Pediatric Rheumatology Online Journal → July 2003 → Dermatomyositis → Clinical Evaluation → Abstract #122

QUANTITATIVE ASSESSMENT OF THE EFFECTS OF EXERCISE ON MUSCLES IN CHILDREN WITH DERMATOMYOSITIS

SM Maillard, R Jones, KJ Murray, CM Owens, CA Pilkington

¹Juvenile Dermatomyositis Research Centre, Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom

Aims
The aim of the study is to investigate the effects of exercise on muscle inflammation in children with juvenile dermatomyositis (JDM) and to examine the validity and reliability of a quantifiable measure of inflammation using magnetic resonance imaging (MRI).
Methods
Children with active JDM, inactive JDM and healthy children received detailed assessments of muscle strength (including myometry) and function, an MRI and the JDM patients had blood taken. A standardised physiotherapy led exercise programme was completed and an MRI was performed immediately afterwards. All children were reassessed with myometry and MRI at 30mins and 60 mins, plus repeat bloods at 60 mins for all JDM subjects.
Results
Ten children with active JDM, 10 with inactive JDM and 20 healthy controls completed the study. The mean age at time of the study was 9.2 years. There was no significant difference in ages between the 3 groups. The pre-exercise MRI T2 relaxation times were significantly increased in active JDM compared to inactive JDM and healthy children (p = 0.05), indicating this is a quantifiable measure of the level of inflammation within the muscles. There were good correlations between the MRI scores and the measures of muscle strength and function. There was no correlation between MRI and blood parameters.
The assessments of muscle inflammation (MRI, myometry and blood parameters) did not change significantly in response to exercise either immediately after or up to 60 minutes after the exercise programme in any group.
Conclusions
The MRI T2 relaxation time can be used as a quantitative measure of muscle inflammation.
Exercise does not change the degree of inflammation within the muscles when measured by MRI, muscle strength and blood parameters in children with active or inactive JDM or in healthy children. Therefore a moderate exercise programme is safe for children with JDM as there is no evidence that it increases the inflammation within the muscles.