History

Fact Explanation
None A small PDA is usually asymptomatic. [1]
Heart failure A large PDA will result in heart failure similar to that encountered in infants with a large VSD. The children will have decreased exercise tolerance, tachypnea, scalp sweating especially during feeds, poor sucking and failure to thrive.
pulmonary hypertension Recurrent lower respiratory tract infections.
Retardation of physical growth This may be a major manifestation in infants with large shunts.
Eisenmenger's syndrome This occurs later in life, due to shunting of deoxygenated blood from the pulmonary circulation to the systemic circulation. These patients have cyanosis and clubbing.
References
  1. KLIEGMAN Robert M. , STANTON Bonita F. , ST GEME III Joseph W., SCHOR Nina F., BEHRMAN Richard E. Nelson Textbook of pediatrics. . 19th Edition, Elsevier, 2011 Chapter 420.8

Examination

Fact Explanation
Features of heart failure These symptoms are present in patients with large left to right shunt. Eg: tachypnea, tachycardia, growth retardation.
Collapsing pulse due to runoff of blood into the pulmonary artery during diastole, there is an increased pressure difference between the systole and the diastole. This increased pulse pressure results in a collapsing pulse.
Prominent and laterally displaced apical impulse Due to the left ventricular hypertrophy and dilatation which occurs with large left to right shunts.
Heaving apex With cardiac enlargement and hypertrophy an apical heave becomes palpable.
A thrill, maximum in the 2nd left inter space. The thrill may radiate toward the left clavicle, down the left sternal border, or toward the apex. The thrill is also felt with the cardiac enlargement. It is usually systolic but may also be palpated throughout the cardiac cycle.
Classic continuous machinery murmur best heard in the left second inter costal space. Since the pressure in the aorta is greater than the pressure in the pulmonary artery there is a continuous shunt of blood from the aorta to the pulmonary artery through out the cardiac cycle. This produces a continuous murmur. The second heart sound (S2) is often inaudible, because of the murmur. In patients with a large left-to-right shunt, a low-pitched mitral mid-diastolic murmur may be audible at the apex. [1] This is due to the increased return to the left heart via the pulmonary veins due to the shunt and as a result large volume of blood flows through the mitral valve resulting a mitral flow murmur.
Paradoxical splitting of the second heart sound. (S2) This a result of early closure of the pulmonary valve, and a prolonged period of ejection across the aortic valve.
References
  1. KLIEGMAN Robert M. , STANTON Bonita F. , ST GEME III Joseph W., SCHOR Nina F., BEHRMAN Richard E. Nelson Textbook of pediatrics. . 19th Edition, Elsevier, 2011 Chapter 420.8

Differential Diagnoses

Fact Explanation
Aortico-pulmonary window defect This may rarely be clinically indistinguishable from a PDA, although, in most cases, the murmur is only systolic and is loudest at the right rather than the left upper sternal border.
Left to right shunts with continuous shunting of blood through out the cardiac cycle. Eg: A sinus of Valsalva aneurysm that has ruptured into the right side of the heart or pulmonary artery, coronary arteriovenous fistulas, an aberrant left coronary artery with massive collaterals from the right coronary artery [1] Although rare all these display dynamics similar to that of a PDA with a continuous murmur and a wide pulse pressure
A peripheral arteriovenous fistula This also results in a wide pulse pressure, but the distinctive precordial murmur of a PDA is not present.
Combined aortic and mitral insufficiency (usually due to rheumatic fever) [1] Mitral insufficiency causes a pan-systolic murmur and the Aortic insufficiency causes diastolic murmur, when combined both produce murmur which can be heard through out the cardiac cycle. However the murmurs should be differentiated by their to-and-fro rather than continuous nature.
Hyper-dynamic circulations. Eg: Anemia, Bacteremia and sepsis. Wide pulse pressure and collapsing pulse is present in all of these situations, but the characteristic continuous murmur is only present in PDA.
Coarctation of the aorta. This results in a systolic murmur in the left infra clavicular area and under the left scapula.
References
  1. KLIEGMAN Robert M. , STANTON Bonita F. , ST GEME III Joseph W., SCHOR Nina F., BEHRMAN Richard E. Nelson Textbook of pediatrics. . 19th Edition, Elsevier, 2011 Chapter 420.8

Investigations - for Diagnosis

Fact Explanation
Chest X Ray usually normal but if the PDA is large and symptomatic the features on chest X-ray are indistinguishable from those seen in a patient with a large VSD. Normal sized or an enlarged heart with increased pulmonary vasculature and prominant pulmonary arteries will be seen in CXR. However the cardiac size depends on the degree of left-to-right shunting.
Electrocardiogram. (ECG) Usually normal and as above if the PDA is large and symptomatic the features on ECG are similar to those seen in a patient with a large VSD. Left ventricular hypertrophy with large left to right shunt. Right ventricular hypertrophy with the development of pulmonary hypertension. Often bi ventricular hypertrophy can be observed in the ECG.
2D Echocardiography assisted by Doppler ultrasound This will readily identify the PDA.
Cardiac catheterization This is not routinely done. Although clinical examination and 2D Echocardiography is adequate for the diagnosis of PDA to be made, for patients with atypical findings Cardiac catheterization helps to establish an accurate diagnosis.
References

Investigations - Fitness for Management

Fact Explanation
Full blood count Hemoglobin levels should be checked and optimized prior to the surgery. This is important because these children tend to have malnutrition due to heart failure and poor feeding.
Renal function test Blood urea, serum creatinine, serum electrolytes should be checked prior to the corrective surgery.
Chest X Ray (CXR) A CXR should be done to rule out respiratory tract infection, and this will help to detect or to exclude heart failure.
References

Investigations - Followup

Fact Explanation
2D Echocardiogram A post operative repeat 2D Echocardiogram is usually enough to establish the closure of the PDA. Regular followup is not necessary provided there are no other anomalies or co-morbidities.
References

Management - General Measures

Fact Explanation
Treatment of Heart failure Once the diagnosis of moderate PDA is made pharmacological treatment should be commenced for heart failure.
Treat any respiratory tract infection. Structural heart defects predispose to recurrent respiratory tract infections in children, due to pulmonary congestion.
Screen for other congenital anomalies VACTREL (Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal anomalies and Limb defects.) anomalies should be looked for.
References

Management - Specific Treatments

Fact Explanation
Closure of the PDA with a coil or an occlusion device In infants with an asymptomatic PDA, closure is recommended to abolish the lifelong risk of bacterial endocarditis. These patients has the least operative mortality when the PDA is considered. In patients with a small PDA, the rationale for closure is prevention of bacterial endarteritis or other late complications. In patients with a moderate to large PDA, closure is accomplished to treat heart failure or to prevent the development of pulmonary vascular disease, or both. Small PDAs are generally closed with intravascular coils. Moderate to large PDAs may be closed with an umbrella-like device or with a catheter-introduced sac which release several coils.
Pharmacological management with intravenous (IV) indomethacin or ibuprofen. This can be done for premature neonates. [1] These inhibit the enzyme cyclooxygenase (COX) there by the synthesis of prostaglandin, which maintains the patency of the duct. Once the prostaglandin synthesis is inhibited the duct closes.
References
  1. OHLSSON A, WALIA R, SHAH S. Ibuprofen for the treatment of patent ductus arteriosus in preterm and/or low birth weight infants. Cochrane Database Syst Rev. Jan 23 2008;CD003481.