Which of the following is a characteristic clinical finding in a patient's lower limb with coarctation of the aorta?

Appeared in: NORCET 10 Mains

Explanation

Coarctation of the aorta is a narrowing of the aorta, which obstructs blood flow to the lower body.
This obstruction leads to decreased blood pressure and perfusion in the lower extremities.
A direct consequence of this reduced flow is a femoral pulse that is weak, difficult to palpate, or delayed when compared to the radial pulse (radio-femoral delay).
This finding is a classic and specific sign of coarctation located in the lower limb, as asked by the question.

Option A: A bounding femoral pulse would indicate increased blood flow to the lower extremities, which is the opposite of the pathophysiology of aortic coarctation.
Option C: While increased blood pressure in the upper limbs is a hallmark sign of coarctation of the aorta, the question specifically asks for a finding in the lower limb.
Option D: This describes a normal circulatory finding. The defining characteristic of coarctation is the inequality of blood pressure between the upper and lower limbs.

Clinical Relevance

Nursing practice connection: Use the key finding related to Clinical manifestations of Coarctation of the Aorta to guide bedside assessment, documentation, and the next nursing action.
A key nursing assessment for suspected coarctation is the simultaneous palpation of radial and femoral pulses to detect radio-femoral delay.
Accurate blood pressure measurement in all four extremities is critical for diagnosis. A systolic pressure in the arms that is more than 20 mmHg higher than in the legs is highly suggestive of coarctation.
What if? If the patient is a neonate with a patent ductus arteriosus (PDA), the femoral pulses may feel normal initially, masking the coarctation. As the PDA closes, the infant can suddenly develop shock and acidosis. This highlights the importance of newborn pulse oximetry screening on both an upper and lower extremity.

How to Approach the Question

First, identify the core concept of the question, which is 'coarctation of the aorta'.
Next, carefully read the question and pinpoint the specific location it asks about: the 'lower limb'. This is a critical detail.
Recall the basic pathophysiology of coarctation: a narrowing in the aorta creates high pressure and strong pulses before the blockage (upper body) and low pressure with weak pulses after the blockage (lower body).
Evaluate each option against this understanding and the 'lower limb' constraint.
Option A (Bounding femoral pulse) is incorrect because flow is reduced, not increased.
Option C (Increased BP in upper limbs) is a correct fact about the condition but describes an upper limb finding, not a lower limb one.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 582-584

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