Tension disorders arising in the pulmonary parenchyma and pleural cavity in infants and children are produced by a variety of causes which show similar roentgen findings. These occur as distinct areas of radiolucency caused by encysted or diffuse trapped air under pressure. The expansile characteristics (1) are produced by a check-valve mechanism in the bronchial tree, the interstitial substance of the lung, or the pleural space. When such a condition is discovered in a critically ill infant with respiratory and circulatory distress, the problem of radical surgical intervention versus conservative management arises. Since the natural history of these lesions allows some of them to regress spontaneously (2), while others progressively jeopardize the life of the patient (3), the need for critical roentgen analysis is obvious. These disorders are either of congenital or acquired origin. Such a distinction is vital to prognosis and treatment, in that the congenital type generally requires major surgical correction while the acquired type does not. The possibility of roentgen differentiation depends largely on a knowledge of the pathological aspects. With this point in mind, the numerous descriptive expressions (4–8) in the medical literature have been correlated according to their clinical, roentgen, and pathological manifestations, and the following classification has been made. Congenital Type Developmental bronchial malformations 1. Locular bronchial cysts (a) Solitary cysts (b) Cystic bronchiectasis (c) Congenital honeycombed lung 2. Cystic hamartomas 3. Sequestration of lung Acquired Type Interstitial and pleural air cysts 1. Regional obstructive emphysema (a) Postinfectious pneumatoceles (b) Interstitial bullae (c) Subpleural blebs 2. Tension pneumothorax 3. Diffuse obstructive emphysema 4. Acquired honeycombed lung Pathological Differentiation Congenital Group: All of the congenital tension disorders manifest in early infancy are due to developmental bronchial malformations (9). The most frequently encountered are the locular bronchial cysts. These form as a result of embryonic blockage in the lumina of the bronchial buds. Single or multiple cystic cavities lined with bronchial structures and filled with secretion are formed peripherally. Norris and Tyson (10) have shown by an ingenious study of serial sections that the original defect is a small irregular dilatation in the bronchioles. Such a focal dilatation, if arrested at that stage, results in the so-called fetal or cystic bronchiectasis (Fig. 1). This condition is characterized by uniform thin-walled cysts ranging from a few millimeters to a centimeter in diameter, diffusely distributed throughout the terminal arborizations of one or more lobes of the lungs. Where the process continues, these bronchiolar dilatations become pinched off to form gradually enlarging cysts.
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Feb 1, 1972
John H Gigax + 3
