Neuromyelitis optica unmasked by a spinal dural arteriovenous fistula.

Neuromyelitis optica spectrum disorder (NMO-SD) and spinal dural arteriovenous fistula (SDAVF) can both cause longitudinally extensive myelopathy. We describe a case of longitudinally extensive myelopathy attributed to a SDAVF. Despite treatment, myelopathy recurred and led to subsequent NMO-SD diagnosis. We consider a possible link between the two disorders which may shed light on the pathophysiology of NMO-SD. To our knowledge, this is the first published case of co-existent NMO-SD and SDAVF leading to myelopathy.