Chronic headache is one of the most common neurologic symptoms. The main focus of the initial evaluation of a patient with chronic headache is to (1) determine if the headache is secondary to some underlying disease or is a primary headache disorder, and (2) classify the headache type to choose optimal treatment.
So-called “red flags” are features in the history that suggest headache may be due to an underlying disease. Most primary headache disorders present in adolescence or early adulthood, so headaches developing after age 50 should raise concern for a secondary cause and prompt brain imaging. Similarly, brain imaging is generally indicated for headaches following recent head trauma; that waken a patient from sleep, worsen with changes in body position or are triggered by Valsalva maneuvers including cough, exercise, or sexual activity; that occur in patients who are pregnant, immunocompromised, or have autoimmune disease or cancer; or that are associated with signs or symptoms of subacute infection. For patients with a known primary headache disorder, consider imaging if headaches develop new characteristics or patterns, or become progressively more severe or frequent. An abnormal neurologic examination should always prompt concern for a secondary cause and consideration of brain imaging. Be certain to evaluate for papilledema, which can indicate elevated intracranial pressure due to malignancy, infection, or idiopathic intracranial hypertension.
Migraine is a common primary headache disorder. Approximately 20%–40% of people with migraine experience an aura with at least some of their migraine attacks. Auras are unilateral, fully reversible neurologic symptoms that develop gradually over 5 minutes lasting up to 60 minutes and are typically followed by a headache with migrainous features. Aura symptoms are most often visual and binocular (scotomas with or without positive phenomena such as fortification spectra and/or scintillations), but can be monocular. They may also affect sensation (numbness or dysesthesias), language (aphasia), or motor function. Brainstem aura (dysarthria, vertigo, tinnitus, diplopia, ataxia, and/or decreased level of consciousness) is rare and additional work up should be considered. Typical migraine aura can also occur without headache.
For migraine without aura, an individual needs to have had at least five attacks of headache with migrainous features (see chart) that last between 4 and 72 hours when untreated or unsuccessfully treated. The associated symptoms help distinguish migraine from other headache disorders. Unless there are concerning features on history or examination, additional testing is not needed.
Trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders characterized by severe unilateral periorbital or temporal pain associated with ipsilateral cranial autonomic symptoms and a sense of restlessness or agitation. Duration and frequency of attacks are different for each disorder, as well as treatment response. Initial diagnostic evaluation for TACs should include magnetic resonance imaging (MRI) of the brain with contrast with special attention to the pituitary gland and cavernous sinus.
Ophthalmologic evaluation should be considered for orbital or periorbital pain, which may also occur with photophobia. Examples of primary ophthalmologic causes of pain include conjunctivitis, uveitis, keratitis, scleritis, corneal abrasions, dry eye syndrome, acute angle-closure glaucoma, orbital cellulitis, and optic neuritis.
Trigeminal neuralgia consists of attacks of very brief, lancinating pain in the distribution of the trigeminal nerve. The ophthalmic division of the trigeminal nerve is typically spared. Pain is often triggered by innocuous stimuli such as brushing teeth, cold air, talking, chewing, or touching the face. Rarely, trigeminal neuralgia is due to demyelination or neoplasm affecting the trigeminal nerve; more commonly it is idiopathic or associated with a compressive vascular loop. It is best evaluated with brain MRI with contrast and thin cuts through the trigeminal nerve and posterior fossa.
Temporomandibular disorders may also show abnormal movements of the mandible and/or decreased range of motion in addition to tenderness on examination. Patient education, dental referral for occlusional splints, and physical therapy may be helpful. The usefulness of imaging is controversial.
With occipital neuralgia, paroxysms of pain are brief and associated with dysesthesia and/or allodynia. Occipital nerve block is both diagnostic and therapeutic. Occipital neuralgia is often overdiagnosed in the setting of migraine, as occipital tenderness is commonly found on examination and occipital nerve blocks often provide pain relief, but they are distinct disorders.
Tension-type headache is the most common primary headache disorder, but most patients do not seek medical advice. Note that it does not have migrainous features such as aggravation by routine physical activity or nausea/vomiting, but may have photophobia or phonophobia. Unless there are concerning features on history or examination, additional testing is not needed.