Pectus Excavatum Clinical Presentation

Updated: Aug 14, 2017
  • Author: Andre Hebra, MD; Chief Editor: Girish D Sharma, MD, FCCP, FAAP  more...
  • Print
Presentation

History

Some patients with pectus excavatum experience chest and back pain that is usually musculoskeletal in origin. The exact cause of the pain is poorly understood. Pectus excavatum and pectus carinatum are frequently associated with scoliosis. Although such association is probably coincidental, the poor posture noted in many patients with pectus deformities may be a key factor in the development of pain.

Pulmonary function

Many physicians attribute the symptomatic impairment in pectus excavatum to a decrease in intrathoracic volume secondary to the sunken chest. However, this relationship is difficult to prove because of the wide range of pulmonary function among healthy individuals and the correlation of pulmonary function with physical training and body habitus. The reported pulmonary function abnormalities have ranged from being normal in young patients to restrictive or obstructive defect in older patients with marked defect. Elevated residual volume has been reported. [1] There has been scientific evidence reported that demonstrates shortness of breath upon exertion in patients with pectus excavatum, primarily due to the decrease in pulmonary reserve. [2]

Clinicians have observed that many patients with pectus excavatum tend to become symptomatic during their teenage years or early in adult life. Patients younger than 10 years who have pectus excavatum do not typically experience symptoms associated with shortness of breath.

A prospective study of preoperative and postoperative pulmonary function following corrective surgery for pectus excavatum found that there is significant improvement in lung function at rest and in VO2 max and O2 pulse after surgical correction of pectus excavatum, with CT index >3.2. According to the study, operative correction significantly reduces CT index and markedly improves the shape of the entire chest and can be performed safely in a variety of centers. [3] ] ,[ [4] In 1984, Cahill et al reported that, after operative repair, lung capacity improved little, and maximal voluntary ventilation significantly improved in patients with pectus excavatum who had low-to-normal vital capacities prior to surgery. [5] Exercise tolerance was also improved, as measured by total exercise time and maximal oxygen uptake. The heart rate at a given level of work or exercise consistently decreased postoperatively, but oxygen consumption to support an improved efficiency of work was not changed.The observed decrease in heart rate at each workload capacity was a result of increased cardiac stroke volume.

In 1967, Weg et al evaluated 25 US Air Force recruits with pectus excavatum and compared them with healthy trainees. [6] Although the lung compartments and mean vital capacities of both groups were equal, the maximum voluntary ventilation significantly deviated from predicted reference range values (P = 0.005).

In 1996, Quigley et al studied 36 adolescents (mean age 16 y) with pectus excavatum. [7] Quigley et al reported a significantly lower forced vital capacity in the study group than in an age-matched control group. Moreover, an inverse relationship was observed between the vital capacity and the degree of sternal compression, suggesting that such patients would benefit from operative correction of the pectus deformity.

Cardiac function

Posterior displacement of the sternum in pectus excavatum can produce a heart deformity, with anterior indentation of the right ventricle. Early pathologic studies demonstrated this finding, and a series of early case reports included cardiac evaluations for patients with severe symptoms. Angiographic studies have demonstrated the sternal imprint on the anterior wall of the right ventricle.

Several studies have demonstrated limitation of cardiac stroke volume in patients with pectus excavatum, particularly in the sitting, or upright, position. When patients with pectus remain in the supine position (lying flat), no significant impairment to cardiac function is apparent. Further evidence has suggested that operative repair of pectus results in normalization of the cardiac function.

One study assessed cardiac workload in 13 patients with pectus excavatum. [8] The patients were assessed in an upright position on a bicycle ergometer. Findings suggested that, following surgery, most patients could more easily reach the target heart rate during exercise without becoming symptomatic. Many use this observation as substantial evidence that operative repair for pectus excavatum results in improved cardiac function. However, the role of conditioning and subjective response to surgery is difficult to assess.

Next:

Physical

The hallmark of pectus excavatum is the caved-in appearance of the anterior chest. As mentioned above, the severity of the defect and the asymmetry of the chest widely vary. Patients may present with a very mild form of pectus excavatum or their sternum may be almost touching the spine. Typically, the lower third of the sternum is more involved, and the upper third may appear fairly normal. A compensatory anterior flaring of the lower ribs at each costal margin is also common. Many patients have associated scoliosis, but this is not directly related to the presence of pectus excavatum.

Heart sounds are typically displaced to the left side because of displacement and rotation of the heart. A click sound of mitral valve prolapse may be present. Lung sounds are clear, but the lung sounds may appear diminished at both bases because of decreased pulmonary volumes.

The term pectus posture refers to the position assumed by most patients with significant pectus excavatum. They appear to create an anterior curvature of the thoracic spine with the shoulders slumped forward. Whether this is a subconscious maneuver to hide the chest wall deformity or a postural defect directly related to pectus excavatum is unclear. Such positioning of the spine appears to accentuate the pectus excavatum and can generate spine problems related to poor posture and inadequate spinal support. Correcting this posture is quite difficult, even after successful repair of the pectus excavatum.

Previous
Next:

Causes

The cause of pectus excavatum is unknown. It probably originates from a genetic defect that results in abnormal musculoskeletal growth. The cartilaginous portion of the rib is very likely the main source of this abnormal growth pattern. Abnormalities of rib morphogenesis and growth are the most likely causes of pectus excavatum and pectus carinatum. In pectus excavatum, the sternum is thought to be pushed in by abnormal growth at the articulation with the ribs and cartilage. Again, the exact mechanism that results in this abnormal growth pattern is not known. Increased work of breathing, as is observed in young patients during exercise or play activity, may contribute to the progression of the pectus deformity, particularly during early the teenage years. However, no scientific evidence supports such a theory.

Previous