A 72-year-old male with a known abdominal artery aneurysm (AAA) (4.2cm diameter) presents to his physician for his annual aneurysm duplex ultrasound. He also complains of left leg pain and a tingling sensation for the last 2 weeks. Additionally, he reports that he has felt a "beating" sensation behind his left knee during bathing this morning. The patient's past medical history includes hypertension, hyperlipidemia and diabetes mellitus. He does not drink alcohol, or use illicit drugs, but he smokes two packs of cigarettes per day for the past 40 years. His vital signs are within normal limits. Aside from a small palpable pulsatile mass in the left popliteal fossa, the rest of physical examination is unremarkable.
What is best next step in management of the patient's symptoms?
Show Answer
The correct answer is: C. Perform a lower limb ultrasound.
The patient complains of left leg pain and a pulsatile mass behind his knee. These findings, given his history of having an AAA, raise strong suspicion for also having a popliteal artery aneurysm. Patients with abdominal aortic aneurysms (AAA) are more prone to develop popliteal artery aneurysms (PAA), but the prevalence is still unknown.1 Recent studies demonstrated that almost one-fifth of patients with AAA who had undergone a radiological examination of their popliteal artery also had a PAA. The majority of PAAs are asymptomatic, however commonly they are the identified cause of severe limb ischemia.2
Acute limb ischemia (ALI) due to PAA can have devastating consequences; the amputation rate is reported to be approximately 20% in this group of patients.3 Thus, all patients with AAA should undergo one radiological examination of their popliteal arteries (Answer C).
Although checking blood cholesterol and sugar levels is important for long-term medical care, this will not help identify the underlying cause of this patient's current symptoms (Answer A).
Although leg pain and paresthesia could be a side effect of his current medication (e.g. paresthesia caused by electrolyte disturbances due to antihypertensive or antidiabetic drugs), the presence of a palpable pulsatile mass could not be explained (Answer B).
Prescribing a NSAID might help relieve some of patient's pain, but it would not address the underlying cause of his symptoms (Answer D).
Educational Objective:
Since patients with AAA are more prone to develop PAA and given the fact that most PAAs are asymptomatic, all patients with AAA should undergo one radiological examination of their popliteal arteries.
References
Tuveson V, Lofahl HE, Hultgren R. Patients with abdominal aortic aneurysm have a high prevalence of popliteal artery aneurysms. Vasc Med 2016;21:369-75.
Trickett JP, Scott RA, Tilney HS. Screening and management of asymptomatic popliteal aneurysms. J Med Screen 2002;9:92–93.
Diwan A, Sarkar R, Stanley JC, Zelenock GB, Wakefield TW. Incidence of femoral and popliteal artery aneurysms in patients with abdominal aortic aneurysms. J Vasc Surg 2000;31:863–69.
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