Suggested Reading
Hinson SR, Roemer SF, Lucchinetti CF, et al. Aquaporin-4-binding autoantibodies in patients with neuromyelitis optica impair glutamate transport by down-regulating EAAT2. J Exp Med. 2008;205(11):2473-2481.
Lennon VA, Kryzer TJ, Pittock SJ, et al. IgG marker of optic-spinal MS binds to the aquaporin-4 water channel. J Exp Med. 2005;202(4):473-477.
Lennon VA, Wingerchuk DM, Kryzer TJ, et al. A serum autoantibody marker of neuromyelitis optica: Distinction from multiple sclerosis. Lancet. 2004;364(9451):2106-2112.
McKeon A, Fryer JP, Apiwattanakul M, et al. Diagnosis of neuromyelitis spectrum disorders: comparative sensitivities and specificities of immunohistochemical and immunoprecipitation assays. Arch Neurol. 2009;66(9):1134-1138.
Pittock SJ, Lennon VA, Krecke K, et al. Brain abnormalities in neuromyelitis optica. Arch Neurol. 2006;63(3):390-396.
Pittock SJ, Weinshenker BG, Lucchinetti CF, et al. Neuromyelitis optica brain lesions localized to sites of high aquaporin 4 expression. Arch Neurol. 2006;63(7):964-968.
Roemer SF, Parisi JE, Lennon VA, et al. Pattern specific loss of aquaporin 4 immunoreactivity distinguishes neuromyelitis optica from multiple sclerosis. Brain. 2007;130(Pt 5):1194-1205.
Wingerchuk Dean M, Lennon V, et al. The spectrum of neuromyelitis optica. Lancet Neurol. 2007;6(9):805-815.
Paroxysmal Dystonia Is Associated With Neuromyelitis Optica
SAN FRANCISCO—Paroxysmal dystonia occurs in 14% of patients with neuromyelitis optica, according to research presented at the 135th Annual Meeting of the American Neurological Association. The rate is similar to its association with multiple sclerosis (MS) and may be a presenting sign in both neuromyelitis optica and MS, reported Nida Usmani, MD, and colleagues.
“The pathogenesis of paroxysmal dystonia in neuromyelitis optica is unknown,” stated Dr. Usmani, of the Department of Neurology at the University of Miami. “In MS, it has been hypothesized to be due to ephaptic transmission in demyelinated axons.”
The researchers conducted a retrospective, longitudinal study of 57 patients with neuromyelitis optica. Eight patients had paroxysmal dystonia, which was defined as spontaneous brief, frequent, stereotyped episodes of abnormal posturing of an extremity, face, or neck. The mean age of onset was 37.4 (range, 13.8 to 54.2), with a seven-to-one ratio of females to males. Neuromyelitis optica antibody was found in one of five patients.
Paroxysmal dystonia appeared after a mean of 24.6 months of diagnosis of neuromyelitis optica. In two patients, paroxysmal dystonia was their initial presentation, and the average interval between onset of paroxysmal dystonia and development of other neurologic deficit was 2.5 months. Five patients had single limbs affected, two patients had ipsilateral arm and leg involvement, and one patient had tonic spasms. Two patients had cervical spine lesions on MRI. Seven patients responded to carbamazepine within one week.
“The incidence of paroxysmal dystonia in our neuromyelitis optica case series was 14%, which is similar to reports of its association with MS—3.8% to 17%,” stated Dr. Usmani. “Heretofore, only one well characterized case of neuromyelitis optica with paroxysmal dystonia has been reported. Unfamiliarity with this association can lead to a diagnostic dilemma, especially in cases of paroxysmal dystonia as a presenting symptom.”