The clinical characteristics of subcutaneous and mediastinal emphysema in anti-melanoma differentiation-associated 5 positive dermatomyositis associated with interstitial lung disease.

OBJECTIVES:To investigate the clinical characteristics of subcutaneous emphysema (SE) and mediastinal emphysema (ME) occurring in patients with anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis associated with interstitial lung disease (anti-MDA5-positive DM-ILD). METHODS:In this retrospective study, a total of 117 anti-MDA5-positive DM-ILD patients were admitted to our hospital. All patients underwent an assessment of autoantibodies, serum ferritin levels, and lung high-resolution CT scans. RESULTS:In patients with anti-MDA5-positive DM-ILD, the incidence of SE/ME was found to be 11.1%, which was significantly higher compared to patients with anti-synthetase syndrome (p<0.01). The mortality rate among anti-MDA5-positive DM-ILD patients with SE/ME was significantly higher than those without SE/ME (p=0.0022). There was no statistically significant difference in the occurrence of SE/ME between patients with positive anti-Ro-52 antibodies and those with negative anti-Ro-52 antibodies (p=0.18). Patients with higher serum ferritin levels (1000 ng/ml ≤serum ferritin ≤1500 ng/ml) had a higher likelihood of developing SE/ME compared to patients with lower serum ferritin levels (serum ferritin <500 ng/ml) (p<0.01). Among 13 anti-MDA5-positive DM-ILD patients with SE/ME, six (46.2%) developed SE/ME within 1 month of being diagnosed and 53.8% of patients underwent positive pressure ventilation prior to the onset of SE/ME. CONCLUSIONS:We found that SE/ME is not uncommon in anti-MDA5-positive DM-ILD and is an important factor associated with poor patient prognosis. The occurrence of SE/ME is correlated with high levels of serum ferritin and is not related to anti-Ro-52 antibodies. Rheumatologists should pay close attention to SE/ME caused by positive pressure ventilation in anti-MDA5-positive DM-ILD patients.