Is there a prodrome to NMOSD? An investigation of neurologic symptoms preceding the first NMOSD attack

Background: It is unknown whether people with aquaporin-4 antibody positive (AQP4-IgG+) neuromyelitis optica spectrum disorder (NMOSD) experience a prodrome, although a few cases report AQP4 + serology up to 16 years before the first attack.

Objectives: To evaluate whether individuals with AQP4-IgG + NMOSD have prodromal neurologic symptoms preceding the first attack.

Methods: We reviewed medical records of participants meeting the 2015 diagnostic criteria for AQP4-IgG + NMOSD from four demyelinating disease centres in the Canadian NMOSD cohort study CANOPTICS. We searched for neurologic symptoms occurring at least 30 days before the first attack.

Results: Of 116 participants with NMOSD, 17 (14.7%) had prodromal neurologic symptoms. The median age was 48 years (range 25-83) at first attack; 16 (94.1%) were female. Participants presented with numbness/tingling (n = 9), neuropathic pain (n = 5), visual disturbance (n = 4), tonic spasms (n = 2), Lhermitte sign (n = 2), severe headache (n = 2), incoordination (n = 2), weakness (n = 1), psychosis (n = 1) or seizure (n = 1). Of eight who underwent magnetic resonance imaging (MRI) brain, orbits and/or spinal cord, five had T2 lesions. Within 1.5-245 months (median 14) from the onset of prodromal neurologic symptoms, participants experienced their first NMOSD attack.

Conclusions: One in seven people with NMOSD experienced neurologic symptoms before their first attack. Further investigation of a possible NMOSD prodrome is warranted.