Isolated optic neuritis and its prognosis for multiple sclerosis: a clinical and paraclinical study with evoked potentials. CSF examination and brain MRI

Abstract

Our study evaluated the frequency of developing multiple sclerosis (MS) after acute isolated optic neuritis (ON), the possible association with risk factors (gender, age), and the diagnostic and prognosis role of paraclinical tests. We studied 100 ON patients (mean age 28.9 years: SD 8.9): 85 patients were regularly followed up. Sixty-six patients underwent multimodality evoked potential (EP) test, examination and brain MRI within six months of the onset of ON. Over a mean follow-up of 5.2 years, MS occurred in 28/85 cases. The risk of developing MS after four years was 0.35 at life-table analysis, regardless of gender or age at the onset of ON. Visual EPs in unaffected eyes were abnormal in 25.4%, brainstem auditory EPs in 6.5% somatosensory EPs in 8.1%, upper limb motor EPs in 6.8% of the tested patients; intrathecal IgG synthesis was revealed in 51.7% and MRI lesions in 73.8%. Fifty-one of the patients who underwent paraclinical tests were followed up for more than one year, and MS occurred in 13 cases. All of these presented MRI lesions, nine intrathecal IgG synthesis, and two abnormal extraocular EPs. The risk of developing MS after four years was 0.33 in patients with MRI lesions; the simultaneous presence of intrathecal IgG synthesis increased the risk to 0.46.

Sudomotor dysfunction in patients with optic neuritis

“…Earlier, using conventional evoked potentials, ON patients have been shown to have silent CNS lesions in the somatosensory [13,25], motor [13,25], visual [13], and auditory pathways [13]. Our results, however, suggest that the central sudomotor pathways may also be lesioned in ON patients.…”

Long-term follow-up of isolated optic neuritis: the risk of developing multiple sclerosis, its outcome, and the prognostic role of paraclinical tests

“…Baseline clinical data have been described in two previous papers [17,32]. The follow-up study was restricted to patients whose paraclinical tests (brain MRI, multiple EPs, CSF examination) had been performed within 6 months of ON onset; 112 cases fulfilled this criterion.…”

Optic neuritis in multiple sclerosis

“…151 However, a more recent study showed some predictive value in the assessment of CSF of patients who have MS. Those who had both abnormal MRI and elevated intrathecal IgG synthesis had an 46% increased risk of developing MS after four years, compared with 33% if they had only an abnormal MRI. 152 Furthermore, a positive ANA did not have any effect on the patient's course or response to any treatment given. 4 Therefore, besides neuroimaging, no further laboratory testing is required for typical optic neuritis.…”