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Abstract Details

A Case of Neural Integrator Failure in Vitamin B1 Deficiency.
P1 - Poster Session 1 (8:00 AM-9:00 AM)

The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are two closely related neural integrators situated in the brainstem responsible for horizontal conjugate eye movement. Thiamine deficiency, a hallmark of Wernicke’s encephalopathy, affects the MVN to a greater extent. We report a case of impaired horizontal gaze holding post-sleeve gastrectomy secondary to Vitamin B1 deficiency.

Case Report

A 24-year-old female presented with new onset diplopia on lateral gaze, dizziness, and lower limb distal paraesthesia eight weeks post-sleeve gastrectomy. Examination revealed conjugate eye movements and horizontal gaze-holding failure bilaterally, with intact convergence and vertical gaze. Normal discs were observed on fundoscopy with no retinal haemorrhages, and visual acuity preserved. She had a normal mental state with mild sensory ataxia. Reflexes were present and symmetrical.

Cerebrospinal fluid analysis was normal, and MRI Brain showed no acute infarction, haemorrhage, or brainstem lesions. Folate, Vitamin B6, B12, and HbA1c levels were within normal range, with a negative infective screen. Vitamin B1 level was found to be low at 44.3nmol/L (normal range: 66.5-200nmol/L). She was commenced on high-dose intravenous thiamine for one week with symptomatic improvement in diplopia and subsequently discharged on long-term thiamine supplementation.

The high metabolic requirements of MVN neurons responsible for high acceleration horizontal vestibulo-ocular reflex (VOR) is postulated to account for the selective vulnerability to thiamine deprivation. This case highlights an unusual presentation of disruption in horizontal gaze-holding mechanisms through failure of neural integrators, particularly the MVN, in the setting of Vitamin B1 deficiency with preservation of vertical gaze.

Hongying Chen, MB BCh BAO
Dr. Chen has nothing to disclose.
Niall Warfield, MBBS Dr. Warfield has nothing to disclose.
Ciaran Nannery, MBBS Dr. Nannery has nothing to disclose.
Zara Abigail Togher, MB BCh BAO Dr. Togher has nothing to disclose.
Yaseen Yacoob, MD (Dr Y Yacoob) Dr. Yacoob has nothing to disclose.