Abstract Details

Title Fixational Upbeat Nystagmus in Wernicke’s Encephalopathy

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P2 - Poster Session 2 (8:00 AM-9:00 AM)

Poster/Presentation
Number 11-006

Objective NA

Background Wernicke’s encephalopathy (WE) caused by thiamine deficiency can show various neuro-ophthalmological abnormalities such as ophthalmoplegia, gaze-evoked nystagmus and impaired vestibulo-ocular reflex ataxia. Patients with WE may also have unusual patterns of spontaneous vertical nystagmus. We report a patient with WE who presented with pure upbeat nystagmus that only appeared during fixation.

Design/Methods NA

Results A 55-year-old man presented with unsteadiness, dizziness and oscillopsia for 4 months. He had a 1-month history of severely restricted food intake due to pray. During fasting, he developed progressive gait disturbance, dizziness and rhythmic oscillation of the surrounding environment. On admission, he was alert and well-oriented in time and space. Extraocular evaluation showed pure upbeat nystagmus with exponentially decreasing slow phases in the primary position with fixation, which was mildly attenuated during vertical gazes and changed into downbeat nystagmus during lateral gazes. The nystagmus disappeared in darkness. Upward smooth pursuit was impaired with superimposed upbeat nystagmus, while downward smooth pursuit was normal. The vestibule-ocular reflex gains were reduced for the horizontal semicircular canals on both sides in video head impulse tests, and the caloric responses were significantly decreased on both sides. Other findings included incoordination in all limbs and a wide-based ataxic gait. Laboratory investigations including thyroid function tests, serum vitamin B1, B12, folic acid, and paraneoplastic antibody were normal. Magnetic resonance imaging of the brain showed no abnormal signal intensity. With a suspicion of Wernicke’s encephalopathy, we gave intravenous thiamine, followed by an oral treatment. Seven month later, his unsteadiness and upbeat nystagmus markedly improved.

Conclusions

Given the exponentially decreasing slow phases and defective upward smooth pursuit, upbeat nystagmus in our patient may be explained by a dysfunction of the neural integrator for vertical eye movements. In addition, the nystagmus that only appeared during fixation may reflect the involvement of cerebellar circuits responsible for visual-vestibular interactions.

Authors/Disclosures
Hyun Sung Kim, MD (Pusan National University Yangsan Hospital) PRESENTER	Prof. Kim has nothing to disclose.
Jae-Hwan Choi (Pusan National University Yangsan Hospital)	Jae-Hwan Choi has nothing to disclose.
Kwang-Dong Choi	Prof. Choi has nothing to disclose.
Sang Min Sung, MD, PhD	Prof. Sung has nothing to disclose.
Bong-Goo Yoo, MD, PhD	Dr. Yoo has nothing to disclose.

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