Segurança e eficácia do exercício físico nas miopatias necrosantes imunomediadas

Abstract

Objectives: To describe retrospectively a case series of patients with immunemediated necrotizing myopathy (IMNM), evaluating the effects of an induction therapy with methylprednisolone (MP) associated or not with intravenous human immunoglobulin (IVIG) on late muscle condition, as seen by muscle magnetic resonance imaging, and on parameters of disease activity. Next, to evaluate prospectively the effects of an assisted and combined physical training program in this sample regarding safety, clinical status, aerobic capacity, muscle strength and function. Methods: Thirteen patients with IMNM (4 patients with anti-hydroxymethyl-glutaryl coenzyme A reductase autoantibodies and 9 patients with antisignal-recognition particle) were initially evaluated in a longitudinal analysis, from 2012 to 2018. By institutional protocol, these patients were treated at diagnosis with an induction scheme with MP pulse therapies associated or not with IVIG. The clinical and laboratory data to calculate the response criteria of the International Myositis Assessment & Clinical Study Group (IMACS) before treatment and at the end of the segment, as well as the magnetic resonance imaging of the thigh at the end of the segment, in order to assess atrophy, edema and fat replacement, were quantified. Additionally, in a quasi-experimental analysis, eight patients of the first sample were also submitted to a supervised physical training program combining aerobic and resisted exercises, twice a week, for 12 weeks. Finally, before and after the training program, the following data were compared: aerobic capacity, through cardiopulmonary exercise test; strength, through the maximal repetition test (RM) in the bench press and in the leg press; and muscular function, through the sit-tostand test (STS) and the timed up-and-go (TUG) test. Results: In the first sample, composed of 9 women and 4 men, the mean age of the patients at diagnosis was 53.5 years and the mean duration of symptoms until the diagnosis was 4 months. All patients received MP and/or IVIG therapy. After an average of 39 months of follow-up, all IMACS parameters improved significantly over baseline parameters. Nine patients had complete clinical response and, among them, two had complete remission. Eleven patients discontinued the use of glucocorticoids at the end of this phase. Only 2 patients had muscle atrophy or fat replacement classified as moderate in magnetic resonance, with the remainder presenting normal or mild findings. Eight patients in the initial sample continued the study and completed the training protocol. No disease activation, worsening of IMACS scores or adverse events were observed throughout the training period. Patients also increased aerobic capacity (time to reach the anaerobic threshold and time to achieve exhaustion), muscle strength (1 RM of the bench press) and muscle function (STS). Conclusion: In this case series, early treatment with MP and/or IVIG pulse therapy with the objective of complete clinical response may have been an effective treatment strat...