Extracranial venous stenosis is an unlikely cause of multiple sclerosis.

Background: Extracranial venous stenosis (EVS) has recently been implicated as the primary cause of multiple sclerosis (MS).Objective: The aim of this study was to determine the presence of EVS in MS patients.Methods: We performed selective extracranial venography on 42 patients with early MS (EMS): clinically isolated syndrome (CIS) or relapsing—remitting MS (RRMS) of less than 5 years duration, and late MS (LMS): RRMS of more than 10 years duration. Magnetic resonance imaging (MRI) and clinical relapse data were reviewed for all patients with EVS.Results: EVS was present in 7/29 patients with EMS and 12/13 patients with LMS, a highly significant statistical difference (p< 0.001). Only 3/42 patients (all in the LMS group) had two vessel stenoses, while the rest had only one vessel involved. EVS was seen in 1/11 patients with CIS compared with 6/18 RRMS patients of less than 5 years duration. Disease duration was greater in patients with EVS overall (p < 0.005). LMS remained an independent predictor of EV...