Abstract
Purpose: :
A significant number of patients presenting with optic neuritis (ON) have radiological evidence of demyelination elsewhere in the central nervous system (CNS) and many subsequently go on to develop multiple sclerosis (MS). It remains unclear whether the early introduction of currently available disease modifying drugs (DMTs), such as Interferon-beta, has an effect on long term disability in MS. As ON is frequently the earliest manifestation of MS it is important to characterise disease progression in these patients before starting such immunotherapies.The purpose of this study is to determine the disease characteristics of patients presenting with optic neuritis as the first clinical manifestation of MS.
Methods: :
Clinical details (sex, age, age disease onset, relapse history and disability scores) were reviewed retrospectively in n=479 subjects (male, n=111, female, n=368; mean disease duration / years ± standard deviation (sd), 11.2±10.3) with confirmed MS seen at the John Radcliffe Hospital, Oxford, UK. Disability scores (Expanded Disability Severity Score (EDSS)) were analyzed using a Microsoft Excel database tool.
Results: :
ON appeared as the first clinical presentation in n=115 (24%) of subjects with MS although overall n=196 (41%) developed ON at some stage of disease. Subjects presenting with ON were significantly younger than those presenting with cortical, brainstem or spinal cord relapses (mean age / years ± sd: 30.3±1.2 versus 32.7±0.5, p=0.033). Recurrence of ON was more frequently observed in subjects presenting with ON rather than other types of relapse (Odds ratio 2.01 (1.28-3.16), p=0.004) but did not determine interattack interval (the time between disease onset and the second relapse) or the total number of relapses. ON at disease onset did not influence disability scores at 5, 10 and 15 years follow-up and the time taken to EDSS 6 (use of single walking aid) was the same in each group (time / years ± sd: 11.5±1.4 versus 12.9±0.9, p=0.414)
Conclusions: :
In our study group, the natural history of MS patients presenting with ON did not differ from those presenting with other clinical syndromes. Although it remains unclear which, if any, of the newer DMTs delay disease progression they are most likely to be efficacious if started early. As patients with ON present at a younger age compared to those with demyelination in less eloquent CNS areas, this subgroup may benefit most if in the future these drugs are found to be neuroprotective.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • neuro-ophthalmology: optic nerve • neuro-ophthalmology: diagnosis