An 6 week old male came to his local pediatrician’s office with 2 days of nasal congestion that was clear. He was formula feeding without problems and had started daycare several days ago. He had no fevers.
The past medical and social history revealed that he was a previously well, full-term baby.
The family history was negative.
The pertinent physical exam revealed a vigorous male with weight, length and head circumference in the 25-75% and growing appropriately. His heart rate = 135, respiratory rate = 30 and normal blood pressure. He was afebrile.
He was noted to have purplish lips, hands and feet. He had clear nasal discharge.
On heart examination, he had a grade III/VI systolic murmur loudest at the lower left sternal border that was described as high frequency. It was not holosystolic but occured through most of systole.
There was a normal S1, S2 with a normal split of S2. There was no other murmurs or thrills.
The liver was 1.5 cm below the right costal margin and a normal spleen was palpable. The peripheral pulses were equal in the upper and lower extremities. There was a 1.5 second capillary refill.
The work-up after being transferred to the local hospital revealed a saturation of 68% and a hyperoxia test showed an increased in the saturation to 80%.
The chest radiograph showed clear lung fields andno cardiomegaly.
The electrocardiogram showed upright T waves in V1 and V2 and mild right ventricular hypertrophy.
An arterial blood gas was normal. a dignosis of of cyanotic congenital heart disease was made, but the patient was also placed on intravenous antibiotics because of his age and possible co-existing sepsis.
He was transported to a regional children’s hospital where an echocardiogram revealed the specific diagnosis of Tetralogy of Fallot. A cardiac catheterization was planned to determine anatomy, pressures and to plan probable surgery to increase pulmonary blood flow.
Cyanosis is a blue coloring of the skin and mucous membranes caused by an increase concentration of reduced hemoglobin. This occurs at a critical level of about 5 g/100 ml of reduced hemoglobin.
Cyanosis is caused by
- Decreased arterial oxygen saturation
- Inadequate alveolar ventilation
- Airway obstruction
- Structural changes in the lungs (e.g. pneumonia, hyaline membrane disease, etc.)
- Central nervous system hypoventilation
- Weakness of the respiratory muscles
- Desaturated blood bypassing the lungs
- Cyanotic congenital heart disease
- Pulmonary arterio-venous fistulas
- Inadequate alveolar ventilation
- Increased capillary deoxygenation
- Acrocyanosis of the newborn
- Congestive heart failure
- Abnormal hemoglobin
- Carbon monoxide poisoning
The hyperoxia test is a screening diagnostic test used to often determine if the cyanosis is caused by the circulatory or pulmonary systems. The infant is placed in room air and the saturation measured. The infant is then placed in 100% oxygen environment and the saturation is again measured.
If the problem is in the lungs, the saturation should increase with supplemental oxygen.
If the problem is caused by cardiac disease, the saturation should not improve with the supplemental oxygen. This is because there is still mixing of saturated and desaturated blood in the heart. The hyperoxia test is useful as a general test, but as each child’s cardiac anatomy may be different, the test may not show these results every time.
Congenital heart disease occurs in ~10 /1000 live-born children. The incidence is higher in stillborn and spontaneous abortuses. The most common congenital heart disease is a ventricular septal defect and the most common cyanotic congenital heart defect is transposition of the great vessels.
Common congenital heart disease incidence as a percentage of all congenital heart disease
Ventricular septal defect 27.1-42 Atrial septal defect 6.8-11.7 Patent ductus arteriosus 5.3-11 (excluding preterm infants) Transposition of the great vessels 3.5-5.3 Tetralogy of Fallot 3.9-6.8 Truncus arteriosus 0.7-1.7 Total Anomalous Pulmonary Venous Return 0.6-1.7 Hypoplastic right heart 1.4-3.2 (mainly tricuspid atresia and pulmonary atresia with intact ventricular septum)
As noted before, the anatomy of an child is highly individualized. But time courses for general symptom presentation can be considered for various congenital heart disease.
Presents Almost Immediately at Birth
- Transposition of the great vessels (D-transposition) – The aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle forming parallel systemic and pulmonary systems. Communication between the systems is required for the infant to survive. These communications can be an atrial septal defect, patent foramen ovale, patent ductus arteriosus or combinations of these.
D-transposition usually presents with severe cyanosis at birth.
- Tricuspid atresia – There is no direct communication between the right atria and right ventricle. Blood must go from the right atrium to the left atrium by an atrial septal defect or patent foramen ovale. A patent ductus arteriosus is the source of blood flow to lungs. There are several variants of tricuspid atresia and associated lesions may determine the presentation.
Presents in the Perinatal Period
- Truncus arteriosus – A single great vessel leaves the heart to supply coronary artery flow, aortic flow and pulmonary flow. There is almost complete mixing of the systemic and pulmonary blood. The degree of cyanosis is dependent on the size of the pulmonary arteries and the magnitude of pulmonary blood flow.
- Total anomalous pulmonary venous return – The pulmonary veins fail to connect normally to the left atrium. Alternate pathways direct flow to the right atrium and then across an atrial communication. The admixture of blood at the atrial level and the right to left atrial shunt result in the cyanosis. When this lesion presents at birth, it is because of obstruction to the pulmonary veins.
- Tetralogy of Fallot (also known as a “TET” or “blue TET”) – The are four abnormalities are: ventricular septal defect, pulmonic stenosis, right ventricular hypertrophy and an overriding aorta. The amount of restriction through the right ventricular outflow tract determines the amount of pulmonary flow and influences the amount of right to left shunt across the ventricular septal defect. The degree of cyanosis is a reflection of the amount of pulmonary flow.
Presents after the Perinatal Period
- Tetralogy of Fallot (also known as a “pink Tetralogy” or “pink TET”) – The amount of restriction through the pulmonary valve and right ventricular outflow tract is less severe and there may be left-to-right shunting through the ventricular septal defect until pulmonary stenosis progresses.
“Tet spells” occur when there is a provocation of a fall in systemic resistance and fixed pulmonary obstruction is present. At these times, the flow across the ventricular septal defect fecomes right to left and the patient has a cyanotic spell.
The spells are characterized by tachypnea, cyanosis and a shorter outflow murmur. Treatment includes calming the child, and increasing the systemic vascular resistance (i.e. knee-to-chest position, volume influsion or sedation) by slowing the heart rate (beta-blocker therapy) to allow longer diastolic filling. Oxygen can also be administered to the infant but if resisted can actually be counterproductive.
Questions for Further Discussion
1. What are the common chest radiographic signs of congenital heart disease?
2. What congenital heart diseases are associated with chromosomal abnormalities?
3. What congenital heart diseases are associated with maternal medications?
- Tetralogy of Fallot
Congenital Heart Disease
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Information prescriptions for patients can be found at MEDLINEplus for this topic: Congenital Heart Disease
and at Pediatric Common Questions, Quick Answers for these topics:
Congenital Heart Disease and Heart Murmurs and Arrhythmias.
To view current news articles on this topic check Google News.
Rudolph CD, et. al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1780-81.
Robertson J, Shilkofski N. The Harriet Lane Handbook. 17th edition. Elsevier Mosby Philadelphia, PA. 2005:159-210.
Park MK. Pediatric Cardiology for Practitioners. 3rd edition. Mosby. St. Louis, MO. 1996;114-128.
ACGME Competencies Highlighted by Case
1. When interacting with patients and their families, the health care professional communicates effecively and demonstrates caring and respectful behaviors.
2. Essential and accurate information about the patients is gathered.
3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
4. Patient management plans are developed and carried out.
7. All medical and invasive procedures considered essential for the area of practice are competency performed.
8. Health care services aimed at preventing health problems or maintaining health are provided.
9. Patient-focused case is provided by working with health care professionals, including those from other disciplines.
10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.
19. The health professional works effectively with others as a member or leader of a health care team or other professional group.
24. Cost-effective health care and resource allocation that does not compromise quality of care is practiced.
Donna M. D’Alessandro, MD
Associate Professor of Pediatrics, Children’s Hospital of Iowa
Dr. D’Alessandro would also like to thank Dr. Jill Morriss, Professor of Clinical Pediatrics for her helpful suggestions in reviewing and improving this case.
January 23, 2006