Anomalous course of left pulmonary artery with respiratory obstruction.

Abstract

Anatomic variations of intrathoracic vessels, particularly of the aortic arch, are now well recognized as a cause of respiratory obstruction in infants and children. Although the variety is almost infinite, these anomalies may be classified into a few broad groups, depending on their anatomic course and the functional or physiologic disturbance which they produce. The true vascular rings, including the double aortic arch and the right aortic arch with a ligamentum arteriosum, encircle both the trachea and esophagus, giving rise to respiratory symptoms in at least 85 per cent of afflicted patients. A second group is made up of individual vessels of the aortic arch having an anomalous origin and course, arising contralaterally to their destined blood distribution and compressing either the trachea or esophagus in crossing the mid-line. The compression defect and symptoms depend on whether the vessel pursues a retro-esophageal, an ante-esophageal, a retro-tracheal, or a straight ante-tracheal course. The group consists of aberrant subclavian vessels, the aberrant innominate artery, and rarely an aberrant common carotid. These cases, although they are much more common than those of the first group, have a far lower incidence of symptoms, probably less than 3 per cent. The surgical treatment has been well defined (1). Belonging in the second group, but not emphasized in clinical papers on aorticarch anomalies and mediastinal vascular malformations, is an anomalous course of the pulmonary artery producing respiratory symptoms. The following report of 2 cases in which the left pulmonary artery followed an anomalous course, producing definite respiratory obstruction, gains significance in light of 3 other cases recently published. These patients present a similar clinical picture, not unlike that of the double aortic arch, and the defects are also amenable to diagnosis and surgical correction. Case Reports Case I: An ll-week-old white male infant was admitted to The Children's Medical Center of Boston with a history of poor weight gain and noisy respirations. He had failed to respond to general and supportive therapy elsewhere. Birth weight was 6 pounds, 2 ounces. At four days of age, intermittent wheezing and respiratory difficulties, with exacerbation during feeding, and a profuse nasal discharge were observed. At seven weeks, the child was admitted to another hospital with these symptoms plus failure to gain weight. On admission to The Children's Medical Center, the weight was? pounds, 4 ounces, the temperature 100° F., pulse 144, and respirations 32. The neck was dorsiflexed, there was flaring of the alae nasi, and the upper chest and suprasternal notch retracted with each respiration. No cyanosis or cough was noted, but the cry was feeble. The anteroposterior diameter of the chest was increased, there was hyperresonance to percussion, and loud inspiratory and expiratory coarse rales were heard throughout both lung fields.