Jillian Belmont Headache is experienced by 90% to 95% of the population and is one of the 10 most common complaints in the outpatient setting.1 Many people with headache are never diagnosed by a physician. Some individuals treat headaches at home with over-the-counter (OTC) medications and home remedies such as ice packs and rest. Research has shown that even with the development of newer medications, up to 57% of patients with headaches use OTC medications, and many do not seek care for their headaches because they do not believe that satisfactory treatment is available.1 It is essential to differentiate secondary from primary headaches because secondary headaches can be harbingers of a potentially more serious medical problem than the benign, primary headaches usually seen in the office setting. Secondary headaches are less common and are usually the result of an underlying disease or condition, such as aneurysm, tumor, hemorrhage, temporal arteritis, or meningitis.1 Once the primary problem has been identified and treated, secondary headaches may dissipate. Primary headaches are more common and are not symptomatic of another medical condition. These are distinct disorders that result from pathophysiologic mechanisms. Types of primary headaches include migraine with and without aura, chronic or episodic tension-type headaches, and chronic or episodic cluster headaches.1 Primary headache disorders affect people of all ages, races, income levels and geographic areas and have an estimated lifetime prevalence of 47% in adults worldwide.2 These headaches may range in intensity from mild to severe but cause considerable distress, expense, and loss of work time. In general, migraine varies by age and sex, increasing in frequency to about the age of 40 years and declining thereafter in both men and women. Women experience migraine three times more often than men do. Similarly, tension-type headache is seen more in women than in men, with a male-to-female ratio of 4 : 5.3 Cluster headache, on the other hand, is more common in men than in women; attacks usually begin between the ages of 20 and 40 years.3 Clinical and research evidence has demonstrated a relationship between migraine and other disease processes, including epilepsy, major depression or panic disorder, and cardiac shunting. The neurotransmitter serotonin has been suggested as a basis for both migraine and major depression. Knowing that a co-occurrence exists helps in the treatment of each disease and provides clues to the pathophysiologic mechanism of migraine.4 The exact mechanism of a headache is still debated. Previously, headaches were thought to be caused by increased blood flow to the head, resulting in distended vessels and pressure on the nerve fibers of the brain.5 This “vascular theory” was popular for many years until the 1930s, when Harold Wolfe determined that migraine, specifically, was caused by both vascular and chemical changes within the brain.5 Many theories have since identified several neurochemicals as key elements in migraine development. Serotonin (5-hydroxytryptamine [5-HT]), a powerful vasoconstrictor, sensitizes the blood vessel walls to painful dilation. Other neurochemicals, such as dopamine, substance P (a polypeptide), and calcitonin gene–related peptide, may alter the excitability of the brain and mediate the vasoconstriction or vasodilation of blood vessels.1 Neurogenic inflammation is responsible for the pain of migraine.5 In review of the various theories, it is clear that during a headache, changes occur in the vasculature of the brain and in the neurochemicals found within the body. These changes are a result of a brain response to a stimulus, or trigger. Vasodilation and vasoconstriction subsequently cause the release of neurochemicals, which may be responsible for the headache and for the feelings of impending doom or fatigue that can occur before and after an attack. The International Headache Society has developed criteria for various types of headache disorders. The criteria can be tedious to use and are not applicable in many primary care settings, but the information may allow the provider to quickly differentiate the various types of primary headache conditions.6 The two major types of migraine are migraine with aura and migraine without aura. Migraine without aura is the more common of the two. In general, the patient complains of an ipsilateral headache. The pain is described as pounding or throbbing, is moderate to severe in intensity, and is aggravated by physical activity. This headache, which is episodic, lasts 4 to 72 hours and may be associated with nausea, vomiting, photophobia, and phonophobia. These patients usually retreat to a dark, quiet room until the attack is over. They often can identify a trigger that will precipitate the attacks. Triggers are an individual characteristic and may be difficult to identify because they may not always stimulate a headache. Common triggers include medication overuse, obesity, depression, stressful life events, sleep problems including snoring, weather changes, foods (cheese, chocolate), alcohol, change in altitude, delay or skipping of a meal, and hormonal changes.1,7 In migraine with aura, the aura usually occurs before the onset of head pain, although it can sometimes extend into the period of headache. The classic aura, or “fortification spectrum,” occurs in about 10% of patients and is described as jagged lines similar to the stone fortifications found around a fort.1 Visual auras can also be characterized by spots, shimmering bright lights, or areas of visual loss (scotomas). Somatosensory-type auras can also occur, with tingling or numbness of the fingers, motor disturbances such as hemiparesis or monoparesis, and cognitive disorders.1 These visual and somatosensory disturbances usually last seconds but can last as long as 20 minutes. The patient then experiences head pain and features similar to those of migraine without aura. A prodrome can be part of a migraine.8 Several days before the aura or start of the head pain, the person may have feelings of doom or fatigue. During this period, increased irritability, decreased energy, and food cravings are common complaints. This can often be an early signal that a severe headache is coming and may enable the patient to use both pharmacologic and nonpharmacologic modalities in the hope of aborting the attack. Acute tension-type headaches are described as feeling like there is a tight band around the head. Nausea and vomiting are not present, and the pain can be mild to moderate in intensity. This headache can last minutes to hours. It usually is not exacerbated by physical activity, but a common trigger is stress. Overall, the acute tension-type headache is a nagging headache that occurs fewer than 15 days per month, is present most of the day, and may start after the person wakes up. It rarely awakens the person. Chronic tension-type headache is similar in presentation to the acute type but occurs more often than 15 days per month.9 The patient with cluster headache, acute or chronic, is usually awakened during the night with severe unilateral, retro-orbital pain. A cluster headache reaches maximum intensity in about 15 minutes and usually lasts about 90 minutes, although some can last 3 hours.6,10 These attacks can occur several times per day. The pain is described as agonizing, and unlike migraineurs, these patients often cannot sit still. The severe intensity of cluster pain causes restlessness, moaning, crying, and often pacing. Patients may indulge in self-hurting behavior and may have thoughts of suicide.11 Other features of cluster headache include ipsilateral injection of the conjunctiva, lacrimation, rhinorrhea, and partial Horner sign. For the patient with acute cluster headache, attacks occur in groups (or clusters) lasting days to weeks and then subside until the next attack. Years can pass between attacks, and the event often occurs at the same time each year. The patient with chronic cluster headache has the same presentation as the patient with the acute type but does not experience any remission longer than 1 month for at least 1 year. These headaches are also relatively resistant to therapy. Although it is well tolerated between attacks, alcohol will often precipitate an attack in patients with acute or chronic cluster headache.6,11 The history is the most important part of the evaluation. With most primary headache disorders, the diagnosis can be made on the basis of the history alone.12 It is important that the patient characterize the headache by describing the duration, quality, and location of the pain. The presence or absence of any precipitating factors, or triggers, and the age at onset should be established. The presence of associated symptoms, such as nausea, vomiting, and photophobia, should be explored. Can the patient be active during these headaches, or does the patient need to lie still in a dark room? How does the patient describe his or her sleep and energy? Sleep is usually labile in the person with headache, and energy may be poor. A medication profile is essential and should include medications that have been tried in the past for headache control. If OTC medications are taken, the number used per month should be identified because patients may not view OTC drugs as medications. Migraine is known to be familial; therefore, it is important to determine whether any family member has had headaches that might have been called sinus headaches or sick headaches or headaches that were disabling. Asking about the presence of any physical abuse is important because it has been shown that a history of abuse contributes to refractory headaches. A targeted physical examination is important in ruling out harmful secondary headache pathologies and confirms any information given in the history.12 The examination findings in primary headache disorders are usually within normal limits. Key aspects of the physical examination include a cardiopulmonary and complete neurologic assessment with a major focus on the following: • Funduscopic and pupillary assessment • Auscultation of the carotid and vertebral arteries • Palpation of the head, neck, and temporal arteries • Evaluation for any neck stiffness, focal weakness, sensory loss and gait Many patients with tension-type headaches or migraines have tight cervical musculature. Painful biceps insertions, along with general aches and pains along the back, hips, and knees, may herald the beginning of fibromyalgia (see Chapter 175), a condition commonly seen in migraineurs. Pain and pressure on palpation of the sinuses accompanied by purulent nasal discharge may be indicative of sinusitis. The temporomandibular joints may click and pop when the mouth is opened and closed, but rarely is this the cause of a headache. Tension is often exhibited in the musculature surrounding this joint, and the subsequent bruxism may potentiate pain in this area. Serious symptoms and findings include a headache accompanied by a stiff neck; fever; malaise; nausea or vomiting; and the presence of any aphasia, weakness, or poor coordination. Other danger signs include the following1,12: • Onset of headache after the age of 50 years • Asymmetry of pupillary responses • Decreased deep tendon reflexes • Headache described as “the worst ever experienced” • Onset of a new or different headache • Onset of a headache that progressively worsens Further investigation and referral to a specialist or hospital would be warranted with any of these signs. Positive neurologic findings on examination are indicative of a central nervous system problem and should not be attributed to migraine unless a prior pattern has been documented with serious findings previously excluded. The use of diagnostic studies depends on the results of the history and physical examination. Most diagnostic studies in the patient with primary headache are unrevealing. If the diagnosis is not clear or the history or physical findings are cause for concern, diagnostic studies should be used to distinguish primary headache from a secondary condition. Blood tests are usually not indicated, although exceptions, based on history and physical examination findings, may include a complete blood count (CBC) to exclude anemia or an infectious process, erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) to help exclude temporal arteritis, and thyroid function tests to identify thyroid dysfunction. Lyme titer or rheumatoid factors may also be indicated in some situations. Practice guidelines developed by the U.S. Headache Consortium advocate three principles for diagnostic testing: (1) testing should be avoided if it will not change the management of the patient, (2) testing is not indicated if the patient is not significantly more likely than the general public to have an abnormality, and (3) testing may make sense in a patient who is excessively concerned that he or she has a serious problem that is causing the headaches.13 Neuroimaging should be considered when any serious signs or symptoms are present during the physical examination, but it is not indicated if the patient has had these headaches for years, if there are no focal neurologic signs, and if the headache improves without the use of analgesics. The history and physical examination will aid in excluding potential diagnoses. The differential diagnosis includes fever, meningitis, pseudotumor cerebri, hemorrhage, rheumatologic disorders (e.g., lupus erythematosus, rheumatoid arthritis), Lyme disease, temporal arteritis, trigeminal neuralgia, thyroid dysfunction, sleep apnea, tumor, aneurysm, and pheochromocytoma, among many others. Headache is a feature of many disease processes (see the differential diagnosis box). Differential Diagnosis Headache
Headache
Definition and Epidemiology
Pathophysiology
Clinical Presentation
Migraine
Tension-Type Headache
Cluster Headache
Physical Examination
Diagnostics
Differential Diagnosis
Headache
Chapter 196
