Blood test helps diagnose neuromyelitis optica

A blood test to identify a severely paralyzing and often blinding disease that is often misdiagnosed as multiple sclerosis may help physicians treat these patients more appropriately sooner, according to a press release from the Mayo Clinic.

Researchers at the Mayo clinic and other centers were able to identify 73% of patients with neuromyelitis optica based on a blood test for an autoantibody they recently identified. The biomarker was found in only 22% of people who had similar symptoms but were ultimately identified as having multiple sclerosis instead.

Neuromyelitis optica, also known as Devic’s syndrome, can be misdiagnosed as multiple sclerosis in up to 30% of cases in some countries, according to the Mayo statement. The syndrome affects both the optic nerves and spinal cord, and within 5 years it causes loss of vision in at least one eye in 50% of affected patients. The prognosis for permanent vision loss and paralysis is worse for patients with Devic’s syndrome than for those with MS, the release said, and it is “particularly difficult” to distinguish from MS in the early phases of the disease.

According to the release, neuromyelitis optica destroys the protective myelin sheath around the optic nerve and spinal cord. If the condition is diagnosed before too much damage to the myelin sheath, however, plasma exchange therapy and immunosuppressive medications can be effective in halting the damage and restoring nerve function.

The disease is regarded as rare in the United States. Ninety percent of those affected are women between 30 and 60 years old, the release said. In addition, some estimates say 25% of African Americans who are diagnosed with MS actually have neuromyelitis optica. The prevalence in Asia is much higher, around 3 per 100,000 citizens, the release said.