Objective To determine the frequency of the association between tonic spasms and neuromyelitis optica (NMO) at our center.
Design An institutional review board–approved retrospective study of clinical, serological, and radiographic characteristics of patients with NMO.
Setting Multiple sclerosis center.
Patients Patients with NMO treated at our center between 1990 and 2008.
Main Outcome Measure Records were examined for documentation of tonic spasms.
Results Of 110 patients with International Classification of Diseases code 341, 57 patients met diagnostic criteria for NMO. Of these, 8 patients (14%) had documented typical tonic spasms (median age at onset, 39.5 years; range, 13.8-54.2 years). Of those patients, 4 were African American, 3 were Hispanic, and 1 was white. Only 1 was male. The NMO-IgG antibody was found in 1 of 6 patients tested. Tonic spasms appeared after a mean of 24.6 months (range, 0-91 months). In 2 of 57 patients meeting NMO criteria, tonic spasms accompanied their initial episodes. Seven of 8 patients who had tonic spasms responded to treatment with carbamazepine within 1 week.
Conclusion Tonic spasms are associated with NMO more commonly than with multiple sclerosis and may be a presenting sign in both diseases.