Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

A case of subacute myelitis with anti-aquaporin 4 antibody after thymectomy for myasthenia gravis: Review of autoimmune diseases after thymectomy

Masayuki Kohsaka, M.D.1), Masami Tanaka, M.D.1), Masayuki Tahara, M.D.1), Yasukiyo Araki, M.D.1), Satoru Mori, M.D.2) and Teturo Konishi, M.D.1)

1)MS Center, Utano National Hospital
2)Department of Neurology, Matsushita Memorial Hospital

We report the case of a 60-year-old woman with myasthenia gravis (MG) and Basedow's disease who seven years after thymectomy developed subacute myelitis, a limited form of neuromyelitis optica (NMO). The patient presented with a centrally located long spinal cord lesion (LCL) on cervical cord MRI, anti-aquaporin 4 (AQP4) antibody in serum, and HLA DPB1*<0501. Brain MRI showed no specific findings of classic multiple sclerosis (MS). CSF study showed elevated protein (67 mg/dl) but a normal IgG index (0.63) and no oligoclonal IgG bands. After repeated methylprednisolone pulse and immunoadsorption therapies, the T2-high signal lesion shrunk and tetraparesis improved.
We reviewed the English and Japanese literature and found reports of 30 patients showing MS including NMO complicated with MG; 27 had been diagnosed as MS after thymectomy. Among these 27, 16 of 17 who were examined by spinal cord MRI and for anti-AQP4 antibodies were NMO. Only one patient with signs and symptoms localized to the optic nerves and spinal cord showed no LCL and was not examined for anti-AQP4 antibodies. In autoimmune disorders of the central nervous system after thymectomy in patients with MG, NMO is more predominant than classic MS.
Full Text of this Article in Japanese PDF (360K)

(CLINICA NEUROL, 50: 111|113, 2010)
key words: Myasthenia gravis, thymectomy, anti-aquaporin4 antibody, multiple sclerosis, neuromyelitis optica

(Received: 13-Jul-09)