By: MICHELE G. SULLIVAN, Clinical Neurology News Digital Network
PHILADELPHIA – A proposed revision of the neuromyelitis optica diagnostic criteria takes into account newly appreciated variations in how the disease can present clinically.
If adopted, the new criteria would offer diagnostic pathways for patients who have symptoms, but who might or might not have the serum antibodies usually associated with the disorder, Dr. Dean Wingerchuk said at the annual meeting of the American Academy of Neurology.
They reflect the current understanding of neuromyelitis optica as a spectrum of clinical symptoms, said Dr. Wingerchuk, professor of neurology at the Mayo Clinic, Scottsdale, Ariz. Neuromyelitis optica spectrum disorder (NMOSD) was identified in 2007 – 1 year after the existing diagnostic criteria were published.
In the new guidelines, “we wanted to encompass all patients who would have previously been diagnosed as having neuromyelitis optica or NMOSD,” he said. A new stratification of antibody positive or antibody negative reflects the fact that not all patients are seropositive at presentation, particularly early in the disease course; 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 still need to be prospectively validated before they could be widely adopted, 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 imaging findings that are nondiagnostic for multiple sclerosis.
• A spinal cord lesion extending over three or more vertebral segments.
• Seropositivity for NMO-IgG.
The newly proposed criteria have been expanded to include six different core characteristics: optic neuritis; acute myelitis; area postrema syndrome (nausea, vomiting, and hiccups); other brain stem syndromes; symptomatic narcolepsy or acute diencephalic syndrome with MRI findings; and symptomatic cerebral syndrome with MRI findings.
Antibody-positive patients need to show at least one of these core characteristics, with no other better explanation for their symptoms.
The bar is a little higher for antibody-negative patients. They need to show at least two of the core characteristics, meeting 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 multiple sclerosis or other demyelinating disorders.
Prospective validation will require follow-up of patients who are seropositive at diagnosis but present with less common syndromes, and detailed descriptions of seronegative groups to determine whether they eventually convert to a clinical NMOSD, Dr. Wingerchuk said.
The project is being funded by the Guthy-Jackson Charitable Foundation. Dr. Wingerchuk disclosed that he has received financial compensation on an adjudication committee for an NMO trial that was sponsored by MedImmune.