RESUMEN
A 30-year-old pregnant woman experienced mild dyspnea in April 2009. She complained of mild myalgia and was subsequently admitted to our hospital in June 2009 because of worsening dyspnea. Physical examination revealed fine crackles in the lower lung field, but no eruptions externally. Laboratory findings revealed elevated serum levels of myogenic enzymes (aldolase, 17.6 IU/l and myoglobin, 247.2 ng/ml) and positive titers for the anti-Jo-1 antibody and hypoxia (PaO(2), 79.4 Torr). The chest radiograph revealed a ground-glass opacity. The patient was diagnosed as interstitial pneumonia (IP) associated with polymyositis (PM) at 20 weeks of gestation. On July 9, we commenced the initial treatment-steroid pulse therapy with 60 mg/day of prednisolone and 3 mg/day of tacrolimus. We also induced abortion. The treatment of corticosteroids and tacrolimus was, however, ineffective even after increasing the tacrolimus dose to 6 mg/day. On July 30, she suddenly experienced chest pain along with severe dyspnea. Computed tomography revealed the presence of pneumomediastinum and deterioration of the IP. We added cyclophosphamide pulse therapy to the existing regimen ; this improved the disease course, reduced hypoxia, and improved radiographic findings. We believe that this is a rare case of IP with PM during pregnancy.