History is key to migraine-related dizziness Dx.

SCOTTSDALE, ARIZ. -- Suspect migraine as the possible cause of recurrent dizziness when the episodes of lightheadedness are associated with the headache syndrome more than 50% of the time, Dr. John G. Oas advised at a symposium sponsored by the American Headache Society.

Guidelines for diagnosing migraine-associated dizziness are few, but the diagnosis involves careful assessment of patient history, combined with consideration of the neurophysiology of the vestibular system, said Dr. Oas, director of the program of vestibular and balance disorders at the Cleveland Clinic.

Lightheadedness, which is not always specific to focal vestibular system dysfunction, can be part of neurocardiogenic or psychogenic syndromes. And true vertigo is not always a symptom of primary vestibular syndromes, he said.

"Despite the diagnostic imprecision of dizziness by description, the history still remains the most critical area of patient assessment," Dr. Oas said. Areas to focus on include how random or provoked the episodes are, the duration and frequency of episodes, and temporal characteristics of the episodes with headache or other symptoms. Episodic dizziness is commonly accompanied by symptoms of motion sickness, and such dizziness is nearly always accompanied by disturbing psychological symptoms of anxiety.

The source of dizziness may be certain common disorders other than migraine, including hearing loss, vertebrobasilar insufficiency, cervicogenic dizziness, and neurocardiogenic dizziness, which can accompany cardiac disease and is potentially lethal if misdiagnosed.

Studies supporting a preferred treatment are "sorely lacking," but he suggested a 3-month trial of a medication with proven efficacy in migraine prevention, along with an event diary to document efficacy.