Acceleration of moyamoya disease after anti-vascular endothelial growth factor intravitreal injections

Moyamoya disease (MMD) is a rare, progressive, irreversible vaso-occlusive disease affecting the cerebral vasculature. The progressive occlusion of blood vessels leads to the development of collateral vessels to compensate for the insufficient blood supply. Some growth factors such as vascular endothelial growth factor (VEGF) may cause excessive and aberrant angiogenesis in MMD. We report a case of a 55-year-old male, following up in retina clinics for diabetic retinopathy and macular edema who received anti-VEGF agents then he presented to the emergency room with left-sided face and body weakness, dysphagia, and dysarthria. Based on his clinical presentation and neuroimaging, he was diagnosed with moyamoya progression. We hypothesize that receiving anti-VEGF agents could have contributed to MMD progression in our patient and interfered with the collateral vessel development in a similar manner to their intended use in regressing neovascularization in diabetic retinopathy.