PHILADELPHIA—A proposed revision of the diagnostic criteria for neuromyelitis optica takes into account newly appreciated variations in the disease’s clinical presentation. The new criteria, which were presented at the 66th Annual Meeting of the American Academy of Neurology, would offer potential diagnoses for patients who have symptoms but who do not have the serum antibodies usually associated with the disorder.
The document reflects the current understanding of neuromyelitis optica as a spectrum of clinical symptoms, said Dean Wingerchuk, MD, Professor of Neurology at the Mayo Clinic in Scottsdale, Arizona. Neuromyelitis optica spectrum disorder (NMOSD) was identified in 2007, one year after the existing diagnostic criteria were published.
“We wanted to encompass all patients who would have previously been diagnosed as having neuromyelitis optica or NMOSD,” in the new guidelines, said Dr. Wingerchuk. A new stratification of patients as antibody-positive or antibody-negative reflects the fact that not all patients are seropositive at presentation, particularly if they present early in the course of the disease; that antibody testing is not available or reliable everywhere; and that as-yet-unidentified antibodies might be implicated in the disorder.
The workgroup that authored the document consisted of 18 members from nine countries. It began its work in 2011. The proposed criteria need to be validated prospectively before they can be adopted widely, noted Dr. Wingerchuk, who was a primary author of the 2006 criteria.
The existing criteria require the presence of transverse myelitis, optic neuritis, and at least two of the following:
- Brain MRI findings that are nondiagnostic for multiple sclerosis (MS)
- A spinal cord lesion extending over three or more vertebral segments
- Seropositivity for NMO-IgG.
The newly proposed criteria include six core characteristics: optic neuritis, acute myelitis, area postrema syndrome (ie, nausea, vomiting, and hiccups), other brainstem syndromes, symptomatic narcolepsy or acute diencephalic syndrome with MRI findings, and symptomatic cerebral syndrome with MRI findings. Antibody-positive patients must have at least one core characteristic to be diagnosed with neuromyelitis optica, and no better explanation for their symptoms should be apparent.
Antibody-negative patients must meet stricter criteria to receive a diagnosis. They must have at least two of the core characteristics and meet the following requirements:
- At least one of the core symptoms must be optic neuritis, myelitis, or area postrema syndrome.
- The core characteristics must be disseminated in space.
- MRI findings must distinguish NMOSD from MS or other demyelinating disorders.
Prospective validation will require follow-up of patients who are seropositive at diagnosis but present with less common syndromes. Validation also will require detailed descriptions of seronegative groups to determine whether they eventually convert to a clinical NMOSD, concluded Dr. Wingerchuk.
—Michele G. Sullivan