(Review article for physicians and patients seeking further information)
   

INTRODUCTION
It is estimated that up to 40 million people in the United States suffer from chronic headaches. These headache sufferers often do not receive treatment because they believe that doctors will consider the problem to be trivial, or they are unaware that treatment is available. Patients who do consult a physician are usually those whose headaches significantly disrupt their lives. Public education about available treatments - through the media and practicing physicians - is a work in progress


HISTORY
Most of the information leading to the diagnosis of the headache type is obtained from the patient's history.

1.
Frequency and duration. Increasing frequency or duration of headaches indicates the need for a re-evaluation of a previously-diagnosed patient. Daily headaches are often the result of caffeine or medication overuse. Very brief, but intense and frequent (several times a day) headaches in women suggest the diagnosis of chronic paroxysmal hemicrania which almost always responds to indomethacin.

2.
Time patterns. Tension-type headaches tend to worsen as the day progresses but it is not unusual to have a tension headache upon awakening. Cluster headaches tend to be very regular in their time of occurrence. They typically awaken patients from sleep in the early morning hours. A patient who wakes up with a headache that quickly resolves without medications should receive immediate further evaluation to rule out a brain tumor or other space occupying lesion.

3.
Character and location of pain. Unilateral and pulsatile pain is most common in migraine and cluster headaches. Burning occipital pain suggests a focal neuropathy.

4.
Precipitating factors. Overexertion and emotional distress are the most common precipitating factors for both tension-type and migraine headaches. Alteration of sleep patterns, tyramine-rich foods, alcohol, chocolate and other foods can provoke a migraine attack. Strong sensory stimuli such as loud noise, strong odors, bright and flashing lights can induce a headache in a susceptible individual. And changes in barometric pressure caused by weather changes, flying or climbing a mountain can provoke headaches as well.

5.
Preceding and accompanying symptoms. Migraine headaches are often preceded by a visual and other types of aura. Nausea, sensitivity to light, noise and movement are typical accompaniments to migraine headaches. Dizziness can occur with migraine and cervicogenic headaches. Agitation, unilateral nasal congestion and tearing frequently occur with an attack of cluster headache.


PHYSICAL EXAMINATION
A general medical examination is necessary to detect many of the systemic conditions that can lead to headaches. After a detailed history, the neurologic examination is the most important diagnostic step. This examination should be normal for the types of headaches described below with few exceptions. Patients with cluster headaches often have Horner's syndrome that can persist for some time after the attack. Benign intracranial hypertension is accompanied by papilledema and can lead to visual field defects and cranial nerve palsies, especially of the sixth nerve. Patients with temporal or giant cell arteritis may have tortuous and tender temporal artery.


ANCILLARY TESTS
A.
If the history or physical examination raises any doubt about the benign etiology of a patient's headaches, an imaging procedure such as a CAT scan or, preferably, an MRI scan should be performed. Concern over a possible brain tumor or another serious condition often makes the headache worse. A negative CAT or MRI scan reassures the patient and can reduce headaches by reducing anxiety.

B.
A CAT or MRI scan of the brain is routinely performed to exclude a subdural hematoma which in the elderly may develop from a trivial head injury suffered many weeks or months earlier. Up to 40% of elderly patients with a chronic subdural hematoma give no history of a head injury. Conditions such as metastatic brain tumor and cerebro-vascular disease are also more common in the elderly than in younger patients.

C.
Laboratory tests on patients who have not had screening blood tests in the past 12 months should include a complete blood count, thyroid function tests and a standard battery of chemistry tests. These tests may detect anemia, systemic infections, renal insufficiency, hypothyroidism and other conditions that may cause headaches.

D.
An erythrocyte sedimentation rate (ESR) must always be obtained in a patient over 60 years of age with a recent onset of headaches. If the ESR is high, a temporal artery biopsy is necessary to confirm the diagnosis of giant cell arteritis.