[Pain in multiple sclerosis: characterization of a Portuguese population of 85 patients]

Multiple sclerosis (MS) is a frequent neurological disease, with an estimated prevalence in Portugal of 60/100.000. It is a disease of the young adult, whose first symptoms are commonly of sensory type. The pathological process is of inflammatory nature, involving the central nervous system. The typical histopathological lesion is an area of demyelination. Initial descriptive studies affirmed that pain was an uncommon symptom in MS. However, it soon became evident that the majority of MS patients experience pain in the course of their disease. In MS it is possible to find any kind of pain syndrome, being the most common central neuropathic pain. A sample of 85 MS patients of the Outpatient Clinic of Demyelinating Diseases of the Neurology Department of São João Hospital, Oporto, Portugal, was studied. The presence of pain, demographic characteristics, disease duration, year of diagnosis, MS subtype, treatments and Expanded Disability Status Scale (EDSS) score were investigated. The group of MS patients with pain completed the short versions of the pain questionnaires The Brief Pain Inventory (BPI) and The McGill Pain Questionnaire (MPQ), for more detailed pain characterization. The prevalence of pain found was 34%. We have not established an association between the existence of pain and disease duration or functional impairment. However, pain interfered significantly with the patients' general activity, mood, work, social relations with others and enjoyment of life. All the pain and MS patients that completed the MPQ employed more than one word to describe their pain, using always words from both the sensory and affective categories. Patient pain descriptions included the word hot-burning in 58,8% of the cases; this word is used commonly in the description of central neuropathic pain. Pain is an important symptom in 85 Portuguese patients with MS, not only because of the high pain prevalence found, but also because of its interference with their quality of life. Pain recognition in MS patients is fundamental to adequately treating MS patients with pain.