A Case of Wernicke's Encephalopathy With Objective Evaluation of Pupil Findings Using a Pupillometer

Wernicke encephalopathy is a nutritionally disabling encephalopathy resulting from thiamine deficiency. The typical triad of symptoms in Wernicke's encephalopathy includes impaired consciousness, ocular motility disturbances, and ataxic gait. Although constricted pupils and diminished light reflexes are recognized features of Wernicke's encephalopathy, few reports have specifically focused on these findings. Here, we highlight the pupil diameter and light reflex abnormalities observed in this case. A 73-year-old man was admitted to our hospital because of dizziness and then referred to our department four days later because of impaired consciousness. He presented with constricted pupils, diminished light reflexes, restricted eye movements, nystagmus, muscle weakness, and ataxia in the trunk and limbs. Magnetic resonance imaging revealed lesions in the cerebellar vermis, brain stem, and bilateral medial thalamus, leading to a diagnosis of Wernicke's encephalopathy. Following thiamine supplementation, his symptoms and magnetic resonance imaging findings improved. His pupil diameter and light reflexes, as assessed with a pupillometer, also improved over time. Tracking pupillary findings using the pupillometer may be useful in determining treatment efficacy in Wernicke's encephalopathy and is reported here.