When the syndrome is severe, and Multiple Sclerosis is ruled out, could it be Neuromyelitis Optica (NMO)?
NMO is known to progress rapidly—within five years, 50 percent of patients lose functional vision in one eye or become unable to walk independently.1 Therefore, it is important to distinguish between the two and provide the appropriate treatment as well as understand the prognosis.
- Most relapses of NMO worsen over several days and then slowly improve in the weeks or months after the maximum clinical deficit is reached. Recovery is usually incomplete, and most patients follow a course of early incremental disability due to frequent and severe relapses.2
- Current evidence suggests that conventional immunomodulatory treatments for MS are ineffective for NMO.3 NMO is a rare and severe disease syndrome of the central nervous system that affects the optic nerves and spinal cord. It is primarily characterized by optic neuritis and transverse myelitis—and the prognosis is serious. Because the symptoms are similar to multiple sclerosis, especially early in the disease course, NMO can be misdiagnosed as MS.
Finding NMO early can make a difference. Consider NMO in the following patients with ON or TM (or both) and an MRI without “typical” lesions:
- Patients who have MS-like symptoms.
- Patients with a spinal cord lesion extending contiguously over three or more spinal segments.
- Patients with normal brain MRI findings that show non-specific white matter lesions that do not fulfill the criteria for diagnosis of multiple sclerosis.
- About five percent of MS patients have “normal” brain MRIs, suggesting they do not have MS. These patients may be “false negatives”.
- Patients with abnormal MRI and MS-looking lesions that are actually “age-related”—some estimate five percent of patients will have a “false positive” diagnosis. A false positive diagnosis can be potentially dangerous because it implies “unnecessary” successive tests and treatments.4
1Wingerchuk DM, et al. The Spectrum of neuromyelitis optica. Lancet, 2007.
2Wingerchuk DM, et al. The clinical course of neuromyelitis optica (Devic’s syndrome). Neurology, 1999.
3Matiello, et al. NMO-IgG predicts the outcome of recurrent optic neuritis, Neurology, 2008.
4Whiting P, et al. Accuracy of magnetic resonance imaging for the diagnosis of multiple sclerosis: systematic review, BMJ, 2006.