Headache

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[edit] Headache

William Pryse-Phillips

T. Jock Murray

Nothing in clinical neurology exceeds the demands on the clinician more than diagnosing and managing the patient with headache, a process that demands a combination of clinical skill and good interpersonal relationships. The physician dealing with the patient who presents with headache will by the history determine the likely diagnosis; by the brief, structured examination receive some reassurance that there is no lurking lesion causing the problem; and by his or her ability to see past the patient's naive words of complaint, recognize a pattern of symptomatology, allowing a confident diagnosis that will allow equally confident management. As always, the physician must determine during the interview what the patient wants—is it pain relief, reassurance that no serious disease underlies the symptoms experienced, or simply an explanation?

The classifications of headaches that will be discussed in this chapter and other types of headaches are listed in Box 160-1.

[edit] MECHANISMS OF CRANIAL PAIN

The extracranial and intracranial pain-sensitive structures all project pain sensation to the cranial surface, usually fairly near to the source of pain. Because many such sources register their pain in the same general area, a pain in any location may represent disordered function in any of several structures, intracranial or extracranial. Some common sites at which cranial pain is felt and the anatomic structures that may be the source of referral to these areas are shown in Fig. 160-1. The sensory pathways responsible for pain from various areas of the cranium are shown in Fig. 160-2.

Figure 160-1 Some areas of the head to which pain is referred (A) by stimulation of certain cranial structures (B). (From Wolff HG: In Dalessio DJ, Silbers SD, editors: Headche and other head pain, ed 6, New York, 1993, Oxford University Press.)

Figure 160-2 Sensory pathways for cranial pain. (From Pryse-Phillips W, Murray TJ: Essential neurology: a concise textbook, ed 4, New York, 1992, Medical Examination Publishing.)

Common mechanisms of cranial pain are illustrated in Fig. 160-3 and include the following:

• Nerve irritation, as with the neuralgias
  
• Pressure or traction on pain-sensitive structures (Fig. 160-3,B)
  
• Vasodilation of pain-sensitive vessels (anoxia, hypercapnea, fever, histamine injection, nitroglycerin ingestion, and sudden rise in blood pressure)
  
• Prolonged contraction of cranial muscles
  
• Inflammation of pain-sensitive structures
  
• Nonorganic pain (a diagnosis of last resort)
  

Figure 160-3 A and B, Mechanisms of cranial pain.

Common causes of acute severe headaches are listed in Box 160-2.

[edit] Danger Signals

The following features of a headache should raise concern about a potentially sinister underlying cause for the headache and suggest the need for further investigation:

• The first or worst headache of the patient's life, particularly if of rapid onset (subarachnoid hemorrhage?)
  
• A change in frequency, severity, or features of the headache attack from that commonly experienced in the past (any new pathology?)
  
• The new onset of headache in middle age or later, or a significant change in any long-standing headache pattern (new pathology?)
  
• The appearance of a progressive or new daily, persistent headache (medication-induced headache?)
  
• The precipitation of head pain with coughing, sneezing, or bending down (mass lesion, Chiari malformation?)
  
• The presence of systemic symptoms such as myalgias, fever, malaise, weight loss, scalp tenderness, or jaw claudication (cranial arteritis?)
  
• The presence of focal neurologic symptoms or any abnormalities on neurologic examination, or of confusion, seizures, or any impairment in the level of consciousness (mass lesion?)
  

[edit] Physical Examination

The physical examination performed at the first consultation for a headache problem should at least evaluate blood pressure, heart rate, cardiac status, sinuses, scalp arteries, cervical paraspinal muscles, the temporomandibular (TMJ) joints, and the range of motion of and presence of pain in the cervical spine. A screening neurologic examination capable of detecting most of the abnormal signs likely to occur in patients with headaches caused by intracranial or systemic disease should include evaluation of the following:

• Neck flexion (for evidence of meningeal irritation)
  
• The presence of bruits over the cranium, orbits, or neck
  
• The optic fundi, visual fields, pupillary reactions, fifth cranial nerve sensory function, and corneal reflexes
  
• Motor power in the face and limbs, muscle stretch reflexes, plantar responses, and gait
  

The presence of any such abnormalities is unusual in uncomplicated migraine and suggests the need for further investigation.

[edit] Investigations

The history is the most important step in the management of a headache patient. Profiles both of an individual attack and of the behavior of this form of headache over years should be drawn, and if the patient has more than one type of headache, separate profiles for each must be formulated. Pointers to serious organic causes are indicated above.

The electroencephalogram (EEG) is not useful in the routine evaluation of patients with headache unless the patient has associated symptoms suggesting a seizure disorder, such as atypical migrainous aura or episodic loss of consciousness. An EEG is inadequate to exclude a structural cause for headache. Many patients with migraines have dysrhythmic EEGs, and when this is reported the physician may become unnecessarily concerned and initiate further tests and consultation.

Lumbar puncture (LP) may have value if the headache is the first or worst in the patient's life; in the presence of severe, rapid onset, recurrent headache, or progressive headache without signs of raised intracranial pressure; with atypical, chronic, and intractable headache; or when headache is associated with fever. We suggest that LP should be performed only if meningitis, encephalitis, subarachnoid hemorrhage, or high-pressure or low-pressure headache syndromes are considered possible. If subarachnoid hemorrhage is the concern, a CT scan will rule out or confirm the diagnosis.

Computed tomography (CT) or magnetic resonance imaging (MRI) scans are only warranted in adult patients whose headaches fit a broad definition of recurrent migraine if there is also any recent substantial change in headache pattern, a history of seizures, or the presence of focal neurologic symptoms or signs.

[edit] MIGRAINE

Migraine is a common clinical disorder that is underdiagnosed and inadequately managed. It affects about 1 in 20 men and 1 in 5 women, most of whom suffer some headache-related disability.

[edit] Migraine Without Aura

The International Headache Society (IHS) criteria of 1988 provide a reliable diagnostic tool for migraines without an aura (Box 160-3), but they do not mention therapy, unlike the Canadian Headache Society guidelines, which do.

No one should expect that a single patient will have a “full-house” of the symptoms listed in Box 160-3, but the more there are, the more likely is the diagnosis of migraine to be correct. The following features also suggest migraine:

• The headaches occur more or less regularly in perimenstrual or periovulatory periods
  
• Food, odors, change in the weather, stress, or let-down after stress consistently precipitate headaches
  
• Headaches are relieved by sleep
  
• Irritability or other mood variations, hyperactivity, inability to concentrate, food cravings, or hyperosmia precede the headaches
  

The painful headache phase during attacks of migraine lasts for 2 to 6 hours and is typically accompanied by phonophotophobia, hyperacusis, hyperosmia, nausea, and vomiting. The pain is usually steady, with an added throbbing character, and it is worse on bending over or walking about. Attacks may recur consistently on one side of the head but often swap sides in different attacks. Persistence on one side may raise the suspicion of organic causes and should stimulate investigation to rule out vascular malformation or other structural disease.

[edit] Migraine With Aura

The diagnostic criteria for migraine with aura are the same as those listed above but include symptoms of neurologic dysfunction (including visual disturbance) occurring before or during the headache. If such symptoms persist after the pain has gone, referral for a neurologic consultation is wise. This form of migraine (Fig. 160-4, A) was described in the writings attributed to Galen and Hippocrates. Its hallmark is the neurologic prodrome to the headache phase (though sometimes this occurs alone). The aura usually has a sharp beginning and ending, lasts for 10 to 60 minutes (most often about 20 minutes), and is followed by the beginning of the headache. A visual aura in the form of a scintillating scotoma (Fig. 160-4, B) is the most common type. It starts as a small, twinkling, corrugated circle of tiny white, golden, or colored lights that form a pattern similar to medieval fortifications (Fig. 160-4, C). The lights appear in one homonymous field, spread peripherally, and are followed by visual loss in the area where the scintillating lights had been (Fig. 160-4, D). Gradually the apparition disappears, vision returns, and the headache begins. Patients are irritable during the prodromes, but during the headache phase they withdraw to some degree, seeking a place free of light, noise, problems, and children.

Figure 160-4 A, Classic migraine. Profile of attack, profile of life history of headache, and “portrait.” On this and similar diagrams the physician may register (above the line) the attack profile—duration, speed of onset and offset, severity, effect of therapy on the attack—and (below the line) the accompaniments of the attack—prodromes, nausea and vomiting, polyuria, etc. In the life profile the frequency and severity of attacks are recorded in relation to milestones in the patient's life (including family history). The portrait shows the location of the symptoms on a diagram of the patient's head and (bottom right) a list of key points in diagnosis. It is suggested that each physician create a similar diagram for patients. B, Scintillating scotomas tend to enlarge and occupy a central portion of the field of vision. This progression was drawn by P.W. Latham for his description of the “Nervous or Sick Headache” in 1873. C, Scintillating scotomas form a pattern like medieval fortifications. See CD-rom for color reproduction. D, Patient artistically depicts visual distortions and scintillating scotoma during aura of migraine headache that may relate temporally with spreading cerebral hypoperfusion. See CD-rom for color reproduction. (C courtesy the Migraine Action Association and Boehringer Ingelheim.)

The next most common and equally characteristic prodrome is the development of prickling in the fingers of one hand that creeps or “marches” up the arm to the face, especially around the mouth, followed by hypoesthesia and/or complete anesthesia ofthe same area that has been “prickled,” until the whole process clears and the headache begins. Fig. 160-5 shows spreading cerebral hypoperfusion correlated with the evolution of a scintillating scotoma and migraine headache demonstrated during a cerebral blood flow study. Less frequent are spots of flashing lights, “seeing through heat waves” (Fig. 160-6), aphasia, confusion, fuguelike states, distortion of the size of objects seen (micropsia), and even sensations of another person being present at one side or the other of the patient.

Figure 160-5 Spreading cerebral hypoperfusion demonstrated by cerebral blood-flow measurement using intracarotid Xenon-133 technique. Patient spontaneously developed migraine during procedure. See CD-rom for color reproduction. (From Woods RP, et al: N Engl J Med 331(25):1689, 1992.)

Figure 160-6 Visual distortion of light and objects experienced by some patients with the aura of migraine. See CD-rom for color reproduction. (Courtesy the Migraine Action Association and Boehringer Ingelheim.)

Prodromes are usually homonymous and seldom bilateral. The headache that follows them can be on either side. Rarely, they recur during the headache or continue after the headache has ceased. In such cases, thorough neurologic investigation should be performed to rule out organic disease.

Many patients have migraines both with and without aura. Attacks without aura are probably about 20 times more frequent than migraine with aura and are more disabling. Migraine attacks commonly diminish in frequency and severity after about age 40 in both males and females, but as patients enter the 60s and 70s, the syndrome may reappear in the form of prodromes without subsequent headache (late-life migraine) and resemble transient ischemic attacks (TIAs). Recurrence of similar phenomena, the march, and occurrence of scintillating scotomas usually serve to identify it as a migrainous “equivalent” rather than as an ischemic process. Occasionally, however, migrainous scotomas in older patients cause a permanent deficit.

A variant characterized by unilateral, constant, steady, or throbbing pain in the lower half of the face, the carotid sheath, and suboccipital areas was once known as lower-half'headache. Its first appearance may be in the form of intermittent attacks resembling migraine, but attacks increase in frequency and duration until they become continuous with dull or moderate pain, by which time anxiety, depression, and dependence on analgesics are common. This type is unusually difficult to relieve with current medications.

[edit] Familial Hemiplegic Migraine

Familial hemiplegic migraine is a severe, if uncommon, form of migraine characterized by the appearance of motor paralysis of central origin during headache attacks accompanied by striking sensory, mood, orientation, and speech phenomena. It is commonly inherited as a dominant characteristic.

The attacks usually begin with the headache, which is followed by dramatic neurologic symptoms, an order of events that is the reverse of the usual in attacks of migraine with aura. Sensory phenomena, motor paralysis, dysarthria, aphasias, ataxia, tinnitus, vertigo, transient global amnesia, confusion, and fever may occur and usually outlast the headache, sometimes for days or even weeks; focal EEG abnormalities may persist even longer. Many patients who have marked sensory disturbances during classic migraine report that they are “paralyzed” during the attacks, but careful questioning shows that actual paralysis is not present. In hemiplegic migraine, however, it is.

[edit] Basilar Migraine

In basilar migraine there are symptoms of occipital lobe, cerebellar, and brainstem dysfunction, these areas being supplied by the basilar artery and its branches. Features include vertigo, ataxia, total blindness, total sensory or motor paralysis (“locked-in syndrome”), and unconsciousness. The disorder is more common in young women in whom attacks occur several weeks or months apart. Menstruation, tense life situations, prolonged mental strain, and use of oral contraceptives seem to bear some relation to the frequency and severity of the attacks, which usually decrease over the years, but in a few patients they reappear in middle or old age, and severe episodes occasionally leave a permanent deficit caused by cerebral infarction.

Treatment of basilar migraine attacks is difficult. Use of triptans is ineffective and also contraindicated. Breathing 90% O₂ with 10% CO₂ for 5-to 10-minute intervals is an old remedy but is not easily accessed. Oral prednisone, 50 mg, repeated twice at 4-hour intervals (or given parenterally), and the use of a calcium channel blocker are of unproven benefit. Prophylaxis of attacks is the same as for other forms of migraine.

[edit] Ophthalmoplegic Migraine

In ophthalmoplegic migraines, headache attacks are associated with a third nerve palsy that outlasts the headache and may become permanent. Some form of arterial imaging angiography is necessary to exclude an aneurysm on the circle of Willis or of the posterior communicating artery. Whether the pain is caused by arterial pressure on the third nerve or a lesion at the level of the III nerve nucleus is unknown. CT scans rarely demonstrate local bleeding or a vascular anomaly and may miss a small aneurysm that may be detected only by contrast or magnetic resonance angiography (MRA). Once organic causes have been ruled out, attacks may be treated symptomatically and prophylactically, similar to migraine without aura. Steroids have been recommended for paralysis outlasting the headache (prednisone tapered from 40 mg daily over several days).

Retinal migraine is characterized by the occurrence of any pattern of visual loss in one eye, with all the usual features of auras and followed by the headache.

[edit] Symptomatic Treatment

Symptomatic treatment is appropriate when the headaches are more than a mild pain and disrupt the patient's ability to function normally. Attacks of differing severity require different levels of therapy.

[edit] Acute Therapy

[edit] Mild Attacks.

The buffered or soluble forms of acetylsalicylic acid (ASA) and ibuprofen or naproxen are effective in mild attacks but may cause gastrointestinal side effects. Acetaminophen is widely used, but often in subanalgesic doses (i.e., less than 1 gm for an adult). Neither dimenhydrinate nor domperidone has been shown to confer advantage as an adjunctive medication, but metoclopramide alone may relieve both the headache and the nausea and will enhance the effect of any analgesic by improving its absorption.

[edit] Moderate Attacks.

Nonsteroidal antiinflammatory drugs may relieve some moderate attacks, but the specific drugs are much better. Sumatriptan, a selective 5HT1 agonist, relieves up to 70% of migraine headaches within an hour. If the 50-mg oral dose is ineffective, a 100-mg dose should be used subsequently. Subcutaneous injection (6 mg) gives relief rates of up to 77% at 1 hour, and an intranasal preparation is also available. The drug is effective when taken at any time during the attack, but in the case of migraine with aura, it should not be taken during the aura phase. The same dosage may be repeated once subcutaneously or twice orally within 24 hours if the headache was relieved initially but recurred. Sumatriptan should not be taken within 24 hours of dihydroergotamine (DHE) or ergotamine.

Zolmitriptan, 5 mg; rizatriptan, 2.5 mg; and eletriptan, 80 mg, are other powerful agents for the relief of pain and other symptoms of the acute migraine attack. Their speeds of onset, relief rates, success in maintaining the patient's headache- free status over 24 hours, and side-effect profiles are more similar than different, and the preparation eventually favored by any one patient is likely to be a personal decision based on his or her sampling of the different drugs available. Naratriptan, 2.5 mg, is somewhat different, having a slower time to maximum effect but a substantially longer period of action and an unusually favorable side-effect profile. Though potentially successful for some patients with severe headaches, our experience is that naratriptan is of particular value for those patients with mild-to-moderate migraines who are happy to trade early for consistent and prolonged relief.

The unwanted effects of all the triptans include chest heaviness, tightness, or pain; pain in the throat; tingling in the head or limbs; and nausea, all of which are usually self-limiting. Patients with cardiac disease or uncontrolled hypertension must not take triptans, and those with hepatic problems should limit the dose. Sumatriptan acts faster and causes less nausea than DHE, but headaches recur more often within 24 hours.

DHE is a nonselective 5HT1 agonist that is effective in providing headache relief with subcutaneous, intramuscular, intravenous, or intranasal use. Its side effects are similar to those of sumatriptan, except that it causes more nausea but is less likely to induce chest and throat discomfort. The duration of action of DHE is longer than that of sumatriptan, so recurrence rates are lower.

Ergotamine has been used for many years in various forms. Its unwanted effects are similar to those of DHE, but nausea is usually more severe. Ergotamine may produce more side effects than benefit, but some patients consider it to be useful, particularly if taken with an antiemetic. Because of slow gastric absorption during migraine, the suppository form of ergotamine is more effective and rapid acting when a headache begins.

Combination medications such as acetaminophen with codeine, ASA with codeine and caffeine, or ASA with butalbital and caffeine (with or without codeine) can be used in patients with mild or moderate migraines who do not respond to the initial choices, or when vasoconstrictors are contraindicated. However, frequent use of such combinations is a prominent cause of medication-induced (rebound) headache, and they should be taken only intermittently and for short periods.

[edit] Severe Attacks.

For severe attacks, the choice of medications is DHE or a triptan, although a weaker alternative is the use of metoclopramide, 10 mg intravenously. If this is ineffective within 20 minutes, it may be followed with DHE, 0.5 to 1.0 mg intravenously, repeated to a maximum of 2 mg over 3 hours, or by sumatriptan, rizatriptan, eletriptan, or zolmitriptan. Another option is chlorpromazine (0.1 mg/kg intravenously over 20 minutes and repeated after 15 minutes to a maximum dose of 37.5 mg). The patient must be pretreated with normal saline, 5 ml/kg body weight, to prevent hypotension. Prochlorperazine (25 mg rectally, or 5 to 10 mg intravenously or intramuscularly) is another option. If no relief is obtained with the above treatments, ketorolac, 30 to 60 mg intramuscularly, or dexamethasone, 12 to 20 mg intravenously, may be effective. The place of butorphanol, a mixed opioid agonist-antagonist, in acute migraine management is still to be determined. We regard butorphanol, meperidine, and all narcotics as treatments of last resort.

[edit] Ultrasevere Attacks (Status Migrainosus).

Prolonged severe headaches should be treated on an in-patient basis so the diagnosis can be confirmed, investigations performed as required, and therapies administered according to the patient's response. Patients vomiting repeatedly during severe migraine attacks need rehydration with normal saline, to which 1 gm magnesium sulfate may be added once daily, because there is evidence of its positive effect in treatment of acute headache, especially for menstrual migraine attacks.

DHE in a 0.5-to 1.0-mg subcutaneous injection (each dose preceded by metoclopramide, 10 mg, to prevent nausea) is the medication of choice, but it may have to be repeated intravenously every 8 hours for 24 hours or more. Zolmitriptan, 5 mg orally, and sumatriptan, 100 mg orally or 6 mg subcutaneously, are often effective (if available in the hospital setting). One repeat dose after 4 hours is allowed, but the agents should not be mixed. In cases still resistant, potentially useful medications, given alone or in combination, include the following:

• Promethazine, 50 mg, and chlorpromazine, 50 mg, intramuscularly, or prochlorperazine, 5 mg intramuscularly
  
• Prochlorperazine, 10 mg, and diphenhydramine, 10 mg, intravenously every 4 to 6 hours as needed until relief is obtained
  
• Chlorpromazine, 10.0 to 12.5 mg (0.1 mg/kg), intravenously after an intravenous bolus of 500 ml normal saline
  
• Dexamethasone, 8 to 20 mg intramuscularly or intravenously, or methylprednisolone, 100 to 250 mg intravenously
  
• Dexamethasone, 8 mg; meperidine, 75 to 100 mg; and promethazine, 50 mg given intramuscularly
  

[edit] Management of Menstrual Migraine

Menstrual migraine headaches are associated with reduction in sex hormone levels. In pregnancy, migraines tend to increase in the first trimester and to decrease thereafter. In true menstrual migraine, the headaches occur exclusively just before or during the menses as a result of estrogen withdrawal, mediated in part by prostaglandins (PG). Treatment options include the following:

• NSAIDs (inhibit prostaglandin synthesis or block PG receptors)
  
• Subcutaneous DHE
  
• Increase usual prescription premenstrually
  
• Magnesium pyrrolidine carboxylic acid, 360 mg/day on days 15 to 30 of the menstrual cycle
  
• Pyridoxine orally
  
• For extremely severe headaches, oral steroids, DHE, or chlorpromazine may be required. Some hormonal therapies have been used in prophylaxis, including danazol, tamoxifen, estrogen, parlodel (in the luteal phase), the combination of estradiol and an androgen, and, as a last resort, artificial menopause.
  

[edit] Prophylactic Treatment

The diagnosis of migraine should be clearly and confidently given after the appropriate history-taking, clinical examination, and (when necessary) investigations have been completed. The patient should be reassured that he or she does not have a serious underlying cause for the headaches, such as a brain tumor. Patients should be provided with a basic interpretation of migraine as a physiologic disorder—a genetically based, neurochemical instability of the nervous system triggered by various intrinsic and/or extrinsic factors. A brief description of what is known of the central and peripheral vascular and humoral mechanisms may aid motivation and an understanding of the treatment plan. Wherever possible, printed materials should be used to reinforce the practitioner's orally presented educational advice. Ideally, patients will be interviewed on at least a second occasion so that their learning can be reviewed. Practitioners should establish realistic goals and expectations of treatment, explaining the possible treatment options available (including their benefits and limitations) and describing the concept of control as opposed to cure. The patient should be encouraged to be an active partner in the treatment plan and share a responsibility for managing the disorder with the physician. Patients may be referred to the local Migraine Association in their country for information, and support and possible referral to local self-help groups.

Before drug prophylaxis is considered, all patients should have been instructed to keep a diary noting potential precipitants of their migraines. They should also follow the monoamine oxidase inhibitor (MAOI) diet, with the added proscription of foods containing aspartame, monosodium glutamate (MSG), or nitrites. Medications known to induce headache should be discontinued. Ideally, the patient should keep a calendar to record headache characteristics, treatment, and response to therapy and should be educated about the general nature of migraine, the action of the medications prescribed, and their interactions, side effects, and contraindications. Any medication prescribed should be continued for an adequate period, usually several months, and withdrawn slowly to prevent exacerbations of headache. If patients do not respond to the initial treatment, or treatment eventually fails, different medications may be tried in sequence, starting with a low dose and building to a maximally effective tolerable dose. Dosages may need adjustment over time. Prophylactic medications are often ineffective while patients are concurrently ingesting analgesics but may work well when the analgesics are withdrawn. The cost of the medications should be considered in the choice of prophylactic agents. Patients must be educated about the diagnosis and nature of migraine, the existence of helpful nonpharmacologic therapies (such as the avoidance of triggers), and the nature of the medications prescribed, as well as their potential side effects, interactions with other medications, and any circumstances that make the ingestion of the drug inadvisable (e.g., pregnancy). The patient should be encouraged to keep a diary of the doses and response to all medications used, and their side effects, and should inform the physician if she becomes pregnant or is contemplating pregnancy.

[edit] Trigger Factors.

The stimuli that trigger migraine attacks may be external, physiologic, or psychologic (Box 160-4). It is essential for the physician to recognize these stimuli and to teach the patient to do so as well. The same triggers have been recorded as relevant in patients with tension-type headaches. The role of dietary factors is uncertain in the absence of published randomized controlled trials, but clinical experience indicates that ingestion of foods containing nitrites, aspartame, or MSG, and the cumulative effects of eating foods with a high content of neurotransmitter precursors such as tyramine, tyrosine, or phenylalanine are associated with the precipitation of migraine headaches and that their avoidance leads to a reduction in headache frequency or severity, although this observation has not been subjected to randomized clinical trial. The vulnerability of the patient to these stimuli varies from time to time in relation to the cyclic behavior of migraine itself and the life-stress situation of the patient. Thus at one time a single stimulus from any one of the three major areas mentioned may set off the explosion of an attack, whereas at other times several stimuli from more than one category may need to appear together to precipitate an attack.

[edit] Drug Prophylaxis.

Drug prophylaxis is indicated when the headaches are severe enough to impair the patient's quality of life, or if the patient has three or more severe migraine attacks per month that fail to adequately respond to symptomatic treatment.

[edit] β-Blockers.

Propranolol, nadolol, metoprolol, and atenolol have each been proven efficacious, but β-blockers are contraindicated in patients with asthma, chronic obstructive pulmonary disease, insulin-dependent diabetes, heart block or failure, or peripheral vascular disease, and are relatively contraindicated in pregnancy. Nadolol and atenolol, excreted by the kidneys, may have fewer CNS side effects than propranolol. One β-blocker may not work whereas another does, so trials of different agents in this class are appropriate. Medication should be tapered because sudden withdrawal may cause rebound headaches and adrenergic side effects. In prescribing these medications, the physician should always begin therapy with a low dose and titrate upward as required.

[edit] Calcium Channel Blockers.

Calcium channel blockers may have a long latency-to-action period (up to several months) and produce many side effects. Flunarizine and verapamil are most commonly used but are contraindicated in patients with hypotension, congestive heart failure, arrhythmias, depression, and pregnancy and must be used cautiously in those with Parkinson's disease and in patients receiving βblockers. Flunarizine is not recommended for patients with depressive illness or extrapyramidal symptoms.

[edit] 5-HT2 (Serotonin) Blockers.

Pizotyline, a serotonin receptor antagonist with mild antihistaminic and anticholinergic properties, is somewhat effective in the treatment of migraine but its side effects include weight gain and sedation. Methysergide (an ergot derivative) may be used for the prophylaxis of severe, recurrent migraine unresponsive to other medications. Contraindications include hypertension; cardiac, lung, liver, kidney, and collagen diseases; thrombophlebitis; peptic ulcers; and pregnancy. Side effects are numerous and include nausea, muscle cramps and aching, claudication, weight gain, and hallucinations. Methysergide should not be used for more than 6 months without a 1-to 2-month drug holiday to reduce the risk of retroperitoneal fibrosis. The dosage should be decreased gradually before discontinuation.

[edit] Tricyclic Analgesics.

Tricyclic analgesics are the so-called antidepressants. Amitriptyline is a useful prophylactic in the treatment of migraine, quite independent of its antidepressant activity and especially in patients who also have tension-type headaches. Oral doses of 10 mg each night should be used initially, with the dose being increased by 10 mg every week up to a maximum of 50 mg, although higher doses are sometimes required. Nortriptyline and desipramine (in similar dosages) produce less sedation and anticholinergic effects. Contraindications to all of these agents include significant cardiac, kidney, liver, prostate, or thyroid disease; glaucoma; hypotension; seizure disorders; and MAOI usage. The use of tricyclics in elderly patients is difficult because of anticholinergic side effects.

[edit] Selective Serotonin Reuptake Inhibitors.

The selective serotonin reuptake inhibitors (SSRIs) have no demonstrably useful role in migraine prophylaxis.

[edit] Sodium Valproate/Valproic Acid/Divalproex Sodium.

Valproic acid and its congeners have been found to be effective for migraine prophylaxis but should be used cautiously in patients taking ASA or warfarin because they affect hemostasis. ASA may displace valproic acid from its protein-binding sites and may lead to valproate toxicity. Side effects include nausea, alopecia, tremor, and weight gain, and their use has been associated with hepatotoxicity, particularly in children. It may also cause neural tube defects and should not be given to women who are pregnant or considering pregnancy. Women with a potential for reproduction should have this risk minimized by the use of appropriate contraception.

[edit] Nonsteroidal Antiinflammatory Drugs.

Both naproxen and naproxen sodium are useful in the prevention of perimenstrual attacks, but it is recommended that nonsteroidal antiinflammatory drugs (NSAIDs) be used only for intermittent prophylaxis because of their gastrointestinal side effects.

Prophylactic medications that are ineffective while patients are concurrently ingesting analgesics regularly can become effective when the analgesics are withdrawn. Some prophylactic medications (especially the calcium channel blockers) may take 1 to 2 months to work. Except in the most resistant cases, only one preventive agent should be used at a time. In the case of lack of response to a combination of prophylactic agents from different groups (such as propranolol plus amitriptyline), neurologic consultation should be obtained. Headache medications other than those prescribed, including medication obtained without prescription, should not be used because the excessive use of other medications may reduce the effectiveness of prophylactic therapy. The cost of medications should be considered in the choice of all therapies.

[edit] Biobehavioral Prophylaxis

[edit] Biofeedback.

Biofeedback refers to the use of monitoring instruments to detect, amplify, and display internal physiologic processes online so the patient may learn to accomplish the alteration of these processes at will. The preferred technique is thermal control, in which the patient learns to elevate finger temperature during therapy sessions using a digital temperature reading device. A meta-analysis of 25 controlled studies of biofeedback indicated that its efficacy is comparable to that of prophylactic medications, and sustained improvement has been demonstrated. Although relaxation therapy and biofeedback probably confer equal therapeutic benefit, there appears to be no advantage to combining them. If biofeedback is locally available, it may be considered as an alternative or adjunct to pharmacologic therapy for patients intolerant of medications.

[edit] Relaxation Therapy.

A biobehavioral approach to migraine using relaxation techniques (including progressive muscular relaxation, breathing exercises, or directed imagery) may reduce attack frequency. Meta-analytic reviews have suggested that relaxation is as effective as biofeedback. Where a treatment effect has been reported, it may be enhanced by the addition of prophylactic agents such as β-blocking drugs. The usual goal of relaxation therapy is the development of long-term prophylaxis rather than the reduction of the pain during an acute event. Relaxation may be taught one-on-one or in a group setting by an appropriately trained physician, psychologist, or other therapist. As with biofeedback, patient acceptance, availability, and the time commitment involved may limit its use. Self-instruction, using audiotapes, may be used. The physician should determine if relaxation therapy is available locally and should select only motivated patients for such training, instructing them that relaxation therapy is intended to provide long-term prevention of headaches rather than short-term pain relief, although other measures may be combined.

[edit] Cognitive-Behavioral Therapy.

Cognitive-behavioral therapy (CBT) is designed to help patients identify and modify those maladaptive responses that may trigger or aggravate a migraine event. The role of emotional reactivity as a trigger for migraine is considered to be pertinent in many patients. CBT is based on the principle that anxiety and distress are aggravators of an evolving migraine; it attempts to introduce a more adaptive approach and to help develop a specific action plan. Stress-management training is often part of this approach. As with other behavioral therapies, factors such as availability, cost, patient acceptance, and the time commitment required may restrict their use. These techniques are usually combined with biofeedback, although uncontrolled studies have shown their efficacy in reducing intensity, duration, and frequency of headaches when used alone.

[edit] Other Approaches.

Psychiatric referral of patients with migraine is indicated solely for the presence of a comorbid psychiatric disorder, although referral to a psychologist to improve stress management may be appropriate in selected cases. Hypnosis may reduce distressing sensory input and may have a placebo effect, as it does in other pain disorders. It was more effective than prochlorperazine in one randomized controlled trial, and a meta-analysis of largely uncontrolled studies also suggested benefit when combined with CBT. Physical measures such as physiotherapy, chiropractic, or other manipulations have rarely been subjected to trial, and evidence for the superiority of any one form of cervical manipulation is lacking. In two randomized studies, one with follow-up, chiropractic manipulations reduced migraine frequency and severity. Aerobic training may reduce the number but not the severity of migraines. Transcutaneous electrical nerve stimulation (TENS) and acupuncture have also been shown to provide some relief. Oral magnesium has been shown to be an effective prophylactic in a single trial. In an open pilot study followed by a small, randomized placebo-controlled trial, riboflavin (400 mg daily) was found to be effective for migraine prophylaxis and could be a promising option. Two small randomized controlled trials have demonstrated the efficacy of the herb feverfew in migraine prophylaxis. Because feverfew appears to have a relatively benign side-effects profile (occasional mouth ulceration, contact dermatitis) it may be considered as an option for migraine prophylaxis, although there are no studies documenting its long-term safety or efficacy. Other treatments, including herbal therapy, naturopathy, and homeopathy, have not been subjected to sufficient critical study to allow appropriate evaluation.

[edit] TENSION-TYPE HEADACHE

Tension-type headache is the most common headache type of all in western populations. The diagnostic criteria are shown in Box 160-5. Muscle contraction is not always the basis of this headache. Pressure on sensory nerves, interference with blood supply of muscles and other tissues, and alterations in the threshold to pain from changes in the central nociceptive system may also be relevant. The headache is described as a tight band around the head, a pressure or fullness, a feeling that the head is in a vise, or a feeling that the head will explode. The whole head and often the neck and upper shoulders are typically involved, as may be the temples, the face, and the region of the upper trapezius (Fig. 160-7).

Figure 160-7 Profile of muscle contraction headache.

Tension-type headaches are benign and hard to treat. The physician should look for evidence of neck injuries and of TMJ dysfunction (especially if the pain is unilateral) and search for clues in the history as to why a person may show the effects of physical, psychologic, or social stress in this way. There are no physical signs other than tenderness in the craniocervical muscles.

Physical and emotional pressures, including states of depression or anxiety, are often considered responsible for tension-type headaches, but if the headache is unilateral, TMJ dysfunction should be considered. Therapy (if no local cause is discovered) might include amitriptyline or nortriptyline, muscle relaxants, psychotherapy (seldom), or other approaches as described under treatments for migraine and in Box 160-6. Such headaches are sometimes treated successfully by physical measures, such as local heat and massage, ultrasonic stimulation, or acupuncture. Relaxation techniques provided by courses of instruction and aided by tapes and biofeedback are often useful.

[edit] Combined Headache

Combined or mixed headache is thought to be related to both vascular and muscle contraction mechanisms. It presents as a constant tightness and pressure, with an added pulsatile component, and at times with nausea and vomiting. The treatment is the same as for migraines. It is common for someone who has had migraine headaches for many years to evolve to a headache that has features of both tension and migraine.

[edit] CLUSTER HEADACHE

The pain associated with cluster headache is said to be the worst known to mankind and it requires prompt diagnosis and management. Diagnostic criteria are shown in Box 160-7. The pain uniquely makes the patient move about in his or her distress. The basic mechanism of cluster headache is unknown.

Each episode of pain is manifest by sudden, very severe pain with a relatively short duration of an hour or two, one or more times per day or night, but usually with the first REM sleep period (Fig. 160-8). Marked autonomic features (ipsilateral sweating, flushing, tearing, enophthalmos, miosis, nasal blocking, and rhinorrhea) accompany the pain. Attacks frequently occur with clocklike regularity during or immediately after REM sleep. During the attacks the patients are up and about, pacing, stamping, locking themselves into rooms, violently resisting help, at times screaming, begging for relief, occasionally going into a trancelike state for short periods. Sometimes patients threaten suicide during an attack, but they rarely if ever perform it. Many patients explain that the pain is worse than that experienced with a fracture, surgery, or childbirth, or that associated with passing a kidney stone. Although the attacks of pain usually remain limited to a given side of the head and face during a given cluster, in some patients the attacks may switch to the other side before the cluster is over and, in a few rare instances, may involve both sides at once during one or several individual attacks.

Figure 160-8 Profile of a cluster headache.

During the clusters, which may last weeks or months, the patient is extremely vulnerable to vasodilating stimuli (e.g., alcohol, nitrites, histamine) and great changes in pace (e.g., weather, time, and activity), such as occur during naps or REM sleep, travel, seasonal changes, and work. Once the cluster has passed, these stimuli are no longer active until the next cluster supervenes.

Cluster headache patients, mostly men, are said to have an athletic build, including increased height, a leonine facies characterized by thick “orange peel” skin; deep furrows in forehead, cheeks, and chin, and telangiectasia, especially on the cheeks and bridge of the nose (Fig. 160-9 and Box 160-8). Clusters may begin during childhood or more often in young adulthood, or they may not occur until middle and late middle age. They may persist over a lifetime into the 70s and 80s, but more often they tend to decrease during the 60s. Intervals between clusters may range from a few weeks to a few months or a few years. The headaches recur occasionally after 10, 15, or even 35 years of freedom.

Figure 160-9 Leonine facies of a cluster headache patient. Note the thick vertical and horizontal furrows, extra crease in the cheek, thick “orange peel” skin, and telangiectasis on the nostril.

[edit] Chronic Cluster Headache

A few unfortunate individuals may remain in a constant or chronic cluster state almost daily for more than a year or even for several years. Usually, chronic clusters result from the gradual compression of periodic clusters closer together until a continuous or chronic state results. Rarely, clusters are chronic or classified as primary chronic cluster from the beginning.

[edit] Differential Diagnosis

Cluster headache is most often confused with tic douloureux or trigeminal neuralgia. However, unless secondary to multiple sclerosis or tumor, tic first appears in patients over 60 years of age, whereas cluster headache begins even during childhood and most frequently during the second, third, and fourth decades of life. Tic pain is described in Chapter 162 . Rarely, cluster pain is accompanied by short shocks or jolts of pain similar to that of tic superimposed on the constant steady pain, creating the so-called cluster-tic syndrome.

Keratitis, corneal abrasions, and glaucoma cause pain and redness of the eye, but the eye examination should confirm the diagnosis. Raeder and Tolosa-Hunt syndromes sometimes present with recurring steady pain in the eye and face lasting days, weeks, or occasionally months (see Chapter 165 ). Malignant growths of the nose and throat may also mimic the pain of cluster headache, even presenting at first with intermittent bouts of pain associated with Horner's syndrome, pain in the cheek and eye, and nasal blockage. Radiographs and CT scans of the nasofacial bones and sinuses may reveal organic lesions in the nasopharynx and sinus areas, with destructive lesions in the hard palate and floor of the skull (Fig. 160-10).

Figure 160-10 Horner's syndrome, causing drooping eyelid and small pupil in the right eye of a 60-year-old woman with a history of cluster headaches increasing in intensity over 3 months. Sinus radiographs revealed destruction of the floor of the maxillary sinus by a nasopharyngeal carcinoma.

[edit] Treatment

Treatment for the pain of the individual acute attack of cluster headache must be immediately available and quick in its action. Patients should always have their treatment with them or within easy reach because the pain develops rapidly. Although it does not last long, the pain is devastating, giving rise to the term suicide headaches. Strenuous exercise for 5 to 10 minutes at onset and ice-cold or very hot applications to the affected area are of questionable value. Acute abortive therapy today comprises breathing 100% oxygen by nasal mask at 7 to 10 L/minute for 10 to 15 minutes at onset of attacks; the intranasal instillation of 4% lidocaine into the nostril on the affected side, with the head dependent; or subcutaneous sumatriptan, 6 mg, or DHE, 1 mg.

The best prophylactic agent is prednisone (or equivalents), 40 to 60 mg/day, reduced by 5 mg/day every 2 or 3 days. The total period of therapy should be no longer than 6 to 8 weeks—preferably 4 weeks—because of possible chronic steroid side effects. Lithium and verapamil are appropriate long-term therapies. One of these drugs should be started at the same time as the steroids are given. The usual dose is 900 mg of lithium carbonate/day in three doses, to achieve a blood lithium level of 0.5 to 1.0 mEq/L. Thyroid function, blood counts, and renal function are monitored as they are in other patients taking lithium. As the patient improves, the dose may be gradually reduced. In chronic cluster headache, it may be wise to continue one dose of lithium per day for many months or even permanently. When headache cycles break through, the dosage may be raised appropriately. Ergot or steroids may be added to the lithium regimen if recurrence takes place.

The calcium channel blocker verapamil (240 mg/day) must be taken for at least a month to obtain full effect. Other drugs that can be used include cyproheptadine (Periactin), 4 mg orally one to four times daily; tricyclics such as amitriptyline (Elavil) and doxepin (Sinequan); and methysergide, 2-mg tablets one to four times daily. This last drug is an effective preventative agent but its side-effect profile includes potentially lethal complications (it must be stopped at 3-month intervals for at least 2 weeks), which lead us to consider it a drug of last resort.

Finally, surgery may be necessary if cluster headache has failed to respond to medical treatment and is seriously affecting the patient's life. Sphenopalatine ganglion block or excision, greater superficial petrosal neurectomy, and nervus intermedius neurectomy by radiofrequency, surgical transection, and/or glycerol injection are other techniques to be considered.

[edit] Chronic Paroxysmal Hemicrania

Chronic paroxysmal hemicrania is a rare variant of cluster headache characterized by its occurrence most often in women (in 90% of cases), the short duration of the attacks (minutes), and their frequent occurrence (perhaps 15 attacks or more per day). The pain resembles that of cluster headache in its unilaterality; its involvement of the eye, cheek, and temples; and the associated autonomic dysfunction. A remarkable feature of this condition is its specific rapid response to indomethacin, 150 to 200 mg daily. Within a few hours of the first dose, attacks usually cease completely. Some patients with this syndrome have multiple daily attacks for several years without relief from any of the ordinary cluster headache remedies.

[edit] POSTTRAUMATIC HEADACHE

The simplest form of posttraumatic headache results from injury to a specific cervical or cranial nerve, leading to causalgic pain. The territory of the pain is denoted by marked skin tenderness on gentle pinching. Such pains may be briefly relieved by local anesthetic infiltration; more permanent relief is obtained from drugs such as dilantin, carbamazepine, or neurontin, or by surgical neurectomy.

Other posttraumatic symptoms are more complicated; a blow to the head involves also a blow to the person and to the state of his or her life, with psychologic consequences. The characteristics of posttraumatic headache are too varied to make their description here of any value, except insofar as the pain is usually felt in the approximate area of the trauma and is almost completely unresponsive to any drug therapies presently available. Other forms of therapy, often psychologic or at least nonpharmacologic, should be considered. The following words of the late Dr. J.R. Graham, the author of this chapter in its first two editions, address these headaches in more detail: Accidents that happen at home or because of one's own carelessness or foolishness are much less likely to produce significant prolonged headache syndromes than those related to circumstances in which someone else is at fault or in some way responsible. The time required for recovery and return to work is much shorter with home accidents than with industrial or motor vehicle accidents. This shorter interval results from not only litigious aspects of the incident, but also from what has been called the “antitherapy factors” that surround industrial accidents and those caused by someone else's neglect. When an industrial accident was caused by work in certain circumstances or with certain machinery, the patient should return to the same situation or should have a lead-in time and perhaps experience in another department or situation to allow regaining of confidence. Settlement of the “case,” although highly desired, may not end the problem because much has happened to this injured individual. The person has been knocked off his or her perch in life, not just “hit on the head.” Such factors are difficult for some physicians, juries, and judges to understand, partly because some individuals with personal gain as an objective take advantage of these situations and provide fuel that leads to distrust of others who have really had a major blow to themselves as well as their head.

[edit] VASCULAR HEADACHES

[edit] Cranial Arteritis

Cranial arteritis, a form of giant cell arteritis, involves the branches of arteries arising from the thoracic aorta, such as the temporal and ophthalmic arteries, and the ophthalmic and intracranial vessels. The condition only affects people over the age of 60 years. If untreated, it leads to blindness in half of the cases. The leading symptom—a mild to moderate, constant, unilateral temporal pain—moves between head regions and is associated with local tenderness and redness over the scalp. The temporal arteries are typically tender, cordlike, and often pulseless. Accompanying the headache may be painful “angina” of the jaw muscles or tongue when chewing or swallowing or dental pain that may lead to misguided extractions. Confusion, impaired concentration, aphasia, and other focal signs reflect intracranial artery involvement. Repeated episodes of blurry or blotted-out areas of vision may precede complete loss of vision in one or both eyes. The patient often feels unwell, with low-grade fever, anorexia, malaise, and symptoms such as morning muscle stiffness and weight loss. An elevated erythrocyte sedimentation rate (ESR) and positive antinuclear antibody (ANA) titers are almost always present. The differential diagnosis includes depression, hypertension, cervical degenerative joint disease, and recurrent migraine.

Temporal artery biopsy is not essential but can be obtained from the most tender and inflamed area of an artery to confirm the diagnosis, even after treatment has been started. Delay in therapy may allow serious vascular events (e.g., retinal artery occlusion) to occur. The value of having a biopsy may be appreciated after several months, when the potential complications of steroid therapy threaten and questions arise as to the veracity of the diagnosis. Doppler flow studies may also help identify areas in the superficial cranial circulation where occlusion is taking place and the process is active.

Immediate treatment with steroids is essential; prednisolone (100 mg/day initially, reduced gradually to a maintenance dose of 5 mg/day) with medication to prevent gastric ulceration (such as ranitidine, 150 mg bid) is appropriate. Gradual tapering of this dose is indicated over weeks and months (and occasionally years) in relation to symptoms and the decreasing ESR. If steroid therapy is contraindicated (active infection, active gastrointestinal ulceration or perforation, serious CNS reaction to steroids), other NSAIDs may be tolerated and prove useful. In some patients the arteritis may continue to be active over 3 to 4 years, with symptoms recurring whenever the steroid dose falls below a certain level. In patients with long-term arteritis, alternate-day steroid therapy to reduce side effects may be practical.

[edit] Hypertension

In hypertensive encephalopathy and crises related to pheochromocytoma and preeclampsia, a sudden rise in blood pressure leads to headache. Hypertension associated with Cushing's syndrome or with aldosterone-producing tumors may also cause headache of a vascular type resembling migraine in a few patients.

[edit] Dialysis Headache

Almost all patients on dialysis experience headache if the dialysate contains too little sodium. Dialysis headache is related to reduction in osmolality caused by large sodium decreases and worsens as blood pressure drops (Fig. 160-11). Headache also is one of the first symptoms of transplant rejection.

Figure 160-11 Dialysis headache. Headache (HA) appears as blood pressure falls during renal hemodialysis. (From Graham JR, Bara DS, Yap AU: Res Clin Stud Headache 6:147, 1978.)

[edit] Headache from Dissection of the Carotid Artery

Acute carotid dissection may cause sudden, severe, unilateral neck pain and headache radiating to the ear, temple, and eye. An ipsilateral Horner's syndrome is the only physical sign unless there is evidence of a TIA or stroke from embolism. During the acute phase the carotid sheath is tender, the pulse is poorly felt, and a carotid bruit may be heard. The patient should be referred for MRA or angiography. There is no evidence to support the use of anticoagulants, but they are commonly prescribed.

[edit] Migraine and Mitral Valve Prolapse (Barlow's Syndrome)

Patients with migraine have an increased incidence of mitral valve prolapse (MVP), which may be responsible for the increased frequency of paroxysmal cardiac arrhythmias reported in patients with migraines. Small cerebral emboli in patients with MVP may simulate classic migraine attacks. Some patients have positive anticardiolipin antibody tests and need specialized assessment. Propranolol is used to treat MVP and so may serve a double purpose. Antiplatelet agents are also used in prophylaxis.

[edit] Headache after Ischemic Cerebral Infarction

After a stroke, many patients complain of a headache that has a vague resemblance to migraine without aura, as first described by Thomas Willis in the seventeenth century. A possible reason is the increase in blood flow in the scalp vessels when a major artery such as a carotid has been occluded. Analgesics are appropriate as therapy in the short term. In many cases the headache fades spontaneously over months. Use of vasoconstrictors is obviously inappropriate.

[edit] Headache Caused by Intracranial Bleeding

The profile of an attack of headache resulting from intracranial hemorrhage from aneurysms or arteriovenous malformations (AVM) is shown in Fig. 160-12. Such lesions rarely cause headache except when they bleed, although in exceptional cases headache may result from pressure of an aneurysm on pain-sensitive structures. The usual presentation is acute: the patient experiences sudden posterior head pain that feels like a hammer blow without apparent cause, although it may occasionally be related to physical stress such as sexual intercourse or weight lifting. In other cases the headache is only minor and may recur repeatedly before a major, perhaps fatal event. If the bleeding is into the subarachnoid space, stiff neck, fever, backache, and severe, sudden headache result. If it extends intracerebrally, local neurologic deficits result. In severe cases, such as subarachnoid hemorrhage caused by rupture of an aneurysm, spread of blood into the ventricles is often fatal. Smaller leaks from an AVM tend to recur and are far less dangerous. Differentiation of either of these from benign exertional headaches is clinically impossible and, at least on the first occurrence, full investigation is essential.

Figure 160-12 Profile of subarachnoid hemorrhage from a vascular anomaly.

Any acute, severe headache, even without stiff neck or other physical signs, should be regarded as evidence of subarachnoid hemorrhage until proved otherwise by CT scan and perhaps LP. Immediate consultation with a neurologist or neurosurgeon is indicated in all such cases. A small subarachnoid leak (producing a “sentinel headache”) will lead to such a severe headache without physical signs. Initially, this should be managed exactly as would a full-blown subarachnoid hemorrhage.

A condition similar to headache caused by intracranial bleeding is exertional headache (including “coital cephalgia” and “weight-lifters headache”), which is manifest by the occurrence of a severe, acute, usually posterior head pain at times of maximal muscular activity—as suggested by the alternate names for the condition. The first time this happens should be the occasion for full investigation (CT scan of the head, and perhaps LP) to exclude a small subarachnoid bleed. If these rule out subarachnoid hemorrhage, and the activity is to be repeated, indomethacin, 25 mg tid, is an effective prophylactic.

The nature of cough headache is unexplained. Its characteristics are those of exertional headache and it occurs at times of violent coughing or during the performance of Valsalva's maneuver. In such cases, the presence of an intracranial mass lesion is possible and must be excluded by appropriate examination and scanning. The Chiari malformation is another, more benign cause.

[edit] TRACTION HEADACHE

Traction headache is a relatively uncommon type of headache that results from traction on the pain-sensitive structures inside the head—the V, VII, IX, and X cranial nerves; the basal meninges; the intracranial venous sinuses; and the intracranial arteries up to their second branch off the circle of Willis. Inflammatory and mass lesions are the most common causes (Fig. 160-13). The pain arising from distortion of intracranial pain-sensitive structures is not as characteristic as one would like and is often described just as a steady, dull, bursting or pressure sensation felt deep within the head that is not as severe as migraine. Unfortunately, patients with other headaches use the same words occasionally, so this description is not diagnostic. The pain has no rhythm to it, but tends to be continuous and is seldom throbbing. It is often relieved by aspirin or cold packs applied to the skull, giving a false sense of security. It is poorly localized and may be referred to the eyes or neck. Special times of occurrence include the early morning, with some relief being obtained from the upright posture as the day goes on. Any further increase in intracranial pressure, as with stooping, coughing, or bending, makes the headache worse. A history of head and/or neck injury during recent months, especially in elderly patients, should raise suspicion of subdural hemorrhage.

Figure 160-13 Profile of a brain tumor.

The site of the headache may have some diagnostic value because most subjects with brain tumors complain of pain over or near to the region of the underlying mass. Those with posterior fossa lesions often have occipital headaches; unfortunately, associated neck muscle tension and neck stiffness or tenderness may suggest muscle contraction headache unless the other characteristics are noted. Another danger is that this headache is often not very bad in the early stages, and the patient's description may not be precise, leading to a false sense of security. Some growing tumors merely accentuate the patient's “usual” headache (e.g., of muscle contraction or migraine). Thus the diagnosis is indeed difficult and this situation points up the need for a careful neurologic examination in all patients with head pain.

The symptoms associated with traction headache depend on the rate of expansion of the mass and its site more than its actual size. Vertigo, nausea, vomiting, drowsiness, pain on ocular movement, and irritability are commonly found in association. If high pressure causes herniation of intracranial contents, then hypertension, drowsiness, bradycardia, and such localizing signs as VI or III nerve palsies may appear, as may any other focal disturbances of brain function. The causes are those of increased intracranial pressure. Idiopathic intracranial hypertension (see below), obstructive hydrocephalus, intracranial infections, cerebral edema, tumor, and hemorrhage are examples. Treatment is determined by the cause, or by temporary reduction of increased pressure using mannitol or steroids.

[edit] Idiopathic Intracranial Hypertension

When a patient (most often a young woman who is obese) presents with complaints of the onset of a new headache and has papilledema without other physical signs, the diagnosis is straightforward. Without such evidence of increased pressure, however, these patients may be labeled as suffering from a functional headache. The headache features are not specific and may resemble those of migraine, traction headache, or both. They are usually worse in the mornings and with any activity that raises intracranial pressure. Patients taking large amounts of vitamin A or hormonal therapy are also at risk. Neurologic referral is suggested in all such cases.

[edit] Low Pressure Headache

Low cerebrospinal fluid (CSF) pressure also may cause headache, especially when the patient sits or stands up. This is usually caused by a leak of CSF after LP. In the presence of a CSF leak, headache manifests when the patient stands up and goes away when he or she lies flat. A repeat study shows that the CSF pressure is very low, perhaps unmeasurable. Eventually the hole in the dural sac will heal and CSF will no longer leak. This type of headache may be avoided by using a small needle for LP with the bevel horizontal (thus splitting rather than cutting the longitudinal fibers of the dura mater) and by requiring the patient to lie flat for 2 hours after the procedure. Occasionally, true “drainage” headaches persist over days, in which case treatment requires the injection of a few milliliters of the patient's own blood into the lumbar spinal canal, “patching” the leaky dural hole. Fluid ingestion and tight abdominal binders are quite useless.

CSF leaks resulting in chronic postural headache occur also as a result of congenital defects, neoplastic invasion of the meninges, or vigorous athletic activity. In these conditions a dural tear opening a passage between the cranial and nasal cavities may have occurred. Constant dripping of clear fluid from the nose is a useful symptom; some of the fluid must be collected for evaluation of glucose content. If glucose is present, the fluid is probably CSF. When such a leak is strongly suspected, a radioimmunosorbent assay (RISA) scan is performed, with pledgets placed in the nose and sinus areas to detect radioactivity from the leaked CSF.

Patients with congenital defects in the cribriform plate and other areas of the skull where CSF can escape into the nasopharynx may have repeated bouts of meningitis. These episodes are often mild but are potentially dangerous.

[edit] HEADACHE ASSOCIATED WITH SUBSTANCE USE OR WITHDRAWAL

[edit] Medication-induced Headache (“Transformed Migraine”)

A medication-induced headache occurs in people whose chronic tension-type headaches or migraines have worsened, in response to which they have ingested increasing amounts of medication (more than three times/week) for 3 months or more. All patients with chronic headaches are prone to this form of chemical dependency, one of the commonest headache types seen in referral practice. The drugs prescribed (or bought over the counter) for management of such headaches and able to induce this syndrome include muscle relaxants, benzodiazepines, ergot preparations, simple analgesics (often with codeine), NSAIDs, and caffeine. The intermittent use of these agents is appropriate but their frequent use leads to down-regulation of nociceptor pathways in the brain, creating the vicious cycle of medication-induced headache. Narcotics should not be prescribed again for these patients.

Typically the headaches are present daily or nearly every day, are present on waking, and are reduced but not removed by ingestion of the usual medication taken. Nausea, malaise, anergia, depression, and sleep disturbances are almost invariable accompaniments, with the production of a syndrome of daily or near-daily “rebound” headaches that are worse on waking in the morning, briefly reduced by the next dose of the usual medication(s), and inhibiting the useful effects of oral prophylactic agents. Many patients utilize several sources of supply for their medications.

The best treatment strategy is to discontinue all of the analgesics the patient has taken, supplying instead DHE, 0.5 to 1.0 mg every 8 hours whether the subject has a headache or not, for three days (nine doses), with metoclopramide, 10 mg, preceding each dose if required to control nausea. This treatment may require hospitalization, but in some cases the use of DHE nasal spray (Migranal) every 8 hours for three days is sufficient.

The second stage of the treatment plan is just as important. After the subject is off the daily analgesics, it is likely that prophylactic medications will be effective again and they should be restarted, even if they had failed before in competition with the analgesics. Behavioral modification with biofeedback, hypnosis, counseling, and, occasionally, formal psychologic or psychiatric therapy may be needed to help remodel lifestyles that are detrimental. When true migraine attacks do occur in the future, specific therapies (the triptans) or DHE should be prescribed rather than the analgesics that got the patient into trouble in the first place.

[edit] Headache Associated With Medication Ingestion

Drugs that may cause headaches when ingested are listed in Box 160-4. Nitrites can precipitate headaches that are often migrainelike in nature. Substitution of β-blockers or calcium channel blockers may eliminate the problem, though calcium channel blockers can also cause headaches if they are also vasodilators. Rebound headache may also follow prolonged use of caffeine, ergotamine, the triptans, and methysergide.

[edit] Withdrawal from Steroids

Withdrawal from prolonged steroid therapy may be accompanied by the first appearance of headaches, probably caused by idiopathic intracranial hypertension. Reinstatement of the previous dose, with subsequent slower reduction of the dose, is the best solution.

[edit] HEADACHE FROM METABOLIC DISORDERS

Medical conditions causing headaches include systemic infections, usually with fever; hypoxia; carbon monoxide poisoning; postconvulsive states; foreign protein reactions; hypoglycemia; hypercapnia; acute pressor reactions; and renal failure. In most of these instances, the headache is a temporary and easily diagnosed problem, but a few conditions warrant comment.

[edit] Headache from Overt Cranial Inflammation

Inflammation caused by infectious agents (bacterial, viral, parasitic) or chemical or autoimmune processes and involving pain-sensitive cranial structures may produce headache. The headache is likely to be a secondary symptom, and diagnosis should be achieved on the basis of the major manifestations of the condition.

[edit] Headache Caused by Chemical Inflammation of the Meninges

Spinal anesthetics, contrast media, antineoplastic drugs, and antibiotics can cause allergic or chemical inflammation in the CNS, with headache, stiff neck, low-grade fever, and sterile pleocytosis in the CSF. The headache is present in all positions, unlike the headache after LP. Analgesics and antihistamines or corticosteroids are helpful, as long as it is ensured that no bacterial infection is present.

[edit] Headache With Systemic Symptoms

Pulsatile headaches and flushing occur rarely in mastocytosis, carcinoid syndrome, and gastrointestinal conditions in which vasoactive peptides are involved. Mastocytosis looks at first like common freckles, but biopsy of new freckles may confirm the diagnosis. Carcinoid tumor may cause flushing, wheezing, diarrhea, and headache. Alcohol, epinephrine, and histamine may induce headaches in both carcinoid tumor and mastocytosis. Bronchogenic carcinoid tumor causes headache before metastasizing to the liver, but liver metastases usually are necessary for gastrointestinal carcinoid tumors to produce these symptoms.

Headaches associated with flushing or pallor, sweating, and acute hypertension require exclusion of pheochromocytoma by blood and urinary catechol tests and appropriate CT or MRI scanning. It is important to examine the patient during such episodes so that blood pressure measurements may be recorded and the physician can make sure that the urine in the patient's bladder at the time of the hypertensive episode is included in the collection to be tested for vanillylmandelic acid (VMA), catechols, and metanephrine.

[edit] Endocrine Conditions

Hypothyroidism, Cushing's syndrome, Addison's disease, and pituitary tumors (especially prolactinomas) may induce headaches of any type until the primary underlying condition is diagnosed and treated.

[edit] REFERRED HEAD PAINS

[edit] Refractive Errors

When headache is caused directly by refractive errors, it usually occurs while the patient is engaged in using the eyes for reading or other fine work, not hours later. Strain from prolonged use of the eyes if refraction or accommodation is imperfect may lead to tension-type headaches. However, this is very generally known, and few patients present for diagnosis of their headache