2014 Volume 73 Issue 4 Pages 186-190
We encountered a patient with posterior fossa arachnoid cyst-induced dizziness. The patient was a 72-year-old female who visited the internal medicine department with the chief complaints of persistent dizziness and vomiting for one month. Subdural hygroma was noted in the cerebellopontine angle on head CT, but it was considered an age-related change after surgery for an aneurysm, and the cause of the complaints could not be identified. Thus, the patient was referred to the otolaryngology department on the 22nd day after the first examination at the internal medicine department. On the first examination at the otolaryngology department, leftward spontaneous nystagmus was observed in the primary gaze, and bilateral fixation nystagmus was noted. Direction-changing upbeat nystagmus was noted on a head nystagmus test, and vertical downbeat nystagmus was noted when the head position was changed from recumbency to sitting in a positional nystagmus test. On head MRI, the brain stem and vermis were compressed by a cyst. Compression by an arachnoid cyst was identified as the cause based on close neurological and neurotological examinations.
