An NMO Presentation Resembling Extensive Multiple Sclerosis

Background: Multiple sclerosis (MS) and neuromyelitis optica (NMO) are both central nervous system demyelinating diseases caused by autoimmunity. Classically NMO has simultaneous or sequential involvement of the optic nerves and spinal cord in a longitudinally extensive manner (greater than 3 segments) with less frequent involvement of the brain.  In MS involvement of the spinal cord is limited to less than 3 vertebral bodies with significant brain involvement Though Aquaporin 4 antibodies are sensitive and specific for diagnosing NMO these antibodies may be present in a small percentage of patients with multiple sclerosis.  Given this overlap cortical involvement has been looked to as a distinguishing feature that is present in multiple sclerosis but not typically in NMO 

Objectives: To demonstrate a spectrum of demyelinating diseases that could have features of specific entities like MS or NMO with overlapping clinical, serological and radiological findings.

Methods: This is a case report and review of the literature.

Results: This is a 70 year old Chinese female who has history of recurrent bilateral lower limb weakness attacks for almost 20 years starting when she was in China leading eventually to severe paraparesis with urinary and  fecal  retention. On her initial assessment in 2005, her MRI of the spinal cord showed STIR signal change involving a long segment of the thoracolumbar cord. Her MRI of the brain showed extensive white matter lesions involving cortical and subcortical regions with almost all the white matter tracts involved.  She also had abnormal visual evoked potentials bilaterally, She had a positive NMO Abs with a titer of 1:7280, Her serologic work up was otherwise negative except she had +ve SSA and JO-1 which were not felt to be indicative of a rheumatologic disorder.  The patient failed to improve radiologically and clinically on two types of  Interferon, IV steroids, and was finally started on Imuran 75mg BID along with prednisone 15 mg daily. She was found to be positive for JC virus antibodies which raised concerns for starting Rituximab due the potential risk of PML. Her most recent exacerbation consisted of right optic neuritis which was confirmed by MRI of the orbit.  She received a pulse treatment for steroids and was discharged in a stable condition with improvement in her vision in the right eye.

Conclusions: Our case illustrates white matter involvement in demyelinating disease can be extensive with characteristics from more than one disease (NMO vs. MS).  In the future more specific biological or radiological markers could be useful in distinguishing these presentations and guiding therapy.