Pulmonary and neuromuscular complications of mixed connective tissue disease: a report and review of the literature.

We report a 34-year-old woman with mixed connective tissue disease (MCTD) who developed severe pulmonary and neuromuscular complications. At presentation, pulmonary function tests and pulmonary mechanics were suggestive of pulmonary vascular disease, and she subsequently developed clinical signs of pulmonary hypertension. These noninvasive tests may be useful in the timing of more invasive hemodynamic studies. She initially had myasthenia gravis and then developed polymyositis, profound peripheral neuropathy, and ventilatory muscle failure. She died despite aggressive immunosuppressive therapy and plasmapheresis. Autopsy showed spinal cord changes secondary to a peripheral neuropathy and signs of neurogenic atrophy confined to the ventilatory muscles. Peripheral neuropathy may be an important cause of ventilatory muscle weakness that can be found in MCTD and systemic lupus.