Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Abstract

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

Keywords: MOG-encephalomyelitis; aquaporin-4 antibodies; diagnostic criteria; immunosuppressive treatment; neuromyelitis optica.

Figure 1

MRI of patients with AQP4-Ab positive NMOSD and patients with MOG-EM. Severe cervical LETM in a NMOSD AQP+ patient: (a) T2 sagittal and (b) T2 axial of a cervical myelon lesion with ring Gd-Enhancement and T1 hypointense center in (c) T1+Gd sagittal and (d) T1+Gd axial. Bilateral opticusneuritis in a MOG-EM patient (e) T1+Gd axial and (f) T1+Gd coronar. Unilateral optic neuritis with chiasmal involvement in a NMOSD AQP4+ patient: (g) T1+Gd axial and (h) T1+Gd coronar. Tumefactive lesion involving the corpus callosum in a NMOSD AQP4+ patient (i–k) T2 axial.