Among 4 instances of lobar pneumonia following measles there was serofibrinous pleurisy 3 times; in 1 instance there is no record of pleural change. In 1 instance of lobar pneumonia (Autopsy 505) the right pleural cavity contained 800 c.c. of serofibrinous exudate and the pericardial cavity contained 510 c.c. of opaque, yellow seropurulent fluid; Pneumococcus II atypical in pure culture was obtained from the blood, lung and pleural and pericardial exudates. Among 9 instances of bronchopneumonia following measles there was fibrinous pleurisy 3 times, serofibrinous 3 times, and no recorded lesion of the pleura 3 times. Empyema, like suppurative pneumonia following measles, is in most instances, but not constantly, caused by invasion of hemolytic streptococci.
The foregoing study has shown that pneumonia which has followed measles has reproduced all of the lesions usually found after influenza. There is no pulmonary lesion peculiar to measles. Lobar pneumonia follows the disease in some instances, but bronchopneumonia with purulent bronchitis is more common. The same tendency to hemorrhagic inflammation found with the pneumonia of influenza is seen after measles. Unresolved pneumonia with chronic inflammatory changes in the interstitial tissue of the lung has all of the characters of the similar lesion following influenza but has been found in a larger proportion of the pneumonias of measles.
B. influenzæ has been found in the bronchi in 14 of 16 examinations, namely in 87.5 per cent of fatal instances of pneumonia. In 1 instance in which B. influenzæ has not been found at autopsy, it has been isolated from the sputum during life. It is not improbable that B. influenzæ has been constantly present in the inflamed bronchi both after influenza and measles. It is noteworthy that the outbreak of pneumonia following measles has been in part coincident with, in part slightly subsequent to, an epidemic of influenza which has exposed every individual in the camp to infection with this disease.
B. influenzæ has been found in the lung with the pneumonia of measles in 7 of 17 examinations, namely, in 41.2 per cent of instances. The microorganism with measles, as with influenza, is found in the inflamed lung only half as frequently as in the bronchi. It appears to be peculiarly adapted for multiplication within the bronchial tubes, and its isolation from the inflamed lung in less than half of the cases of pneumonia is perhaps referable to its presence in the small bronchi and bronchioles. The presence of B. influenzæ in the lungs in pure culture in 3 instances at first sight suggests that the microorganism produces pneumonia, but a more intimate survey of these cases gives little support to this view. In Autopsy 450 B. influenzæ has been found in pure culture in the lung, but Pneumococcus IV has been isolated from the blood of the heart and has been with little doubt the cause of typical lobar pneumonia present in this instance. In Autopsy 486 the condition is almost identical, for in the presence of lobar pneumonia B. influenzæ has been found in the lung in pure culture, but Pneumococcus II atypical has been isolated from the pleural cavity and from the bronchus; in both autopsies the pneumococci which have caused lobar pneumonia have disappeared from that part of the consolidated lung from which a culture has been made; and here doubtless its invasion has been effectively resisted although it is still present in other organs. In Autopsy 481 in which B. influenzæ has been isolated from the lung in pure culture, the part of pneumococci in the production of the fatal disease is less evident; in this instance, Pneumococcus II atypical, S. hemolyticus and B. influenzæ have been isolated from the bronchus.
The presence of microorganisms which have a well-established etiologic relation to pneumonia explains the occurrence of pneumonia and makes unnecessary the assumption that B. influenzæ, which is present in the lungs in less than half of the instances examined, is essential to the production of the pneumonic consolidation. In view of the well-recognized etiology of lobar pneumonia we may conclude that this lesion is referable to the pneumococci (Pneumococcus II atypical in 3 instances and Pneumococcus IV in 1 instance) isolated from the autopsies in which this lesion occurred. Pneumococcus (Pneumococcus II atypical in 3 instances and Pneumococcus I in 1 instance) has been isolated from the lungs or heart’s blood in 4 of 5 instances of acute bronchopneumonia unaccompanied by suppuration. With unresolved bronchopneumonia with no suppuration, pneumococci have been in no instance found in the lungs or blood though their presence in the washed sputum during life or in the bronchus at autopsy suggests the possibility that they may have disappeared from the lungs.
In all instances in which suppuration has occurred hemolytic streptococci have been found in the lungs or blood, or in both. The occurrence of pneumococci in the lungs in 2 of 5 instances of suppurative pneumonia indicates that infection with S. hemolyticus is in some instances at least superimposed upon acute bronchopneumonia caused by pneumococci. Bronchopneumonia in 3 instances has the character of that caused by pneumococci. It is probable that the sequence of infection frequently observed after influenza, namely, bronchial infection by B. influenzæ, followed by pneumonia caused by pneumococci, followed in turn by infection by hemolytic streptococci with necrosis or suppuration, is not uncommon after measles.
Pneumonia Associated with Acute Infectious Diseases Other than Influenza and Measles.—A small group of autopsies have been excluded from the list of those which accompanied the epidemic of influenza, because pneumonia has been associated with an acute infectious disease to which it is perhaps secondary. These few instances of pneumonia, like those following measles reproduce characters of the pneumonia following influenza and may be in part referable to influenza which has attacked an individual suffering with typhoid fever, mumps or scarlet fever.
In 2 instances pneumonia followed typhoid fever and appeared on September 23 and 26 shortly after the epidemic of influenza had become evident. In the following autopsy there was acute lobar pneumonia which appeared ten days after onset of typhoid fever.
Autopsy 245.—O. H., white, aged twenty-one, a farmer, resident of Oklahoma, had been in military service twenty-one days. Onset of illness was on September 13 with chill, headache, cough and nausea. The patient was admitted two days later with the diagnosis of acute bronchitis. On September 20 the abdomen was tense, the spleen was enlarged and rose spots were present. Signs of lobar pneumonia were found September 23. Death occurred September 25, twelve days after onset of typhoid fever and two days after recognition of pneumonia.
Anatomic Diagnosis.—Typhoid fever with necrotic ulcers in lower ileum and in colon; hyperplasia of ileocecal lymphatic nodes; acute splenic tumor; parenchymatous degeneration of liver and kidneys; acute lobar pneumonia with gray hepatization in left lower lobe and red hepatization and edema in left upper lobe and in right lung; serofibrinous pleurisy on left side.