When a patient presents for evaluation of headache(s), the goal of the history and examination is to answer two questions:

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  Is there an underlying cause of headache(s) in need of further laboratory/neuroimaging evaluation (i.e., secondary headache)?

  
  
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  If there is no underlying cause of headache(s), which primary headache syndrome best describes the headache (e.g., migraine, tension, cluster)?

When headaches are determined to be primary rather than secondary, although they may be benign with respect to etiology, such headaches can be extremely disabling. Proper recognition of the precise primary headache syndrome is important because different headache syndromes respond to different abortive and prophylactic medications.

Importantly, a headache syndrome that perfectly fits the description of one of the primary headache syndromes does not always signify that there is no underlying cause. Acute stroke or a structural lesion can produce headaches that meet clinical criteria for primary headache syndromes such as migraine (symptomatic migraine), so clinical context is important in determining the need for further evaluation.

The causes of secondary headache range from benign (e.g., eye strain due to need for prescription glasses) to life threatening (e.g., aneurysmal rupture, bacterial meningitis). Causes of secondary headache can be broadly classified as related to:

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  Intracranial structures: meninges, brain, and/or cerebral blood vessels

  
  
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  Head and neck structures: eyes, ears, nose, sinuses, jaw/teeth, neck

  
  
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  Systemic causes: hypertension, systemic infection, medications

In some patients in whom a cause for headache cannot be found, headache may be a symptom of an underlying psychiatric disorder (e.g., somatization disorder).

Red flags in a patient’s history that should raise concern for a serious underlying etiology of headache can be divided into (Table 26-1):

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  Characteristics of the headache itself:

  
  
  
  
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    Onset: concerning if acute and maximal in intensity at or shortly after onset (thunderclap headache)

    
    
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    Evolution: concerning if increasing in frequency and/or severity

    
    
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    Timing: concerning if worse at night

    
    
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    Relation to prior headaches: concerning if different in quality, severity, and/or timing

  
  
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  Provoking factors: concerning if worsens with coughing, straining, sneezing, supine position

  
  
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  Accompanying symptoms/signs: concerning if fever, seizure, focal neurologic signs, and/or papilledema present

  
  
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  Context/patient history: concerning if:

  
  
  
  
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    New headache in an older adult with no prior history of headache

    
    
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    History of cancer

    
    
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    History of immunosuppression (e.g., medications or HIV)

Any of these features warrant evaluation with neuroimaging to look for an underlying cause.

In addition to these classic red flags, other patterns of headache that require particular evaluation include:

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  New headache in a patient ≥60 years old with scalp tenderness, jaw claudication, myalgias, and/or visual loss should raise concern for giant cell (temporal) arteritis. This diagnosis should be pursued by checking erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and considering temporal artery ultrasound and/or biopsy. If caught early and treated with steroids, visual loss can be prevented.

  
  
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  Headache that is worse with standing and improves in the supine position (orthostatic headache) should raise concern for intracranial hypotension. This can be caused by cerebrospinal fluid (CSF) leak due to prior trauma or prior lumbar puncture, or may be spontaneous. (See “Decreased Intracranial Pressure (Intracranial Hypotension)” in Ch. 25.)

  
  
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  Headaches with visual changes and/or pulsatile tinnitus in a patient with obesity, endocrine disease, or in a child taking tetracycline should raise concern for pseudotumor cerebri (idiopathic intracranial hypertension). Early intervention with weight loss and/or acetazolamide can prevent visual loss. (See “Pseudotumor Cerebri” in Ch. 25.)

Migraine

Clinical Features of Migraine

The classic migraine headache is unilateral, pulsating/throbbing, sufficiently severe to impede daily activities, lasts hours to a few days, is accompanied by photophobia, phonophobia, nausea, and/or vomiting, and causes the patient to seek a dark, quiet, relaxing space. An aura accompanies migraine headache in only about 20%–25% of patients.

Migraine aura is most commonly visual or somatosensory. The visual aura is often described as bright spots or wavy lines that move through the visual field (scintillating scotoma). The somatosensory aura that may accompany migraine is generally unilateral tingling that slowly spreads over minutes across one side of the body. Although somatosensory seizures can produce similar spreading tingling symptoms, the spread of symptoms in migraine is generally slower as compared to the rapid spread of symptoms with somatosensory seizures. Migraines and seizures both generally cause positive symptoms (e.g., tingling, scintillating scotoma) as compared to transient ischemic attack (TIA) and ischemic stroke, which typically cause negative symptoms (e.g., numbness or visual field deficit), though there can be exceptions.