Background: Although brain lesions are now recognized more frequently in neuromyelitis optica spectrum disorder (NMOSD), most of them have been reported to be nonspecific and rarely symptomatic. We describe clinical and imaging characteristics of patients with NMOSD, who presented with brain symptoms. Methods: We measured anti-aquaporin 4 antibody (anti-AQP4 Ab) by cell based assay or ELISA from the sera of 314 consecutive CNS inflammatory disease patients who attended the multiple sclerosis (MS) clinic of the National Cancer Center, Korea, from May 2005 to Dec 2009. Eighty-three patients were seropositive. Among them, 16 (19%) presented with brain symptoms as the initial manifestation. We retrospectively reviewed their clinical and MRI findings. Results: The median age at the first presentation was 34 years (8-54 years). Among the 16 enrolled patients (male:female = 1:15), 6 showed encephalopathy, such as confusion, seizure, and memory disturbance, with or without other neurological symptoms including hemi- or quadriparesis and dysarthria. The other 10 patients presented with variable brainstem symptoms, including diplopia, nystagmus, hiccup, and bulbar dysfunction, without encephalopathy. Two patients showed one of the typical symptoms of NMO in addition to brain symptoms at the first presentation, and rest of them showed neither optic neuritis nor myelitis. However, they eventually developed either one of them or both. The median duration to develop one of the NMO symptoms was 32 months (2-116 months). Brain MRIs at onset were available in 11 patients, and their features were different from those seen in prototypic MS. In patients presented with encephalopathy, multiple lesions involving corticospinal tracts, extensive (> 3 cm) lesions involving cerebral white matters, and diffuse cortical or subcortical lesions were commonly found. Periependymal lesions surrounding lateral, third, or fourth ventricles were also shown. Meanwhile, in patients without encephalopathy, brainstem lesions involving dorsal part of medulla or pons, located immediately adjacent to the fourth ventricles, were exclusively found. Conclusion: A considerable proportion of NMOSD patients manifested brain symptoms at the first presentation, and their clinical and MRI findings differ from those of prototypic MS. Therefore, to make an early diagnosis of NMOSD, it is recommended to test anti-AQP4 Ab in patients who present with brain symptoms with clinical and MRI features atypical for MS.
Read More: Brain abnormalities as an initial manifestation of neuromyelitis optica spectrum disorder