Relevance of ultrasonography in assessing disease activity in patients with idiopathic inflammatory myopathies.

AIM: Idiopathic inflammatory myopathies (IIM) comprise a group of rare and heterogeneous diseases difficult to diagnose and follow up. Precise measures for assessing disease activity are not available at the moment. Our objective was to evaluate the usefulness of ultrasonography (US) as a monitoring tool in IIM.

METHOD: The study evaluated IIM patients diagnosed and followed up from 2005 to 2015 in our department. Fifteen patients with a mean age of 52.2 ± 22.09 years and mean disease duration of 4.6 ± 3.20 years were included. Physical examination including muscle strength tests, laboratorial analysis and a selective muscle US assessment were performed for each patient at a scheduled visit.

RESULTS

Nine of the 15 patients were in clinical remission and US assessment revealed a preserved muscle pattern. Symmetrical proximal muscle atrophy was found on US in one patient with longstanding polymyositis (PM) with proximal weakness. Inflammation and focal or generalized muscle edema were present on US in the remaining five patients with muscular weakness suggesting active disease. One of these patients in acute flare presented with atrophy changes in addition to edema. Early untreated myositis presented in one patient with moderate power Doppler (PD) signal.

CONCLUSION

As far as muscle US assessment is concerned, a single specific pattern was not observed in our study. A mixture of muscle edema and atrophy was detected depending on disease activity and duration. US findings seem to correlate well with disease activity, suggested by clinical data, and may be a useful tool to complement patient evaluation.