Progressive necrotizing myelopathy: part of the spectrum of neuromyelitis optica?

This case series reviews the clinical, radiographic and laboratory findings of five patients with progressive idiopathic myelopathy with evidence of cord necrosis who presented in our institution over a 5 year period ending in May 2005. Patients fulfilling the following criteria were included: (1) presentation with myelopathy without overt visual involvement at initial presentation; (2) demonstration with magnetic resonance imaging (MRI) of contiguously abnormal signal in the spinal cord spanning at least three vertebral segments without evidence of arteriovenous malformation or significant disk disease; (3) absence of systemic disease or neoplasm. All patients were women, identified themselves as African American and were older than 35 years. Pain was reported at initial presentation in four cases. The distinctive feature was a relapsing course with intervening variable improvement of function and progression to quadriplegia in less than 4 years. An increased IgG index and/or oligoclonal banding was detected in two patients. The leukocyte count in the cerebrospinal fluid (CSF) was elevated in all cases but in only one specimen did the count exceed 50 cells. None of the patients initially had clinical signs of an optic neuropathy but unilaterally prolonged visual evoked potentials were present in one individual who went on to developed optic neuritis 19 months after the first clinical presentation. Another patient developed optic neuritis 45 months after disease onset. Immunomodulatory and plasma exchange therapy were of some benefit at least early in the course but the disease progressed despite these interventions. Neuromyelitis optica (NMO)-IgG antibody, a serum or CSF marker described in individuals with classic NMO and optico-spinal multiple sclerosis (MS), was present in all cases. On the basis of shared clinical and imaging features in the cord, progressive necrotizing myelopathy observed in this case series exhibits key features of a limited form of NMO (Devic's disease) and opticospinal MS. The presence of NMO-IgG antibody marker suggests that progressive necrotizing myelopathy is part of a disease spectrum of which traditional NMO is a select presentation.