Makindo Medical Notes

Classically continuous machinery murmur left subclavicular . Patent ductus arteriosus carries a high risk of endocarditis. It is a congenital heart defect where the ductus arteriosus, a blood vessel that allows blood to bypass the lungs in a fetus, fails to close after birth. This results in abnormal blood flow between the aorta and the pulmonary artery.

About

• Common in premature babies
• Abnormal blood flow between the aorta and the pulmonary artery.
• PGE keeps PDA open and NSAIDs close PDA

Risks

• Premature babies or female births at altitude
• Maternal rubella in first trimester
• Fetal alcohol syndrome
• Female-to-male ratio, 2:1

Aetiology

• Fetal life, the DA allows blood from RV to pass into the descending aorta.
• The DA should close hours after birth. It can persist post-birth.
• There is increased continuous flow into the pulmonary circulation
• Can result in Eisenmenger's syndrome

Dynamic response to chemicals

• Increased oxygen and NSAIDs close the DA
• Prostaglandin E2 (PGE2) opens the DA

Clinical

• Infant: SOB, Sweating, poor feeding, weight loss or no weight gain.
• Left subclavicular thrill, Enlarged left heart and apical heave
• Continuous machinery murmur, Wide pulse pressure and bounding pulse
• Respiratory infections and risk of Endocarditis
• Eisenmenger's with cyanosis due to shunt reversal and clubbing of the toes but not the fingers.

Investigations

• Bloods:FBC, U&E, CRP, B-type natriuretic peptide: may be elevated and can help guide treatment
• Electrocardiogram (ECG): may be normal or T wave and ST changes
• Chest X-ray: pulmonary plethora (high volume going via lungs) Cardiomegaly
• Echocardiogram: PDA best seen parasternal short axis view and from the suprasternal notch
• Cardiac catheterization: Catheterization and Angiography: assess size and anatomy

Management

• Spontaneous closure of the patent ductus arteriosus (PDA) is common particularly in premature infants, the PDA may close on its own. NSAIDs such as indomethacin or ibuprofen are frequently effective in closing a patent ductus arteriosus (PDA) if it is administered in the first 10-14 days of life. Other drugs include Aspirin
• Medical management of heart failure e.g. diuretics, Digoxin
• Transcutaneous: catheter can be used to close the patent ductus arteriosus (PDA) using an Amplatzer duct occluder. Even if not completely occluded the PDA will usually thrombose.
• Surgical: Surgical ligation may be necessary if the PDA is large
• The prognosis for children with PDA is generally good, especially if treated early. Most children who undergo treatment recover fully and lead normal lives. However, if left untreated, a large PDA can lead to complications such as pulmonary hypertension, heart failure, and increased risk of endocarditis.