Teaching Case

A 65-year-old male patient with rheumatoid arthritis was admitted to the Emergency Department with a three-week history of fatigue, weight loss and night sweats. Blood work revealed leukocytosis and acute renal failure. Haemoglobin and haematocrit were normal. Urine routine showed excess white blood cells.

Urgent ultrasound showed an enlarged left kidney with hydronephrosis and ureteric dilation conditioned by a 3 cm common iliac artery saccular aneurysm associated with a peripheral collection.
Contrast-enhanced multidetector computed tomography (CT) showed left hydronephrosis in the kidney revealing a delayed nephrogram and multiple fluid collections, in keeping with complicated pyelonephritis. CT also demonstrated aneurysmal dilation of the left common iliac artery with a mural thrombus and a high-attenuating crescent sign suggesting fresh bleeding. There was also a peripheral irregular collection adjacent to the left psoas muscle, but no contrast extravasation, suggesting a contained rupture. The aorta was noted to be normal in calibre.
Aneurismectomy was performed followed by an aorto-femoral bypass with a Dacron graft and spontaneous repermeabilization of the ureter ensued.
A Salmonella spp was cultured from both urine and aneurysm surgical sample of the peripheral collection. Based on these findings, the diagnosis was infected iliac aneurysm.

Involvement of the iliac arteries is seen in 10%– 20% of patients with abdominal aortic aneurysms (AAA) [1]. Isolated aneurysms of the iliac arteries are extremely rare, comprising less than 2% of all aneurysmal disease [2]. Like the abdominal aorta counterparts, these aneurysms are typically seen in older men. Iliac artery aneurysms (IAA) occur much more frequently in the common and internal iliac arteries than in the external iliac arteries. The most common aetiologic factor is atherosclerosis and other causes include pregnancy, trauma, infection, dissection, excessive athletic effort, paraanastomotic graft failure and connective tissue disorders (Marfan and Ehlers-Danlos syndromes) [1] and vasculitis. Their natural history, although fairly indolent, carries a significant risk of rupture when the aneurysms have attained a large size [3]. They can be clinically manifested by pulsatile mass, abdominal pain, urinary, gastrointestinal or neurological symptoms and thromboembolic phenomena. However, in most cases, patients are asymptomatic until rupture, which can be intra or retroperitoneal. Angiographic CT is advocated for the diagnosis. Repair is generally recommended for aneurysms larger than 3.5 cm or those associated with compressive symptoms.
Operative mortality is significantly higher when undertaken as an emergency (up to 50%) compared with an elective procedure (7%–11%), emphasizing the importance of early diagnosis and appropriate management [2].
IAA without compressive symptoms can be treated with endovascular treatment or open surgery, while in those with compressive symptoms the latter is preferred as endovascular treatment cannot rapidly reduce aneurysm size.
In case of infected aneurysms, which generally progress to rupture if left untreated, treatment options include in situ placement of an aortic graft (which carries a high risk of graft infection) or resection of the aneurysm followed by arterial ligation and creation of an extraanatomic bypass [1].