Ventricular septal defect — structured clinical encounter

Station brief (candidate)

You are the paediatric registrar in the emergency department. A six-week-old term infant presents with a three-week history of worsening tachypnoea, taking 40 minutes to finish 60 mL of feeds while sweating, and crossing two weight centiles downward. On examination there is a pansystolic murmur at the lower left sternal border, an apical mid-diastolic murmur, a hyperactive precordium, and hepatomegaly. Oxygen saturations are 98 percent in air. The team asks you to establish the diagnosis and immediate management, then proceed to the echocardiogram, the closure plan, and the family counselling. You have 12 minutes with the team and 5 minutes for examiner discussion. [1]

Information available on request

• Term infant, six weeks old, previously well; pregnancy and delivery uncomplicated. [1]
• Three-week history of worsening tachypnoea, prolonged sweaty feeds, crossing two weight centiles downward. [1]
• Examination: pansystolic murmur at lower left sternal border, apical mid-diastolic murmur, hyperactive precordium, hepatomegaly; saturations 98 percent in air. [1]
• Chest radiograph (on request): cardiomegaly with pulmonary plethora. [1]
• Echocardiogram (on request): a perimembranous VSD with a Qp:Qs of 2.4, a moderate gradient, left atrial and left ventricular dilation, and a pulmonary artery pressure estimate at the upper limit of normal; aortic valve normal. [1] [9]

Tasks

1. Give the diagnosis and explain why it has presented now, at six weeks, rather than at birth. [1]
2. Outline your immediate medical management with the specific drug doses you would use as a bridge. [1]
3. State the indications for definitive closure, the usual timing, and the surgical versus device options for this defect. [9]
4. State the complication that the whole strategy is designed to prevent, and why closure is harmful once it has occurred. [6]
5. Counsel the parents on the endocarditis-prophylaxis position and the immediate outlook. [8]

Marking anchors

Must-hit

• Diagnoses a moderate-to-large ventricular septal defect with pulmonary overcirculation and left-heart failure; explains the four-to-eight-week window as the postnatal fall in pulmonary vascular resistance exposing the left-to-right shunt; the apical mid-diastolic rumble is correctly identified as the sign of a large shunt through increased mitral inflow. [1]
• Starts a medical bridge with a loop diuretic (furosemide 1 to 2 mg/kg/day), an angiotensin-converting-enzyme inhibitor, and increased caloric density of feeds; uses oxygen cautiously with the correct physiological rationale. [1]
• Refers for closure within the first year (surgical patch for a perimembranous defect; device closure an option for selected favourable anatomy), and identifies the prevention of fixed pulmonary vascular disease as the goal of the strategy. [9]

Merit

• Names the spontaneous-closure natural history for small muscular defects (Du and Roguin), the device-closure evidence (Butera), and the Eisenmenger management with bosentan (BREATHE-5, Galiè), demonstrating the full breadth of the topic. [4] [6]

Fail

• Administers high-flow oxygen indiscriminately without recognising that it lowers pulmonary resistance and can increase the shunt, or delays referral and echocardiography on the grounds that the infant is "not yet sick enough". [1]
• Counsels that routine antibiotic endocarditis prophylaxis is required, against the 2021 AHA position. [8]