DYSPNEA IN A PATIENT YEARS AFTER SEVERE POLIOMYELITIS - THE ROLE OF CARDIOPULMONARY EXERCISE TESTING

Dyspnea after polio can occur for a variety of reasons, including neur omuscular disease and upper airway abnormalities resulting from prolon ged intubation, including tracheal stenosis, tracheomalacia, and vocal cord paralysis. Routine studies such as spirometry and maximum volunt ary ventilation (MVV) measurements can give similar results in these c onditions. We present a 50-year-old woman who as a child developed pol iomyelitis that required tracheostomy and negative pressure ventilatio n. Thirty-nine years later, she developed breathlessness with normal s pirometry but decreased MVV. The flow volume loop showed flattening of the inspiratory and expiratory limbs, consistent with a fixed upper a irway obstruction or neuromuscular weakness. Exercise testing with mea surement of exercise flow volume loops and respiratory pressures was p erformed. The patient was ventilatory limited with increasing end-expi ratory lung volume through exercise. Flow volume loops confirmed flow limitation. Respiratory pressures did not change after maximal exercis e. Further evaluation confirmed left vocal cord paralysis and tracheom alacia. This patient demonstrates that the causes of dyspnea after pol iomyelitis can be multifactorial, and that routine evaluation may fail to elucidate the limiting factor. In this case, exercise testing prov ided valuable insight into the limiting factor for this patient and pr ovided useful data for counseling and for further management.