Definition.—A dilatation of the air-vesicles or a rupture of the vesicles, allowing the air to escape into the connective tissue. The forms of emphysema are: Hypertrophic or large-lunged emphysema, atrophic or small-lunged emphysema, and compensating emphysema.
Etiology.—While it is true that, in rare cases, emphysema has occurred where there has been no apparent cause other than a feeble condition of the lung tissue, the strain of normal respiration being too great for the vesicles, the common and almost invariable cause is the result of severe straining due to disease of the respiratory apparatus, or to the physical exertion necessarily used in certain lines of work. Thus the blowing of wind instruments, or the strain upon the lung as used by glass-blowers.
The most frequent cause is the violent strain attending the paroxysm of coughing in bronchitis, whooping-cough, or asthma. Although found in all ages, it occurs more frequently after middle life, and more frequently in males than females, the greater exposure among the former readily accounting for the difference in sex.
Pathology.—The characteristic change in the lungs is the loss of its elasticity from over-distention of the air-vesicles, and consequent weakening of the elastic tissue of the alveolar septa, As a result, the lungs are of undue size, being greatly distended, and do not collapse when the chest is opened. The apices project above the clavicles, while the diaphragm is displaced downwards. The voluminous lungs crowd the thorax, giving it the characteristic barrel-shaped thorax.
In color, the lungs are gray, being almost bloodless, though they may be streaked with pigment. To the touch they are soft, downy, and may pit on pressure. They do not crepitate, and when placed in water float higher than the normal lungs. The walls of the alveoli, from pressure, become very much distended and lose their elasticity. Often the septa are destroyed, causing the coalescence of several cells.
The bronchial mucous membrane shows chronic inflammation, and is frequently bathed in muco-pus. The right heart is generally hypertrophied, due to obstruction of the pulmonary circulation.
Where there are pathological changes in a portion of, or in an entire lung, such as tuberculosis, adhesion pleurisy, and in lobar pneumonia, the other lung may become emphysematous from the increased work thrown upon it, and is known as compensating emphysema.
In elderly people, atrophy of the lung sometimes occurs, the alveolar walls and septa completely atrophying; there is a coalition of air-cells, which gives rise to large air-sacs, though the lung itself is much smaller than in health. This is known as senile emphysema.
Symptoms.—There are no characteristic symptoms in the early stages, the disease coming on slowly and insidiously, the only symptoms being those of the primary disease, bronchitis, asthma, or whooping-cough.
The first notable symptom is dyspnea, which occurs often after slight exertion, such as going upstairs or performing the daily duties more hurriedly than usual. A hearty meal may be attended by shortness of breath.
As the disease progresses, the dyspnea increases; at first the most marked obstruction is in expiration; but later, as in asthma, both inspiration and expiration seem equally labored, and are attended by more or less wheezing.
Cyanosis.—As the disease progresses and the right ventricle becomes involved, the patient takes on a cyanotic appearance. At first the lips and fingers become blue, but as compensation gives way, or when the dyspnea is severe, the face becomes puffy and very blue.
Cough.—This is due to the bronchitis, that usually precedes and accompanies the emphysema, being worse in the fall and winter months. Expectoration varies in quantity and consistency, and corresponds to the type of bronchial inflammation. The general health naturally suffers, the patient losing flesh and strength. The temperature is normal or subnormal, while the pulse is feeble, though not much more frequent, save after exertion.
The patient is slightly stooped, and becomes cachectic, owing to cardiac disturbances with congestion of the viscera; there is edema of the feet, though generally dropsy is rare.
Physical Signs.—Inspection reveals the characteristic "barrel-shaped chest," the thorax being rounder than when normal, the antero-posterior diameter being equal and sometimes greater than the transverse. The sternum, scapulae, and clavicles are prominent. The shoulders are drawn forward, and the patient appears stooped. The interspaces of the ribs are widened on inspiration and expiration, and the chest is raised and lowered as though a solid cage, rather than expanded. The respiratory muscles are prominent.
The apex beat disappears, and epigastric pulsation is noticed. In the advanced state the veins of the neck are distended and pulsate.
Palpation reveals a diminished tactile fremitus, a feeble apex beat, which finally disappears, a distinct systolic shock over the ensiform cartilage, due to changes of the right heart, and a marked epigastric pulsation.
Percussion gives a hyper-resonant or tympanitic sound, the usual cardiac dullness disappearing, owing to distention of the lungs; the normal dullness over liver and spleen being much lower, owing to downward displacement.
Auscultation.—The vesicular respiratory murmur is lost, inspiration is short, while respiration is prolonged. When bronchitis is present, the rales peculiar to that affection are noticed. There is a pronounced accentuation of the pulmonary second sound.
Diagnosis.—The diagnosis is comparatively easy, and scarcely can be taken for any other disease. The characteristic "barrel-shaped chest," the absence of the apex beat, the epigastric pulsation, the hyper-resonance of the chest, the dyspnea and cyanotic appearance, are conclusive evidence of emphysema.
Prognosis.—While the patient may live for years, if too great physical exertion is not used, the prognosis is unfavorable, the disease being progressive, finally terminating fatally.
Treatment.—Where possible, the patient should be removed to a dry, equable climate. Any obstruction of the nasal cavities or pharynx by polypi, adenoids, etc., should be removed. The diet should be carefully selected, sugar and starchy foods restricted, and alcoholic beverages prohibited. Such remedies as bryonia, ipecac, lobelia, sticta pul., tartar emetic, and sanguinaria will be useful in relieving the bronchitis.
Cactus, strophanthus, crataegus, digitalis, and other cardiac remedies will be used in the latter stages. Laxatives and diuretics should be used as may be indicated.