EMPHYSEMA, a medical term applied to two conditions— "pulmonary emphysema" (the word "pulmonary" is frequently omitted) and "surgical emphysema." Of pulmonary emphysema there are two forms, vesicular and interstitial (or interlobular). In vesicular emphysema there is enlargement of air-vesicles, from excessive distension and destruction of the septa between con tiguous vesicles (see RESPIRATORY SYSTEM). In interstitial em physema air is present in the connective tissue beneath the pleura and between the pulmonary air-cells.
The former variety is by far the more common and generally is caused by forced expiration against a closed glottis, as in coughing. Hence emphysema is most evident over relatively 'For the titles of 13aatXe6c, Imperator Augustus, etc., applied in the loth century to the Anglo-Saxon kings, see EMPIRE (note) . The claim to the style of emperor, as a badge of equal rank, played a considerable part in the diplomatic relations between the sultan and certain European sovereigns. Thus, at a time when this style (padi shah) was refused by the sultan to the tsars of Russia, and even to the Holy Roman emperor himself, it was allowed to the French kings, who in diplomatic correspondence and treaties with Turkey called themselves "emperor of France" (empereur de France).—(ED.) unsupported parts of the lungs, e.g., above the collar bone and between the ribs. Probably an impaired nutritive condition of the lung tissue conduces towards the change. Emphysema is a pro gressive condition, since the distended air vesicles have lost their elasticity. Moreover, many of the pulmonary capillary blood vessels which run in the inter-vesicular septa have been destroyed and the rest are elongated and narrowed. Hence an increased strain is thrown on the right ventricle, with a consequent dilatation leading on to heart failure and all its attendant troubles. The chief symptom in this complaint is shortness of breath, more or less constant, but greatly aggravated by exertion and by attacks of bronchitis, to which persons suffering from emphysema appear to be specially liable. The respiratory rhythm is altered, the expiratory portion being far longer than the inspiratory. In severe forms of the disease the patient has a puffy cyanosed appearance and the chest becomes barrel-shaped.
Interstitial emphysema, arising from the rupture of air-cells in the immediate neighbourhood of the pleura, may occur as a complication of the vesicular form, or separately as the result of some sudden expulsive effort, such as a fit of coughing, or, as has frequently happened, in parturition. Gangrene or post-mortem decomposition may lead to the presence of air in the interstitial tissue of the lung. Occasionally the air infiltrates the cellular tissue of the posterior mediastinum, and distends the whole sur face of the body.
Surgical emphysema signifies the effusion of air into the general connective tissues of the body. The commonest causes are a wound of some air-passage, or a penetrating wound of the chest wall without injury to the lung. Its severity varies, from a little crepitation felt under the skin to extreme cases where the whole body is blown up and death is imminent from impeded respiration and failure of the action of the heart. In mild cases no treatment is necessary, as the air gradually becomes absorbed ; but in severe cases incisions must be made in the swollen cellular tissues to allow the air to escape. The condition must be distinguished from those in which gas is formed in the tissues during the growth of pathogenic bacteria (e.g., gas gangrene).