Respuesta favorable a tratamiento inmunosupresor en paciente con dermatomiositis anti-MDA5 positivo y enfermedad pulmonar intersticial rápidamente progresiva

Abstract

Anti-MDA5 dermatomyositis (DM) is a subgroup of autoimmune myopathies whose prevalence ranges from 0.55 to 6 cases per 100,000 population. This condition is frequently associated with rapidly progressive interstitial lung disease, leading to increased morbimortality, The therapeutic approach to anti-MDA5 DM is currently challenging due to its heterogeneous clinical presentation and lack of a standardized treatment. Case presentation: A 49-year-old male patient attended a health center complaining about proximal muscle weakness, weight loss, cough, dyspnea on moderate to low exertion and a cutaneous rash. He had a family history of rheumatoid arthritis and hypothyroidismus. Laboratory findings showed moderate leukopenia, CK, LDH and Aldolase A in normal range. Ferritemia extremely elevated. Rheumatic tests were negative. The autoantibody screening panel for inflammatory myopathies showed positivity for anti-MDA5. As an anatomical correlate of the latter finding, a reticular interstitial pattern with bibasal predominance was found both in the chest x-ray and in the pulmonary CT. A diagnosis of Dermatomyositis associated with a rapidly progressive interstitial lung disease was made, and immunosuppressive therapy with high doses of glucocorticoids and azathioprine was started. A significant improvement of muscle weakness and skin lesions was seen in response to immunosuppressive therapy. There was also improvement of lung function parameters. After 26 months of treatment, the patient was .swichted to mycophenolate mofetil, because o due to slighty decreased FEV1 on a control spirometry and alterations in stress blood gases. The present case illustrates the current limitations in treating the rapidly progressive interstitial pneumopathy which usually appears in association with anti-MDA5 positive dermatomyositis.