Vestibular signs of thiamine deficiency during the early phase of suspected Wernicke encephalopathy.

Non-encephalopathic presentations of CNS thiamine deficiency may be difficult to diagnose. We describe neuro-otologic findings of Wernicke syndrome in 5 patients with vestibular manifestations. Diagnosis was confirmed by low serum levels, response to replacement, and brain MRI to exclude other causes. All had bilaterally abnormal horizontal head impulse vestibulo-ocular reflex (VOR) responses and pathologic gaze-evoked nystagmus, without encephalopathy. After thiamine replacement, 4 had total resolution of vestibular and oculomotor findings. Novel findings included 2 patients whose VOR function improved within minutes of IV repletion and 1 whose recovery was documented by serial quantitative recordings. Early diagnosis of Wernicke by examining vestibular reflexes and prompt IV treatment might prevent encephalopathy and other neurologic or systemic complications of thiamine depletion.