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Abnormal presence of air in mediastinal tissues; multiple causes include pulmonary interstitial emphysema, ruptured bleb, perforation of the cervical or thoracic esophagus or airways, cervicomediastinal infection, and perforated abdominal viscus.
Synonym(s): mediastinal emphysema
[G. pneuma, air, + mediastinum]
mediastinal emphysemaThe presence of air in mediastinal soft tissues.
Severe chest pain, dyspnoea, Hamman sign.
• Respiratory tract—trauma to lungs, perforation of upper airways, asthma, Mycoplasma pneumoniae pneumonia.
• GI tract—rupture of oesophagus, bowel.
• Other (e.g., obesity).
Usually conservative, as emphysema slowly resolves on its own; in the face of lung collapse, the patient must lie on the side of the collapsed lung.
mediastinal emphysemaPneumomediastinum Surgery Air in mediastinal soft tissues which may be linked to perforation of the trachea. See Mediastinal crunch, Mediastinum.
me·di·as·ti·nal em·phy·se·ma(mē'dē-ă-stī'năl em'fi-sē'mă)
Deflection of air, usually from a ruptured emphysematous bleb in the lung, into the mediastinal tissue.
a pathological accumulation of air in tissues. The air may derive from a skin laceration and be drawn in by the movements of muscles. A discontinuity of the tracheal mucosa is a common cause, either by way of laceration or ulceration. Extension from a pulmonary lesion is also common. The syndrome resulting depends on the location of the air. See also pulmonary emphysema and subcutaneous emphysema (below).
acute bovine pulmonary emphysema
see pulmonary emphysema (below).
emphysema in which bullae form in areas of lung tissue so that these areas do not contribute to respiration.
may occur after head trauma which permits escape of air from the paranasal sinuses.
see emphysematous/putrescent fetus.
widespread distribution of air, including subcutaneous tissues, seen with pneumomediastinum.
pulmonary emphysema due to a developmental abnormality, resulting in a reduced number of alveoli, which are abnormally large.
accumulation of air in the septa between lobules of the lungs.
presence of air in the peribronchial and interstitial tissues of the lungs.
a condition marked by accumulation of gas under the tunica serosa of the intestine.
emphysema involving less than all the lobes of the affected lung.
may occur after trauma to the head which permits escape of air from the paranasal sinuses; appears as swelling with crepitus under the conjunctiva or periocular skin.
panacinar emphysema, panlobular emphysema
generalized obstructive emphysema affecting all lung segments, with atrophy and dilatation of the alveoli and destruction of the vascular bed.
distention of the lung caused by overdistention of alveoli and rupture of alveolar walls (alveolar emphysema) and in some cases escape of air into the interstitial spaces (interstitial emphysema). It is a common pathological finding in many diseases of the lung in all species, but also occurs independently, especially in horses, as a principal lesion in chronic obstructive pulmonary disease. It is also a prominent lesion in bovine atypical interstitial pneumonia. It is always secondary to a primary lesion which effectively traps an excessive amount of air in the alveoli. It is characterized clinically by cough, dyspnea, forced expiratory effort and poor work tolerance. A double expiratory effort is a characteristic sign—hence broken wind.
occurs with fractures involving the paranasal sinuses.
air or gas in the subcutaneous tissues. The characteristic lesion is a soft, mobile swelling which crackles like stiff paper when palpated. There is no pain, nor heat and no ill effects unless the pharyngeal area is sufficiently involved to cause asphyxia.
subcutaneous emphysema following operation.
emphysema affecting only one lung, frequently due to congenital defects in circulation.
see panacinar emphysema (above).
of or pertaining to the mediastinum.
an abscess that causes systemic signs of toxemia and fever but also severe pain with each inspiration, causing grunting as in pleurisy but without the auscultatory findings of pleurisy.
remnants of branchial pouches may be found in the anterior mediastinum, particularly in brachycephalic dogs; bronchogenic cysts are found in the posterior mediastinum.
movement of the tissues and organs of the mediastinum back and forth with each movement of air in and out of an open sucking wound in the thoracic cavity. The condition can produce serious impairment of cardiopulmonary function and is fatal if not treated promptly. Signs are similar to those of mediastinal shift (see below).
mediastinal lymph node enlargement
a condition due to abscess formation or neoplastic growth which may cause obstruction to the esophagus and dysphagia, or to the bronchi, causing inspiratory dyspnea. If it is in the anterior chest and of considerable size, it may mimic congestive heart failure, with jugular vein engorgement and edema of the brisket.
characterized by progressive weight loss, reduced exercise tolerance, dyspnea, hydrothorax, areas of dullness on auscultation or percussion over lungs, neoplastic cells in pleural fluid if lesion intrudes into pleural cavity.
a shifting or moving of the tissues and organs that comprise the mediastinum (heart, great vessels, trachea and esophagus) to one side of the chest cavity. The condition occurs when a severe injury to the chest causes the entrapment of air in the pleural space (tension pneumothorax). As the volume of air increases on the affected side, the lung collapses and the organs and tissues of the mediastinum are crowded to the opposite side of the chest. This can produce compression of the other lung and kinking or twisting of one or more of the great blood vessels, which in turn seriously impairs blood flow to and from the heart.
a partial septum of the testis that contains the rete testis.