HEADACHE

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Headache: Introduction Headache is among the most common reasons that patients seek medical attention. Diagnosis and management is based on a careful clinical approach that is augmented by an understanding of the anatomy, physiology, and pharmacology of the nervous system pathways that mediate the various headache syndromes.

General Principles A classification system developed by the International Headache Society characterizes headache as primary or secondary Primary headaches are those in which headache and its associated features are the disorder in itself, whereas secondary headaches are those caused by exogenous disorders. Primary headache often results in considerable disability and a decrease in the patient's quality of life. Mild secondary headache, such as that seen in association with upper respiratory tract infections, is common but rarely worrisome. Life-threatening headache is relatively uncommon, but vigilance is required in order to recognize and appropriately treat patients with this category of head pain. Common Causes of Headache Primary Headache Secondary Headache Type % Type % Migraine 16 Systemic infection 63 Tension-type 69 Head injury 4 Cluster 0.1 Vascular disorders 1 Idiopathic stabbing 2 Subarachnoid hemorrhage <1 Exertional 1 Brain tumor 0.1 Source: After J Olesen et al: The Headaches. Philadelphia, Lippincott, Williams & Wilkins, 2005. Anatomy and Physiology of Headache Pain usually occurs when peripheral nociceptors are stimulated in response to tissue injury, visceral distension, or other factors. In such situations, pain perception is a normal physiologic response mediated by a healthy nervous system. Pain can also result when pain-producing pathways of the peripheral or central nervous system (CNS) are damaged or activated inappropriately. Headache may originate from either or both mechanisms. Relatively few cranial structures are pain-producing; these include the scalp, middle meningeal artery, dural sinuses, falx cerebri, and proximal segments of the large pial arteries. The ventricular ependyma, choroid plexus, pial veins, and much of the brain parenchyma are not pain-producing. The key structures involved in primary headache appear to be the large intracranial vessels and dura mater the peripheral terminals of the trigeminal nerve that innervate these structures the caudal portion of the trigeminal nucleus, which extends into the dorsal horns of the upper cervical spinal cord and receives input from the first and second cervical nerve roots (the trigeminocervical complex) the pain modulatory systems in the brain that receive input from trigeminal nociceptors The innervation of the large intracranial vessels and dura mater by the trigeminal nerve is known as the trigeminovascular system. Autonomic symptoms, such as lacrimation and nasal congestion, are prominent in the trigeminal autonomic cephalalgias, including cluster headache and paroxysmal hemicrania, and may also be seen in migraine. . Migraine and other primary headache types are not "vascular headaches";. Clinical Evaluation of Acute, New-Onset Headache The patient who presents with a new, severe headache has a differential diagnosis that is quite different from the patient with recurrent headaches over many years. In new-onset and severe headache, the probability of finding a potentially serious cause is considerably greater than in recurrent headache. Patients with recent onset of pain require prompt evaluation and often treatment. Serious causes to be considered include meningitis, subarachnoid hemorrhage, epidural or subdural hematoma, glaucoma, and purulent sinusitis. When worrisome symptoms and signs are present (Table 15-2), rapid diagnosis and management is critical. Headache Symptoms that Suggest a Serious Underlying Disorder "Worst" headache ever First severe headache Subacute worsening over days or weeks Abnormal neurologic examination Fever or unexplained systemic signs Vomiting that precedes headache Pain induced by bending, lifting, cough Pain that disturbs sleep or presents immediately upon awakening Known systemic illness Onset after age 55 Pain associated with local tenderness, e.g., region of temporal artery A complete neurologic examination is an essential first step in the evaluation. In most cases, patients with an abnormal examination or a history of recent-onset headache should be evaluated by a CT or MRI study. . The psychological state of the patient should also be evaluated since a relationship exists between head pain and depression. Many patients in chronic daily pain cycles become depressed, although depression itself is rarely a cause of headache. Drugs with antidepressant actions are also effective in the prophylactic treatment of both tension-type headache and migraine. Underlying recurrent headache disorders may be activated by pain that follows otologic or endodontic surgical procedures. Thus, pain about the head as the result of diseased tissue or trauma may reawaken an otherwise quiescent migrainous syndrome. Treatment of the headache is largely ineffective until the cause of the primary problem is addressed. Serious underlying conditions that are associated with headache are described below. Brain tumor is a rare cause of headache and even less commonly a cause of severe pain. The vast majority of patients presenting with severe headache have a benign cause.

Secondary Headache The management of secondary headache focuses on diagnosis and treatment of the underlying condition. Meningitis Acute, severe headache with stiff neck and fever suggests meningitis. LP is mandatory. Often there is striking accentuation of pain with eye movement. Meningitis can be easily mistaken for migraine in that the cardinal symptoms of pounding headache, photophobia, nausea, and vomiting are present. Intracranial Hemorrhage Acute, severe headache with stiff neck but without fever suggests subarachnoid hemorrhage. A ruptured aneurysm, arteriovenous malformation, or intraparenchymal hemorrhage may also present with headache alone. Rarely, if the hemorrhage is small or below the foramen magnum, the head CT scan can be normal. Therefore, LP may be required to definitively diagnose subarachnoid hemorrhage.. Brain Tumor Approximately 30% of patients with brain tumors consider headache to be their chief complaint. The head pain is usually nondescript—an intermittent deep, dull aching of moderate intensity, which may worsen with exertion or change in position and may be associated with nausea and vomiting. This pattern of symptoms results from migraine far more often than from brain tumor. The headache of brain tumor disturbs sleep in about 10% of patients. Vomiting that precedes the appearance of headache by weeks is highly characteristic of posterior fossa brain tumors. A history of amenorrhea or galactorrhea should lead one to question whether a prolactin-secreting pituitary adenoma (or the polycystic ovary syndrome) is the source of headache. Headache arising de novo in a patient with known malignancy suggests either cerebral metastases or carcinomatous meningitis, or both. Head pain appearing abruptly after bending, lifting, or coughing can be due to a posterior fossa mass (or a Chiari malformation). . Temporal Arteritis Temporal (giant cell) arteritis is an inflammatory disorder of arteries that frequently involves the extracranial carotid circulation. It is a common disorder of the elderly; its annual incidence is 77 per 100,000 individuals ages 50 and older. The average age of onset is 70 years, and women account for 65% of cases. About half of patients with untreated temporal arteritis develop blindness due to involvement of the ophthalmic artery and its branches; indeed, the ischemic optic neuropathy induced by giant cell arteritis is the major cause of rapidly developing bilateral blindness in patients >60 years. Because treatment with glucocorticoids is effective in preventing this complication, prompt recognition of the disorder is important. Typical presenting symptoms include headache, polymyalgia rheumatica , jaw claudication, fever, and weight loss. Headache is the dominant symptom and often appears in association with malaise and muscle aches. Head pain may be unilateral or bilateral and is located temporally in 50% of patients but may involve any and all aspects of the cranium. Pain usually appears gradually over a few hours before peak intensity is reached; occasionally, it is explosive in onset. The quality of pain is only seldom throbbing; it is almost invariably described as dull and boring, with superimposed episodic stabbing pains similar to the sharp pains that appear in migraine. Most patients can recognize that the origin of their head pain is superficial, external to the skull, rather than originating deep within the cranium (the pain site for migraineurs). Scalp tenderness is present, often to a marked degree; brushing the hair or resting the head on a pillow may be impossible because of pain. Headache is usually worse at night and often aggravated by exposure to cold. Additional findings may include reddened, tender nodules or red streaking of the skin overlying the temporal arteries, and tenderness of the temporal or, less commonly, the occipital arteries. The erythrocyte sedimentation rate (ESR) is often, though not always, elevated; a normal ESR does not exclude giant cell arteritis. A temporal artery biopsy followed by treatment with prednisone 80 mg daily for the first 4–6 weeks should be initiated when clinical suspicion is high. The prevalence of migraine among the elderly is substantial, considerably higher than that of giant cell arteritis. Migraineurs often report amelioration of their headaches with prednisone; thus, caution must be used when interpreting the therapeutic response. Glaucoma Glaucoma may present with a prostrating headache associated with nausea and vomiting. The headache often starts with severe eye pain. On physical examination, the eye is often red with a fixed, moderately dilated pupil. .

Primary Headache Syndromes Primary headaches are disorders in which headache and associated features occur in the absence of any exogenous cause. The most common are migraine, tension-type headache, and cluster headache. Migraine Headache Migraine, the second most common cause of headache, afflicts approximately 15% of women and 6% of men. It is usually an episodic headache that is associated with certain features such as sensitivity to light, sound, or movement; nausea and vomiting often accompany the headache. A useful description of migraine is a benign and recurring syndrome of headache associated with other symptoms of neurologic dysfunction in varying admixtures. Migraine can often be recognized by its activators, referred to as triggers. Symptoms Accompanying Severe Migraine Attacks in 500 Patients Symptom Patients Affected, % Nausea 87 Photophobia 82 Lightheadedness 72 Scalp tenderness 65 Vomiting 56 Visual disturbances 36 Photopsia 26 Fortification spectra 10 Paresthesias 33 Vertigo 33 Alteration of consciousness 18 Syncope 10 Seizure 4 Confusional state 4 Diarrhea 16 Source: From NH Raskin, Headache, 2d ed. New York, Churchill Livingston, 1988; with permission. The brain of the migraineur is particularly sensitive to environmental and sensory stimuli; migraine-prone patients do not habituate easily to sensory stimuli. This sensitivity is amplified in females during the menstrual cycle. Headache can be initiated or amplified by various triggers, including glare, bright lights, sounds, or other afferent stimulation; hunger; excess stress; physical exertion; stormy weather or barometric pressure changes; hormonal fluctuations during menses; lack of or excess sleep; and alcohol or other chemical stimulation. Knowledge of a patient's susceptibility to specific triggers can be useful in management strategies involving lifestyle adjustments. Pathogenesis The sensory sensitivity that is characteristic of migraine is probably due to dysfunction of monoaminergic sensory control systems located in the brainstem and thalamus (Fig. 15-1). Figure 15-1 Brainstem pathways that modulate sensory input. The key pathway for pain in migraine is the trigeminovascular input from the meningeal vessels, which passes through the trigeminal ganglion and synapses on second-order neurons in the trigeminocervical complex. These neurons in turn project in the quintothalamic tract and, after decussating in the brainstem, synapse on neurons in the thalamus. Important modulation of the trigeminovascular nociceptive input comes from the dorsal raphe nucleus, locus coeruleus, and nucleus raphe magnus. Diagnosis and Clinical Features Diagnostic criteria for migraine headache are listed in Table 15-4. A high index of suspicion is required to diagnose migraine: the migraine aura, consisting of visual disturbances with flashing lights or zigzag lines moving across the visual field or of other neurologic symptoms, is reported in only 20–25% of patients. A headache diary can often be helpful in making the diagnosis; this is also helpful in assessing disability and the frequency of treatment for acute attacks. Patients with episodes of migraine that occur daily or near-daily are considered to have chronic migraine (see "Chronic Daily Headache," below). Migraine must be differentiated from tension-type headache (discussed below), the most common primary headache syndrome seen in clinical practice. Migraine at its most basic level is headache with associated features, and tension-type headache is headache that is featureless. Most patients with disabling headache probably have migraine. Simplified Diagnostic Criteria for Migraine Repeated attacks of headache lasting 4–72 h in patients with a normal physical examination, no other reasonable cause for the headache, and: At least 2 of the following features: Plus at least 1 of the following features: Unilateral pain Nausea/vomiting Throbbing pain Photophobia and phonophobia Aggravation by movement Moderate or severe intensity Source: Adapted from the International Headache Society Classification (Headache Classification Committee of the International Headache Society, 2004). Table 15-7 Preventive Treatments in Migrainea Drug Dose Selected Side Effects Pizotifenb 0.5–2 mg qd Weight gain Drowsiness Beta blocker Propranolol 40–120 mg bid Reduced energy Tiredness Postural symptoms Contraindicated in asthma Tricyclics Amitriptyline 10–75 mg at night Drowsiness Dothiepin 25–75 mg at night Nortriptyline 25–75 mg at night Note: Some patients may only need a total dose of 10 mg, although generally 1–1.5 mg/kg body weight is required Anticonvulsants Topiramate 25–200 mg/d Paresthesias Cognitive symptoms Weight loss Glaucoma Caution with nephrolithiasis Valproate 400–600 mg bid Drowsiness Weight gain Tremor Hair loss Fetal abnormalities Hematologic or liver abnormalities Gabapentin 900–3600 mg qd Dizziness Sedation Serotonergic drugs Methysergide 1–4 mg qd Drowsiness Leg cramps Hair loss Retroperitoneal fibrosis (1-month drug holiday is required every 6 months) Flunarizineb 5–15 mg qd Drowsiness Weight gain Depression Parkinsonism No convincing evidence from controlled trials Verapamil Controlled trials demonstrate no effect Nimodipine Clonidine SSRIs: fluoxetine aCommonly used preventives are listed with reasonable doses and common side effects. Not all listed medicines are approved by the FDA; local regulations and guidelines should be consulted. bNot available in the United States. Drug Trade Name Dosage Simple Analgesics Acetaminophen, aspirin, caffeine Excedrin Migraine Two tablets or caplets q6h (max 8 per day) NSAIDs Ibuprofen Advil, Motrin, Nuprin, generic 400 mg PO q3–4h Tolfenamic acid Clotam Rapid 200 mg PO. May repeat x 1 after 1–2 h 5-HT1 Agonists Oral Ergotamine Ergomar One 2 mg sublingual tablet at onset and q1/2h (max 3 per day, 5 per week) Ergotamine 1 mg, caffeine 100 mg Ercaf, Wigraine One or two tablets at onset, then one tablet q1/2h (max 6 per day, 10 per week) Rizatriptan Maxalt Maxalt-MLT 5–10 mg tablet at onset; may repeat after 2 h (max 30 mg/d) Sumatriptan Imitrex 50–100 mg tablet at onset; may repeat after 2 h (max 200 mg/d) Nasal Dihydroergotamine Migranal Nasal Spray Prior to nasal spray, the pump must be primed 4 times; 1 spray (0.5 mg) is administered, followed in 15 min by a second spray Sumatriptan Imitrex Nasal Spray 5–20 mg intranasal spray as 4 sprays of 5 mg or a single 20 mg spray (may repeat once after 2 h, not to exceed a dose of 40 mg/d) Zolmitriptan Zomig 5 mg intranasal spray as one spray (may repeat once after 2 h, not to exceed a dose of 10 mg/d) Parenteral Dihydroergotamine DHE-45 1 mg IV, IM, or SC at onset and q1h (max 3 mg/d, 6 mg per week) Sumatriptan Imitrex Injection 6 mg SC at onset (may repeat once after 1 h for max of 2 doses in 24 h) Dopamine Antagonists Oral Metoclopramide Reglan,a generica 5–10 mg/d Prochlorperazine Compazine,a generica 1–25 mg/d Parenteral Chlorpromazine Generica 0.1 mg/kg IV at 2 mg/min; max 35 mg/d Metoclopramide Reglan,a generic 10 mg IV Prochlorperazine Compazine,a generica 10 mg IV Other Oral Acetaminophen, 325 mg, plus dichloralphenazone, 100 mg, plus isometheptene, 65 mg Midrin, Duradrin, generic Two capsules at onset followed by 1 capsule q1h (max 5 capsules) Nasal Butorphanol Stadola 1 mg (1 spray in 1 nostril), may repeat if necessary in 1–2 h aNot all drugs are specifTension-Type Headache Tension Type Headache Clinical Features The term tension-type headache (TTH) is commonly used to describe a chronic head-pain syndrome characterized by bilateral tight, bandlike discomfort. The pain typically builds slowly, fluctuates in severity, and may persist more or less continuously for many days. The headache may be episodic or chronic (present >15 days per month). A useful clinical approach is to diagnose TTH in patients whose headaches are completely without accompanying features such as nausea, vomiting, photophobia, phonophobia, osmophobia, throbbing, and aggravation with movement. Such an approach neatly separates migraine, which has one or more of these features and is the main differential diagnosis, from TTH. However, the International Headache Society's definition of TTH allows an admixture of nausea, photophobia, or phonophobia in various combinations, illustrating the difficulties in distinguishing these two clinical entities. Patients whose headaches fit the TTH phenotype and who have migraine at other times, along with a family history of migraine, migrainous illnesses of childhood, or typical migraine triggers to their migraine attacks, may be biologically different from those who have TTH headache with none of the features. Pathophysiology The pathophysiology of TTH is incompletely understood. It seems likely that TTH is due to a primary disorder of CNS pain modulation alone, unlike migraine, which involves a more generalized disturbance of sensory modulation. Data suggest a genetic contribution to TTH, but this may not be a valid finding: given the current diagnostic criteria, the studies undoubtedly included many migraine patients. The name tension-type headache implies that pain is a product of nervous tension, but there is no clear evidence for tension as an etiology. Muscle contraction has been considered to be a feature that distinguishes TTH from migraine, but there appear to be no differences in contraction between the two headache types. Tension-Type Headache: Treatment The pain of TTH can generally be managed with simple analgesics such as acetaminophen, aspirin, or NSAIDs. Behavioral approaches including relaxation can also be effective. Clinical studies have demonstrated that triptans in pure TTH are not helpful, although triptans are effective in TTH when the patient also has migraineically indicated by the FDA for migraine. Local regulations and guidelines should be consulted. For chronic TTH amitriptiline is the only proven treatment. Trigeminal Autonomic Cephalalgias, Including Cluster Headache The trigeminal autonomic cephalalgias (TACs) are a group of primary headaches that includes cluster headache, paroxysmal hemicrania, and SUNCT (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing). TACs are characterized by relatively short-lasting attacks of head pain associated with cranial autonomic symptoms, such as lacrimation, conjunctival injection, or nasal congestion (Table 15-8). Pain is usually severe and may occur more than once a day. Because of the associated nasal congestion or rhinorrhea, patients are often misdiagnosed with "sinus headache" and treated with decongestants, which are ineffective. Table 15-8 Clinical Features of the Trigeminal Autonomic Cephalalgias Cluster Headache Paroxysmal Hemicrania SUNCT Gender M>F F=M F~M Pain Type Stabbing, boring Throbbing, boring, stabbing Burning, stabbing, sharp Severity Excruciating Excruciating Severe to excruciating Site Orbit, temple Orbit, temple Periorbital Attack frequency 1/alternate day– 8/d 1–40/d (>5/d for more than half the time) 3–200/d Duration of attack 15–180 min 2–30 min 5–240 s Autonomic features Yes Yes Yes (prominent conjunctival injection and lacrimation)a Migrainous featuresb Yes Yes Yes Alcohol trigger Yes No No Cutaneous triggers No No Yes Indomethacin effect — Yesc — Abortive treatment Sumatriptan injection or nasal spray Oxygen No effective treatment Lidocaine (IV) Prophylactic treatment Verapamil Methysergide Lithium Indomethacin Lamotrigine Topiramate Gabapentin aIf conjunctival injection and tearing not present, consider SUNA. These are the common varieties of headache we come across in our daily life....