Myelin Oligodendrocyte Glycoprotein (MOG) Associated Neuromyelitis Optica (NMO) Presenting with Isolated Absent F Wave

Abstract

We describe an unusual presentation of Neuromyelitis Optica (NMO). A young boy presented with two days history of acute onset flaccid paraplegia. Electrophysiological study showed only absence of F wave. Initial exam was suggestive of Gullian-Barre Syndrome (GBS). Nevertheless, MRI spine demonstrated a contrast enhancing lesion in conus medullaris. Few days later, patient developed bilateral optic neuritis. NMO was diagnosed then. Antibody to Aquaporin 4 was not found in the serum, but to Myelin Oligodendrocyte Glycoprotein (MOG) was present. Patient was refractory to IV IgG therapy. He continued to develop symptomatic new lesions in brain and spine. Later Rituximab therapy initiation ceased the disease. However, absent "F wave" in Nerve Conduction is quite a perplexing association. It may reflect concurrent peripheral nerve involvement which needs to be explored. This case is unique due to its atypical presentation and also to the best of our knowledge this is the first reported case of MOG positive NMO from Saudi Arabia.