The disease, as has been indicated, may be confined to the bronchial tree. In these circumstances, it is almost necessary to suppose that the larger bronchi alone are involved. When the delicate bronchioles are affected, there is always a more or less extensive involvement of the pulmonary parenchyma (124), for the bronchioles have a more direct communication with the alveoli, and their walls present a less formidable barrier to the extension of the inflammation to the surrounding air sacs.
FIG. XI. AUTOPSY NO. 140. ILLUSTRATES A LATE CHANGE IN THE BRONCHIOLE; THE EXUDATE IS BEING ORGANIZED AND THE EPITHELIAL LINING IS PROLIFERATING AND HAS INVADED THE SURROUNDING LUNG TISSUE. COMPARE FIGURES XLVIII AND XLIX. ]
FIG. XII. AUTOPSY NO. 209. A SMALL BRONCHIECTATIC CAVITY FILLED WITH PUS. THE GROSS APPEARANCE IS ILLUSTRATED IN FIGURE L. ]
FIG. XIII. AUTOPSY NO. 96. RIGHT LUNG. A WATER COLOR DRAWING OF A GROSS LUNG IN THE ACUTE STAGE. NOTE THE SIZE OF THE LUNG, THE HEMORRHAGES ON THE PLEURAL SURFACE, AND THE BLUE AREAS OF CONSOLIDATION. ]
Clinically, there is reason to believe that the disease may begin with a period of general malaise, during which the respiratory symptoms may be more or less severe. In the fulminating cases, the malaise may be associated from the beginning, not only with a tracheobronchitis, but also with pulmonary involvement. In less severe types the malaise may be accompanied only by tracheobronchitis, and may present no symptoms referable to the pulmonary parenchyma; there may follow or not, a definite period of clinical improvement, after which pneumonic involvement becomes evident. However, even where a fulminating type of the disease is not associated with clinical evidence of pulmonary involvement, the post-mortem examination may show extensive change in the lung parenchyma (110).
Whether this grouping of the disease is correct or is based upon a fallacious deduction from more or less satisfactory clinical histories, is open to question; and a decision may be reached from comparison of the opinions based upon carefully observed cases treated in different institutions. From the report of the epidemic at the Johns Hopkins Hospital (Bloomfield and Harrop (14)), where two hundred sixty-eight cases were studied in which the complication of pneumonia was uncommon as compared with cases in other hospitals—the New Haven Hospital, for instance—and where the percentage of the deaths was low, the conclusion was reached that the disease is primarily a general one and that the pulmonary involvement is secondary, just as in an exanthem, like measles. By way of comparison, at the New Haven Hospital, where more than eleven hundred patients with influenza were observed, the type of disease described by Bloomfield and Harrop was relatively rare. Of course, there were cases of that type where general malaise, with or without respiratory symptoms, was followed by a period—usually of from two to three days—of definite improvement in the symptoms; and later extensive and serious pulmonary complications ensued. However, in another group, largely composed of individuals who entered the hospital seriously ill, the histories indicate an acute onset resembling that of lobar pneumonia and with early manifestations of pulmonary involvement (2, 17, 52, 145). This discrepancy, probably, may be explained in part by variations in the sensitivity to minor indisposition on the part of the different individuals.