CHAPTER 6
Migraine Headache
Presentation
Migraine headache may occur with or, more commonly, without aura. The patient, more commonly female, complains of a pulsating, severe unilateral headache lasting 4 to 72 hours, usually with photophobia and nausea, with or without vomiting and aggravated by moderate physical activity (e.g., walking or climbing stairs). Less commonly, the headache may be bilateral and pressing, and it may follow ophthalmic or neurologic symptoms that resolved as the headache developed. Scintillating castellated scotomata in the visual field, corresponding to the side of the subsequent headache, form the classic aura pattern, but fully reversible visual loss, sensory symptoms (pins and needles and/or numbness), or dysphasia may occur. Basilar-type migraine may be associated with fully reversible dysarthria, vertigo, tinnitus, decreased hearing, double vision, or ataxia. Unlike other headaches, migraines are especially likely to wake the patient in the morning. There may be a family or personal history of similar headaches, and onset during the patient’s teens or 20s is common. Primary headaches, which include migraine, tension-type headache, and cluster headache, are benign; these headaches are usually recurrent and not caused by organic disease. Secondary headaches are caused by underlying organic diseases, ranging from sinusitis to subarachnoid hemorrhage.
What To Do:
Migraine headaches (and similar recurrent primary headache syndromes, with or without nausea and vomiting) are usually treated successfully with IV prochlorperazine (Compazine), 10 mg (0.15 mg/kg up to 10 mg for pediatric migraine headaches), or metoclopramide (Reglan), 10 mg, with or without a bolus of saline to counteract vasodilatation and orthostasis. To help prevent mental and motor restlessness (akathisia), administer diphenhydramine (Benadryl), 12 to 25 mg IV, along with the prochlorperazine or metoclopramide.
If the migraine is of recent onset, the patient has not already taken ergotamines, and starting an IV line may be difficult, treatment should be begun with sumatriptan (Imitrex), 6 mg SC, or dihydroergotamine (DHE 45), 0.25 to 1 mg IM, in a single dose. These drugs are more expensive than prochlorperazine and metoclopramide and can have adverse cardiovascular effects. If DHE is administered IV, pretreatment with an antiemetic, such as prochlorperazine, is necessary.
If the pain has been present most of the day and has precipitated a secondary muscle headache, evinced by muscle tenderness at bony insertions, add ketorolac (Toradol), 60 mg IM, or ibuprofen (Motrin), 800 mg PO for a nonsteroidal anti-inflammatory drug (NSAID) effect (see Chapter 9).
Administer intranasal 4% lidocaine (Xylocaine). Use a 1-mL syringe. Have the patient lie supine with the head hyperextended 45 degrees and rotated 30 degrees toward the side of the headache, and drip 0.5 mL (10 drops) of the lidocaine solution into the ipsilateral nostril over 30 seconds. The patient should remain in this position for 30 minutes. If the headache is bilateral, repeat on the other side. Another technique is to take 4% lidocaine jelly, apply it to a long cotton pledget, and slide it down the nasal canal using bayonet forceps, posterior to the middle turbinate on the side of the headache. The clinician should be aware that the evidence for the effectiveness of intranasal lidocaine in the acute treatment of migraine is inconsistent.
Another relatively benign and inexpensive alternative to narcotics that may be added to regimens including either prochlorperazine or metoclopramide is an IV infusion of magnesium sulfate, 1 to 2 g in a 10% solution over 5 to 10 minutes.
If the pain remains severe and drug dependency has been considered, add a narcotic analgesic (e.g., hydromorphone [Dilaudid], 1 to 2 mg, or morphine sulfate, 4 to 10 mg IV) and have the patient lie down in a dark, quiet room. It can be cruel to attempt to obtain a complete history and physical examination (and it is unrealistic to expect the patient to cooperate) before some pain relief has been achieved.
After 20 minutes, when the patient is feeling a little better, take the history and perform a physical examination that includes a funduscopic and a complete neurologic examination. If there are persistent changes in mental status, fever, or stiff neck, or, on neurologic examination, focal findings such as diplopia or unilateral hyperreflexia, paresthesias, weakness, or ataxia, proceed with CT examination, lumbar puncture (LP), or both, to rule out intracranial pathology or infection as the cause of the “migraine.”
Other danger signals that should trigger a more intensive diagnostic workup, looking for secondary disorders, include hyperacute onset of a new, severe headache (“the worst ever”); a progressive history of seizures; onset with exertion, cough, bending, or sexual intercourse; onset during pregnancy (cerebral venous thrombosis) or during or after middle age; and the presence of a systemic malignant disease, infection, compromised immune system, any new neurologic findings or papilledema on funduscopic examination.
In patients who are older than the age of 50, consider the possibility of temporal arteritis and obtain an erythrocyte sedimentation rate (ESR). If temporal arteritis is present, there should be jaw claudication and tenderness over the temporal artery. The ESR should be found elevated to more than 50 mm per hour.
If the presentation is indeed consistent with a migraine or other primary headache, allow the patient to sleep in the emergency department (ED) or clinic undisturbed except for a brief periodic neurologic examination. Typically, the patient will awaken after 1 to 3 hours, with the headache completely resolved or much improved and with no neurologic residua.
For future attacks, if acetaminophen or NSAIDs have been ineffective and there are no cardiovascular risks, prescribe a self-injector preloaded with 6 mg of sumatriptan. If the patient prefers to take medication orally, try tablets of ergotamine, 1 mg, and caffeine, 100 mg (Cafergot)—two at the first sign of the aura, then one every half hour up to a total daily dosage of six tablets with a maximum of 10 per week. If nausea and vomiting prevent the use of oral medication, Cafergot is also available in rectal suppositories at the same dosage, but one or two suppositories are usually sufficient to relieve a headache. Both oral and rectal absorption of ergotamine is erratic. Sumatriptan can also be administered as a nasal spray. Use the lowest effective dose, either one or two 5-mg sprays or one 20-mg spray. The dose may be repeated once after 2 hours, not to exceed a total daily dose of 40 mg. Rizatriptan (Maxalt, Maxalt MLT—absorbable wafer) can be given, 5 to 10 mg orally every 2 hours, to a maximal dosage of 30 mg per day. Frovatriptan (Frova) and almotriptan (Axert) and eletriptan (Relpax) are oral triptans approved by the US Food and Drug Administration (FDA). There have been few head-to-head trials of the triptans and none since the reformulation of the oral form of sumitriptan to a faster-acting form in 2004. According to one study, prior to the reformulation of sumitriptan, rizatriptan (10 mg), eletriptan (80 mg), and almotriptan (12.5 mg) provide the “highest likelihood of consistent success” for acute migraine. Individual patient responses may vary, and there is no clear indication to choose one over another.
Parenteral administration of dexamethasone (10 to 25 mg IV) has been shown to prevent early recurrence of migraine headaches within 24 to 72 hours, in a meta-analysis of several studies (number needed to treat = 9). Oral administration of prednisone does not provide any benefit. Dexamethasone does not provide any relief of the acute headache. For patients who are not frequently being treated with dexamethasone, but who commonly have early recurrence of headache, this appears to be a good option to add to the standard abortive therapy. Frequent treatment with dexamethasone may result in adrenal suppression.
Instruct the patient to return to the ED if there is any change in or worsening of the usual migraine pattern, and make arrangements for medical follow-up. First-time migraine attacks warrant a thorough elective neurologic evaluation to establish the diagnosis. Long-term prophylaxis may include nonprescription plain magnesium gluconate (200 to 400 mg tid), antidepressants, calcium channel antagonists, NSAIDs, beta-blockers, or anticonvulsants. Lifestyle changes, such as eliminating caffeine, smoking, and certain food triggers, may also be indicated.
What Not To Do:
Do not initiate a comprehensive laboratory workup and perform neuroimaging when the patient presents with a typical benign primary headache with no neurologic deficits.
Do not prescribe medications containing ergotamine, caffeine, or barbiturates for continual prophylaxis. They will not be effective used this way, and withdrawal from these drugs may produce headaches.
Do not omit follow-up, especially for first attacks.
Do not overlook possible meningitis, subarachnoid hemorrhage, glaucoma, or stroke, conditions that may deteriorate rapidly if undiagnosed. Patients with subarachnoid hemorrhage who have normal mental status on presentation are at highest risk for misdiagnosis. Do not talk yourself out of doing a CT/LP in any patient with sudden onset (hyperacute) of the worst headache of their life just because the patient looks good or has a normal examination.
Unilateral pain is even more characteristic of migraine than is the aura. (“Migraine” is a corruption of “hemicranium.”) The pathophysiology is probably unilateral cerebral vasospasm (producing the neurologic symptoms of the aura), followed by vasodilation (producing the headache). Neurologic symptoms may persist into the headache phase, but the longer they persist, the less likely it is that they are caused by the migraine. Cluster headaches and other trigeminal-autonomic cephalalgias are characterized by trigeminal activation coupled with parasympathetic activation. These headaches are intermittent, short lasting, sharp, excruciating, and unilateral, accompanied by lacrimation and rhinorrhea. Attacks occur in clusters lasting from 7 days to 1 year, and during the pain, patients are usually agitated and restless. The treatment of an attack is usually the same as that for migraines.
Acute migraine headaches are self-limited and respond well to placebos, and, therefore, several different therapies are effective. No single drug or class of drug has clearly emerged as the best treatment for acute migraine. The wide variability in patient needs and responses means that many agents will continue to play important roles. Although butalbital-containing compounds are often used to treat migraine, their use should be limited because of the risk of overuse and consequent medication overuse headache and withdrawal problems. Be cautious in the use of ergot or serotonin agonists to treat any patient who has angina, focal weakness, or sensory deficits. It is possible to precipitate ischemia of the brain or heart in such patients by using preparations that act by causing vasoconstriction. Sumatriptan should not be administered to postmenopausal women, men older than 40 years, and patients with vascular risk factors, such as hypertension, hypercholesterolemia, obesity, diabetes, smoking, or a strong family history of vascular disease. Sumatriptan also should not be used within 24 hours of administration of an ergotamine-containing medication.
Patients with aneurysms or arteriovenous malformations can present clinically as migraine patients. If there is something different about the severity or nature of this headache, consider the possibility of a subarachnoid hemorrhage. Headaches that are always on the same side and in the same location are very suspicious for an underlying structural lesion (e.g., aneurysm, arteriovenous malformation).
To help reassure patients, it can be noted that isolated headache was the first and only clinical symptom in just 8.2% of patients with an intracranial tumor.
Many patients seeking narcotics have learned that faking a migraine headache is even easier than faking a ureteral stone, but they usually do not follow the typical course of falling asleep after being given a shot and waking up a few hours later with pain relief. It is a good policy to limit narcotics for treatment of migraine headaches to one or two shots and avoid prescribing oral narcotics in the ED or doctor’s office.
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