Final answer:
Coarctation of the aorta is a congenital condition resulting in narrowed aorta that can cause a difference in blood pressure between the arms and legs, which is a key diagnostic feature.
Step-by-step explanation:
Coarctation of the aorta should be suspected when the blood pressure in the arms is different from the blood pressure in the legs. This condition represents a congenital narrowing of the aorta, often near the insertion of the ligamentum arteriosum, which can lead to restricted blood flow through the body's primary systemic artery. A key diagnostic feature is higher blood pressure in the arms compared to the legs, due to the narrowed segment of the aorta often being located after the arteries that supply the arms. As a result, blood flow beyond the narrowing, to areas such as the lower extremities, can be diminished, leading to a measurable difference in blood pressure. Other possible symptoms might include difficulty breathing, poor appetite, fainting, and chest pain, but these are less specific and can be associated with a variety of other medical conditions.