What type of headache is the patient experiencing?

Determining Headache Type: A Systematic Diagnostic Approach

The specific type of headache cannot be determined without key clinical details including onset pattern (sudden vs. gradual), temporal characteristics (morning, constant, episodic), associated symptoms, and patient demographics—but the diagnostic algorithm below will systematically identify the headache subtype based on these features. 1, 2

Critical Initial Classification Framework

The headache type depends fundamentally on whether this is a primary headache disorder (migraine, tension-type, cluster) or a secondary headache (due to underlying pathology). 3, 2

Essential Historical Features to Determine Type

Onset Pattern:

• Thunderclap (sudden, maximal at onset): Consider subarachnoid hemorrhage, cerebral venous thrombosis, or reversible cerebral vasoconstriction syndrome—this requires immediate CT head without contrast followed by lumbar puncture if CT is negative. 4, 5, 2
• Progressive over days to weeks: Suggests cerebral venous thrombosis (typically diffuse headache worsening over days), space-occupying lesion, or idiopathic intracranial hypertension. 4
• Recurrent episodic attacks: Points toward migraine (4-72 hours, unilateral, pulsating, with nausea/photophobia) or tension-type headache (bilateral, pressing quality, no significant associated symptoms). 3, 2

Temporal Characteristics:

• Morning headaches resolving within hours: Classic for obstructive sleep apnea—requires sleep study if accompanied by snoring, obesity, or daytime fatigue. 1
• Morning headaches improving with upright positioning: Suggests intracranial hypotension—warrants brain MRI to evaluate for sagging brain structures and pachymeningeal enhancement. 4, 1
• Chronic daily (>15 days/month for >3 months): Consider medication overuse headache if taking analgesics >10 days/month, chronic migraine, or chronic tension-type headache. 1, 6

Location-Specific Patterns:

• Occipital/suboccipital with neck pain: Indicates cervical strain subtype, especially post-trauma—look for cervical tenderness, limited range of motion, and upper extremity radicular symptoms. 4
• Frontal with eye pain/pressure: Suggests ocular-motor dysfunction subtype (convergence insufficiency, accommodation problems) or sinus pathology. 4
• Unilateral with autonomic features (tearing, rhinorrhea, ptosis): Diagnostic of trigeminal autonomic cephalalgia (cluster headache, paroxysmal hemicrania). 3

Age-Specific Diagnostic Considerations

Age >50 years with new-onset headache:

• Mandatory workup: ESR and CRP to exclude giant cell arteritis (temporal arteritis), which can cause permanent vision loss if untreated. 1, 6
• Lower threshold for neuroimaging: MRI brain with contrast to exclude mass lesion, subdural hematoma, or cerebral venous thrombosis. 4, 1

Reproductive-age women:

• Consider cerebral venous thrombosis if on oral contraceptives, pregnant, or postpartum—headache is present in 90% of CVT cases and may be isolated without focal findings in 25%. 4

Post-Concussion Headache Subtypes

If there is recent head trauma, classify into specific subtypes that guide treatment: 4

• Migraine/headache subtype: New or worsened headaches with migraine features (nausea, photophobia, phonophobia)
• Cervical strain: Occipital headache with neck pain, stiffness, and cervical tenderness
• Ocular-motor dysfunction: Frontal headache with difficulty reading, screen time intolerance, convergence insufficiency
• Vestibular: Headache with dizziness, imbalance, motion sensitivity

Red Flags Requiring Immediate Imaging

Obtain non-contrast CT head emergently if: 2

• Thunderclap onset (maximal intensity within seconds to minutes)
• Fever with meningeal signs (nuchal rigidity, Kernig's/Brudzinski's signs)
• Papilledema with focal neurologic deficits
• Altered consciousness or confusion
• New headache in immunocompromised or cancer patient

Obtain MRI brain (with and without contrast) for: 4, 1, 7

• Headache with papilledema (evaluate for mass, venous sinus thrombosis, idiopathic intracranial hypertension)
• Progressive headache over weeks
• Headache with abnormal neurologic examination
• New headache pattern in patient >50 years

Common Diagnostic Pitfalls

Medication Overuse Headache (MOH):

• Often missed—directly ask about over-the-counter medication use, not just prescribed medications. 1, 6
• Using analgesics, NSAIDs, or triptans >10 days/month causes rebound headaches that mimic chronic migraine. 6
• Critical error: Starting daily analgesics worsens the problem—preventive therapy will not work until medication overuse is eliminated. 6

Cerebral Venous Thrombosis:

• Can present with isolated headache (25% of cases) without focal findings or papilledema, making diagnosis challenging. 4
• Migrainous features can occur with CVT, potentially leading to misdiagnosis as primary migraine. 4

Rebound Headache Post-Treatment:

• Following epidural blood patch for intracranial hypotension, patients may develop rebound intracranial hypertension with phenotypically opposite headache (worse lying down, better upright, frontal location). 4
• Mistaking this for treatment failure leads to unnecessary repeat procedures that worsen the condition. 4

When Neuroimaging is NOT Indicated

Do not obtain imaging for: 4

• Migraine with normal neurologic examination and typical features (unless atypical features present)
• Tension-type headache with normal examination
• Recurrent headaches with stable pattern and normal examination

The threshold is lower for atypical features or headaches not fulfilling strict migraine criteria. 4