Clinical and serological feature s of patients with dermatomyositis complicated by spontaneous pneumomediastinum / 中华风湿病学杂志

ABSTRACT

Objective To explore the clinical and serological features of patients with pneumomdiastinum (PNM) and dermatomyositis associated interstitial lung disease (DM-ILD).Methods A total of 145 polymyositis/dermatomyositis (PM/DM) patients hospitalized in our department from March,2010 to December,2012 were recruited.The sera,clinical and laboratory data were collected.Anti-aminoacyl-tRNA synthetase (anti-ARS) and anti-melanoma differentiation-associated gene 5 (MDA5) antibodies were detected by RNA-immunoprecipitation (RNA-IP) and ELISA,respectively.Anti-NXP2,anti-TIF1γ,anti-SRP,anti-SAE and antiMi2 antibodies were detected by immunoprecipitation-Western blotting.Variables were compared between DM patients with and without PNM,as well as between DM-ILD patients with and without PNM.Chi square test,Fisher's exact test,t test,Mann-Whitney U test and a multivariate logistic regression model were used for statistical analysis.Results A total of 11 DM patients (10 patients positive for anti-MDA5 and 1 patient positive for anti-Mi2) developed spontaneous PNM.No PM patient developed PNM.No differences of sex,age at the onset of DM,serum ferritin levels and C reactive protein (CRP) levels was observed between DM patients with and without PNM.Compared with DM patients without PNM,DM patients with PNM had significantly higher frequencies of rapidly progressive ILD (RP-ILD) (63.6％ vs 24.4％,x2=7.25,P=0.01),anti-MDA5 antibodies (90.9％ vs 52.4％,x2=5.86,P=0.02),clinically amyopathic DM (CADM) (63.6％ vs 22.0％,x2=8.57,P=0.007) and cutaneous ulcers (36.4％ vs 11％,x2=5.20,P=0.04),but significantly lower creatine kinase (CK) levels [58.5 (30.5,394.3) U/L vs 284 (73.0,917.0) U/L,t=207.5,P=0.04].The logistic multivariate analysis indicated that cutaneous ulcer was the only independent risk factor for the occurrence of PNM in DM [OR=5.98,95％ confidence interval (CI) (1.12,31.98),P=0.037].In the comparisons between DM-ILD patients with and without PNM,a higher frequency of CADM was observed in the PNM group (63.6％ vs 27.9％,x2=5.37,P=0.03),but no significant difference of the frequencies of RP-ILD,anti-MDA5 antibodies,cutaneous ulcers and CK levels was found in these two groups.All patients with PNM were treated with corticosteroids and immunosuppressants.During the follow-up period,6 patients died of respiratory failure.Conclusion Spontaneous PNM is a refractory complication with poor prognosis,and tends to occur in DM patients with RP-ILD,anti-MDA5 antibody,CADM diagnosis and low CK level,especially in patients with cutaneous ulcers.