Infection Risk in Patients with Dermatomyositis Associated with Anti-MDA5 Antibodies: A Historical Cohort Study

Spontaneous pneumomediastinum in anti-MDA5-positive dermatomyositis: Prevalence, risk factors, and prognosis

OBJECTIVE

To depict the clinical panorama of spontaneous pneumomediastinum (SPM) in anti-MDA5 antibody-positive dermatomyositis (anti-MDA5+ DM).

METHODS

A total of 1352 patients with idiopathic inflammatory myopathy (IIM), including 384 anti-MDA5+ DM patients were retrospectively enrolled. The clinical profiles of anti-MDA5+ DM-associated SPM were analyzed.

RESULTS

We identified that 9.4 % (36/384) of anti-MDA5+ DM patients were complicated with SPM, which was significantly higher than that of non-anti-MDA5+ DM and other IIM subtypes (P all <0.001). SPM developed at a median of 5.5 (3.0, 12.0) months after anti-MDA5+ DM onset. Anti-MDA5+ DM patients complicated with SPM showed a significantly higher frequency of fever, dyspnea, and pulmonary infection including viral and fungal infections compared to those without SPM (P all < 0.05). Cytomegalovirus (CMV) and fungal infections were identified to be independent risk factors for SPM development in the anti-MDA5+ DM. SPM and non-SPM patients in our anti-MDA5+ DM cohort showed comparable short-term and long-term survival (P = 0.236). Furthermore, in the SPM group, we found that the non-survivors had a lower peripheral lymphocyte count, higher LDH level, and higher frequency of intensification of immunosuppressive treatment (IST) than survivors. The elevated LDH level and intensification of IST were independent risk factors for increased mortality in anti-MDA5+ DM-associated SPM patients.

CONCLUSIONS

Nearly one-tenth of patients with anti-MDA5+ DM develop SPM. Both CMV and fungal infections are risk factors for SPM occurrence. The development of SPM does not worsen the prognosis of anti-MDA5+ DM patients, and the intensification of IST does harm to the SPM prognosis.

Pyomyositis Secondary to Localized Cellulitis in a Dermatomyositis Patient: A Case Report and Review of Infectious Complications in Dermatomyositis

Dermatomyositis (DM) is an autoimmune disorder characterized by proximal muscle weakness and distinct cutaneous features. Unfortunately, infection is a frequent and potentially life-threatening complication in patients with DM. Here, we present a case of pyomyositis in a patient with DM resulting from localized cellulitis. The patient also presented with subcutaneous calcification nodules and dermatomyositis-associated lipodermatosclerosis nodules. To our knowledge, there have been no reports of pyomyositis in patients with DM to date. Furthermore, we reviewed the infectious complications related to DM and polymyositis (PM). We found that idiopathic inflammatory myopathy (IIM) patients exhibit a considerable infection-related mortality rate, ranging from 4.3% to 7.2%. In IIM, infections were identified as the primary cause of mortality in a substantial proportion of cases, accounting for 22.0-83.3% of deaths. These findings have implications for the importance of identifying and managing infections in IIM patients and suggest the need for further research into infection-related complications in these patients.