1,2Saloua Mrabet, 1,2Imen Kacem, 1,2Amira Souissi, 1,2Alya Gharbi, 1,2Mohamed Ahmed Nour, 1,2Mouna Ben Djebara, 1,2Amina Gargouri, 1,2Riadh Gouider
1Department of Neurology, Clinical Investigation Centre Neurosciences and Mental Health, University Hospital Razi, Manouba, Tunisia; 2Faculty of medicine, University Tunis El Manar, Tunis, Tunisia
Multiple Sclerosis (MS) prevalence has increased substantially in Tunisia since the first reports of Ben Hmida in 1977. However, to date, data regarding progressive MS remains limited. Our objective is to describe the demographic and clinical characteristics of progressive MS in a Tunisian cohort.
Material(s) and Method(s):
A retrospective study was conducted in the department of Neurology of Razi hospital-Tunisia including patients diagnosed with primary progressive MS (PPMS) according to 2017 McDonald criteria and secondary progressive MS (SPMS) according to the definition of Lorscheider et al. Data regarding sex-ratio, age of disease onset, first clinical attack characteristics were described and compared between the two groups. Pediatric MS (PoMS) was considered if age of disease onset was below 18 years. Late onset MS (LoMS) was considered for patients whose age of disease onset was above 50 years. Disability progression was evaluated via the median time to reach Expanded disability status scale (EDSS) 4 and 6 and MS severity score (MSSS). A statistically significant difference was validated if p<0.05.
Of the consecutive records of 504 patients diagnosed with MS, 115 (22.8%) were found to be progressive: SPMS (n=70; 13.9%) and PPMS (n=45; 8.9%). Female predominance was more pronounced during SPMS (F/M=2.88) compared with PPMS (F/M=1.5) (p=0.1). MS age of onset was higher in the PPMS group (41 years ±10.7) compared to the SPMS group (28 years±8.4) (p=0.000), and was comparable between individuals from SPMS (40.4 years ±9.7) and PPMS (41 years ±10.7) groups, once the progressive phase was initiated (p=0.5). For SPMS, only one case with PoMS was identified (14 years) followed with a transition to the progressive phase after 22 years. Similarly, in PPMS, only one case with PoMS was noted (16 years). LoMS was described in one patient diagnosed with SPMS versus 11 patients classified as PPMS (p=0.000). During the first clinical attack, motor symptoms were more prevalent in the PPMS group (91.1% versus 58.5%; p=0.000), meanwhile visual symptoms were more frequently reported in the SPMS group (25.7% versus 6.6%; p=0.012). Median time to reach EDSS4 (SPMS=6 years; PPMS=7 years (p=0.7)) and EDSS 6 (SPMS=8.5 years; PPMS=7.5 years (p=0.7)) were comparable between the two groups. MSSS were also comparable between SPMS patients (7.67±1.7) and PPMS (7.87±1.87) (p=0.3).
In our cohort, progressive MS prevalence, sex ratio and age at disease onset were consistent with previous studies. PoMS was not common during these two conditions, meanwhile, late onset MS was more frequent during PPMS. PPMS patients tend to be older with a mean age at onset of first symptoms after forties. Motor symptoms were more frequent during PPMS, which could be related to the higher prevalence of spinal cord lesions during this condition. SPMS was associated with a higher prevalence of visual symptoms, as onset optic neuritis is more common during the relapsing onset MS. SPMS and PPMS, regarding disability accumulation, are comparable. In fact, it was suggested that progressive MS do progress at the same rate, regardless of the events that led up to the onset of progression.