Diaphragm dysfunction in mixed connective tissue disease. A case report.

A patient with mixed connective tissue disease (MCTD) presented the typical signs of respiratory muscle weakness and marked diaphragm dysfunction: reduced maximal ex- and inspiratory transrespiratory pressures (measured at FRC), maximal transdiaphragmatic pressures and transpulmonary pressures at TLC, FRC and RV. this insufficiency of the diaphragm was also responsible for the restrictive ventilatory defect and the decreased static lung compliance with high diffusing capacity per unit lung volume.