[Dermatomyositis associated with anti-MDA5 antibodies and pneumocystis pneumonia: Two lethal cases]

Dermatomyositis associated with anti-MDA-5 autoantibodies is a recently-described clinical entity. Herein we report two lethal cases involving pneumocystis pneumonia.

Case n^o 1. A 56-year-old male patient developed cutaneous symptoms consistent with dermatomyositis without muscular involvement. Antinuclear antibodies were present and anti-MDA5 auto-antibodies were identified. The scan showed interstitial lung disease without infection. Significant improvement was obtained with corticosteroids. One month later, the patient presented acute respiratory illness (hypoxemia: PaO₂ 60mmHg, exacerbation of lung disease evidenced by a scan, and diagnosis of pneumocystis pneumonia on bronchoalveolar lavage). He died despite appropriate antibiotic therapy and immunosuppressant therapy. Case n^o 2. The second case concerned a 52-year-old Vietnamese man who developed more atypical cutaneous symptoms of dermatomyositis without muscular involvement. ANAb responses were positive (1/400) and MDA5 was present. The patient was treated with corticosteroids (40mg/d), hydroxychloroquine, and intravenous immunoglobulin. After significant improvement, the patient developed an acute respiratory illness due to superinfection with pneumocystis and he died despite specific treatment and cyclophosphamide bolus.

In dermatomyositis, anti-MDA5 antibody screening is essential for the prognosis since the disease carries a risk of complication with severe lung disease. Bronchial fibroscopy with bronchoalveolar lavage should be considered at the time of diagnosis. Our two cases suggest the need for early screening for pneumocystis pneumonia in the event of respiratory distress and possibly for prophylactic treatment at the start of immunosuppressant therapy.