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Vertigo: some uncommon causes of a common problem.

Vertigo, an extremely common symptom, may be caused by numerous disorders affecting the central or peripheral vestibular systems. Patients can usually be categorized into four groups based on the clinical presentation: monophasic, prolonged episodes of vertigo due to acute unilateral vestibular hypofunction; recurrent episodes of vertigo, due to transient vestibular dysfunction; vertigo provoked by changes in head position with respect to gravity (positional vertigo); and bilateral vestibulopathies, which present with imbalance and oscillopsia. Although each clinical syndrome is usually caused by a limited number of disorders, many less common entities must be considered in the differential diagnosis. This article reviews the clinical presentation of the less common causes of vestibular syndromes and discusses their medical and nonmedical management.