The following statements are true of patent ductus arteriosus(PDA) except – a) Spontaneous closure occurs in some term infantsb) Pulmonary hypertension developsc) Bacterial endocarditis is more frequent with small PDAd) Recurrent chest infection and congestive failure may develope) Anatomic existence of PDA is an indication for surgery
Spontaneous closure of PDA
1) In premature infants

In premature infants, spontaneous closure of PDA may occur because in these infants PDA is due to unresponsiveness to oxygen and there is no structural abnormality.

2) In Full-term infants

Unlike that in premature infants, spontaneous closure of a PDA does not usually occur in full-term infants.
This is because the PDA in term infants results from a structural abnormality of the ductal smooth muscle.

Clinical manifestations of PIA

Patient may be asymptomatic
Symptoms develop early and CHF may develop at 6 to 8th weeks of age.
Common symptoms → Dysnea on exertion, palpitation and frequent chest infections.

Signs

Tachypnea & Tachycardia
Bounding pulse with wide pulse pressure (with elevated systolic and lower diastolic pressure).
Hyperkinetic cardiac impulse
Systolic or continuous thrill.
Accentuated S1
The narrow or paradoxical split of S2 (But it may be masked by continuous murmur since the maximum intensity of continuous murmur occurs at S2).
Continuous (machinery) murmur → Murmur starts after S and reaches the peak at S2. It then diminishes and is audible only during a part of the diastole. Murmur is best heard at second left intercostal space and is also heard below left clavicle.
S3 may occur at apex followed by a delayed diastolic murmur.
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