CAPILLARY BRONCHITIS AND BRONCHOPNEUMONIA (CATARRHAL PNEUMONIA) Bronchitis is apt to involve the finer and the finest bronchi, and is then designated as bronchiolitis or capillary bronchitis. With unusual frequency the disease extends from here to the lung tissues proper, and in this way- leads to a bronchopneumonia (catarrhal pneumonia) which may also be described less accurately as "lobular pneumonia." The bronchopneumonia invades the lung tissue with numerous scattered nodules about the size of peas or nuts, which are principally found in posterior inferior portions, and which, by increase and spread to the inter vening tissues containing air, may steadily cause larger portions to become consolidated. The course of the disease is acute, subacute, or chronic.
Since the treatment of capillary bronchitis and of bronchopneu monia coincide, and the clinical picture and the pathological anatomy have much similarity and present inseparable transitions, a joint description is ady-isable.
Pathology.—Capillary bronchitis presents an enormous dilatation of the corresponding blood vessels. The lumen of the bronchiolis is diminished by- the greatly swollen mucosa and occluded by purulent and occasionally sanguinous exudate. The occlusion of the bronchioles leads to atelectasis of the alveolar areas, which formerly was regarded as the chief cause of the development of the bronchopneumonic areas. The pneumonic areas do not develop as the result of direct extension of the inflammation from the bronchioles to the alveoli, but by spread of the inflammation from the walls of the bronchioles and through the walls themselves to the surrounding tissue (Aufrecht), which is markedly infiltrated with lymphocytes.
An inflammatory cedema now extends from the septa of the alveoli to the neighboring alveoli leading to colonization of bacteria in this re gion, to casting off of alveolar epithelium, and to distention of the alve oli with white blood corpuscles. A small quantity of fibrin is also found in the alveoli but never in the same amount as in croupous pneumonia. Frequently also red corpuscles are found in varying numbers. In the beginning, bronchopneumonia produces areas of peribronchitis varying from about the size of the head of a pin to that of a pea, which surround the pus-distended bronchioles between which lie areas that are still intact and that contain air (see Plate 54). The areas gradually become
more numerous and increase to the size of a nut. Becoming confluent, they may involve an entire lobe. As a rule, the bronchopneumonic areas are dark blue in color and tough, later becoming grayish yellow in appearance with prominence of the infiltrated lobuli. On pressure, thick pus oozes from the bronchioles which are partly dilated. In addition to the pneumonic areas, as a result of the shutting off of the air, larger and smaller areas of atelectasis are to be found, especially in the dependent portions of the lungs. In the later stages, the connective tissue around the bronchi is very inuch increased (interstitial peribronchitis), leading, in some cases, to obliteration of the bronchi and the lung tissue. In addition, gangrene and abscesses of the lungs may occasionally result. The bronchial and tracheal lymphatic glands are enlarged (see also Plate 4S).
general, the etiology is identical with that of sim ple bronchitis. The disease occurs in connection with inflammatory conditions of the upper air-passages or simultaneously with them, very often in certain infectious diseases especially, frequently in measles, whooping-cough, grippe, influenza, diphtheria, and often also, as an accompaniment of severe intestinal disturbances. Some authors are of the opinion that certain forms of bronchopneumonia are contagious.
Capillary bronchitis and bronchopneumonia are preeminently dis eases of early life (infantile pneumonia). They become less frequent after the fourth year. The largest number of cases are seen between the ages of six months and two years. The disease probably' always is of an infectious character. Occasionally the bacteria of the primary diseases are found in the bronchioles or alveoli (diphtheria, influenza, typhoid), frequently in mixed infection. The most frequent findings are Fran kel's pneumococci, often in pure cultures, especially in primary cases, and streptococci (always in diphtheria), and often Friedlander's pneumo-bacillus, staphylococci, etc. (Netter).