|Pectus Excavatum |
Lyall A. Gorenstein, MD
Pectus excavatum is a malformation of the chest wall in which several ribs and the sternum grow abnormally, resulting in a caved-in, or sunken appearance. It is a relatively common congenital deformity and occurs more often in males than in females. Approximately 40% of pectus excavatum patients have one or more family members with the defect.
Often present at birth, the condition may also develop during puberty and can range from mild to severe. Although its causes are not completely understood, the condition is believed to arise from excessive growth of the cartilage connecting the ribs to the breastbone, which pulls the sternum inward.
Pectus excavatum can compromise lung and heart capacity, especially when it is severe, causing the patient to experience fatigue, shortness of breath, chest pain, and a fast heartbeat. In some patients, the proximity of the sternum and the pulmonary artery may cause a heart murmur. For ordinary everyday activities, a person with pectus excavatum may have no symptoms, but with rigorous exercise, symptoms often appear. Lung capacity may be curtailed because lungs are confined and cannot properly expand. During exercise, the patient compensates by engaging the diaphragm in breathing in order to enable the lungs to expand more and obtain adequate oxygen and carbon dioxide exchange for the demands of the body. The additional energy utilized for breathing in this manner contributes to fatigue. Patients with severe pectus excavatum often notice that they are incapable of similar levels of activity as their peers. This can be especially difficult for adolescents, who often withdraw from participating in sports or other high stress physical activities.
In addition to its more serious symptoms, pectus excavatum may have negative psychosocial effects in children and teenagers, who experience self-consciousness and difficult peer interactions stemming from their appearance. Often these patients avoid activities that expose the chest.
Multiple tools are used to diagnose the condition and gauge its extent, including:
- Visual examination of the chest
- Ausculation — analysis of sounds of the heart and chest to detect the condition's effect on heart and lung function
- Electrocardiogram (ECG)
- Echocardiogram (a noninvasive test that takes a picture of the heart taken with sound waves)
- Pulmonary function testing (patient breathes into a mouthpiece connected to an instrument that measures the amount of air breathed over a period of time)
- Chest X-ray
- Haller Index: A measure of the extent of pectus excavatum by means of the CT scan. It is calculated by obtaining the ratio of the horizontal distance of the inside of the ribcage and the shortest distance between the vertebrae and sternum. A Haller Index of greater than 3.25 is generally considered severe (a normal Haller Index is 2.5).