Part 27

Thus whereas we have indicated that the inflammation of the trachea and of the large bronchi is of a peculiar kind and remains confined to the tissue lying inwardly from the cartilage rings, we found that where these structures give place to a loose muscle tissue with a more extensive lymphatic drainage the zone of inflammation is not so limited, but proceeds outwardly into the neighboring tissues. We often use the terms bronchus and bronchioles very freely without clearly distinguishing any real difference. In a study of the inflammatory reactions of the respiratory tubes in epidemic influenza (as well as in other infections) it is best to accept the anatomical definition that the bronchioles not only represent the minute tubules passing to the alveoli, but also those small air passages which devoid of cartilage, mucous glands and heavy connective tissue stroma are in close relation to the parenchymatous tissues of the lung. These soft muscular tubes possess blood and lymphatic vessels which freely communicate with the blood vessels of the lung alveoli. It is in association with these distant tubes that concomitant inflammatory reactions are found in the alveoli and in the bronchial tubes.

Desquamation of the epithelial lining is to be found in every size of bronchial tube where the infection has caused an acute inflammatory reaction. Throughout the pulmonary tissues where the lung is found in some stage of influenzal pneumonia the bronchial tubes, both large and small, are either entirely denuded of the mucosa or show only remnants attached to irregular areas. In the smaller passages dense clusters of desquamated cells are sometimes found within the lumen and indicate the accumulation of a desquamated epithelium obtained from portions of the tubular system in deeper portions of the lung. In the early stages, this desquamation is accompanied by a serous exudate and a certain amount of hemorrhage. Later we find masses of leucocytes which fill up the tube, and though appearing to arise from these structures have in fact largely come from the lung alveoli. Like the larger bronchial tubes the distant ramifications show relatively little cellular reaction in their walls in the early period. It is only when the neighboring lung tissues are extensively implicated in a purulent inflammation that we find a similar exudate occupying the tissues of the bronchioles. Polymorphonuclear leucocytes are equally distributed through the region of the basement membrane, submucosa, muscular coat and outer connective tissue layer. Some grades of degeneration may occupy the inner surface wherein the basement membrane first shows a homogeneous swelling and later a granular degeneration. In a few instances where the small bronchioles have communicated with regions with abscess formation an ulcerating surface occupied the inner boundary.

The evidence in the smaller bronchial tubes, both those with cartilage and those without, that an inflammatory reaction of some degree may occupy the muscular coat is of importance. We have found reactions of inflammation in the muscular coat varying from a mild œdema and cellular exudate to an intense polymorphonuclear leucocyte involvement. In the latter the muscle fibers showed evidence of degenerative change and suggested an acute weakening of this layer. We lay particular importance upon this finding as indicating a causative factor in the development of acute bronchiectasis as was met with in one of our cases. In this particular instance the bronchi passing to the lower lobes of each lung were unusually dilated and could be followed, in the gross, to their distant extremities. The dilatation was more or less uniform and no large pouches or cavities had developed. A mucopurulent exudate was found occupying these dilated tubes. Others have likewise observed the development of acute bronchiectasis under these conditions. Goodpasture and Burnett found that as early as the second to the fourth day one of the striking appearances was the gaping dilated condition of the infundibula, and the tendency to dilatation of the air passages was manifested in a bronchiectasis in 4 out of 30 cases. Boggs as well as Lord have reported upon chronic bronchiectasis associated with the B. influenzæ and there appeared to be evidence that a certain percentage of cases recovering from influenza permanently develop irregular dilatations of the bronchial tubes.

The recognition of inflamed bronchi or bronchioles was never difficult. In the gross the presence of the abnormal exudate and the intense injection of the mucosal surfaces always attracted attention to the inflammatory state. Furthermore where the mucosa had been desquamated the surface of these tubes was found to be quite granular if closely observed. With moderate magnification by means of a hand lens the granular appearance was shown to be due to the engorged vessels. Much easier, of course, was the recognition of the inflammatory reaction by the microscope. The importance, however, of the bronchitis and bronchiolitis lay in the amount of involvement which had occurred in the neighboring tissues. As we, however, indicated elsewhere, we do not doubt that many of the cases of three-day fever have a state of tracheitis and bronchitis equal to that which we have observed in many of our cases. Whether the inflammatory reaction progressed beyond the firmer bronchial tubes to the softer and more vascular structures would be difficult to say where our evidence rests upon the clinical findings alone. It is, however, probable that a certain number of the severe and sharp attacks of influenza not only cause a tracheitis and bronchitis of the larger tubes, but also extend more deeply into the smaller ramifications tending to simulate the reactions which we have above described. When we ask ourselves, however, how distantly must the infection invade the smaller bronchial tubes before involving the parenchymatous tissues of the lung we are at a loss to enunciate a general rule. It is more than probable that there are modifying influences which determine whether the bronchitis with a certain amount of its bronchiolitis will progress to a true pneumonia or will remain localized to these tubular systems. I can well appreciate that in the event that a bronchitis has an inflammatory reaction accompanied by much serous exudate there is great danger of flooding the neighboring alveoli with this inflammatory fluid and of carrying the large numbers of the micro-organisms within the tubes to the air sacs of the lung. Under these conditions the virus has an unusual ability to develop the disease from one localized in the air passages to that of a true pneumonia. It is probable that the peculiar early acute reaction which is present in the air passages in epidemic influenza is responsible for the extensive involvement of the lung in the severe and dangerous form of inflammation.

TABLE VI.

EXTENT AND DISTRIBUTION OF PNEUMONIA.

═══════╤════╤════════════════════════════╤════════════╤══════════════════════ AUTOPSY│AGE.│ RIGHT LUNG. │ TYPE OF │ LEFT LUNG. NUMBER.│ │ │ LESION. │ ───────┼────┼──────┬─────────────────────┼────────────┼────────┬───────────── │ │WEIGHT│INVOLVEMENT OF LOBES.│ │ WEIGHT │ INVOLVEMENT │ │ OF │ │ │OF LUNG.│ OF LOBES. │ │LUNG. │ │ │ │ ───────┼────┼──────┼──────┬───────┬──────┼────────────┼────────┼──────┬────── │ │ │UPPER.│MIDDLE.│LOWER.│ │ │UPPER.│LOWER. ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 741│ 18│720 G.│ + │ + │ ++ │Lobar S. & │ 850 G.│ + │ ++ │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 743│ 20│825 G.│ + │ + │ + │Lobular S. &│ 1375 G.│ +++ │ +++ │ │ │ │ │ │ H. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 744│ 30│900 G.│ + │ – │ ++ │Lobar and │ 900 G.│ ++ │ ++ │ │ │ │ │ │ Lobular S.│ │ │ │ │ │ │ │ │ & H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 745│ 18│575 G.│ + │ – │ ++ │Lobular S. &│ 480 G.│ – │ ++ │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 746│ 21│900 G.│ + │ ++ │ +++ │Lobar S. & │ 650 G.│ + │ +++ │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 747│ 27│ 1510│ +++ │ ++ │ +++ │Lobar S. & │ 1000 G.│ +++ │ +++ │ │ G.│ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 748│ 22│900 G.│ + │ + │ +++ │Lobar and │ 1250 G.│ + │ +++ │ │ │ │ │ │ Lobular S.│ │ │ │ │ │ │ │ │ & H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 749│ 23│ 1480│ ++ │ ++ │ +++ │Lobar S. & │ 1250 G.│ ++ │ +++ │ │ G.│ │ │ │ H. Slight │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 750│ 24│ 1200│ +++ │ + │ +++ │Lobar and │ 825 G.│ + │ +++ │ │ G.│ │ │ │ Lobular. │ │ │ │ │ │ │ │ │ Early │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 751│ 22│ 1250│ – │ – │ +++ │Lobar │ 610 G.│ ± │ ± │ │ G.│ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 752│ 27│ 1125│ +++ │ + │ +++ │Lobar S. & │ 775 G.│ ± │ +++ │ │ G.│ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 756│ 22│ 1000│ ++ │ ++ │ ++ │Lobar S. & │ 820 G.│ +++ │ ++ │ │ G.│ │ │ │ H. Slight │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 757│ 21│815 G.│ ++ │ – │ ++ │Lobular S. &│ 1075 G.│ +++ │ +++ │ │ │ │ │ │ H. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 758│ 22│ 1150│ +++ │ + │ + │Lobar │ 1400 G.│ +++ │ +++ │ │ G.│ │ │ │ Purulent │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 761│ 21│ 1250│ +++ │ ++ │ +++ │Lobar S. & │ 550 G.│ + │ + │ │ G.│ │ │ │ H. and │ │ │ │ │ │ │ │ │ Lobular │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 762│ 21│680 G.│ + │ + │ + │Lobular S. &│ 750 G.│ + │ +++ │ │ │ │ │ │ H. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 763│ 22│920 G.│ + │ – │ + │B. P. and │ 540 G.│ – │ + │ │ │ │ │ │ Lobar S. &│ │ │ │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 764│ 23│725 G.│ – │ + │ + │Lobular S. &│ 550 G.│ + │ + │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 765│ 25│ 1100│ ++ │ – │ ++ │Lobar S. & │ 1400 G.│ – │ +++ │ │ G.│ │ │ │ H. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 767│ 25│ 1075│ + │ +++ │ +++ │Lobar and │ 850 G.│ – │ ++ │ │ G.│ │ │ │ Lobular S.│ │ │ │ │ │ │ │ │ & H. and │ │ │ │ │ │ │ │ │ Lobular │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 770│ 21│900 G.│ ++ │ ++ │ ++ │Lobar S. & │ 750 G.│ ++ │ ++ │ │ │ │ │ │ H. and │ │ │ │ │ │ │ │ │ Lobular │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 773│ 22│ 2050│ +++ │ ++ │ +++ │Lobar S. & │ 780 G.│ – │ +++ │ │ G.│ │ │ │ H. and │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 778│ 22│ 1100│ ++ │ + │ ++ │Interstitial│ 975 G.│ ++ │ ++ │ │ G.│ │ │ │ Pneumonia.│ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 781│ 21│ 1000│ +++ │ ++ │ +++ │Lobar S. & │ 540 G.│ + │ +++ │ │ G.│ │ │ │ H. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 782│ 18│650 G.│ + │ – │ ++ │Lobular S. &│ 875 G.│ ++ │ +++ │ │ │ │ │ │ H. Slight │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 783│ 21│ 1250│ +++ │ +++ │ +++ │Lobar S. & │ 580 G.│ + │ ++ │ │ G.│ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 784│ 21│ 1590│ +++ │ +++ │ +++ │Lobar │ 1400 G.│ +++ │ +++ │ │ G.│ │ │ │ Purulent. │ │ │ │ │ │ │ │ │ │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 786│ 20│ 1100│ ++ │ +++ │ +++ │Lobar S. & │ 700 G.│ – │ ++ │ │ G.│ │ │ │ H. Slight │ │ │ │ │ │ │ │ │ Lobular │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 787│ 21│750 G.│ ++ │ – │ ++ │Lobular S. &│ 1125 G.│ +++ │ +++ │ │ │ │ │ │ H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 791│ 21│775 G.│ + │ ++ │ ++ │Lobular S. &│ 1050 G.│ ++ │ +++ │ │ │ │ │ │ H. and │ │ │ │ │ │ │ │ │ Purulent. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 792│ 21│ 1050│ + │ + │ +++ │Lobar and │ 950 G.│ + │ ++ │ │ G.│ │ │ │ Lobular S.│ │ │ │ │ │ │ │ │ & H. │ │ │ ───────┼────┼──────┼──────┼───────┼──────┼────────────┼────────┼──────┼────── 793│ 18│500 G.│ – │ – │ + │Slight │ 435 G.│ - │ + │ │ │ │ │ │ Lobular S.│ │ │ │ │ │ │ │ │ & H. │ │ │ ───────┴────┴──────┴──────┴───────┴──────┴────────────┴────────┴──────┴──────