HEADACHE. Robert Kaniecki, MD Director, the Headache Center Chief, Headache Division Assistant Professor of Neurology University of Pittsburgh

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1 HEADACHE Robert Kaniecki, MD Director, the Headache Center Chief, Headache Division Assistant Professor of Neurology University of Pittsburgh OVERVIEW The lifetime prevalence of headache is more than 90%. In recent populationbased surveys of U.S. adults, nearly 25% annually report recurrent episodes of severe headache and 4% daily or near-daily headache. Prescription or non-prescription products are used by 9% of U.S. adults each week to treat headache, matching hypertension as the primary reason for medication use. The majority of patients presenting to physicians will have primary headache syndromes such as tension-type, cluster, and migraine. Less than 2% of patients in office and 4% of patients in emergency department settings will be found to have headaches secondary to significant pathology. Recurrent headaches provoke consultation when they are debilitating, frequent, or associated with worrisome neurologic or systemic symptoms. Episodic tension-type headache annually affects 38% of U.S. adults yet rarely requires medical attention given the typical absence of disability or concerning symptoms. Cluster headache generally leads to significant disability and assorted autonomic features, but it is uncommon in office practice due to low population prevalence (less than 0.1%). Migraine headache is disproportionately represented in office settings because of its high prevalence, (13% of U.S. adults) significant disability, and common association with neurological and gastrointestinal symptoms. Research has shown that more than 90% of initial headache consultations in a primary care office setting will involve patients experiencing attacks meeting International Classification of Headache Disorders (ICHD-II) criteria for migraine, while only 3% experience solely episodic tension-type headache. DIAGNOSTIC CLASSIFICATION AND MANAGEMENT In the diagnostic system designed by the International Headache Society, headaches are broadly divided into two main categories: primary headaches (headache is the problem) and secondary headaches (headache is a symptom of a problem). (Table 1) Since headache may arise from conditions that range from benign to catastrophic, the initial step in headache assessment requires screening for secondary origins. Acute headache is often the most prominent complaint from patients experiencing a host of serious nervous system disorders, including subarachnoid hemorrhage, bacterial meningitis, encephalitis, or stroke. Subacute headache may also be associated with an assortment of worrisome disorders, including brain tumors, intracranial hypertension, or temporal arteritis. Thorough history combined with general and focused neurological examinations are mandatory. Neuroimaging procedures or serum/cerebrospinal fluid 185

2 analyses are required when one of the red flags of secondary headache presentations is encountered. (Table 2) The available data are insufficient to recommend either computed tomography or magnetic resonance imaging as a more sensitive modality. The routine use of electroencephalography in the evaluation of headache patients is no longer warranted. The majority of patients in primary care settings will experience episodic primary headache disorders. Traditional diagnosis is founded on a symptom-base paradigm initially developed by the IHS for purposes of clinical research. Significant symptom overlap among the primary headaches and between primary and secondary headaches has raised concerns regarding the clinical specificity of such a system. Migraine Epidemiology and Clinical Features More than 90% of patients who have recurrent headache on presentation to primary care offices or emergency departments have migraine. This extraordinarily high figure results from the high prevalence of migraine, which affects approximately 13% of adults in the United States, and the disabling nature of the condition. Migraine usually begins in late childhood or early adolescence and follows various courses: the headache may go into remission after a few years, recur in cycles of variable headache activity for many years or decades, or evolve into a chronic and more refractory state. Migraine is more common in preadolescent boys than girls but becomes three times more common in adult women than men. Prevalence peaks in the fifth decade of life, drops significantly in the sixth and seventh decade, and is exceedingly uncommon in later decades. Although a typical migraine episode consists of a unilateral, throbbing headache accompanied by photophobia, phonophobia, and nausea, there is extensive variability in the clinical expressions of migraine, often leading to misdiagnoses of tension headache in the presence of bilateral steady pain or sinus headache when the discomfort is a frontal or facial pressure. (Table 3) Migraine is preceded or accompanied by focal neurologic symptoms termed aura in up to 30% of patients. The most common aura is a visual experience consisting of a flashing light or an enlarging blind spot rimmed with a shimmering edge or jagged lines in the peripheral vision. An aura is defined as typical if it involves any combination of visual, hemisensory (usually face and hand), or language abnormalities with each symptom developing over a minimum of 5 minutes and lasting a maximum of 60 minutes. The associated migraine usually occurs within 1 hour, but some auras do not progress to head pain. Auras should be investigated further if they extend beyond 60 minutes, involve any focal motor weakness ( hemiplegic migraine ), or display brainstem symptoms such as diplopia, dysphagia, ataxia, vertigo, dysarthria or synchronous bilateral sensory dysfunction ( basilar migraine ). Migraine is subclassified not only based on the presence or absence of aura, but also based on average monthly frequency of headache occurrences. Most have headache fewer than 15 days per month and are classified as episodic migraine. Patients with chronic (previously transformed ) migraine have headache at least 15 days per month for more than three months, with the individual headache episodes meeting criteria for 186

3 migraine on at least 8 of those days. Chronic migraine affects 2% of the world population and results in substantial individual disability and enormous societal costs. Transformation of episodic into chronic migraine has been shown to occur at a rate of 3% per year in the general population and 14% per year in clinic-based populations. Evidence suggests risk factors for such transformation include: Older age Major life changes or significant stressors Female sex Low education/socioeconomic status Head/neck trauma Obesity Presence of comorbid pain, sleep, or psychiatric disorders High caffeine or nicotine intake Overuse of acute headache medications The final risk factor for migraine transformation, overtreatment with acute medication, is now termed medication overuse headache (MOH) instead of rebound headache. MOH is present in up to 80% of individuals with chronic migraine presenting to medical attention, and thus it is critical that all patients be questioned about the use of both prescription and non-prescription products during a headache history. Several studies assessing the relationship between migraine transformation and acute medication use have drawn the same conclusions: opiates (critical exposure 8 days per month) and barbiturates (critical exposure 5 days per month) are associated with high rates of migraine progression, while nonsteroidal anti-inflammatory agents (NSAIDs) and triptans induce progression only in those with frequent episodic migraine (10-14 days per month) but not overall. Migraine Pathophysiology Migraine is a heritable biological disorder of the central nervous system characterized by baseline hypersensitivity to external stimuli and intermittent episodes of head pain. The condition appears to be genetically heterogeneous, with recent research identifying genetic alterations in migraine with and without aura, adding to prior work establishing 3 different genetic abnormalities in the rare subform of migraine known as familial hemiplegic migraine. Functional imaging techniques have linked migraine aura with a slowly propagating electrical wave of brain depolarization and hyperpolarization known as cortical spreading depression (CSD). Subsequent activation of the trigeminal vascular system plays a role in migraine headaches, but the exact mechanism and the precise connection with CSD are unknown. Basic science and clinical data support the concept that migraine pain arises from activation of trigeminal nerve fibers that innervate the dura. When stimulated these neurons release a number of neurochemicals (substance P, calcitonin gene related peptide, or neurokinins) which provoke vasodilation of dural vessels, local sterile inflammation, and pain. Pain signals generated on the dural surface are then transmitted and modulated by central nervous system structures, involvement of which may help explain migraine persistence (recurrence, status migrainosus) or progression. Migraine Management Evidence from well-designed placebo-controlled trials supports the efficacy of NSAIDs, dihydroergotamine mesylate, and triptans in the management of acute migraine. Despite 187

4 their widespread use, there is no evidence supporting the efficacy of butalbital compounds and little evidence supporting the efficacy of isometheptene compounds in the treatment of acute migraine. Opioids are recommended only when migraine-specific agents and NSAIDs are contraindicated or in rare cases of rescue when such agents have failed. Antiemetics are helpful adjunctive therapies when used with NSAIDs or triptans. NSAID s may be helpful in cases of mild or moderate migraines, with the data best for ibuprofen, naproxen, aspirin, and the combination product of aspirin-acetaminophencaffeine. Among the triptans sumatriptan, rizatriptan, zolmitriptan, naratriptan, almotriptan, eletriptan, and frovatriptan all have tablet formulations with established efficacy in moderate-to-severe migraine. Both sumatriptan and zolmitriptan are available in nasal preparations. The agent with greatest speed of onset and efficacy is subcutaneous sumatriptan. In addition to acute headache management, patients with migraine should receive lifestyle recommendations regarding headache prevention. Regulation of sleep and meal patterns, adequate amounts of hydration and exercise, limitation of caffeine and other stimulants, and the intake of certain nutritional supplements (magnesium, butterbur root) are often encouraged. If migraine attacks occur more frequently than 5-6 days per month a course (6-12 month) of daily migraine preventive medication is often considered. The selection of a drug should be based first on efficacy, with consideration given to coexisting psychiatric or medical disease, patient preference, and patient adherence. Evidence in episodic migraine prevention is strongest for propranolol ( mg/d), timolol (5-30 mg/d), amitriptyline ( mg/d), divalproex sodium ( mg/d), and topiramate ( mg/d). Recent trials have documented the efficacy of only 2 agents for chronic migraine, oral topiramate and injectable onabotulinumtoxina. Tension-type headache (Table 4) is the least distinct of the primary syndromes, defined by the absence of associated features. The pain is mild and moderate in intensity, generally bilateral, and nonpulsatile. It typically remains unchanged or improves with physical activity. Stress is listed as the most common trigger. Due to its limited disability, episodic tension-type headache rarely is the basis for consultation in primary care or specialty settings. Acetaminophen, aspirin, and NSAID s have all been shown to be effective for acute management. Preventive medications are not particularly helpful, but amitriptyline is the drug of choice. Cluster headache (Table 5) is distinguished by its distinctive temporal pattern of grouped headache attacks recurring over several weeks or months. The episodes are characterized by minutes-to-hours of intense unilateral periorbital pain associated with nasal or ocular autonomic features. Due to its low population prevalence, cluster headache is also an infrequent consultation in primary care. Given the brevity and severity of attacks, acute management requires approaches that are rapidly effective. Inhaled oxygen at liters/minute for minutes and subcutaneous sumatriptan are the approaches of choice. Corticosteroids may help shorten a cycle of cluster, while verapamil is the preventive drug of choice for more lengthy cycles. There is no scientific evidence to support the existence of an independent entity known as sinus headache. Although acute sinusitis may be associated with headache, the symptom of headache is generally one of the minor features in the presentation. In the 188

5 absence of acute sinusitis, there is no clear evidence that sinus inflammation irritation results in headache. Interestingly the phenomenon of sinus headache appears to be a uniquely American phenomenon. A recent large study of sinus headache in the United States population revealed that approximately 90% of individuals with the self-diagnosis or clinician-diagnosis of sinus headache actually meet criteria for migraine. 189

6 Table 1 Headache Classification (ICHD-II) Migraine headache Tension-type headache Cluster Headache and other trigeminal autonomic cephalgias Miscellaneous primary headaches Headache attributed to head and/or neck trauma Headache attributed to cranial or cervical vascular disorder Headache attributed to non-vascular intracranial disorder Headache attributed to a substance or its withdrawal Headache attributed to infection Headache attributed to disorder of homeostasis Headache or facial pain attributed to disorders of extracranial structures Headache attributed to psychiatric disorder Cranial neuralgias and central causes of facial pain Table 2 Red Flags for Secondary Headache Disorders (Nasty Nine) 1. First/worst headache 2. Abrupt onset headache 3. Progression or fundamental change in pattern of headache 4. New headache in those less than 5 years old, greater than 50 years old 5. New headache with cancer, immunosuppression, or pregnancy 6. Headache with syncope or seizure 7. Headache triggered by exertion/valsalva/sex 8. Neurologic symptoms greater than one hour in duration 9. Abnormal general or neurological examination Table 3 Migraine Headache Migraine without Aura A. At least five attacks fulfilling B-D B. Attacks lasting 4-72 hours (untreated or Unsuccessfully treated) C. At least two of the following characteristics: 1. Unilateral location 2. Pulsating quality 3. Moderate or severe intensity (inhibits or Prohibits daily activities) 4. Aggravation by routing activity D. At least one of the following: 1. Nausea and/or vomiting 2. Photophobia and phonophobia Migraine with Aura A. At least two attacks fulfilling B B. At least three of the following characteristics: 1. One or more fully reversible aura symptom indicating focal cerebral cortical and/or brain stem dysfunction 2. At least one aura symptom develops gradually over more than four minutes or two or more symptoms occur in succession 3. No aura symptom lasts more than 60 minutes. If more than one aura symptom is present, accepted duration is proportionally increased 4. Attack follow aura with a free interval of less than 60 minutes (may also begin before or simultaneously with the aura) 190

7 Table 4 Tension-Type Headache Tension-Type Headache A. Headache duration 30 minutes-7 days, either for < 15 days per month ( episodic ) or for > 15 days per month for over 6 months ( chronic ) B. At least two of the following pain characteristics: 1. Pressing/tightening quality 2. Mild or moderate severity (may inhibit, but does not prohibit activities) 3. Bilateral location 4. No aggravation by walking stairs or similar routine physical activity C. Both of the following: 1. No vomiting 2. No more than one of the following: nausea, photophobia, phonophobia Table 5 Cluster Headache Cluster Headache A. At least five attacks fulfilling B-D B. Severe unilateral orbital, supraorbital, and/or temporal pain lasting 15 to 180 minutes Untreated C. Attack is associated with at least one of the following signs on the side of pain: Conjunctival injection Lacrimation Nasal congestion Rhinorrhea Forehead and facial sweating Miosis Ptosis Eyelid edema Pacing or restlessness D. Frequency: from one every other day to eight per day 191