Patent ductus arteriosus

What it is

In persistent ductus arteriosus the duct has failed to close by 1 month after the expected date of delivery, because of a defect in the constrictor mechanism of the duct. The result is a left to right shunt.

Causes and risk

Patent ductus arteriosus is one of the medical problems associated with pre term birth, beside respiratory distress syndrome, apnoea and bradycardia, jaundice and retinopathy of prematurity.

It also belongs to a number of syndromes. In congenital rubella syndrome the cardiac defects are particularly patent ductus arteriosus and pulmonary artery stenosis. It is among the cardiac findings of trisomy 21 (Down syndrome), and among the cardiac defects of trisomy 18 (Edwards syndrome) after ventricular septal defect and atrial septal defect.

How it presents

The child may be asymptomatic. Otherwise there is apnoea and bradycardia, or HF. The pulse is bounding and collapsing.