Musculoskeletal · Chest Wall Deformities
The facts most likely to be tested
Pectus excavatum is a congenital chest wall deformity characterized by posterior depression of the sternum.
The condition is frequently associated with connective tissue disorders, most notably Marfan syndrome.
Physical examination reveals a caved-in appearance of the chest that may result in cardiac compression or displacement.
Patients often present with a systolic ejection murmur at the left sternal border due to right ventricular outflow tract obstruction or cardiac displacement.
Echocardiography is the diagnostic test of choice to evaluate for cardiac compression, mitral valve prolapse, or aortic root dilation.
Surgical correction via the Nuss procedure is indicated for patients with severe Haller index scores or significant cardiopulmonary compromise.
The Haller index is calculated using computed tomography (CT) measurements of the transverse diameter divided by the anteroposterior diameter, with a value greater than 3.25 indicating severe disease.
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A 16-year-old male presents for a sports physical. He is tall and thin with long, slender fingers. On physical exam, there is a noticeable posterior depression of the sternum. Auscultation reveals a systolic ejection murmur at the left upper sternal border. He denies chest pain or dyspnea during exercise. An echocardiogram is ordered to assess for associated structural abnormalities.
Which of the following is the most likely underlying genetic association in this patient?
Marfan syndrome
The patient exhibits classic physical findings of pectus excavatum and Marfanoid habitus, which is highly associated with Marfan syndrome (Bet 2).
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Etiology / Epidemiology
Congenital chest wall deformity characterized by sternal depression. Most common in males with a 3:1 ratio.
Clinical Manifestations
Presents as funnel chest with sternal concavity. Often associated with Marfan syndrome.
Diagnosis
CT chest is the gold standard to calculate the Haller index; a value >3.25 indicates surgical candidacy.
Treatment
Surgical correction via Nuss procedure for severe cases. Avoid surgery in asymptomatic patients with mild deformity.
Prognosis
Excellent outcomes post-repair. Restrictive lung disease is the primary long-term complication if left untreated.
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Epidemiology & Etiology
This is the most common congenital chest wall deformity, occurring in approximately 1 in 400 births. It is strongly associated with connective tissue disorders, most notably Marfan syndrome and Ehlers-Danlos syndrome. A positive family history is present in up to 40% of cases.
Pertinent Anatomy
The condition involves the posterior displacement of the sternum and the inward growth of the costal cartilages. This creates a funnel chest appearance that reduces the anterior-posterior diameter of the thoracic cavity. Severe cases may cause cardiac displacement or rotation into the left hemithorax.
Pathophysiology
The primary mechanism is the overgrowth of costal cartilages, which forces the sternum inward during development. This structural change leads to decreased thoracic volume, which can compress the right ventricle and limit cardiac output. Over time, this results in restrictive pulmonary physiology and reduced exercise tolerance.
Clinical Manifestations
Patients typically present with a visible funnel chest deformity that is often noted at birth or during the adolescent growth spurt. Physical exam reveals a sternal depression and potential mitral valve prolapse if associated with connective tissue disease. Red flag symptoms include exertional dyspnea, chest pain, and syncope, which necessitate immediate cardiopulmonary evaluation.
Diagnosis
The Haller index is the definitive diagnostic metric, calculated by dividing the transverse diameter of the chest by the anterior-posterior diameter on CT chest. A Haller index >3.25 is the standard threshold for surgical intervention. Pulmonary function tests often demonstrate a restrictive pattern with decreased total lung capacity.
Treatment
Asymptomatic patients require only observation and reassurance. The Nuss procedure (minimally invasive repair) is the first-line surgical treatment for symptomatic patients or those with a high Haller index. Contraindications for surgery include mild deformity without functional impairment or severe underlying comorbidities that preclude general anesthesia.
Prognosis
Surgical correction typically results in significant improvement in exercise tolerance and self-image. Restrictive lung disease and chronic cardiac compression are the primary long-term risks of untreated severe cases. Patients should be monitored for recurrence or hardware-related complications post-Nuss procedure.
Differential Diagnosis
Pectus Carinatum: characterized by anterior sternal protrusion (pigeon chest)
Scoliosis: lateral curvature of the spine often co-occurring with chest wall deformities
Marfan Syndrome: systemic connective tissue disorder with characteristic arachnodactyly
Poland Syndrome: unilateral absence of the pectoralis major muscle
Cardiac tumor: can present with similar chest wall prominence or displacement