Benign multiple sclerosis? Clinical course, long term follow up, and assessment of prognostic factors
- aNorthern Ireland Regional Neurology Service, Royal Victoria Hospital, Belfast, Northern Ireland, UK, bSchool of Clinical Medicine, The Queen’s University of Belfast, Belfast, Northern Ireland, UK
- Dr GV McDonnell, Northern Ireland Regional Neurology Service, Quin House, Royal Victoria Hospital, Belfast BT12 6BA, Northern Ireland, UK. Telephone 0044 1232 240503 ext 4325; fax 0044 1232 235258.
- Received 20 October 1998
- Revised 16 December 1998
- Accepted 20 January 1999
OBJECTIVE To establish the characteristics of patients following a benign course of multiple sclerosis and evaluate the importance of potential prognostic factors. Also, an assessment of the value of the Kurtzke EDSS as a prognostic indicator has been undertaken in patients previously determined to have benign multiple sclerosis, after 10 years of follow up.
METHODS A prevalence study in the Coleraine, Ballymena, Ballymoney, and Moyle districts of Northern Ireland used the Kurtzke expanded disability scale score (EDSS) in 259 patients with multiple sclerosis. Of these, 181 had had multiple sclerosis for⩾10 years, 36 having benign disease (EDSS⩽3.0) ⩾10 years after onset. Clinical and demographic details of the various patient groups, including the minimal record of disability, were compared. The 1987 study in Northern Ireland identified 33 patients with benign multiple sclerosis. Twenty eight were available for follow up in 1996 along with 42 contemporary non-benign patients.
RESULTS Patients with benign multiple sclerosis were predominantly women (ratio 4.1:1 v 2.1:1) and younger at onset (25.8 v 31.2 years). Commonest symptoms at onset were sensory and optic neuritis (33.3% each). Patients with late onset (older than 40 years) were less likely to have a benign course, more likely to have a progressive course from onset, significantly more likely to have motor disturbance at presentation, and had a lesser female predominance. Optic neuritis was significantly more common in those with a younger age at onset. In the follow up study, patients with benign multiple sclerosis continued to have a more favourable course than non-benign counterparts but progression of disability and to the secondary progressive phase remained significant.
CONCLUSIONS The association of female sex, early onset, and presentation with optic neuritis and sensory symptoms with a favourable course is confirmed. However, although the EDSS does provide a useful indicator of prognosis, the label “benign multiple sclerosis” is often temporary as apparently benign disease often becomes disabling.