A 8 month old infant presents with severe dyspnea on exertion with clubbing of digits and bluish sclerae. The Chest X-ray diagnosis is?
Correct Answer: Tetralogy of Fallot
Description: Ans. A. Tetralogy of Fallota. Tetralogy of Fallot is the most common cyanotic congenital heart defect with an incidence of approximately 420 per million live births. It is caused by malalignment of the infundibular septum, which leads to right ventricular outflow (RVOT) obstruction, a subaortic VSD with aortic override and right ventricular hypertrophy.b. Trans-thoracic echocardiography is the imaging modality of choice for initial diagnosis and assessment. Initial chest radiographic appearances may include right ventricular heart silhouette, a boot-shaped heart, small hila, pulmonary oligemia or asymmetry and concave pulmonary artery segment. The aortic arch is right sided in about 30%.c. Current management consists of early single stage reconstructive surgery, with closure of the VSD, and relief of the RVOT obstruction, with possible placement of a trans annular patch. Staged reconstruction is still required if there is significant hypoplasia of the central pulmonary arteries, with placement of a modified Blalock-Taussig (BT) shunt--a systemic-to-pulmonary anastomosis, usually between the innominate artery and the right pulmonary artery.d. This shunt is then taken down during subsequent definitive repair.e. Cross-sectional imaging has a role in delineating pulmonary artery anatomy in the younger child, defining whether reconstructive pulmonary artery surgery is required prior to definitive surgery.f. However, the main role of imaging in patients with tetralogy of Fallot is the assessment of postoperative complications Chest radiography at this stage may show evidence of previous BT shunt surgery, asymmetric pulmonary circulation, and calcification of the trans annular patch.g. The most common late postoperative complication is pulmonary regurgitation secondary to trans annular patch reconstruction of the RVOT/pulmonary annulus and is often associated with aneurysmal dilatation of the RVOT. Surgical or transcatheter valve replacement is the current method of managing patients with severe pulmonary regurgitation.h. Accurate quantification of regurgitation and assessment of RVOT anatomy and right ventricular function are particularly important in deciding the type, timing, and multiplicity of procedures. Branch pulmonary stenosis may also be present in this patient group and is best imaged by MRA.i. This can contribute to right ventricular dysfunction, and significant obstructions should be repaired at the same time as valve replacement. The final role of MRI is in evaluating right ventricular function.j. This is important for timing of invasive therapeutic measures and evaluating the effect of any invasive procedure. It has been shown that, using a combination of MR ventricular volumetry and tricuspid and pulmonary flow maps, precise information about global and diastolic ventricular function can be assessed in patients with repaired tetralogy of Fallot.
Category:
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