Background:Systemic sclerosis can affect multiple organs. Diaphragm function has not been evaluated in this group of patients so far. Diaphragm dysfunction is often unrecognized due to a lack of available diagnostic tests.

Aims and objectives:This study aimed to evaluate the mobility of the diaphragm in respiration measured by ultrasound in patients with systemic sclerosis (SSc) compared to known values for healthy subjects. In a study from Boussuges,A. et al.Chest 2009;135:391-400 on 200 healthy subjects lower values of normal diaphragm mobility on the right side were 3.6cm for women and 4.7cm for men during deep breathing and 1cm for women and 1,1cm for men in quiet breathing.

Methods:In this multicentric cross-sectional study ultrasonic parameters of diaphragm mobility in deep and quiet breathing on the right side as well as mMRC scale, spirometry and diffusing capacity for carbon monoxide (DLCO) were analyzed in patients with SSc. Differences in observed values in relation to diaphragm mobility were compared.

Results:A total of 50 patients were included. Ten patients (20%) had lower diaphragm mobility in deep breathing and 6 (12%) patients had lower diaphragm mobility in quiet breathing. Patients with lower values of diaphragm mobility in deep breathing had lower values of DLCO (Mann Whitney U test; p= 0.01), alveolar volume (p= 0.007), higher mMRC score (p=0,02), and lower height (p=0.009).

Conclusion:Patients with SSc are at increased risk for diaphragm dysfunction. Patients with lower diaphragm mobility in deep breathing had lower values of DLCO and more pronounced dyspnea (mMRC) score. Ultrasound of the diaphragm is a useful test for diaphragmatic dysfunction and should be considered in patients with SSc with dyspnea.