NMO may be preceded by:
(1) a viral infection
(2) a bacterial infection
(3) an autoimmune disease (associated with autoantibodies)
(4) multiple sclerosis
Diagnostic features:
(1) The onset of both optic neuritis and transverse myelitis, either together or one after the other.
(2) The absence of involvement elsewhere in the central nervous system.
(3) Pleocytosis in the CSF with a predominance of neutrophils.
The optic neuritis is associated with ocular pain and visual loss that may be unilateral or bilateral.
The transverse myelitis may result in:
(1) paraparesis or quadriparesis
(2) motor, sensory and sphincter dysfunction
(3) tonic seizures
(4) respiratory paralysis (if the cervical cord is involved)
An MRI will show characteristic lesions in the optic chiasm and spinal cord. A key finding is the absence of lesions elsewhere in the CNS.
The illness may be monophasic or it may follow a relapsing course.
