Red Flags for Headaches Requiring Immediate Medical Attention
Patients with headaches should be immediately evaluated for secondary causes when presenting with red flags such as thunderclap headache, focal neurological symptoms, fever with neck stiffness, or headache following head trauma, as these may indicate life-threatening conditions requiring urgent intervention. 1, 2
Patient History Red Flags
- Thunderclap headache - Sudden onset, severe headache reaching maximum intensity within seconds to minutes (suggests subarachnoid hemorrhage) 1
- Atypical aura - May indicate transient ischemic attack, stroke, epilepsy, or arteriovenous malformations 1
- Head trauma - Recent head injury suggests possible subdural hematoma 1
- Progressive headache - Worsening pattern may indicate intracranial space-occupying lesion 1
- Positional aggravation - Headache worsened by postures or maneuvers that raise intracranial pressure 1
- Valsalva-induced headache - Pain brought on by sneezing, coughing, or exercise may suggest intracranial space-occupying lesion 1
- Associated symptoms - Headache with weight loss and/or changes in memory or personality 1
- New onset after age 50 - Suggests secondary headache; consider temporal arteritis 1, 2
- Abrupt change in headache pattern - Marked change in previously stable headache 1, 3
- Worst headache ever experienced - Often described as "the worst headache of my life" 4
- Headache that awakens from sleep - Particularly concerning when persistent 1
- Headache during pregnancy - May indicate serious complications 3
- Headache while on anticoagulant therapy - Increased risk of intracranial bleeding 3
Physical Examination Red Flags
- Unexplained fever - May indicate meningitis 1
- Neck stiffness - Suggests meningitis or subarachnoid hemorrhage 1
- Focal neurological symptoms or signs - Any neurological deficit accompanying headache 1, 4
- Weight loss - Unexplained weight loss with headache suggests secondary cause 1
- Altered mental status - Impaired memory, altered consciousness or personality changes 1
- Papilledema - Swelling of the optic disc indicating increased intracranial pressure 4
- Immunocompromised state - Increases risk of CNS infections or malignancy 4
Concerning Headache Patterns
- Headache aggravated by exercise - May indicate structural abnormality 4, 5
- Headache resistant to appropriate treatment - Failure to respond to standard therapies 2
- Headache with seizures - Combination suggests structural lesion 6
- High pain intensity - Exceptionally severe headache without prior history 5, 3
- Cognitive changes - Personality changes or cognitive decline with headache 6
- Syncope with headache - Loss of consciousness accompanying headache 3
- Suspected glaucoma - Eye pain, halos around lights, nausea/vomiting 3
Diagnostic Approach for Concerning Headaches
When red flags are present, further investigation is warranted:
Neuroimaging - The primary diagnostic tool when secondary headache is suspected 1, 2
- CT without contrast for suspected intracranial hemorrhage
- MRI preferred for most other conditions due to higher resolution and no radiation exposure
Lumbar puncture - Indicated when meningitis or subarachnoid hemorrhage is suspected, especially if imaging is negative but clinical suspicion remains high 2, 7
Blood tests - Consider CBC, ESR, CRP when inflammatory causes are suspected 2
Common Pitfalls to Avoid
- Misdiagnosing "sinus headache" when symptoms are actually migraine with autonomic features 2
- Confusing migraine aura with transient ischemic attack 2
- Failing to recognize medication overuse headache in patients with chronic daily headaches 2
- Assuming a preexisting headache disorder excludes a new secondary cause 5
- Relying solely on neuroimaging when clinical suspicion for subarachnoid hemorrhage is high (lumbar puncture may be necessary) 7
Remember that while most headaches are benign primary headaches, the presence of these red flags significantly increases the likelihood of a dangerous secondary cause requiring immediate medical attention.