MOG-IgG1 and co-existence of neuronal autoantibodies.

BACKGROUND: The presence of co-existent neuronal antibodies (neuronal-IgG) in patients with myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG1) is not yet well understood. OBJECTIVES: The aim of this study was to investigate the co-existence of a broad range of neuronal-IgG in MOG-IgG1+ patients. METHODS: MOG-IgG1+ patients were tested for 17 neuronal-IgGs in cerebrospinal fluid (CSF) and serum including NMDA-R-IgG, AMPA-R-IgG, GABAB-R-IgG, LGI1-IgG, CASPR2-IgG, GABAA-R-IgG, GAD65-IgG, mGLUR1-IgG, DPPX-IgG, CRMP5-IgG, amphiphysin-IgG, PCA1,2,Tr, and ANNA1,2,3. Clinical and radiological features of MOG-IgG1+ with NMDA-R-IgG in CSF were compared to a control cohort of MOG-IgG1+ patients without NMDA-R-IgG. RESULTS: A total of 376 MOG-IgG1+ patients underwent testing for neuronal-IgGs. Serum testing for neuronal-IgGs (113 adults, 142 children) identified one child with NMDA-R-IgG (0.7%), one child with CASPR2-IgG (0.7%), one adult with LGI1-IgG (0.9%) and one adult with GABAA-R-IgG (0.9%). CSF testing for neuronal-IgGs (97 adults, 169 children) identified seven children (4%) and seven adults (7%) with NMDA-R-IgG, and one adult with GABAA-R-IgG (1%). The MOG-IgG1+/NMDA-R-IgG+ patients had a median age of 17 (range: 2-39) years. Features associated with MOG-IgG1+/NMDA-R-IgG+ included encephalopathy (p = 0.001), seizures (p = 0.045), and leptomeningeal enhancement (p = 0.045). CONCLUSION: NMDA-R-IgG was the most frequently detected neuronal-IgG to co-exist with MOG-IgG1. MOG-IgG1+/NMDA-R-IgG+ patients most often presented with encephalopathy and seizures. Testing for MOG-IgG1 and NMDA-R-IgG may be warranted in patients with encephalopathy and inflammatory demyelinating syndromes.

Electromyography and nerve conduction studies of the lower extremity: uses and limitations.

Electrodiagnostic testing (EDX), the combination of electromyography and nerve conduction studies, is a useful extension of the physical exam. In the proper clinical context, it can help distinguish between the various nerve processes that may contribute to foot pain. This article discusses those processes, their clinical presentation, and the relative usefulness of EDX for each.

Response of the dropped head/bent spine syndrome to treatment with intravenous immunoglobulin.

Weakness of neck extension causing a dropped head may result from many neuromuscular disorders. One etiology is isolated neck extensor myopathy. A similar focal myopathy of the lower axial muscles may cause the bent spine syndrome, which manifests as flexion of the trunk and inability to stand upright. Combination of both dropped head and bent spine myopathies is uncommon. Inflammation is usually not pronounced in these conditions and response to immunosuppressive treatment is rare. We present an 81-year-old man who developed progressive weakness of neck and trunk extension over several months, with a prominent inflammatory process in the thoracic paraspinal muscles, which responded dramatically to treatment with intravenous immunoglobulin (IVIg). This case, together with other rare reports, suggests that the presence of inflammation in the biopsy of an affected muscle may predict treatment response.