Pulmonary stenosis تضيق رئوي
INSTRUCTION Examine this patient's heart. SALIENT FEATURES History · Ask for a history of maternal rubella. · Patients may be asymptomatic. · Dyspnoea on exertion or fatigability may occur (when the stenosis is severe); less often, patients may have retrosternal chest pain or syncope with exertion. Eventu-ally, right ventricular failure may develop, with resultant peripheral oedema and abdominal swelling · Cyanosis and clubbing (if the foramen ovale is patent, shunting of blood from the right to the left atrium may occur). Remember. The presence or absence of symptoms, their severity, and the prognosis are influenced by the severity of stenosis, the right ventricular systolic function, and the competence of the tricuspid valve. Examination · Round plump facies. · Normal pulse. · Prominent 'a' wave in the JVP. · Left parasternal heave. · Ejection click (valvular stenosis) (Br Heart J 1951; 13:519). · Soft P2, with a wide split second sound. · Ejection systolic murmur in the left upper sternal border, best heard on inspiration. The murmur radiates to the left shoulder and left lung posteriorly. The more severe the stenosis, the longer the murmur, obscuring the second aortic sound A2. Proceed as follows: Look for central cyanosis and clubbing (Fallot's tetralogy). DIAGNOSIS This patient has pulmonary stenosis (lesion) which is a congenital anomaly (aetiology) and the patient is severely limited by her symptoms (functional status). QUESTIONS What is the underlying cause of pulmonary stenosis? · Congenital (commonest cause). · Carcinoid tumour of the small bowel. ADVANCED-LEVEL QUESTIONS What is the normal area of the pulmonary valve? The area of the pulmonary valve orifice in a normal adult is about 2.0 cm2 per square metre of body surface area, and there is no systolic pressure gradient across the valve. How is the severity of pulmonary valve stenosis determined? · Mild: it' the valve area is larger than 1.0 cm2 per square metre, the transvalvular gradient is less than 50 mmHg, or the peak right ventricular systolic pressure is less than 75 mmHg. · Moderate: if the valve area is 0.5-1.0 cm2 per square metre, the transvalvular gradient is 50-80 mmHg, or the right ventricular systolic pressure is 75-100 mmHg. · Severe: if the valve area is less than 0.5 cm2 per square metre, the transvalvular gradient is more than 80 mmHg, or the right ventricular systolic pressure is more than 100 mmHg. How would you investigate this patient? · Electrocardiogram: Right axis deviation and right ventricular hypertrophy. · Chest radiograph: The aortic knuckle is normal whereas the pulmonary conus is either normal or enlarged (due to post-stenotic dilatation of the main pulmonary artery) and the pulmonary vascular markings are diminished. The cardiac silhouette is usually normal in size or may be enlarged (when the patient has right ventricular failure or tricuspid regurgitation). · Echocardiogram: The site of obstruction can be visualized in most patients but right ventricular hypertrophy and paradoxical septal motion during systole are evident. Doppler flow studies accurately assess the severity of stenosis so that cardiac catheterization and angiography are usually unnecessary. What are the complications of this condition? · Cardiac failure. · Infective endocarditis: blood cultures are rarely positive; the emboli are entirely in the pulmonary circulation and not systemic. What are the types of pulmonary stenosis? · Valvular. · Subvalvular: infundibular and subinfundibular. · Supravalvular. Do you know of any eponymous syndromes linked to pulmonary stenosis? · Noonan's syndrome: short stature, ptosis, downward slanting eyes, wide-spaced eyes (hypertelorism), low-set ears, webbed neck, mental retardation and low posterior hairline. About two thirds of patients with Noonan's syndrome have pulmonary stenosis due to valve dysplasia. · Watson's syndrome: cafe-au-lait spots, mental retardation and pulmonary stenosis. · Williams syndrome: infantile hypercalcaemia, elfin facies and mental retardation, in addition to supravalvular pulmonary stenosis. Subvalvular pulmonary stenosis, which is caused by the narrowing of the right ventricular infundibulum or sub-infundibulum, usually occurs in association with a ventricular septal defect. How would you manage a patient with pulmonary stenosis? · Mild valvular pulmonary stenosis: these patients are usually asymptomatic. Survival among such patients is excellent (94% are still alive 20 years after diagnosis) and therefore they do not require surgical correction. It is important that patients with mild valvular stenosis who are undergoing elective dental or surgical procedures should receive antibiotic prophylaxis against infective endocarditis. · Severe stenosis: the stenosis should be relieved, since only 40% of such patients do not require any intervention by 10 years after diagnosis. · Moderate pulmonary stenosis has an excellent prognosis with either medical or interventional therapy, lnterventional therapy is usually recommended, since most patients with moderate pulmonary stenosis eventually have symptoms requiring such therapy. Valve replacement is required if the leaflets are dysplastic or calcified or if marked regurgitation is present. What is the role of balloon valvuloplasty in pulmonary stenosis? Relief of valvular stenosis can be accomplished easily and safely with percutaneous balloon valvuloplasty (Am J Cardiol 1990; 65: 775) and a delay in intervention offers no advantage. Balloon valvuloplasty, the procedure of choice, is usually successful, provided the valve is mobile and pliant; its long-term results are excellent. The secondary hypertrophic subpulmonary stenosis that may occur with valvular stenosis usually regresses after successful intervention. In a series of 100 patients, balloon dilatation resulted in a significant reduction in the transvalvular gradient. which was maintained at 12 months' follow-up (lnt J Cardio11988; 21: 33542). What is Erb's point? The third left intercostal space adjacent to the sternum is Erb's point. The murmur of infundibular pulmonary stenosis is best heard in this space and in the left lourth intercostal space.