Trebst et al. published an article in 2014 about the Neuromyelitis Optica Study Group’s recommendation for diagnosing and treating neuromyelitis optica (NMO). NMO is characterized by optic neuritis (ON) and transverse myelitis (TM), typically with lesions extending over three or more vertebral segments. The prevalence of NMO is from less than 1 to 4.4 per 100,000 people, with more women than men having the disease. Most cases of NMO (80-90%) are relapsing, and the median age of onset is 39. A diagnosis of NMO is typically made when an individual has had at least one episode of ON, one episode of TM, and two of three of these criteria:
“(1) Contiguous spinal cord MRI lesion extending over three or more vertebral segments
(2) Brain MRI not meeting Paty’s diagnostic criteria for MS at disease onset (Four or more white matter lesions, or more than three white matter lesions if one of these is located in the periventricular region)
(3) NMO-IgG seropositive status.”
A patient with NMO may not always fit into these criteria, so Trebst et al. state that these criteria should be used to make NMO diagnoses but not exclude diagnoses of NMO. Trebst et al. also recommend a detailed medical history, including symptoms that are more likely to occur in NMO patients than MS patients, such as brainstem symptoms, neuropathic pain, and painful tonic spasms. They also recommend basic laboratory tests, and tests for the AQP4 antibody, as AQP4 is present in approximately 60-90% of patients who fit the diagnostic criteria for NMO. Even though AQP4 antibodies may still be detectable during treatment with immunosuppressants, Trebst et al. recommend adequately sensitive AQP4 antibody testing before patients are treated with immunosuppressants. They also recommend testing cerebrospinal fluid, including for oligoclonal bands (OCBs). Those with NMO may initially test positive for OCBs but then later test negative, and this is not usually the case for those with MS. Other biomarkers, such as IL-6 may also be biomarkers for NMO. Magnetic resonance imaging (MRI) with and without contrast of the brain and the entire spinal cord is also recommended. MRI in those with NMO often show lesions extending more than three segments, and may show brain lesions in up to 60% of NMO cases.
Since there is currently no cure for NMO, treatment aims to improve symptoms and prevent relapse. During an acute attack, the authors recommend treatment with steroids, and potentially plasma exchange. After an acute attack and after a definitive diagnosis of NMO has been made, Trebst et al. recommend that immunosuppressants should be started. These include Azathioprine (first-line therapy), Rituximab (first-line therapy), high dose IVIg (can be first-line therapy), Mycophenolate mofetil (second-line therapy), methotrexate (second-line therapy), Mitoxantrone (second-line therapy), Tocilizumab (third-line therapy), combination therapy (third-line therapy), or Cyclophosphamide (if other treatment options no longer work). Trebst et al. do not recommend interferon-beta/glatiramer acetate, natalizumab or fingolimod as these have been shown to have negative effects on those with NMO.
The authors note that research in NMO has expanded greatly in recent years and will continue to grow, potentially leading to new discoveries and treatments.
This summary was written by Gabrielle (GG) deFiebre, Research Associate at a Public Health non-profit in New York city who was diagnosed with Transverse Myelitis in 2009. GG volunteers with the Transverse Myelitis Association.
Original research: Trebst C et al. Update on the diagnosis and treatment of neuromyelitis optica: Recommendations of the Neuromyelitis Optica Study Group (NEMOS). J Neurol. 2014;261:1-16.