Pneumonia begins with a chill, while pulmonary oedema has no chill. Pneumonia is a febrile disease, while in pulmonary oedema there is no rise in temperature. In pneumonia there is pain in the side; there is no pain in pulmonary oedema. The sputum in pneumonia is viscid, rusty, and microscopically pathognomonic; pulmonary oedema is accompanied by a profuse watery expectoration. Pneumonia is commonly unilateral, and can occur in any part of the lung, while pulmonary oedema is bilateral, and usually occurs in the most dependent portion of the lung. In pneumonia we have the crepitant, dry râle, while in pulmonary oedema we have subcrepitant râles, larger and more liquid than those in pneumonia. Bronchial breathing and bronchophony occur in pneumonia, and are absent in pulmonary oedema. Percussion dulness is more marked in pneumonia than in pulmonary oedema, and the diseases with which the latter condition is apt to arise will aid us very much in the diagnosis. Urinary symptoms are negative in pulmonary oedema, while in pneumonia the chlorides are diminished or absent.
The stage of resolution in pneumonia is not infrequently mistaken for general capillary bronchitis, but, though the subcrepitant râle is present in both, it is heard all over the chest in capillary bronchitis, while it is confined to a comparatively small space in pneumonia. The expectoration is muco-purulent in bronchitis, and viscid and fibrinous in pneumonia. The temperature is lower in bronchitis (100°–103°) than in pneumonia (104°–106°). Capillary bronchitis is bilateral, pneumonia usually unilateral. Capillary bronchitis does not commonly begin with a chill, like that which occurs in pneumonia, but comes on more insidiously and without pain. Capillary bronchitis gives an exaggerated percussion note, while there is dulness on percussion in pneumonia. There is bronchial breathing in pneumonia, and a feeble vesicular murmur in capillary bronchitis. In capillary bronchitis the cyanotic appearances are very much more marked than in pneumonia, and there is no perversion of the pulse-respiration ratio. The breathing is labored in capillary bronchitis, and panting in pneumonia. In capillary bronchitis there are several slight attacks of chilliness; in pneumonia there is usually only one chill, at the onset.
The chief points in making the diagnosis between pneumonia and pleurisy are the pain, sputum, and percussion note. Pneumonia is ushered in by a distinct chill, followed by a rise in temperature to 104° to 105°, while pleurisy begins with chilliness or a number of slight rigors, and the temperature is lower, rarely above 100°. The dry hacking cough of pleurisy may be accompanied by slight mucous expectoration, while in pneumonia the expectoration is characteristic. In pleurisy the breathing is catching; in pneumonia it is panting. In pleurisy the face is pale and anxious; in pneumonia the cheek bears a dull mahogany-colored flush. In pleurisy the pulse is firm, small, tense, and wiry; in pneumonia it is full and bounding. The amount of chlorides in the urine is not altered in pleurisy, but in pneumonia they are diminished or absent. The pulse-respiration ratio is not affected in pleurisy, while in pneumonia it may fall as low as 2:1. There are no critical days in pleurisy, while in pneumonia crisis occurs about the fifth or seventh day. In pleurisy with effusion there may be bulging of the intercostal spaces, and the heart may be displaced; these phenomena never occur in pneumonia. The vocal fremitus is feeble or absent in pleurisy, while in pneumonia it is much increased. In pneumonia there is dulness on percussion, while percussion over a pleuritic effusion elicits flatness, which changes with the position of the patient. In pleurisy the grazing, rubbing, or sticky friction-sound may be heard with both respiratory acts; in pneumonia we hear the crepitant râle. In pleurisy the respiratory sounds are feeble or absent, as are the vocal sounds, while bronchial breathing and bronchophony are marked in pneumonia. It may be remembered, however, that if adhesions from an old pleurisy bind the lung to the chest, vocal fremitus may be increased in pleurisy. Again, bronchophony and bronchial breathing may exist in pleurisy, but they are always diffuse, never sharp and tubular, as in pneumonia, and are usually confined to the scapular region.
Hypostatic congestion of the lungs is accompanied by copious, watery, blood-stained expectoration. In pneumonia the sputa, though bloody, are rarely watery. Pneumonia occurs anywhere in the lung, and has well-marked rational symptoms; hypostatic congestion occurs in the most dependent portion of the lung, disappears when the patient sits up, is accompanied by no rational symptoms except dyspnoea and expectoration, and usually can be traced to a long-continued recumbent posture in those who are suffering from extensive blood-changes.
It is often difficult to decide whether a child has catarrhal or croupous pneumonia. It is to be remembered that catarrhal pneumonia is always secondary, while croupous is primary. Catarrhal pneumonia usually follows a bronchitis, croupous pneumonia rarely. In catarrhal pneumonia both lungs are involved; in croupous but one, and often only a single lobe. Catarrhal pneumonia is accompanied by a catarrhal sputum, while croupous pneumonia has a viscid, rusty, fibrinous expectoration. There is no day of crisis in catarrhal pneumonia, while croupous pneumonia in children almost always ends in well-marked crisis. In catarrhal pneumonia dulness on percussion is generally confined to the posterior dorsal region, and does not extend so far forward as in lobar pneumonia. Again, the extent of the physical signs and the rapidity of their development in catarrhal pneumonia are in contrast with those of croupous.
The range of the temperature is a most valuable guide in their differential diagnosis, since not only the height of the fever is greater in croupous, but the temperature-curve is different, as seen in the accompanying tracings:
| FIG. 39. |
| Acute Lobar (croupous) Pneumonia in a Child: Recovery. |
| FIG. 40. |
| Acute Lobular (catarrhal) Pneumonia in a Child: Recovery. |