Pain in multiple sclerosis: a clinical and instrumental approach

Abstract

Background Pain is a frequent and disabling symptom in multiple sclerosis (MS) patients. In this study we assess the frequency and intensity of pain, as well as its impact on the quality of life and activities of daily living, in a sample of MS patients. Methods One hundred and twenty eight MS patients underwent a neurological examination, a structured interview designed to assess pain, and a Medical Outcome 36-item Short Form Health Survey. Functional status was assessed by means of the Barthel Index (BI) and Rivermead Mobility Index. We also assessed the presence of depression, by means of the Montgomery and Asberg Depression Rating Scale, and fatigue, by means of the Fatigue Severity Scale. An algometer was used to measure thermal and discomfort thresholds in all of the patients and a group of 61 age- and sex-matched healthy subjects. Results Pain was present in 61 patients. No differences were found between patients with and those without pain in disease duration, disease form or Expanded Disability Status Scale and its functional systems. Patients with pain had a lower vitality score (p = 0.008), mental health score (p = 0.03) and physical (p < 0.001) and mental composite scores (p = 0.01) than patients without pain. Furthermore, there was a significant difference between patients with and those without pain in the BI (p = 0.04). Both thermal and discomfort thresholds, as assessed by means of the algometer, were statistically lower in MS patients than in controls, whereas no difference was observed between patients with and those without pain. There was a statistically significant improvement in the thermal threshold in patients with pain who were treated pharmacologically when compared with those who were not treated (p = 0.049). Conclusion The results of this study provide further evidence of the negative impact that the presence of pain has on both the quality of life and activities of daily living in MS patients. The lower thermal and discomfort thresholds observed in our MS patients, compared with controls, may represent a predisposition to develop pain during the course of the disease.