Transient Isolated Downbeating Vertical Nystagmus as a Complication of Intrathecal Anesthesia (P6.022)

Objective: To describe a case of transient isolated downbeat nystagmus with oscillopsia in the setting of intrathecal anesthesia. Background: Vertical nystagmus is most commonly seen as part of a constellation of neurologic signs and symptoms associated with lower brain stem or cerebellar lesions. Transient isolated downbeating nystagmus can be a rare complication of intrathecal anesthesia, with few case reports presented in the literature. Its pathophysiologic mechanism is unclear, though it has been proposed that it may be related to opiate-mediated inhibition of binding sites located in the vestibular nuclei and cerebellum. Design/Methods: A 35 year-old G1P0 was admitted for labor. She underwent cesarean section for nonreassuring fetal heart tracings and prolonged labor, and received intrathecal anesthesia with morphine, fentanyl, and bupivacaine. While laying down in the operating room, she experienced sudden onset oscillopsia with movement of static objects, described “as if you were driving and looking at the lane divider on the road”. She reported this to the anesthesiologist, who noted bilateral downbeating vertical nystagmus but without other focal neurologic signs. This persisted post-operatively for less than 2 hours with complete resolution in the recovery room. She reported no headache, weakness, numbness or other neurological symptoms. Results: The patient was monitored in the recovery room with rapid resolution of her oscillopsia. Neurological exam was normal and nystagmus was unable to be elicited with provocative maneuvers. She did not receive naloxone. Given the relatively short duration and spontaneous resolution of her symptoms, this was felt most likely to represent a medication side effect rather than a transient ischemic event. Conclusions: Transient isolated downbeating nystagmus is a rare self-limiting complication of intrathecal anesthesia administration, but should be considered as a potential etiology once other vascular causes have been ruled out. Administration of naloxone in suspected cases may help to confirm this diagnosis. Disclosure: Dr. Leung has nothing to disclose. Dr. Motiwala has nothing to disclose.