INFLUENZA is usually recognizable by the suddenness of the attack, by the great prostration, by the severe headache, by the cutaneous hypercesthesia and mus cular pain, and by the disproportion be tween the great respiratory distress and the comparative paucity of physical signs. In cases of gradual onset and of extensive pulmonary involvement the diagnosis is much more difficult and depends upon the general association of symptoms. One point in favor of influenza in a given case would be the fact that a compara tively high fever-104° or 105° F.—in an adult is borne with little discomfort, the patient perhaps being scarcely con scious of fever. The character of the sputum, its sago-like appearance, is also significant.
At St. Mary's Free hospital for Chi] dren, New York, cases in which the physical signs are those of bronchitis, but in which the children appear un usually sick and have a temperature ranging above 102.5° in the axilla or in the groin, are regarded as possible cases of broncho-pnemnonia and are treated accordingly. George M. Swift (Archives of Ped., Apr., '96).
Etiology. — Broncho-pneumonia is sometimes an independent affection aris ing from "cold" or from direct irritation by smoke and noxious vapors and gases, and, in cases of such origin, it may like wise be associated with or arise by exten sion from inflammatory processes in the upper air-passages. It may be caused by chloroform and less often by ether ad ministered for surgical anesthesia in the presence of artificial light by combustion.
It may arise from purely local infec tion by agents recognized and not recog nized, and probably not specific. It may occur in extension from bronchitis of any origin.
It is, however, usually met with as a complication or sequel of one of the in fectious diseases, and especially of those of childhood. Even when it is the only or most prominent manifestation of the existence of infection,—as, for example, in influenza or tuberculosis,—it is to be regarded as secondary.
It may be associated with, or follow, measles, scarlet fever, small-pox, whoop ing-cough, influenza, tuberculosis, ery sipelas, dysentery, meningitis, and ty phoid fever.
It also occurs from the aspiration of food (schlock - pneumonia, deglutition pneumonia, inspiration pneumonia) or infectious materials in cases of anmsthe sia or paralysis of the larynx, in coma of any origin, in malignant disease of the larynx and oesophagus, following life moptysis, following operations about the mouth and upper air-passages, and in some cases through the inspiration of matters from a vomiea or from a bron chiectatic cavity, or, in exceptional in stances, from the rupture into the lung of a purulent collection in the pleura, liver, or elsewhere.
Tuberculous bronchopneumonia is the most common and most fatal form. Next in frequency is infectious broncho pneumonia associated with the diseases of childhood, which, according to distin guished pmdiatric authors, causes more deaths than do the fevers themselves. Rickets and diarrhoea are likewise men tioned by authors among the predispos ing causes affecting children. Thus, while the disease occurs at all ages, it is much more frequent in childhood and infancy. Old age may likewise be con sidered a factor in creating susceptibility to the disease; and it occurs in associa tion with the various diseases and degen erative conditions incident to the decline of life. At all ages the disease is most prevalent among the poor.
It is, therefore, essentially a morbid process occurring in persons of lowered or innately poor vital resistance; and in conditions which favor mechanically the entrance of infectious material into the bronchi.
Bacteriology.—Apart from the tuber cle bacillus, the organisms most fre quently found in bronchopneumonia are the micrococcus lanceolatus, the strepto coccus pyogenes, the staphylococcus au reus, the staphylococcus albus, the bacil lus pneumonim of Friedlander. In cases of diphtheria the Klebs-Loeffler bacillus is frequently found; and in influenza Pfeiffer's and other organisms have been reported. It is rare for pure cultures to be found except in the case of the pneu mococcus, which is most frequently asso ciated with the pseudolobar type of the disease, the streptococcus being most common in the lobular type. Mixed in fection is the rule. Wright and Mallory have described a new capsular bacillus found by them in the lungs of a man who, three weeks after diphtheria, died with severe broncho - pneumonia (see colored plate).