Spontaneous Mediastinal Emphysema

Abstract

THE credit for bringing this rare condition to the attention of the medical profession belongs largely to Hamman (3). In 1937 he reported five cases, two of which had a small spontaneous pneumothorax associated with their mediastinal emphysema. The same year Scott (6) reported two cases and called attention to the similarity of the pain of mediastinal emphysema to the angina of coronary thrombosis. There are a few case reports of this condition in the literature, sometimes occurring alone, and sometimes with pneumothorax as a result of definite causes. Some have occurred during influenza or pneumonia and have been ascribed to rupture of the alveolus during coughing. Faulkner and Wagner (2) reported a case in an uncontrollable asthmatic. A few such cases have occurred following artificial pneumothorax in which air may have been injected directly into lung tissue or in which the air in the pleural cavity escaped through the pleura into the mediastinal space. Trauma to the trachea or to the pleura may cause mediastinal emphysema. It sometimes follows thoracotomy and thyroidectomy. Strains of any kind, such as lifting, straining at stool, crying, paroxysms of coughing, or childbirth may be responsible for the rupture of an alveolus. From the paucity of case reports of spontaneous mediastinal emphysema in the literature one would be led to believe that the condition is either rare or not well understood. It is an important condition to diagnose not because of its seriousness but because of the seriousness of the conditions it may simulate. As Hamman (3) and Scott (6) have pointed out, mediastinal emphysema must be differentiated from such serious conditions as coronary thrombosis, acute pericarditis, ruptured aneurysm, and pulmonary embolus. As has been stated, there may be a direct cause or an alveolus may rupture spontaneously. Such ruptures may occur more often than one would think, and be responsible for some of the pains in the chest that occur without apparent cause. After rupture, the air escapes through the rent in the alveolus and dissects its way through the fibrous tissue about the bronchi and blood vessels, escaping into the mediastinum through the hilum of the lung. From thence, if enough accumulates, it may dissect its way up into the neck and over the shoulders. Occasionally, the air from an alveolus will dissect its way to the pleura and escape into the pleural cavity, producing a spontaneous pneumothorax as well as a spontaneous mediastinal emphysema. The onset of the condition is apt to be sudden and dramatic. The pain strikes the patient suddenly and is often severe in character, being located along the border of the sternum and referred to the shoulder and down the arm. There is an increase in pulse rate and sometimes an elevation of temperature.