Clinical and demographical characteristics of primary progressive multiple sclerosis in Isfahan, Iran.

Primary progressive multiple sclerosis (PPMS) is an uncommon form of multiple sclerosis (MS) in which the course of disease is progressive from onset. In a retrospective study amongst 1606 MS patients registered in Isfahan MS Society (IMSS) from April 2003 to 31 December 2005, 92 PPMS cases were identified. That means, the frequency of PPMS amongst all included MS patients would be 5.7% (95% CI: 6.7% and 4.7%). The mean expanded disability status scale (EDSS) for the group was 5.09 +/- 1.3. The commonest mode of presentation was motor disturbance in 55 (59.8%), other modes of presentation were, vertigo in 15 (16.3%), visual problems in 12 (13%), sensory disturbances in six (6.5%), and diplopia in four (4.3%). The current [corrected] existing symptoms were motor problems in all 92 (100%), cerebellar symptoms in 46 (50%), and cognitive impairment in only 6corrected. Interestingly, two (2%) were affected by poliomyelitis during childhood and presenting symptom in both was limb weakness. Primary progressive form of MS is less common in Persian population and some of the rates observed in PPMS patients differ from those in other regions, these differences may be due to different ethnicity of Persian patients or to geographical differences.