A patient presents with unequal femoral pulses and a cool, pale left leg. This most likely indicates which condition?

A patient presents with unequal femoral pulses and a cool, pale left leg. This most likely indicates which condition?

• A. Thoracic aneurysm.
• B. Abdominal aneurysm.
• C. Pulsus paradoxus.
• D. Deep vein thrombosis.

Answer: (B)

Diminished arterial inflow to the leg is the key idea here. Unequal femoral pulses with a cool, pale leg point to acute arterial insufficiency in that limb, often from blockage of the iliac/femoral arteries. An abdominal aortic aneurysm can extend or develop thrombus that embolizes into the distal arteries, cutting off blood supply to one leg and producing a pale, cool limb with weak or absent pulses. The other options don’t fit as well. A thoracic aneurysm wouldn’t typically cause a unilateral leg pulse deficit or a cool, pale leg. Pulsus paradoxus is about a large fall in blood pressure with inspiration, seen in tamponade or severe airway disease, not peripheral limb perfusion. Deep vein thrombosis affects the veins and usually causes swelling and warmth with intact arterial pulses, rather than a cool, pale limb with reduced pulses. So, the finding most consistent with the scenario is an abdominal aortic aneurysm compromising arterial flow to the leg.

Diminished arterial inflow to the leg is the key idea here. Unequal femoral pulses with a cool, pale leg point to acute arterial insufficiency in that limb, often from blockage of the iliac/femoral arteries. An abdominal aortic aneurysm can extend or develop thrombus that embolizes into the distal arteries, cutting off blood supply to one leg and producing a pale, cool limb with weak or absent pulses.

The other options don’t fit as well. A thoracic aneurysm wouldn’t typically cause a unilateral leg pulse deficit or a cool, pale leg. Pulsus paradoxus is about a large fall in blood pressure with inspiration, seen in tamponade or severe airway disease, not peripheral limb perfusion. Deep vein thrombosis affects the veins and usually causes swelling and warmth with intact arterial pulses, rather than a cool, pale limb with reduced pulses.

So, the finding most consistent with the scenario is an abdominal aortic aneurysm compromising arterial flow to the leg.