Distinct Acute Spinal Cord Syndrome Between Aquaporin-4IGG Seropositve And Seronegative Longitudinally Extensive Transverse Myelitis (P2.272)

Objective: To describe acute spinal cord syndrome (SCS), spinal fluid an neuroimaging in LETM patients according to aquaporin-4 IgG status Background: LETM refers to acute SCS suitable to inflammation seen as propagate hyperintensity on T2-weighted magnetic resonance imaging (MRI). Aquaporin-4 antibody (AQP4-IgG) seropositive LETM patients (SP-LETM) are in high risk to recurrence and the term neuromyelitis optica spectrum disorders (NMO) are used in this setting. The acute presentation of LETM patients according AQP4-IgG status has been scarcely studied, and seropositive and seronegative LETM (SP-LETM and SN-LETM) has been considered undistinguishable. Methods: Forty-one consecutive patients, 66% (27/41) female, 80% (33/41) afro-brazilian, 40 years median age of onset, were admitted between 2005 until 2011, with idiopathic first ever LETM. According to presence or absence of AQP4-IgG, evaluated by cell based assay, patients were classified into SP-LETM and SN-LETM, respectively. Demographical, SCS at onset, laboratorial and neuroimaging features were compared. P value < 0,05 was regarded significant. Results: Twelve out of 41 patients (29.4%) were positive to AQP4-IgG Female gender and afro-brazilian ancestry showed a tendency to AQP4-IgG seropositivity (p=0,08 and 0,06, respectively). Clinical features associated with SP-LETM were: painfull tonic spasms (p=0,01), spinal cord shock (p=0,001), respiratory dysfunction (p=0,05) and higher EDSS score (p=0,04). Para-clinical findings associated with SP-LETM were: presence of anti-nucler antibody (ANA) (p=0,03), spinal fluid pleocytosis (p=0,04), MRI showing medullar and cervico-thoracic involvement (p=0,03) and length of spinal cord lesions over 6 vertebral segments (p < 0,001). Conclusion: Clinical and para-clinical features discern seropositive and seronegative LETM patients in acute setting. In clinical point of view, these clues may help when AQP4-IgG serology is not available. Further prospective studies may evaluate which features predict relapses and conversion to NMO. Disclosure: Dr. Apostolos has received personal compensation for activities with Biogen Idec. Dr. Sato has received research support from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, and Ichiro Kanehara Foundation. Dr. Jorge has received personal compensation for activities with Novartis and Teva Neuroscience. Dr. Melo has nothing to disclose. Dr. Marchiori has nothing to disclose. Dr. Callegaro has received personal compensation for activities with Teva Neuroscience.