| SPUTUM | IN BLOOD, LUNGS OR BRONCHUS AT AUTOPSY | ||
|---|---|---|---|
| Autopsy | 240 | Pneum. IV | Pneum. IV |
| 246 | Pneum. atyp. II, B. inf. | ||
| 247 | Pneum. IV, B. inf. | Pneum. IV | |
| 250 | Pneum. atyp. II, B. inf. | Pneum. atyp. II | |
| 253 | Pneum. atyp. II | Pneum. II | |
| 285 | Pneum. atyp. II, B. Inf. | S. hem., B. inf. | |
| 288 | S. hem., B. inf. | S. hem., B. inf. | |
| 291 | Pneum. IV, B. inf. | Staph., B. inf. | |
| 300 | Pneum. atyp. II, B. inf. | Pneum. atyp. II, B. inf. | |
| 312 | Pneum. IV, S. hem., B. inf. | S. hem., B. inf. | |
| 346 | Pneum. IV, B. inf. | S. hem., B. inf. |
In 2 instances (Autopsies 285 and 346) among this small group of cases, pneumococci but no hemolytic streptococci were found in the sputum several days before death, whereas death occurred as the result of secondary invasion with hemolytic streptococci and no pneumococci were found at autopsy. It is probable that this sequence of events is not uncommon. B. influenzæ finds its way into the bronchi and pneumococci follow it; pneumonia limited to peribronchiolar alveoli may occur in consequence of this invasion. Later hemolytic streptococci may follow the same path and cause death with bacteremia.
Hemorrhagic Peribronchiolar Consolidation.—Peribronchiolar pneumonia accompanied by diffuse accumulation of blood within the alveoli is one of the most frequent complications of influenza. The lung tissue is laxly consolidated, and on section there is a homogeneous dull deep red background upon which are seen small gray spots (1.5 to 2 mm. in diameter) grouped in clusters about the smallest bronchi (Fig. 5). Wide areas of lung tissue are implicated and the lesion is more common in the dependent parts of the lung than elsewhere. In common with other forms of bronchopneumonia the lesion is in most instances associated with changes in the bronchi; in 55 instances of hemorrhagic bronchiolar pneumonia purulent bronchitis was found in 43 instances; it is noteworthy that purulent bronchitis often is not evident in the presence of pulmonary edema and edema is not infrequent with this pneumonic lesion.
Microscopic examination demonstrates the presence of acute bronchitis; the lumina of the small bronchi contain polynuclear leucocytes and red blood corpuscles. Accumulation of blood may separate the epithelium from the basement membrane. The mucosa immediately below the epithelium contains polynuclear leucocytes in fair abundance and the blood vessels of the bronchial wall are much engorged. Respiratory bronchioles are distended with polynuclear leucocytes and red blood corpuscles. In a zone about each bronchiole, in areas corresponding to the small gray spots seen upon the cut surface of the lung, the alveoli are filled with polynuclear leucocytes. In the lung tissue intervening between these spots of leucocytic pneumonia the alveoli are distended with red blood corpuscles.
Fig. 5.—Bronchopneumonia with hemorrhagic peribronchiolar consolidation.
In favorable sections it is occasionally possible to follow the bronchiole and alveolar duct, both filled with leucocytes, into an infundibulum. The proximal part of the infundibulum contains polynuclear leucocytes, whereas the distal part and its tributary alveoli are filled with serum and red blood corpuscles.
When the lesion has persisted for a short time there is evidence of beginning migration of polynuclear leucocytes from the blood vessels into the alveoli which are filled with blood. The alveolar walls contain numerous polynuclear leucocytes and leucocytes which have entered the intraalveolar blood are numerous in contact with the wall but occur in scant number in the center of the alveolar lumen.
Alveolar epithelium in contact with the blood in the lumen is usually swollen and often uniformly nucleated.
The inflammatory process is evidently transmitted from the bronchioles and to a less degree from the small bronchi to the adjacent alveoli. Polynuclear leucocytes fill the lumen of the bronchiole and the alveoli immediately adjacent; at the periphery of the focus of pneumonia, the alveoli may contain fibrin. In such instances small bronchi (lined by a continuous layer of columnar epithelial cells) may be surrounded by alveoli containing fibrin.