Most cases of benign paroxysmal positional vertigo (BPPV) involve the posterior or horizontal semicircular canal, whereas that involving the anterior semicircular canal is rare. We herein report a case of anterior BPPV that was difficult to diagnose and treat.
The case was a 16-year-old male. Vertigo while lying down appeared in November 2003, and he consulted The Department of Neurosurgery of our hospital on January 13, 2004. As there was neither central nervous system signs nor abnormal finding on brain computerized tomography, he was referred to our department. At the initial visit, downbeat nystagmus was noted in the suspensory head position. Central nystagmus was suspected, head MRI was undertaken. Since there was no apparent abnormality on imaging, a wait-and-see approach was taken under a diagnosis of idiopathic vertigo. On November 22, 2005 (18 years old), downbeat nystagmus with a clockwise movement (from the examiner) was seen in the left and right head-down position using the Dix-Hallpike method. On review of the clinical history, it was noted that he had hit his head forcefully during a backflip when he was fourteen years old, and he had a habit of lying in a prone position in bed. Therefore, we diagnosed left anterior BPPV. Non-specific exercise therapy was performed but not effective. A modified canalith repositioning maneuver was conducted three times and we instructed him not to remain in a prone position in bed. As a result, the subjective symptoms disappeared.
The need to use the Dix-Hallpike method in diagnosing BPPV was reconfirmed. In addition, detailed history taking including the habitual position in bed is useful for diagnosis and treatment.
