[Interstitial lung disease as an initial manifestation of dermatomyositis]

To explore the clinical features and prognosis of dermatomyositis patients with interstitial lung disease (ILD) as an initial manifestation.

Medical records of 184 dermatomyositis inpatients complicated with ILD, admitted into Peking Union Medical College Hospital from January 1999 to January 2013, were retrospectively analyzed. The clinical features, biochemical parameters, positive rates of autoantibodies, radiology, pulmonary function tests, pathology, treatments and prognosis were compared between two subgroups of ILD-initial and non-ILD-initial dermatomyositis.

The incidence of ILD of dermatomyositis inpatients was 17%. The average age was 48 ± 12 years and the gender ratio of male-to-female was 63: 121. Eighty eight (47.8%) dermatomyositis patients had ILD as an initial manifestation, including (n = 42, 22.8%) of ILD concomitant dermatomyositis (within 1 month) and (n = 46, 25.0%) of ILD before dermatomyositis with an average ahead time of (11 ± 3) months. Patients of ILD-initial dermatomyositis had a higher incidence of dyspnea on exertion, cough and lung crackles, but there were lower incidences of heliotrope rash, chest V area rash, shawl sign and joint involvement than non-ILD-initial dermatomyositis (P < 0.05). The positive rate of anti-Jo-1 antibodies of ILD-initial dermatomyositis group was 13.6%. The main performances of ILD-initial dermatomyositis on pulmonary function tests were diffusing and restrictive ventilation impairment. And there was a lower diffusing rate of carbon monoxide than non-ILD-initial dermatomyositis group (P < 0.01). Organic and non-specific interstitial pneumonias were the major clinical pathology types of ILD-initial dermatomyositis. The mortality rate of ILD-initial dermatomyositis patients was 19.3% and there was no significant difference from non-ILD-initial dermatomyositis (P > 0.05). The main course of ILD-initial dermatomyositis was respiratory failure due to progressive ILD (n = 13, 76.5%).

ILD as an initial manifestation is a common complication and a major mortality cause of dermatomyositis inpatients. And the frequent clinical pathology types are organic and non-specific interstitial pneumonias. Symptoms of skin and muscle, creatine kinase and anti-synthetase antibodies should be closely monitored.