MOG-IgG-Positive Spinal Myelitis a Likely Variant of Neuromyelitis Optica: Overcoming Difficulties in Clinic, Diagnostic, and Therapy

Introduction: Neuromyelitis optica (NMO) is an inflammation demyelinating autoimmune disease; it is now known to be its own entity. NMO now refers to a syndrome characterized by severe bilateral optic neuritis associated with a transverse extensive myelitis, which spans more than three consecutive vertebral segments. Furthermore , AQP4 antibody is a specific autoantibody and targets aquaporin-4 water channel. It is detected in 80% of adult NMO patients. Our report presents a patient with relapsing severe longitudinal myelitis, AQP-4-seronegative, which we would tend to class etiologically as an NMO variant. Case Report: First and only child of nonconsanguin parents with a genetically unclassified Keratitis-Ichthyosis-Deafness syndrome. Aged 9.5 years, developing spinal ataxia, aggravating over a period of 14 days. Spinal magnetic resonance imaging (MRI) increased signal throughout nearly the whole spinal cord with enlarged, edematous central cord. Postcontrast no enhancement was observed. Somatosensory evoked potentials ( N. tibialis ) were not reproducible. Comprehensive diagnostics (metabolic investigations, steroid sulfatase, phytanic acid, T- and B-cell function, AQP-4-antibody, Biochip-mosaic, virology, and bacteriology) remained inconspicuous apart from clearly elevated myelin oligodendrocyte glycoprotein (MOG) antibody as well as slightly elevated cerebrospinal fluid albumin. After methylprednisolone (MP) for 3 days, the patient improved, but still ataxia gait. After 14 days, control of spinal MRI revealed regression of radiological findings. No indication for new lesions and normal brain MRI was seen. Within 2 months, the boy presented with gait loss, spinal MRI showed progressive damage with postcontrast enhancement. Because of deterioration in spite of repeated MP therapy, intravenous immunoglobulin (IVIG) was established resulting in only slight improvement and eventually plasmapheresis was done. This again led to further slight amelioration. But 2 months later, he developed a posterior reversible encephalopathy syndrome with seizures and arterial hypertension. In the course of disease diaphragm, paralysis developed and it required a mask ventilation during night. On the basis of suspicions of an auto immunological pathomechanism (MOG-antibodies permanently high) therapy with corticosteroids, azathioprine, and IVIG was started. Improvement was brought about a disconnection of mask ventilation, increasing agility of legs but without gait capability.