Pectus excavatum is a congenital malformation of the sternum and costochondral cartilages resulting in a ventral dorsal narrowing of the chest or a depression of the sternum into the chest cavity. This deformity reduces effective pulmonary function and may also interfere with cardiac function.
Causes that have been discussed have included congenital predisposition, intrauterine pressure abnormalities, shortening of the central tendon of the diaphragm, thickened substernal ligament, congenital deficiency of the musculature in the cranial diaphragm, abnormal osteogenesis and chondrogenesis, upper respiratory obstruction, environmental factors, and posturing difficulties.
In humans, it is more frequently found in males and may be inherited as an autosomal dominant characteristic. In one survey it was twice as frequent in male than female cats, but not in dogs.
Signs often include exercise intolerance, weight loss, dyspnea, pneumonia, cyanosis, coughing, postural deficits. A heart murmur may be asculted and echocardiography is recommended to exclude the possibility of a concurrent primary heart disease. This is especially true in older cats that develop clinical signs as adults. It has been associated with other congenital defects e.g. pericardio-diaphragmatic hernia.
Radiographic findings may include decreased thoracic volume, cardiomegaly, and left displacement of the cardiac silhouette.
Congenital, Genetic, hereditary
AFEBRILE, ANOREXIA, CARDIAC MURMUR, COUGHING, CYANOSIS, DYSPNEA, GAIT ABNORMAL, WEAKNESS
Cachexia, Malaise, Weight gain insufficient
Exercise intolerant or reluctant to move, Walking difficulty
Heart sounds muffled, moist lung noises
Rapid breathing, Panting, Hyperventilation, Restrictive breathing pattern
Pulmonary infections recurrent
Thoracic radiographs showing cardiac displacement, cardiomegally, lordosis and sternal concavity.
1. Those with moderate to severe deformity should be treated surgically with placement of an external fiberglass splint contoured to normal thoracic shape. One possible adverse side effect of exteral splint correction is re-expansion pulmonary edema.
2. Older patients who have less thoracic compliance may benefit from a partial sternectomy.