Causes and Symptoms
Most congenital heart
defects are thought to arise from maternal infections or the intake of certain drugs during pregnancy. The developing fetal heart is particularly susceptible to these effects during the second month of pregnancy, when major developmental changes are taking place.
Four distinct defects, called the tetralogy of Fallot, occur in infants suffering from blue baby syndrome. The first is a narrowing (stenosis) of the pulmonary
trunk that takes blood to the lungs, where it is oxygenated. Narrowing of the pulmonary trunk is accompanied by a narrowing of the pulmonary semilunar valve, which resides in the pulmonary trunk. These two defects decrease blood flow to the lungs, resulting in a decreased oxygenation of the blood. Second, the wall that separates the left and right ventricles of the heart fails to form completely, thereby allowing the poorly oxygenated blood in the right ventricle to mix with the well-oxygenated blood in the left ventricle and decreasing oxygen delivery to tissues. Third, the aorta, which typically opens from the left ventricle and carries oxygenated blood to the tissues, is misaligned such that it opens from both the left and right ventricle. Fourth, the right ventricular muscle is thickened, as this muscle must work harder to push blood through the narrowed
pulmonary semilunar valve and pulmonary trunk.
The first three defects result in poorly oxygenated blood being delivered to tissues, causing the skin and mucous membranes to appear bluish within minutes after birth, a condition called cyanosis. Children with uncorrected blue baby syndrome suffer from breathlessness after any form of exertion.
Treatment and Therapy
The tetralogy of Fallot is relatively rare, occurring in about one in every 1,500 births. Most defects can be corrected surgically. Successful correction of these defects early in the child’s life prevents delayed growth and other complications of poor oxygen delivery.
Bibliography:
Gersh, Bernard J., ed. The Mayo Clinic Heart Book. 2d ed. New York: Morrow, 2000.
Koenig, Peter, Ziyad M. Hijazi, and Frank Zimmerman, eds. Essential Pediatric Cardiology. New York: McGraw, 2004.
Levin, Daniel L., and Frances C. Morriss, eds. Essentials of Pediatric Intensive Care. 2d ed. New York: Churchill, 1997.
MacDonald, Mhairi G., Mary M. K. Seshia, and Martha D. Mullett, eds. Avery’s Neonatology: Pathophysiology and Management of the Newborn. 6th ed. Philadelphia: Lippincott, 2005.
Neill, Catherine A., Edward B. Clark, and Carleen Clark. The Heart of a Child: What Families Need to Know about Heart Disorders in Children. 2d ed. Baltimore: Johns Hopkins UP, 2001.
Nixon, Harold, and Barry O’Donnell. The Essentials of Pediatric Surgery. 4th ed. Boston: Butterworth, 1992.
Park, Myung K. The Pediatric Cardiology Handbook. 4th. New York: Mosby, 2010.
Rosenblum, Laurie. "Tetralogy of Fallot." Health Library, Sept. 12, 2012.
Schumacher, Kurt R. "Tetralogy of Fallot." MedlinePlus, Dec. 1, 2011.
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