June 2002 / Volume 47 / Number 6 / Page 693
Unilateral Expiratory Airflow Obstruction During Forced Exhalation
We present a case of unilateral airflow obstruction during forced exhalations. The patient presented with episodic dyspnea and wheezing, particularly when he lay in the right lateral decubitus position. Spirometry revealed symmetric, marked reductions in forced expiratory volume in the first second and forced vital capacity values, while plethysmography demonstrated a near-normal total lung capacity. Bronchoscopy revealed a polypoid lesion in the right main bronchus, of which biopsy specimens demonstrated adenoid cystic carcinoma. Following a right pneumonectomy, total lung capacity was markedly reduced; interestingly, however, spirometry was essentially unchanged. This case is an elegant illustration of the effects of respiratory maneuvers and body position on airway caliber.
Key words: adenoid cystic carcinoma, pulmonary function testing, PFT, airflow obstruction.
[Respir Care 2002;47(6):693–695]
This case describes a 60-year-old nonsmoking man with cystic adenoid carcinoma obstructing the right main bronchus. His presenting symptoms misled his physicians to believe he had asthma. One prominent finding was that the patient had more pronounced symptoms when in right lateral decubitus position -- a result of positional changes in airway caliber. Pulmonary function testing was also consistent with obliteration of airflow through the right main bronchus when airway caliber was reduced, such as during the forced vital capacity maneuver or when expiring below the functional residual capacity. Bronchoscopy provided the correct diagnosis.