Visual Hallucinations in a Patient With Moyamoya Disease: A Review and Case Report

Moyamoya disease (MMD) is characterized by the progressive development of stenosis in the distal carotid territory and an abnormal vascular network. It is a rare disease with a higher prevalence in Asian countries compared with other countries. The most common symptoms of MMD vary from stroke to epileptic seizure and headaches. However, individuals with MMD may also experience psychiatric symptoms such as depression, anxiety, and, in rare cases, psychosis. We report the case of a 34-year-old man with MMD who suffered from psychosis accompanied by visual hallucinations. The man was diagnosed with MMD and attends periodic follow-ups in our neurology outpatient clinic. After undergoing programmed neurosurgery, the man's immediate postoperative follow-up neuroimaging showed an extensive right frontotemporal acute ischemic lesion for which he was treated and released. Almost a year later, he presented to an outpatient psychiatric clinic where he complained of visual hallucinations and delusions. This time, there was no change in neuroimaging. Treatment with olanzapine was successful, and the man's symptoms were completely reversed. To our knowledge, this is the first reported case of visual hallucinations in an individual with MMD. This case is especially relevant because the visual hallucinations were not associated with an occipital ischemic lesion or with epileptic activity. We propose a topographic hypothesis to explain such findings.