Causes and Treatments of Migraine Headaches (cont.)

Migraine headaches affect 17% of females and 6% of males in the United States. Before puberty, boys and girls get migraines at about the same rate, although boys may get them slightly more often. In individuals older than 12 years, the frequency of migraines increases in both males and females. The frequency declines in individuals older than 40 years.

In the United States, white women have the highest frequency of migraine, while Asian women have the lowest. The female-to-male ratio increases from 2.5:1 at puberty to 3.5:1 at age 40 years, after which it declines. The rate of migraine headaches in females of reproductive age has increased over the last 20 years.

Migraine Headaches, Causes

The causes of migraine headaches are not clearly understood. In the 1940s, it was proposed that a migraine begins with a spasm, or partial closing, of the arteries leading to the main part of the brain (called the cerebrum). The first spasm decreases blood supply to part of the brain, which causes the aura (lights, haze, zig-zag lines, or other symptoms) that some people experience. These same arteries then become too relaxed, which increases blood flow and causes pain.

About 30 years later, the chemicals dopamine and serotonin were found to play a role in migraine headaches. (These chemicals are called neurotransmitters.) Dopamine and serotonin are normally found in the brain, but they can cause blood vessels to act in uncharacteristic ways if they are present in abnormal amounts or if the blood vessels are unusually sensitive to them.

Together, these 2 theories have come to be known as the neurovascular theory of migraine, and it is presently believed that both theories provide insight into the causes of headache.

Various triggers are thought to initiate migraine headaches in people who are prone to developing them. Different people may have different triggers.

• Smoking has been identified as a trigger for many people.
  
  
• Certain foods, especially chocolate, cheese, nuts, alcohol, and monosodium glutamate (MSG), may trigger migraine headaches. (MSG is a flavor enhancer used in many foods, including Chinese dishes.)
  
  
• Missing a meal or changing sleep patterns may bring on a headache.
  
  
• Stress and tension are also risk factors. People often have migraines during times of increased emotional or physical stress.
  
  
• Contraceptives (birth control pills) are a common trigger. Women may have migraines at the end of the pill cycle as the estrogen component of the pill is stopped. This is called an estrogen-withdrawal headache.

Migraine Headaches, Association with other diseases

Migraines may occur more frequently in persons with the following diseases:

• Epilepsy
  
  
• Familial dyslipoproteinemias (abnormal cholesterol levels)
  
  
• Hereditary hemorrhagic telangiectasia
  
  
• Tourette syndrome
  
  
• Hereditary essential tremor
  
  
• Hereditary cerebral amyloid angiopathy
  
  
• Ischemic stroke: Migraine with aura is a risk factor (odds ratio, 6:1).
  
  
• Depression and anxiety
  
  

Migraine Headaches, Clinical features

Headache is seldom the only feature of migraine, and it is sometimes entirely absent. Some patients report a prodromal phase (an early phase before the start of a full-blown condition, usually accompanied by certain symptoms) 24 hours before the headache. Symptoms during this early phase may include irritability, depression, or hyperexcitability. Migraine with aura (classic migraine) usually has several early visual symptoms, including photopsia (flashes of light) and fortification spectra (wavy linear patterns in the visual fields), or migrating scotoma (patches of blurred or absent vision). The headache is usually described as throbbing or pulsing. Migraines are typically unilateral (affecting one side), but the side affected in each episode may change. Unilaterality is not a requirement for migraine diagnosis, however.

Nausea, vomiting, photophobia (sensitivity to light), phonophobia (sensitivity to sound), irritability, and malaise (general discomfort or uneasiness, an “out-of-sorts” feeling) are common. The headache usually lasts for 6-24 hours. Migraineurs generally prefer to lie quietly in a dark room.

Sometimes, a history of certain triggers can be identified. Common associations in migraine include head injury, physical exertion, fatigue, drugs (nitroglycerine [Nitrostat], histamine, reserpine [Serpasil], hydralazine [Apresoline], ranitidine [Zantac], estrogen), and stress.

If the headache is always on one side, the doctor must look for a structural lesion by using imaging studies like magnetic resonance imaging (MRI). Having a history of migraine attacks and determining what brings them on are important, because a secondary headache can mimic a migraine headache and thus mask a new medical problem.

Migraine Headaches, Variants

• Migraine without aura (common migraine) is a throbbing headache without the early visual symptoms.
  
  
• Ophthalmic migraine is a type of migraine associated with eye problems. This variant is sometimes called retinal migraine or ocular migraine.
  
  
• Abdominal migraine is the term used to describe periodic abdominal pain in children that is not accompanied by headache.
  
  
• Complicated migraine is a type of migraine in which migraine attacks are accompanied by permanent problems like paralysis.
  
  
• Vertebrobasilar migraine manifests without headaches but with symptoms like vertigo, dizziness, confusion, speech disturbances, tingling of extremities, and clumsiness.
  
  
• Status migrainosus is the term used to describe migraine attacks that persist for days. These attacks may result in complications such as dehydration.
  
  

Migraine Headaches, Treatment overview

• Avoid factors that cause a migraine attack (for example, lack of sleep, fatigue, stress, certain foods, vasodilators).
  
  
• Treat accompanying conditions (for example, anxiety, depression).
  
  
• Oral birth control agents (contraceptives) may increase the frequency of headaches in females. Women may be advised to discontinue oral contraceptives (or to use a different form) for a trial period to see if they are a factor.
  
  

Migraine Headaches, Abortive treatment

Abortive treatments stop migraines quickly. Many drugs are now available for immediate treatment of migraine attacks. The goal is rapid and effective relief of headache. The most effective drugs for stopping a migraine are the triptans, which specifically target serotonin receptors. They are all very similar in chemical structure and action. The following is a list of triptans:

• Sumatriptan (Imitrex, Imigran)
  
  
• Zolmitriptan (Zomig, Zomig-ZMT)
  
  
• Naratriptan (Amerge, Naramig)
  
  
• Rizatriptan (Maxalt, Maxalt-MLT)
  
  
• Almotriptan (Axert)
  
  
• Frovatriptan (Frova)
  
  
• Eletriptan (Relpax)
  
  

The following nontriptans also act on the serotonin receptors. They also act on some other receptors, most likely on those for dopamine and noradrenalin. Sometimes, they are effective when the triptans fail.

• Ergotamine tartrate (Cafergot)
  
  
• Dihydroergotamine (D.H.E. 45 Injection, Migranal Nasal Spray)
  
  
• Acetaminophen-isometheptene-dichloralphenazone (Midrin)
  
  

The following are primarily used when nausea is a complicating factor in migraine headache. In some cases, they also help relieve the headache.

• Prochlorperazine (Compazine)
  
  
• Promethazine (Phenergan)
  
  

Combination drugs like butalbital-acetaminophen-caffeine (Fioricet), butalbital-aspirin-caffeine (Fiorinal), or acetaminophen with codeine (Tylenol With Codeine) are general painkillers in the narcotic class. They can help relieve any kind of pain to some degree, whereas the triptans, ergotamines, and Midrin are used specifically for headaches and do not help relieve arthritis, back pain, or menstrual cramps.

Treatment strategies are more successful if they are tailored to the individual patient and are initiated early in the headache.

Patients with severe nausea and vomiting at the onset of an attack may at first respond best to intravenous prochlorperazine. These patients may be dehydrated; adequate fluid intake is necessary.

Vasoconstrictors (agents that narrow the blood vessels), such as ergotamines or triptans, should not be given to patients with known complicated migraine without the advice of a headache specialist. Instead, acute attacks should be treated with one of the other available agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or prochlorperazine.

Mild and infrequent attacks may not always require the use of ergotamines or triptans and may be adequately treated with acetaminophen (Tylenol), NSAIDs, propoxyphene (Darvon, Darvocet), or a combination of these.

About 40% of all attacks do not respond to triptans or any other substance. If all else fails, migraineurs with an attack lasting more than 72 hours (status migrainous) can be treated with intravenous medications. Brief hospitalization may be needed.

Migraine Headaches, Preventive treatment

Patients who have frequent acute migraine attacks and report that the attacks affect their quality of life should consider preventive therapy as a supplement to the specific headache-stopping drugs (abortive treatments) they use.

The goals of preventive therapy include decreasing the frequency and severity of acute attacks and improving quality of life.

Patients with complicated migraine headaches who have a history of neurological symptoms associated with their attacks are definite candidates for preventive therapy. For these patients, even a single previous complicated migraine episode qualifies them for long-term preventive therapy.

The choice of preventive medication should be tailored to the individual's profile, taking into account comorbidities (concurrent medical conditions) such as depression, weight gain issues, exercise tolerance, asthma, and pregnancy plans. All medications have side effects; therefore, selection must be individualized.

Preventive drugs include beta-blockers, tricyclic antidepressants, some anticonvulsants, calcium channel blockers, cyproheptadine (Periactin), and NSAIDs such as naproxen (Naprosyn). Unlike the specific headache-stopping drugs (abortive drugs), most of these were developed for other conditions and have been coincidentally found to have headache preventive effects. The following drugs also have preventive effects; unfortunately, they also have more side effects:

• Methysergide maleate (Sansert): This drug has many side effects.
  
  
• Lithium (Eskalith, Lithobid): This drug has many side effects.
  
  
• Indomethacin (Indocin): This drug can cause psychosis in some people with cluster headaches.
  
  
• Steroids: Prednisone (Deltasone, Meticorten) works extremely well for some people and should be tried if other therapies fail.
  
  

How long a person should follow a preventive therapy plan is a function of his or her response to the drug being taken. If headaches completely stop, it is reasonable to gradually reduce the dosage so long as headaches do not recur.