Sun Hoo Foo, M.D.

(presented at the 1998 CAMS Annual Scientific Meeting)

Migraine headache was often perceived as an emotional problem. Research and knowledge have proven that migraine is a debilitating disease with neurological causes. Approximately 18% of adult women are afflicted with this disorder with the disease ratio of 3:1 over men. It is estimated over 23 million Americans suffer from migraines, of which 11 million experience moderate to severe disability. 71% of males and 59% of females with the disease were undiagnosed. This reflected both the inadequate use of the health care system and the failure of the health care system such as ignoring patients’ complaints and not making a specific diagnosis. As a result, 89% of the migraine sufferers worked an average of 2.2 work days a month. This not only affects lost labor but also results in leisure time loss, inability to carry out daily activities, disruption of family and social life.

The unified neurovascular hypothesis of migraine pathogenesis correlates cortical and brainstem events with changes in the cerebral vasculature and neyral function, ans migraine is regarded as a state of central neuronal hyperexcitability. Predisposing factors which lower migraine threshold will result in inactivation of neurons containing serotonin as well as norepnephrine in locus ceruleus and dorsal raphe of the brain stem. The subsequent release of neuropeptides then cause vasodilation and extravasation, resulting in a "sterile" inflammatory process. The distended blood vessels and the inflammatory response stimulate the trigeminal nerve to transmit impulses back to the brain, perceived as pain. During a migraine attack, blood levels of 5-HT decrease and urinary concentration of 5-HT metbolites increase. Since the 5-HT receptors decline with age, it is probably the reason for the migraine to diminish as the patient grows older. There are at least seven types of 5-HT receptors. The most important receptors involved in migraine are 5-HT 1B and 2D. Agonists of these receptors can abort migraine attacks whereas 5-HT 2 receptor antagonists could prevent a migraine attack.

Headache due to organic causes is rare in the age group most affected by migraine. The important symptoms or signs to differentiate organic disease from migraine are as follows: sudden onset of headache, meningeal irritation (stiff neck), altered consciousness or cognition, papilledema or hemorrhage of the ocular fundus, unequal pupils, visual loss, abnormal vital signs, clumsiness or loss of balance, reflex asymmetry or abnormal plantar response.

Although there are specific migraine medications (such as Ergotamine, Isometheptene, various triptan), other medications including over the counter analgesics (such as acetaminophen, asprin), nonsteroidal anti-inflammatory drugs, antiemetics, phenothiazines and combinations of these also prove to be effective in the majority of cases. Because of excessive use or abuse of medications, one has to watch for rebound headache. The signs of symptomatic abuse of medications include multiple pain pills, persistent calls for prescription refills, shorter interval between requests, creative excuses for needing prescription refills and "doctor shopping". Rebound headache is characterized by bilateral diffused headache every day or nearly every day aggravated by mild physical or mental exertion, early morning headache, emotional stress such as restlessness, nausea, forgetfulness, asthenia, and depression. Patients show a tolerance to acute/abortive migraine medication and no response to preventive migraine medication.

Prophylactic medications used in the treatment of migraine include beta blockers, tricyclic antidepressants, NASIDS, anti-serotonin drugs, calcium channel blockers, monoamine oxidase inhibitors and anticonvulsants such as valproic acid etc.

There are at least four selective 5-HT 1 agonists effective in the treatment of migraine. The first agonist, sumatriptan (Imitrex), in the oral dosage of 50 or 100 mg is effective in aborting headache in 70% of the cases. However, headache recurrs in about 40% of patients. The subcutaneous form and nasal spray are useful in cases with severe nausea or vomiting. Naratriptan (Amerge) in dosage of 1 to 2.5 mg offer similar relief . It has better CNS penetration because of its high lipid solubility and is believed to cause lower rate of headache recurrence. Rizatriptan (Maxalt-MLT) oral disintegrating tablet which offers immediate disintegration of the tablet in the mouth without liquid, is another alternative. The other agonist, zolmitriptan (Zomig) in dosage of 2.5 or 5 mg, is equally effective.

In summary, the availability of various triptans which could effectively abort migraine headache have improved the quality of life of migraine sufferers.