In children the crepitant râle is frequently absent, and, though it may be heard at the end of a full inspiration after coughing, it is never so fine or distinct as in adults. In children there will be no increase in vocal fremitus if, as often happens, a large bronchus leading to the inflamed spot is plugged with mucus.
In old age the physical signs of adult pneumonia are modified by certain physiological changes which occur in the lungs and chest-cavity of the aged. The more complete bony union of the chest-walls, the curvature of the spine, the rigidity of the bronchial tubes, the rounded form of the chest, and the senile rarefaction of the lungs, give rise to extra resonance on percussion as compared with an adult chest. On account of the great arching of the sternum and the deposition of carbonaceous material at the apex of the lung, the clavicular region near the median line gives a dull percussion sound. The scapular and supra-scapular regions are less resonant than in the adult, on account of the tilting of the scapulæ due to curvature of the spine. There is a loss in the vesicular element of the respiratory murmur, and it resembles the sound produced by a forceful expulsion of air from the compressed lips. When the septa or the alveoli are torn and greatly distended, it has a bronchial character. Its intensity varies: at one moment it is loud, at another hardly perceptible; the variation occurs not only in the same individual, but in different individuals of the same age. The vocal sounds are loud and bronchophonic in character, and have a vibration closely resembling oegophony. It is also to be mentioned that it is almost a physiological condition for old people to have bronchorrhoea; hence mucous râles may be present during the whole period of advanced life, and if one relies on the usual crepitating râles of adult pneumonia for a diagnosis he will be misled.
Inspection and palpation in the first stage of senile pneumonia furnish little positive information. Percussion will give little dulness until the lung has reached the stage of red hepatization, and even then it may be so slight as to pass unnoticed. Very early in the disease the respiratory murmur is feeble and indistinct over the affected portion, while the portion of lung that is not involved assumes, for the time, all the characters of a normal adult respiratory murmur. Again, the breathing over the pneumonia may be intensely puerile and interrupted.
The crepitant râle is rarely present in the first stage of senile pneumonia, but subcrepitant râles and large moist râles resembling those of bronchitis are heard during the whole of this stage. The explanation of the absence of the crepitant râle is to be found in the physiological condition of the air-cells just referred to. Sometimes, on a deep inspiration after violent coughing, fine crepitation is heard, but upon careful examination it will not be found to differ from the râles of capillary bronchitis. It may be stated as a general rule that the feebler and more superficial the respirations the less distinct will be the adventitious sounds.
The physiological rigidity of the bronchi in old age favors the early development of bronchial breathing, which is often the first physical sign of senile pneumonia. One of its peculiarities, when occurring in the stage of engorgement, is that it is most distinct at the root of the inflamed lung.
Stage of Red Hepatization.—The physical signs of the second stage of croupous pneumonia are more diagnostic than those of either of the other stages.
Inspection shows the expansive movements of the affected side to be more markedly diminished than in the first stage, while those of the healthy side are increased. Frequently there is absolute loss of motion over the inflamed lung.
Palpation.—By palpation the vocal fremitus is usually increased on the affected side over the consolidated lung-tissue. In some instances it may be only slightly increased, and in rare instances it will be found less marked upon the affected side than upon the healthy. Palpation may also reveal slight displacement of the heart from the pressure of the distended lung; and in rare cases well-marked pulsation is felt over the affected lung.43
43 Skoda, Stokes, and Graves regard this as the result of increased pulsation of the arteries in the inflamed spot; and Walshe and Fox rather admit it, but Grisolle denies it.
It is evident that the vibrations of the vocal cords can be transmitted from the trachea through the bronchi and lung to the chest-wall, and there is no reason why the cardiac impulse may not likewise be transmitted through a solidified lung to the chest-wall.