Obliterative Bronchitis and Bronchiolitis with Bronchiectasis*

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358 A review of her plain x-ray film revealed no abnormality; however, a bronchogram showed ectasia of the basal segments of the left lower lobe. The parenchyma surrounding these seg- mental bronchi was hyperlucent. On October 31, 1961, the basal segments were excised and blocks of tissue were prepared from the termination of the bronchi close to the pleural surface. Serial sections were studied and a severe degree of peribronchiolar fibrosis was found in a se- quential review of an obliterated bronchiole as it reached close to the pleura (Fig. 3C). A thick fibrous strand extending beyond the point of obliteration of the bronchiolar lumen was seen to contain the smooth muscle remnants of the bronchiole. The parenchyma surrounding this obliterated bronchiole showed the emphysematous changes of alveolar distention and interalveolar septai degeneration. Comment : The persistence of aeration surrounding this obliterated bronchiole immediately subjacent to the pleural surface must represent collateral air-drift. At this level, the aeration could not result from the direct bronchiolar ventilation from an adjacent primary lobule, but rather intrasegmental collateral air-drift through interalveolar septa1 pores. The occurrence of obliterative bronchitis or bronchiolitis is quite common, but is only infrequently recognized. In the period since the publication of Churchill's classic papers on the physiology and pathology of the lung,zJ little further reference has been made to obliterative bronchitis and its sequel of collateral ventilation. In 1950, Lynne Reid,' in a correlative study of bronchiectasis by macroscopic and microscopic dissection with the use of serial sections, was able to demonstrate a frequent occurrence of obliterative bronchitis. She reported that some of the bronchi termin- ated in cords of tissue which contained remnants of obliterated bronchial structures such as muscle bundles, elastic tissue, and occasionally plates of cartilage. The cases reported here demonstrate this same bronchial obliterative process and bronchial remnants. Bronchiectasis is a term applied to a varied group of conditions with a single finding of dilated bronchi common to all. The parenchyma may be totally dissimilar Downloaded From: http://intl.chestjournal.chestpubs.org/ on 06/23/2013 MORRIS M. CULINER Diseases of the Chest pathologically and radiographically in different patients. Radiographic parenchymal opacity is associated with a gross tissue finding of a consolidation-atelectasis. This degree of parenchymal abnormality is due to massive inflammatory reaction and fibrosis. In contrast with this, patients frequently show the parenchyma around ectatic bronchi to be hyperlucent and subject to air- trapping.''3 In specimens from these patients, one finds obliterated bronchi and bronchioles surrounded by emphysematous lung parenchyma. Just as the parenchymal pathologic changes may vary, so may the degree of inflammatory reaction and destruction of the bronchial wall constituents be different from patient to patient, and from one area of involvement to another in any given patient. The specimen from Case 1 shows different bronchi with varying degrees of pathologic involvement from total obliteration of the lumen, to ectasia, and to almost completely normal architecture. The ectatic bronchi demonstrate degenerated or de- creased cartilage, muscularis and elastic tissue. In addition, although the lobe was excised at a time of apparent clinical free- dom from infection, the microscopic figures show evidence of acute and chronic inflammatory changes as well as of normal tissue. It seems that in all these patients the repeated inflammatory episodes, recorded in their histories, have brought about the bronchial wall changes noted above. With weakening of those components, cartilage, muscle and elastics, which nor- mally maintain the integrity of the bronchial architecture, ectasia has occurred. This is the result of the interaction of the post-inflammatory fibrotic contraction with changes of intrabronchial pressure that are concomitant with coughing, straining and normal respiration. Our major concern is with the bronchial obliterative process found in the cases presented. The ectasia, which represents ar- chitectural changes due to a lesser degree of inflammatory destruction of the bronchial wall components, is an incidental
44 No. October l9k3 BRONCHITIS AND BRONCHIOLITIS WITH BRONCHIECTASIS 359 change, for it is the bronchial obliterative process with its resultant deprivation of normal ventilatory channels of the lobules which induces collateral air-drift and its invariable sequel, regional With obliteration of the bronchial lumen, the retrograde flow of bronchial mucus into the surrounding parenchyma is pre- ~ented.'~"~-~~ Under these circumstances, the pores of Kohn14 which function as imperfect check-valves, remain open. This permits collateral air-flow to continue unimpeded and indefinitely from adjacent areas of parenchyma with normal bronchi. Emphysema results from the pathophysiology of collateral ventilation and its resultant air-trapping.'O"'"S The cases presented above demonstrated bronchi or bronchioles whose lumina became obliterated as the walls ended in fibrous strands containing remnants, smooth muscle or cartilage, of the preexisting bronchi. Each of these fibrotic remnants was surrounded by aerated and emphysematous lung. The pathway of this persistent aeration must have been via collateral channels.'' The source of the collateral air-drift is felt to be an adjacent patent bronchial conduit. There was a decrease in the volume of the pathologically involved lobes or lung in each of the three cases presented above. This is an apparent paradox in view of the known overdistention of emphysema. These same areas of emphysema, however, were subject to the fibrotic contraction of repeated inflammatory processes. Thus, the two opposing forces of emphysematous over-distention and fibrotic contraction may cause the diseased area to be over-distended, normal or contracted, depending upon the degree of each. Case 2 (F.P.) presents a further point of interest in that the entire left lung was altered by the disease processes, which then gave it the appearance ascribed to the socalled entity of "unilateral hyperlucent lung."48 The uniformity of the radiologic appearance throughout the lung suggests the likelihood that the bronchial oblitera- Downloaded From: http://intl.chestjournal.chestpubs.org/ on 06/23/2013 tive process found in the resected lingula and lower lobe was also present in the upper lobe which was not resected. In view of the present knowledge of obliterative bronchitis, collateral ventilation and its sequel of emphysema, the pathogenesis of the entity of "unilateral transradiancy" becomes evident. Most of the cases reported as being representative of the so-called "unilateral hyperlucent lung" show bronchiectasis and are associated with histories of recurrent infections. Other cases of the entity have not shown bronchiectasis, but all have shown a paucity of ipsilateral bronchial subdivisions on bronchography. The radiologic similarity of the above case, to those previously reported suggests the possibility that the bronchial obliterative process was present in all cases. This is further supported by the physiologic ventilatory abnormalities of obstructive air-ingress and air-egress reported by all the authors describing the entity of "unilateral hyperlucent lung." The ventilatory pattern is identical with that found with collateral ventilation as described by Ch~rchill~~~ Culiner and Reich" and Culiner and Grimes.'' There is an apparent decrease in the caliber of the ipsilateral pulmonary artery reported to be present in cases of "unilateral hyperlucent lung." This may only re- flect a decrease in perfusion volume sec- ondary to the marked obliteration of the intrapulmonary capillary bed associated with both emphysema and inflammatory fibrosis. Swyer and James7 and Margolin et al.' studied cases of "unilateral hyperlucent lung" during surgery and post mortem. They found normal pulmonary arteries in areas which radiologically appeared to show hypoplastic arteries. At the time of resection of Case 2, no decrease in caliber of the left pulmonary artery or its lobar branches was noted. A radiologic prediction of obliterative bronchitis in association with bronchiectasis can be made quite easily. When bron- chographic studies are carried out in patients suspected of having bronchiectasis,
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Obliterative Bronchitis and Bronchiolitis with Bronchiectasis*

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