This patient is suffering from an aortic coarctation, which is associated with Turner Syndrome.
Aortic coarctation is a congenital condition that is most often found when the aorta narrows in the region where the ductus arteriosus inserts. The narrowing creates a blood flow/pressure gradient resulting in a decrease in blood flow/pressure to the lower extremities. The vascular system compensates by increasing flow through other vessels including the subclavian and intercostal arteries thus leading to notching of the ribs (erosions from the vasculature). Similar to aortic stenosis due to the narrowing the left ventricle must generate significantly higher pressures to generate blood flow throughout the peripheral circulation. In the long-term this can result in structural changes to the heart.
Deluca discusses the presentation and diagnosis of coarctation of the aorta. The gold standard in diagnosis involves arteriography. In the pre-ductal type blood flows through the ductus arteriosus to the lower extremities. In the post-ductal type blood flows through the subclavian and intercostals to the lower extremities.
Tanous et al. review the current approaches for open and transcatheter closure of coarctation of the aorta. Currently recurrence of the coarct and aneurysm formation is common after surgical or endovascular repair. Hypertension often remains after surgical correction. Patient's must be monitored for the long-term for both local and systemic complications.
illustration A is a 3D angiogram of a patient with an aortic coarctation. Note the narrowing of the aorta.
Answer 1: In general in coarctation associated with Turner Syndrome there is an increase in blood pressure in the upper extremities and a decrease in the lower extremities thus making the ankle brachial index a useful test.
Answer 2: Though Barr bodies are not a sensitive or specific test, one would expect to see an absence of Barr bodies (condensed X chromosome).
Answer 3: An endocardial cushion defect is due to defective neural crest cell migration and is seen commonly in Down Syndrome.
Answer 5: Atrophy of the lower extremities could be seen in aortic coarctation. In contrast pseudohypertrophy of the calves would be seen in Duchenne's muscular dystrophy.
Deluca SA. Coarctation of the aorta. Am Fam Physician. 1990 Nov;42(5):1285-8
PMID:2239636 (Link to Abstract)
Tanous D, Benson LN, Horlick EM. Coarctation of the aorta: evaluation and management. Curr Opin Cardiol. 2009 Nov;24(6):509-15
PMID:19667980 (Link to Abstract)