
• Secondary headaches account for a minority of all headache presentations but carry significant morbidity and mortality if missed 2, 3

Common Pitfalls to Avoid

• Failing to recognize that a patient with a pre-existing primary headache disorder can develop a secondary headache 3
• Attributing new neurological symptoms to migraine without considering secondary causes 7
• Administering triptan medications before excluding secondary causes, which can worsen outcomes in cases of stroke or vascular events 7
• Overlooking the need for neuroimaging when red flags are present 1
• Assuming that normal vital signs rule out serious pathology 2

Algorithmic Approach to Headache Evaluation

1. Assess for red flags in history and physical examination
2. If any red flags present, proceed with appropriate neuroimaging:
   • For suspected subarachnoid hemorrhage: CT without contrast
   • For most other suspected causes: MRI preferred 1, 4
3. Consider lumbar puncture if meningitis is suspected or to rule out subarachnoid hemorrhage when CT is negative but clinical suspicion remains high 4
4. In absence of red flags, consider primary headache disorders (migraine, tension-type, cluster) using ICHD-3 criteria 1, 8

Remember that early identification of red flag symptoms can significantly reduce morbidity and mortality in patients with potentially life-threatening causes of headache 2, 3.