Question

An 8-year-old boy was found to have high blood pressure during a school physical examination. He was referred to his physician, who verified the high blood pressure and noted that his femoral pulses were weak in comparison to the radial and carotid pulses. His feet seemed cool to the touch and the patient said he always had to wear warm socks even in summer. A chest radiograph was remarkable for irregular notches along the lower borders of several of the ribs on both sides of his chest.

Questions:

1. How can unequal pulses in the upper and lower limbs be explained?

2. Which vessels caused the notching along the ribs, and in which direction was blood flowing through them?

3. Rib notching was absent from the upper two ribs. Why?

4. Would auscultation of the thorax reveal any abnormal sounds?

Answer 1

Question 1

Answer: An unequal pulse between upper and lower extremities is seen in the case of coarctation to the aorta. Coarctation of the aorta is a congenital heart condition whereby the part of the aorta is narrowed, usually in the area where the ductus arteriosus.

Question 2

Answer: Rib notching is a radiologic sign where the surface of the rib is deformed.'Notching' on the ribs occurs if the collateral blood vessels develop because of aortic coarctation and rib notching is associated with aortic coarctation which results in the dilatation of intercostal arteries. Narrowing down of aortic blood vessel lead to decreased blood pressure in the posterior intercostal arteries and increased pressure in anterior intercostal arteries. Therefore, this difference in blood pressure causes the blood flow direction from anterior intercostal arteries to posterior intercostal arteries (towards heart or reverse flow).

Question 3

Answer: This is because the aortic coarctation leads to increased blood pressure in anterior intercostal arteries and first 2 posterior intercostal arteries of the ribs, while decreased blood pressure in posterior intercostal arteries of ribs, three and below. Because of equal blood pressure in first 2 posterior intercostal arteries and anterior intercostal arteries, blood flow is normal. Therefore, there is no blood vessel notching in upper two ribs (absent).

Question 4

Answer: Auscultation is the term for listening to the internal sounds of the body while examining the circulatory system, respiratory system, and gastrointestinal system generally using a stethoscope.

Yes, auscultation of the thorax produces an abnormal murmur sound which is one of a symptom of aortic coarctation along with high blood pressure, unequal pulse between upper and lower extremities.