What is the recommended approach for a headache workup?

Recommended Approach for Headache Workup

Neuroimaging should be performed in patients with nonacute headache who have unexplained abnormal findings on neurologic examination, as these patients have significantly increased likelihood of intracranial pathology. 1

Initial Assessment: Red Flags Requiring Urgent Evaluation

The workup for headache should focus on identifying red flags that warrant immediate neuroimaging:

• Abnormal neurologic examination findings 1
• "Worst headache of life" 2, 3
• New headache pattern after age 50 2
• Headache worsened by Valsalva maneuver 1, 2
• Headache that awakens patient from sleep 1, 2
• Rapidly increasing frequency of headaches 1
• Progressively worsening headache pattern 2
• Headache with focal neurologic deficits 2, 3
• Fever and meningeal signs 4
• Papilledema 4, 5
• Impaired consciousness 4
• History of immunocompromised state 5
• Headache after trauma 5

Diagnostic Algorithm

Step 1: Evaluate for Secondary Causes

• For emergent presentations with thunderclap headache: Immediate noncontrast CT of the head to exclude intracranial hemorrhage 4, 5
• If CT is negative but subarachnoid hemorrhage is still suspected: Perform lumbar puncture 4
• For less urgent cases with concerning features: MRI of the brain is preferred 4

Step 2: Classify Primary Headaches (if secondary causes ruled out)

Use the International Classification of Headache Disorders (ICHD-3) criteria 2:

• Migraine without aura: Recurrent headaches lasting 4-72 hours with at least two of (unilateral location, pulsating quality, moderate/severe intensity, aggravation by activity) and at least one of (nausea/vomiting, photophobia and phonophobia)
• Migraine with aura: At least 2 attacks with fully reversible aura symptoms lasting 5-60 minutes
• Tension-type headache: Most common primary headache but less likely to present for medical care 4
• Chronic migraine: Headache on ≥15 days/month for >3 months, fulfilling migraine criteria on ≥8 days/month 2

Neuroimaging Recommendations

• When to image:

  • Patients with abnormal neurologic examination (Grade B recommendation) 1
  • Patients with any of the red flags listed above 2, 4

• When imaging is not usually warranted:

  • Patients with migraine and normal neurologic examination (Grade B recommendation) 1
  • Primary headache disorders without red flags or abnormal examination findings 4

• Imaging modality:

  • Emergent situations: Noncontrast CT of the head 4, 5
  • Non-emergent situations: MRI with contrast is preferred 2, 5
  • Limited evidence suggests MRI may be more sensitive for clinically insignificant abnormalities, but not necessarily more sensitive for clinically significant pathology 1

Common Pitfalls and Caveats

1. Overimaging: Avoid neuroimaging if it will not lead to a change in management 1

2. Underimaging: Maintain a lower threshold for imaging in patients with:

   • Atypical features or headaches that don't fulfill migraine definition 1
   • New-onset headache in older patients 1
   • Any concerning red flag symptoms 2

3. Medication overuse headache: Consider in patients using acute medications frequently (≥15 days/month for NSAIDs, ≥10 days/month for triptans) 2

4. Misdiagnosis of migraine as sinus headache: Recurrent "sinus headaches" may actually be migraines 4

5. Tension-type headache: Limited evidence exists regarding neuroimaging recommendations for tension-type headaches 1

The U.S. Headache Consortium emphasizes that the presence of abnormal neurologic examination findings significantly increases the likelihood of finding intracranial pathology, while their absence decreases this likelihood 1. However, the absence of other red flag features (such as headache worsened by Valsalva or awakening from sleep) does not reliably reduce the odds of abnormality on imaging 1.