Is optic neuritis more benign than other first attacks in multiple sclerosis?

Area of Science:

• Neurology
• Neuroimmunology
• Clinical Neuroscience

Background:

• Optic neuritis is a common initial presentation of demyelinating diseases.
• The prognosis of Clinically Isolated Syndromes (CIS) varies based on initial topography.
• Understanding conversion risk to multiple sclerosis (MS) is vital for patient management.

Purpose of the Study:

• To compare the conversion rates to MS across different CIS topographies.
• To investigate the role of baseline MRI in predicting MS conversion.
• To determine if optic neuritis has a different prognosis compared to other CIS types.

Main Methods:

• Prospective evaluation of 320 patients with CIS.
• Categorization of CIS by topography: optic neuritis, brainstem, spinal cord, and other.
• Serial brain MRI (baseline and 12 months) and clinical follow-up for a median of 39 months.
• Assessment of conversion to clinically definite MS or MS fulfilling MRI criteria.

Main Results:

• Patients with optic neuritis showed lower conversion rates to clinically definite MS.
• A smaller proportion of optic neuritis patients met MRI criteria for dissemination in space/time.
• Baseline MRI abnormalities, regardless of CIS topography, were associated with similar conversion rates to MS.
• 49.2% of optic neuritis patients had normal baseline MRI vs. 24% (brainstem), 24% (spinal cord), and 18.5% (other).

Conclusions:

• Optic neuritis CIS generally carries a lower risk of conversion to MS.
• Baseline MRI findings are a more significant predictor of MS conversion than initial CIS topography.
• Early MRI assessment is critical for risk stratification in patients with CIS.