Pulmonary Stenosis in Children
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Direct answer
Valvular pulmonary stenosis is obstruction at the pulmonary valve, the commonest form of right ventricular outflow obstruction in children. It produces an ejection systolic murmur with an early ejection click at the upper left sternal border. Balloon valvuloplasty is the first-line treatment for significant valvular stenosis.
What you must remember
- Murmur: an ejection systolic murmur at the left upper sternal border that radiates to the back and increases with inspiration.
- Ejection click: a sharp early systolic click from a mobile, pliable valve; it is typically lost when stenosis is severe and the leaflets are fixed.
- Severity grading: peak Doppler velocity below 3 m/s is mild, 3 to 4 m/s is moderate, and about 4 m/s or above, roughly a peak gradient of 64 mmHg, is severe.
- Noonan syndrome: dysplastic pulmonary valve and stenosis are typical, often with hypertrophic cardiomyopathy.
- ECG and X-ray: right ventricular hypertrophy with right axis deviation in severe disease, and post-stenotic dilatation of the pulmonary trunk.
- Infundibular stenosis: narrowing below the valve, part of tetralogy of Fallot, usually without an ejection click.
- Surgery: reserved for dysplastic valves, failed dilatation or significant pulmonary regurgitation.
From murmur to valvuloplasty
A pulmonary ejection murmur needs a Doppler gradient before any decision. The steps below follow the usual sequence from examination to intervention.
- Clinical clues: a systolic ejection murmur with a click at the left upper sternal border, and a palpable thrill in severe cases.
- Echocardiography: Doppler measures the peak velocity across the valve and estimates right ventricular pressure. Several views are used so that the highest velocity is captured.
- Grading: mild, moderate or severe is assigned by velocity, with about 4 m/s marking severe disease.
- Ventricle assessment: right ventricular size, function and tricuspid regurgitation show whether the ventricle has adapted.
- Decision: symptomatic severe disease, or a significant gradient with right ventricular strain, points to intervention.
- Balloon valvuloplasty: a balloon is inflated across the valve, usually through a venous approach, and the gradient is measured again.
- Follow-up: pulmonary regurgitation and the need for reintervention are monitored with serial echocardiography. A repeat echo after intervention documents the residual gradient.
Where the exam tries to catch you
Pulmonary stenosis questions test grading and the first-line procedure. Watch for these traps.
- Trap: Thinking a loud pulmonary murmur always means severe stenosis. Correct: Severity depends on the Doppler gradient, so a loud murmur with a mobile valve can still be mild.
- Trap: Choosing surgery as first-line for valvular stenosis. Correct: Balloon valvuloplasty is first-line; surgery is reserved for dysplastic valves or failed dilatation.
- Trap: Treating a Noonan child's pulmonary stenosis as isolated. Correct: Noonan syndrome carries dysplastic valves and hypertrophic cardiomyopathy, so the echo should assess the myocardium too.
Frequently asked questions
What Doppler gradient defines severe pulmonary stenosis?
Severe pulmonary stenosis is usually defined by a peak Doppler velocity of about 4 m/s or more, which corresponds to a peak gradient of roughly 64 mmHg. Moderate stenosis lies between about 3 and 4 m/s, and mild stenosis is below 3 m/s.
Why does the ejection click disappear in severe pulmonary stenosis?
In severe valvular pulmonary stenosis the leaflets become thickened and fixed, so they no longer open with a sharp snap. Loss of the ejection click in a child with a harsh murmur therefore suggests more severe obstruction.
Which children with pulmonary stenosis need balloon valvuloplasty?
Children with symptomatic or severe valvular pulmonary stenosis, or with a significant gradient and right ventricular strain, are typically referred for balloon valvuloplasty. Surgery is kept for dysplastic valves, failed dilatation or severe pulmonary regurgitation.
Which genetic syndrome is most associated with valvular pulmonary stenosis?
Noonan syndrome is the classic genetic syndrome associated with valvular pulmonary stenosis, typically with a dysplastic valve. Children with it may also have hypertrophic cardiomyopathy, so echocardiography should assess the myocardium as well as the valve.