Downbeat nystagmus caused by a paramedian ponto-medullary lesion

Background: Downbeat nystagmus (DBN) is commonly caused by cerebellar disorders involving the (para-)floccular lobe. Cases of DBN caused by isolated lesions in sites other than the caudal cerebellum are rare. We describe a patient who developed DBN secondary to a hemorrhaged venous cavernoma located at the ponto-medullary junction. Patient and Methods: A 45-year-old man, who had suffered a hemorrhage from a venous cavernoma located at the ponto-medullary junction two years previously, presented at our dizziness unit with blurred vision and unsteadiness of gait. On clinical examination, he had downbeat nystagmus…