Patent Ductus Arteriosus

Patent: open, unobstructed
Ductus: fetal blood vessel which joins the aorta and pulmonary artery
Arteriosus:  pertaining to artery

Patent Ductus Arteriosus:  (PDA)  This abnormal opening between the pulmonary artery and the aorta allows left to right shunting of blood from the aorta to the pulmonary artery.  This results in recirculation of arterial blood through the lungs.

In the early stages, PDA may produce no clinical effects, but in time it can precipitate pulmonary vascular disease, causing symptoms to appear by age 40.  The patients with a small shunt or who undergo effective surgical repair have a good chance of recovery.  But PDA may advance to intractable CHF, which may be fatal.

Most prevalent in premature infants, PDA often accompanies rubella syndrome.  It may be associated with other congenital defects, such as coarctation of the aorta, ventricular septal defect, and pulmonary and aortic stenoses.

Cause:  Results from failure of the fetal ductus arteriosus (a fetal blood vessel that connects the pulmonary artery to the descending aorta) to close within days to weeks after birth.

Symptoms:

For infants, especially premature ones with a large PDA usually develop respiratory distress with signs of CHF. 
Frequent respiratory infections
Slow motor development
Failure to thrive.

Most children with PDA have only cardiac symptoms.  Others may exhibit signs of heart disease, such as physical underdevelopment and fatigability.

By age 40, adults with untreated PDA may develop fatigability and dyspnea on exertion.  Cyanosis appears in the final stages of illness.

Murmur (called Gibson murmur)  This continuous murmur is best heard at the base of the heart, at the second left intercostal space under the left clavicle in most children with PDA.

May have bounding peripheral arterial pulses (Corrigan's pulse), may have widened pulse pressure.

Cardiomegaly
Tachycardia
Dilated ascending aorta

Treatment:

For infants with PDA that has no symptoms (asymptomatic) the patient may not require immediate treatment.

Those with CHF require fluid restriction, diuretic, and digitalis to minimize or control symptoms.  If theses measure does not control CHF, the patient requires surgery to ligate the ductus.  The doctor may delay surgical correction until age 1 if the patient has only mild symptoms.
Before surgery, children with PDA require antibiotics to protect against infective endocarditis.

Other forms of therapy include cardiac catheterization to deposit a plug in the ductus to stop shunting, or administration of indomethacin I.V. (a prostaglandin inhibitor that provides an alternative to surgery in premature infants) to induce ductus spasm and closure.

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