What is the initial approach to a headache workup?

Initial Headache Workup

Begin with a focused history applying ICHD-3 criteria and a complete neurological examination to identify red flags that distinguish secondary from primary headache disorders, reserving neuroimaging only for patients with abnormal neurological findings or specific warning features. 1, 2

Step 1: Focused History

Obtain specific details about:

• Temporal pattern: Age at onset, duration of episodes (4-72 hours suggests migraine), frequency, and progression over time 1, 3
• Pain characteristics: Location (unilateral vs bilateral), quality (pulsating vs pressing/tightening), and intensity (moderate-severe suggests migraine; severe suggests cluster) 1, 3
• Accompanying symptoms: Nausea/vomiting, photophobia, phonophobia (migraine features), or ipsilateral autonomic symptoms like lacrimation, conjunctival injection, nasal congestion (cluster headache features) 1, 4
• Aura symptoms: Visual distortions, scotomas, hemisensory disturbances lasting 5-60 minutes (migraine with aura) 1, 3
• Triggers: Dietary factors (alcohol, caffeine, tyramine, nitrates), environmental factors (stress, fatigue, perfumes, glare), hormonal changes, or missed meals 1, 3
• Medication use: Frequency and type of acute medications (≥15 days/month for non-opioid analgesics or ≥10 days/month for other acute medications suggests medication-overuse headache) 1, 2
• Family history: Strong genetic component in migraine 3

Step 2: Screen for Red Flags

Red flags mandate immediate further investigation and include:

• History red flags: Thunderclap onset ("worst headache ever"), new-onset headache in patients ≥50 years, progressively worsening headache, headache awakening patient from sleep, headache worsened by Valsalva maneuver, atypical aura, recent head trauma, or syncope 1, 2
• Examination red flags: Abnormal neurological findings (focal deficits, altered mental status, abnormal reflexes, nystagmus), unexplained fever, impaired memory, or papilledema 1, 2
• Associated features: Dizziness with progressive headache (consider cerebral venous thrombosis), active/recent pregnancy, coagulopathy, malignancy, immunosuppression, or visual deficits 2, 5

Step 3: Complete Neurological Examination

Perform systematic assessment of:

• Mental status
• Cranial nerves (all 12)
• Motor and sensory function
• Deep tendon reflexes
• Coordination and cerebellar function
• Gait 2, 6

An abnormal neurological examination significantly increases the likelihood of intracranial pathology and warrants neuroimaging. 1, 2

Step 4: Neuroimaging Decision Algorithm

Neuroimaging is indicated when:

• Abnormal neurological examination findings are present (Grade B recommendation) 1, 3
• Any red flag features are identified in history or examination 1, 4
• Atypical headache features that don't fulfill migraine criteria (Grade C recommendation) 1, 3

Neuroimaging is NOT warranted when:

• Patient has migraine with normal neurological examination (Grade B recommendation) 1, 3
• Patient meets ICHD-3 criteria for primary headache disorder without red flags 1, 3

When neuroimaging is needed:

• MRI is preferred over CT for higher resolution and no ionizing radiation exposure 1
• CT may be equivalent to MRI for detecting clinically significant pathology, though MRI detects more clinically insignificant abnormalities 1

Common pitfall: MRI can reveal clinically insignificant abnormalities (white matter lesions, arachnoid cysts, meningiomas) that alarm patients and lead to unnecessary further testing. 1

Step 5: Classify the Headache Type

Migraine (affects 12% of population):

• Unilateral, pulsating, moderate-to-severe pain lasting 4-72 hours
• Aggravated by routine physical activity
• Accompanied by nausea/vomiting and/or photophobia and phonophobia 1, 2, 7

Tension-Type Headache (affects 38% of population):

• Bilateral, mild-to-moderate, pressing/tightening quality
• NOT aggravated by routine physical activity
• Lacks migraine-associated symptoms 1, 7

Cluster Headache (affects 0.1% of population):

• Strictly unilateral, severe-to-very severe intensity
• Short duration (15-180 minutes)
• Frequency of 1-8 attacks per day
• Ipsilateral autonomic symptoms (lacrimation, conjunctival injection, nasal congestion, ptosis) 1, 4

Medication-Overuse Headache:

• Headache ≥15 days/month
• Regular overuse of acute medications >3 months
• Non-opioid analgesics ≥15 days/month OR other acute medications ≥10 days/month 1, 2

Critical pitfall: Only 20% of patients meeting criteria for chronic migraine are properly diagnosed; overlooking medication-overuse headache leads to misdiagnosis and treatment failure. 2

Step 6: Additional Testing (When Indicated)

Lumbar puncture is necessary when:

• Suspected subarachnoid hemorrhage with negative CT
• Suspected meningitis/encephalitis
• Suspected intracranial hypotension or high-pressure syndromes 2

Blood work may be indicated based on specific clinical suspicion for systemic causes (infection, temporal arteritis in patients >50 years). 6, 5

Key Principles

• Avoid testing that won't change management 1
• Don't test if the patient isn't significantly more likely than the general population to have a significant abnormality (prevalence of significant intracranial abnormality is only 0.2% in migraine patients with normal examination) 1
• Testing may be reasonable in excessively worried patients even when not otherwise indicated (Grade C, consensus-based) 1