Lobar Pneumonia
The frequency with which the confluent lobular consolidation of bronchopneumonia involving whole lobes or parts of lobes follows influenza has emphasized the desirability of distinguishing carefully between lobar and confluent lobular pneumonia. The pulmonary lesion has been designated lobar pneumonia when it exhibited the well-known characters of this lesion, namely, firm consolidation of large parts of lobes, coarse granulation of the cut surface, fibrinous plugs in the bronchi and, on microscopic examination, homogeneous consolidation and fibrinous plugs within the alveoli. With confluent lobular consolidation of bronchopneumonia the consolidated area is in most cases obviously limited by lobule boundaries, and well-defined lobules of consolidation occur elsewhere in the lungs.
Lobar pneumonia occurred in 98 among 241 instances of pneumonia following influenza, namely, in 40.7 per cent of autopsies.
The difficulty of separating lobar and bronchopneumonia following influenza has been increased by the frequent combination of the two lesions in the same individual. There were 34 instances in which lobar and bronchopneumonia occurred together. The anatomic diagnosis of lobar pneumonia was made only when lobes or parts of lobes were firmly consolidated and exhibited the characters of the lesion enumerated above; in several instances, in which there was some doubt concerning the nature of the lesion, microscopic examination was decisive. The associated bronchopneumonic lesions represented all the types which have been associated with influenza. In the group of 34 cases of coexisting lobar and bronchopneumonia, lobular consolidation occurred 10 times, peribronchiolar consolidation 14 times (recognized in all but 4 instances by microscopic examination), hemorrhagic peribronchiolar consolidation 9 times, peribronchial pneumonia 4 times. The intimate relation of these lesions to changes in the bronchi is well shown by the frequent presence of purulent bronchitis. The associated lesions of the bronchi in these cases were as follows: purulent bronchitis in 23 instances; peribronchial hemorrhage in 6; bronchiectasis in 11. The frequency of purulent bronchitis and other bronchial lesions in association with coexisting lobar and bronchopneumonia is in sharp contrast with the occurrence of these lesions in association with lobar pneumonia alone; with 69 instances of lobar pneumonia alone purulent bronchitis occurred 17 times and bronchiectasis once.
Lobar pneumonia following influenza passes through the usual stages of red and gray hepatization. Red hepatization was found 16 times, combined red and gray hepatization 28 times, and gray hepatization 20 times. The average duration of pneumonia with red hepatization was 3.7 days, with combined red and gray hepatization 5.1 days and with gray hepatization 7.5 days. These figures, it will be shown later, have some importance in relation to the stage at which hemolytic streptococcus infects lungs the site of lobar pneumonia.
Bacteriology of Lobar Pneumonia.—Table XXX is compiled with the purpose of determining the bacteriology of the bronchi, lungs and heart’s blood in autopsies performed on individuals with lobar pneumonia. In some instances bacteriologic examination of one or other of these organs was omitted; the percentage incidence is an index of the presence of pneumococci, hemolytic streptococci, staphylococci or B. influenzæ in the bronchi, lungs or heart’s blood and measures the invasive power of these microorganisms during the course of lobar pneumonia following influenza.
| Table XXX | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| NO. OF CULTURES | PNEUMOCOCCI | HEMOLYTIC STREPTOCOCCI | STAPHYLOCOCCI | B. INFLUENZÆ | |||||
| NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | NO. POSITIVE | PER CENT POSITIVE | ||
| Bronchus | 44 | 56.9 | 14 | 31.8 | 22 | 37 | 84.1 | 96 | 79.3 |
| Lung | 53 | 77.3 | 13 | 24.5 | 8 | 26 | 49.1 | 70 | 45.7 |
| Blood | 87 | 65.5 | 11 | 12.6 | 1 | 0.5 | |||
Pneumococci, the recognized cause of lobar pneumonia, were found in the lungs in 73.3 per cent of autopsies; failure to find the microorganism in all instances is doubtless the result of its disappearance from the lung, which, it is well known, occurs not infrequently particularly during the later stages of the disease. In 65.5 per cent of instances of fatal lobar pneumonia pneumococci have entered the heart’s blood.
Hemolytic streptococci unlike pneumococci were found more frequently in the bronchi than in the lungs; this microorganism which exhibits little tendency to disappear, once it has established itself within the body, found entrance into the bronchi in 31.8 per cent of instances of lobar pneumonia and in 24.5 per cent entered the lungs. Its invasive power is further illustrated by its penetration into the heart’s blood approximately in half this proportion of autopsies.
Staphylococci enter the bronchi in many instances (50 per cent), but relatively seldom (15.1 per cent) invade the lung and rarely if ever penetrate into the blood.