How is pectus carinatum diagnosed in a pubertal adolescent?

Diagnosis of Pectus Carinatum in Pubertal Adolescents

Pectus carinatum is diagnosed clinically through visual inspection and physical examination of the anterior chest wall, revealing characteristic sternal and costal cartilage protrusion, with chest radiography and CT imaging used to confirm the diagnosis and quantify severity.

Clinical Diagnosis

The diagnosis is primarily clinical and visual 1. During the physical examination of pubertal adolescents:

• Inspect the anterior chest wall for asymmetric protrusion of the sternum and adjacent costal cartilages, noting whether the deformity is symmetric or asymmetric 2
• Document the specific type: inferior pectus carinatum (most common), lateral pectus carinatum, or superior pectus carinatum, as this determines treatment approach 1
• Assess chest wall flexibility by applying manual pressure to the protruding area—flexible deformities in teenagers indicate candidacy for orthotic bracing, while rigid deformities suggest surgical intervention 1, 3
• Evaluate for Harrison's sulcus (horizontal grooves along the lower chest), which when present with pectus carinatum indicates more severe thoracic restriction 4

Imaging Confirmation

While diagnosis is clinical, imaging provides objective documentation:

• Chest radiography (PA and lateral views) confirms the diagnosis and excludes other thoracic abnormalities 1
• CT scanning quantifies severity using the modified Haller index and provides detailed anatomic assessment for surgical planning if needed 5, 1
• CT is particularly useful for calculating the improved Haller index, which can automatically diagnose and classify pectus carinatum severity 5

Mandatory Associated Evaluations

Because pectus carinatum frequently signals underlying genetic syndromes, complete cardiac evaluation is mandatory 6, 4:

• Echocardiography to screen for mitral valve prolapse (10-20% prevalence in chest wall deformities), aortic root dilation, and congenital heart defects 4
• In patients with Noonan syndrome phenotype, actively evaluate for pulmonary valve stenosis and right ventricular outflow tract obstruction 6
• Screen for Marfan syndrome and Noonan syndrome through detailed dysmorphological examination looking for joint hypermobility, skin hyperextensibility, arachnodactyly, and other syndromic features 4

Pulmonary Assessment

• Pulmonary function testing should be performed when the adolescent can cooperate (typically age 5+), looking for restrictive patterns with FVC reduction and abnormal FEV1/FVC ratios 4
• The restrictive pattern primarily affects the lateral thorax rather than being solely related to the sternal protrusion 6, 4

Common Pitfalls to Avoid

• Do not dismiss as purely cosmetic: Up to 60% of patients have restrictive lung disease, and the psychological impact is substantial with disturbed body image and reduced quality of life 7, 4
• Do not skip cardiac evaluation: The association with genetic syndromes and structural cardiac abnormalities (especially mitral valve prolapse) is well-established and requires systematic screening 6, 4
• Do not delay referral: Pubertal adolescents with flexible chest walls are ideal candidates for conservative bracing therapy, which becomes less effective as the thorax rigidifies with skeletal maturity 3