Positional nystagmus reversing from geotropic to apogeotropic: a new central vestibular syndrome

Abstract

Central positional paroxysmal vertigo (CPPV) is rarely encountered in clinical practice. It must be distinguished from the more frequent benign positional paroxysmal vertigo (BPPV) [1, 2] and only an accurate clinical evaluation can identify it. Mostly, CPPV is due to cerebellar disease from various aetiologies, including neoplasm, as in the case reported here [3–5]. In this patient, clinical examination with video-oculography revealed right beating horizontal nystagmus in the right lateral head position (geotropic nystagmus) that reversed direction (to apogeotropic nystagmus) while the head position was maintained. In the left lateral position, the patient had again geotropic nystagmus reversing to apogeotropic nystagmus. Brain imaging revealed the presence of a right hemisphere cerebellar neoplasm causing compression of the IV ventricle and hence the vestibular disturbance. A 50-year-old female patient was referred to our neurootology service because of imbalance and vertigo subacutely developed a fortnight earlier. She had a history of breast cancer treated with surgery in May 1997, followed by adjuvant chemotherapy and hormone therapy. Neurological examination revealed a retropulsion in Romberg position and a backward displacement on the Fukuda stepping test. Coordination was only mildly impaired, with limb dysmetria on right finger-to-nose test. Cranial nerves were intact. Tendon reflexes were symmetrical with flexor plantar responses. Video-oculography showed no spontaneous nystagmus in primary position and no gaze-evoked nystagmus was revealed. Head-shaking test was normal. A slight delay was observed on the horizontal head impulse test toward the right side. Upon slowly positioning the patient in the right lateral head position, first-phase nystagmus manifested itself as right beating paroxysmal nystagmus (geotropic) without any latency. It gradually diminished, only to reverse its direction after about 10 s with the development of left beating (apogeotropic) second-phase nystagmus, as shown in the video (Online resource 1). On the left side, a similar, although less intense, geotropic nystagmus was observed. It reversed its direction in about 20 s, changing to apogeotropic nystagmus, as shown in the video (Online resource 2). Recording of the nystagmus activity revealed a maximal slow-phase velocity (SPV) of 19.6 /s for right geotropic nystagmus, while on the left side it showed an SPV of 8.6 /s. First-phase nystagmus was more intense both on the right and left sides, although it didn’t last as long as secondary apogeotropic nystagmus (Fig. 1). When tested in the straight head-hanging position, no nystagmus was detected. Electronic supplementary material The online version of this article (doi:10.1007/s00415-010-5701-6) contains supplementary material, which is available to authorized users.