PLEURISY ; TUBERCULOSIS OF THE LUNGS.
Dropsy of the Lungs.—A condition of the lungs in which the pulmonary tissue as \ yell as the pulmonary vesicles are saturated with serum which comes from the blood. It is known also as pulmonary cedema, or " filling up " of the lungs, and is always a serious secondary affection. It occurs as a temporary state in rare cases of heart-defects and chronic affections of the kidneys. Usually it is a sign of approaching death, and is due to defective circulation.
The most characteristic symptom of this severe disturbance of the circula tion of the blood is marked shortness of breath. Breathing is very rapid, very laboured, and there is rattling in the chest. The skin and the visible mucous membranes are bluish in colour, and the patients are usually forced to sit erect in bed. and to exert all the auxiliary respiratory muscles in order to pump air enough into the lungs to keep them alive. The sputum, which is usually very profuse at the beginning of an attack, becomes arrested as soon as the respiratory muscles relax, and remains in the air passages, thus still further increasing the danger of suffocation. If the body becomes excessively charged with carbonic acid gas, unconsciousness will set in from which the patient cannot he aroused. As already stated, dropsy of the lungs is not a disease of itself, but a terminal stage of many severe affections.
Emphysema of the Lungs.—An affection in which the pulmonary vesicles lose their natural elasticity, so that they become unable to contract on ex piration, and, as a result, remain more or less permanently dilated. A moderate degree of this condition is often observed in elderly people, as the natural consequence of the gradual weakening of the lung-tissues. Emphysema is found also in younger persons, without being attributable to any known injury. In these cases there is usually present a congenital weakness of the lung-tissue. As a rule, however, the affection can be traced to certain pernicious influences, among which over-exertion is one of the most important. Hence the disease is found most frequently in glass-blowers, among players of wind instruments, in workmen who perform hard bodily work which causes acceleration of respiration and increase of air-pressure during expiration, and in athletes who run too much. Severe whooping
cough, persistent bronchial catarrhs, asthma, and certain heart-diseases may also cause the development of emphysema.
The symptoms of emphysema are fairly well marked. If the distention be slight, only mild disturbances of respiration may be present, particularly if the patient keeps quiet. Cough, expectoration, and oppression of the chest become more marked after bodily exertion, or when a bronchial catarrh (which usually is present) becomes aggravated. Unfavourable weather increases the respiratory disturbances. As the disease progresses, and the dilatations become more pronounced, the difficulty in breathing becomes more marked ; and the patients are forced to -make considerable exertion, especially to force the air out of the lungs. A further consequence of the obstruction to respiration is an impairment of the interchange of gases. and the resultant over-charge of the blood with carbon dioxide. This is manifested by a bluish discoloration of the skin and mucous membranes. In the further course of the disease, the heart also becomes implicated. The right half of the heart, by performing an increased amount of labour, endeavours to remove the congestion of the blood in the lungs, caused by destruction of many of the finest pulmonary blood-vessels ; and it therefore becomes dilated. If, at length, the power of the heart relaxes, the conges tion in the veins of the body becomes greater, and watery extravasations occur under the skin and in the thoracic and abdominal cavities, directb, endangering the life of the patient.
It is often possible to recognise the affection from an inspection of the upper part of the body. The neck is usually short and thick ; the muscles situated in front and on the sides of the throat (especially those that sup port the head) are greatly strained and thickened ; the veins of the throat are dilated and stand out distinctly as bluish cords ; the thorax is com paratively short, but conspicuously broad and deep (see Plate XVII. 3); inspiration is short and laboured, and expiration prolonged.