Problem
A 4-month-old male infant is brought into the pediatric clinic by his mother. She reports that, over the past several weeks, her baby's lips, mouth, fingernails, and toenails have become a bluish gray color. She also states that he seems to tire easily and that even nursing seems to wear him out. Lately, he has had several spells where he suddenly turned blue, had difficulty breathing, and has been very irritable. During one of these spells, he turned limp and seemed to have passed out for a short time. An echocardiogram reveals a thickening of the right ventricular wall with overriding of the aorta, a large subaortic VSD, and narrowing of the pulmonary outflow with stenosis of the pulmonary valve.
Task
Address the following:
1) What is this infant's probable diagnosis?
2) Describe the shunting of blood that occurs with this disorder and its relationship to the development of cyanosis.