Chapter 29: Evaluation & Management of Headache

Headache is among the most common pain syndromes presenting in primary care with a lifetime prevalence of >90% among adults. Population-based studies of US adults reveal that the prevalence of migraine and probable migraine is approximately 16%, with a female-to-male ratio of approximately 3:1. The prevalence among both genders is 31.2–38.3% for episodic and 2.2% for chronic tension-type headache. The main task before the primary care provider is to determine whether the patient has a potentially life-threatening headache disorder and, if not, to provide appropriate management to limit disability from headache.

A distinction between primary headaches (benign, recurrent headaches having no organic disease as their cause) and secondary headaches (those caused by an underlying, organic disease) is practical in primary care. Over 90% of patients presenting to primary care providers have a primary headache disorder. These disorders include migraine (with and without aura), tension-type headache, and cluster headache. Secondary headache disorders constitute the minority of presentations; however, given that their underlying etiology may range from sinusitis to subarachnoid hemorrhage, these headache disorders often present the greatest diagnostic challenge to the practicing clinician. The International Headache Society provides a detailed classification of primary and secondary headache disorders on their website http://ihs-classification.org/en/02_klassifikation/.

A. Symptoms and Signs

1. History

The majority of patients presenting with headache have a normal neurologic and general physical examination; for this reason, the headache history is of utmost importance (Table 29-1). A key issue in the headache history is identifying patients presenting with “red flags”—diagnostic alarms that prompt greater concern for the presence of a secondary headache disorder and a greater potential need for additional laboratory evaluation and neuroimaging (Table 29-2).

The onset of primary headache disorders is usually between 20 and 40 years of age; however, they may occur at any age. Patients without a history of headaches who present with a new-onset headache outside this age range should be considered at higher risk for a secondary headache disorder. Additional testing or neuroimaging in these patients or those complaining of their “first or worst” headache should be seriously considered. Temporal (giant cell) arteritis should be a consideration in any patient aged ≥50 years with a new complaint of head, facial, or scalp pain, diplopia, or jaw claudication.

Symptoms suggesting a recurring, transient neurologic event, typically lasting 30–60 minutes and preceding headache onset, strongly suggest the presence of an aura and an associated migraine headache disorder. Migraine without aura, the most common form of migraine (formerly called common migraine), may present with unilateral pain in the head (cephalalgia) with subsequent generalization of pain to the entire head. Bilateral cephalalgia is present in a small percentage of migraineurs at the onset of their headache. Nausea accompanying a migraine may be debilitating and warrant specific treatment. After excluding secondary headache disorders, the combination of disability, nausea, and sensitivity to light has a positive predictive value of 0.93 for migraine headache among primary care patients.

Cluster headaches are strictly unilateral in location and are typically described as an explosive, deep, excruciating pain. They are associated with ipsilateral autonomic signs and symptoms, and have a much greater prevalence in men.

Tension-type headaches, the most prevalent form of primary headache disorder, often present with pericranial muscle tenderness and a description of a bilateral bandlike distribution of the pain.

Patients with chronic medical conditions have a greater possibility of having an organic cause of their headache (see Table 29-2). Patients with cancer, hypertension (with diastolic pressures >110 mmHg), or human immunodeficiency virus (HIV) infection may present with central nervous system (CNS) metastases, lymphoma, toxoplasmosis, or meningitis as the etiology of their headache. Numerous medications have headache as a reported adverse effect, and medication overuse headache (formerly drug-induced headache) may occur following frequent use of analgesics or any antiheadache medication, including the triptans (eg, sumatriptan). The duration and severity of withdrawal headache following discontinuation of the medication varies with the medication itself; withdrawal is shortest for triptans (4.1 days) compared with ergots (6.7 days) or analgesics (9.5 days), respectively. Medical or dental procedures (lumbar punctures, rhinoscopy, tooth extraction, etc) may be associated with postprocedure headaches. Any history of head trauma or loss of consciousness should prompt concern for an intracranial hemorrhage in addition to a postconcussive disorder.

2. Physical examination

Physical examination is performed to attempt to identify a secondary, organic cause for the patient’s headache. Additionally, any red flags identified during the headache history (see Table 29-2) warrant special attention. A general physical examination should be performed, including vital signs; general appearance; and examinations of the head, eyes (including a funduscopic examination), ears, nose, throat, teeth, neck, and cardiovascular regions. Palpation of the head, face, and neck should also be a priority.

A detailed neurologic examination should be performed and the findings well documented. Assessment includes mental status testing; level of consciousness; pupillary responses; gait; coordination and cerebellar function; motor strength; sensory, deep tendon, and pathologic reflex testing; and cranial nerve tests. The presence or absence of meningeal irritation should be sought. Examinations such as evaluation for Kernig and Brudzinski signs should be documented; both signs may be absent, however, even in the presence of subarachnoid hemorrhage.

B. Laboratory Findings and Imaging Studies

Additional laboratory investigations should be driven by the history and any red flags that have been identified (see Table 29-2). The routine use of electroencephalography is not warranted in the evaluation of the patient with headache. Although various characteristics may lead to selection of either computed tomography (CT) or magnetic resonance imaging (MRI) (Table 29-3), routine use of neuroimaging is not cost-effective.

The US Headache Consortium has provided evidence-based guidelines on neuroimaging in the patient with nonacute headache. They revealed the prevalence of patients with a normal neurologic examination, and migraine having a significant abnormality (acute cerebral infarct, neoplastic disease, hydrocephalus, or vascular abnormalities, eg, aneurysm or arteriovenous malformation) on a neuroimaging test is 0.2%. Their recommendations are as follows:

• Neuroimaging should be considered in patients with nonacute headache and an unexplained abnormal finding on neurologic examination.

• Evidence is insufficient to make specific recommendations in the presence or absence of neurologic symptoms.

• Neuroimaging is seldom warranted for patients with migraine and normal neurologic examination. For patients with atypical headache features or patients who do not fulfill the strict definition of migraine (or have some additional risk factor), a lower threshold for neuroimaging may be applied.

• Data were insufficient to yield an evidence-based recommendation regarding the use of neuroimaging for tension-type headache.

• Data were insufficient to yield any evidence-based recommendations regarding the relative sensitivity of MRI compared with CT in the evaluation of migraine or other nonacute headache.

Although the US Headache Consortium based the preceding recommendations on a review of the best available evidence, clinicians must individualize management plans to meet a variety of needs, including addressing patient fears and medicolegal concerns.

Within the first 48 hours of acute headache, CT scanning without contrast medium followed, if negative, by lumbar puncture and cerebrospinal fluid (CSF) analysis, is the preferred approach to attempt to diagnose subarachnoid hemorrhage. Xanthochromia, a yellow discoloration detectable on spectrophotometry, may aid in diagnosis if the CT scan and CSF analysis are normal yet if suspicion of subarachnoid hemorrhage remains high. Xanthochromia may persist for ≤1 week following a subarachnoid hemorrhage.

In addition to CSF analysis, lumbar puncture is useful for documenting abnormalities of CSF pressure in the setting of headache. Headaches are associated with low CSF pressure (<90 mm H₂O as measured by a manometer) and elevated CSF pressure (>200–250 mm H₂O). Headaches related to CSF hypotension include those caused by posttraumatic leakage of CSF (ie, after lumbar puncture or CNS trauma). Headaches related to CSF hypertension include those associated with idiopathic intracranial hypertension and CNS space–occupying lesions (ie, tumor, infectious, mass, hemorrhage).

In addition to migraine, tension-type, and cluster headaches, the differential diagnosis for acute headaches in adults is presented in Table 29-2.

Treatment of headache is best individualized with respect to a thorough history, physical examination, and the interpretation of appropriate ancillary testing. Secondary headaches require accurate diagnosis and therapy directed at the underlying etiology (see Tables 29-2 and 29-3). Nonpharmacologic measures and cognitive behavioral therapy (CBT) are worth consideration in most patients with primary headache disorders. CBT may have a prophylactic effect in migraine similar to propranolol (an approximate 50% reduction). Cluster headache, chronic tension-type headache, and medication overuse headache respond poorly to CBT as monotherapy. The evidence for a benefit of acupuncture in preventive migraine and tension-type headache treatment now reveals it to be an effective prophylactic option. A systematic review [six total randomized controlled trials (RCTs)] revealed no positive effect of various manual therapies in the treatment of tension-type headache.

A. Migraine

The US Headache Consortium lists the following general management guidelines for treatment of migraine patients:

• Educate migraine sufferers about their condition and its treatment, and encourage them to participate in their own management.

• Use migraine-specific agents [triptans, dihydroergotamine (DHE), ergotamine, etc] in patients with more severe migraine and in those whose headaches respond poorly to nonsteroidal anti-inflammatory drugs (NSAIDs) or combination analgesics such as aspirin plus acetaminophen plus caffeine.

• Select a nonoral route of administration for patients whose migraines present early with nausea or vomiting as a significant component of the symptom complex.

• Consider a self-administered rescue medication for patients with severe migraine who do not respond well to (or fail) other treatments.

• Guard against medication overuse headache (the terms rebound headache and drug-induced headache are sometimes used interchangeably with medication overuse headache; however, the latter is the recommended terminology).

Pharmacologic treatment options are numerous in the management of migraine headache. Effective acute/abortive treatment options include an oral, intranasal, or subcutaneous triptan (eg, sumatriptan), intravenous (DHE 45), or intranasal (Migranal) DHE, and intravenous antiemetics (eg, prochlorperazine, metoclopramide, promethazine). On the basis of available evidence, first-line use of these agents is preferred over the commonly used meperidine (or other narcotic analgesics) or ketorolac in abortive migraine treatment. A meta-analysis of seven RCTs (pooled data on 742 patients) of the addition of dexamethasone to standard acute migraine treatment in the emergency department (ED) setting revealed a moderate benefit [relative risk (RR) = 0.87, 95% confidence interval (CI) = 0.80—0.95] to reducing the risk of having a moderate or severe migraine headache at 24–72 hours after ED evaluation.

The goal of therapy in migraine prophylaxis is a reduction in the severity and frequency of headache by ≥50%. The strongest evidence surrounds the use of amitriptyline, propranolol, timolol, and divalproex sodium for migraine prevention. Topiramate also has proven prophylactic effects in migraine treatment. Botulinum toxin A has been found to lead to a reduction in headache days for chronic migraines and chronic daily headaches but not for episodic migraine.

B. Tension-Type Headache

Initial medical therapy of episodic tension-type headache often includes aspirin, acetaminophen, or NSAIDs. Avoidance of habituating, caffeine-containing over-the-counter (OTC) or prescription drugs as well as butalbital-, codeine-, or ergotamine-containing preparations (including combination products) is recommended given the significant risk of developing drug dependence or medication overuse headache.

Similar general management principles for treatment of migraine headaches can be applied to the treatment of chronic tension-type headaches. In a randomized placebo-controlled trial of tricyclic antidepressant use (amitriptyline hydrochloride, ≤100 mg/d or nortriptyline hydrochloride ≤75 mg/d) and stress management (eg, relaxation, cognitive coping) therapy, combined therapy produced a statistically and clinically greater reduction (≥50%) in headache activity. A meta-analysis of antidepressant treatment (eg, tricyclic antidepressants, serotonin antagonists, and selective serotonin reuptake inhibitors) of chronic headache (eg, migraine, tension-type, or both) revealed that treated study participants were twice as likely to report headache improvement and consumed less analgesic medication than nontreated patients. Other considerations for prophylaxis of chronic tension-type headaches include calcium channel blockers and β-blockers. Botulinum toxin A use is not associated with an improvement in the frequency of either chronic or episodic tension-type headaches.

C. Cluster Headache

Acute management of cluster headache includes the use of sumatriptan in either its subcutaneous (FDA-approved indication), intranasal, or oral forms (the latter two are less effective), intranasal zolmitriptan, 100% oxygen at 7–10 L/min via face mask, and intranasal lidocaine. Verapamil, lithium, divalproex sodium, gabapentin, lithium, melatonin (possibly), topiramate (possibly), methysergide, and prednisone may be considered for prophylaxis. Because of side effects related to chronic use, methysergide and prednisone should be used with caution.

D. Referral

Referral to a headache specialist should be considered for patients whose findings are difficult to classify into a primary or secondary headache disorder. Additionally, referral is often warranted in cases of daily or intractable headache, drug rebound, habituation, or medication overuse headache, or in any scenario in which the primary care provider feels uncomfortable in making a diagnosis or offering appropriate treatment. Patients who request referral, who do not respond to treatment, or whose condition continues to worsen should be considered for referral.