Mycotic aneurysm is a serious clinical conditions associated with significant morbidity and mortality. Treatment consists of antibiotic therapy combined with surgical intervention, such as aggressive surgical debridement of the infected tissue, vascular reconstruction, and endovascular intervention. Herein, we report a case with iliac artery mycotic aneurysm rupture with pseudoaneurysm, which obstructed the ureter resulting in left septic pyonephrosis.

A 51-year-old hypertensive and previous ICH male patient presented to our emergency department with severe left flank pain, thigh numbness, and fever. Renal sonography revealed left hydronephrosis. Urinary diversion was suggested for left hydronephrosis relief because of persisted pain with fever off-and-on for one month. High fever(41.5^。C) attacked after PCN insertion. Laboratory results were as the following: white blood cell count: 15,700/mm³ ; Band form: 5% and serum creatinine: 2.8mg/dL. Hence, he was referred to intensive care units for urosepsis treatment. It could not but abdomen contrast-enhanced computed tomography was arranged and revealed a 23 x 26 x 28 mm pseudoaneurysm of left internal iliac artery (IIA) with rupture leading to large retroperitoneal hematoma at left iliac fossa and left obstructive uropathy. (Figure 1) Pus culture from left nephrostomy reported “Salmonella species growth”, so imipenem was administered afterward. One week later, left IIA pseudoaneurysm was repaired with 6x100mm Viabahn stent-graft, and left external iliac artery was stented with 10x100mm Viabahn stent-graft. (Figure 2) After deployment of the stent graft system, left diagnostic ureteroscopy and double-J stent insertion were performed. Removal of residual left retroperitoneal hematoma and debridement were done one week later, and culture reported as “Salmonella species growth” as well.  Later, he was discharged with stable conditions, and recovered uneventfully during 3-month follow- up.

Primary iliac artery mycotic aneurysm rupture with pseudoaneurysm is a challenging clinical scenario requiring appropriate antibiotics and emergent stent-graft repair. Early identification of the possible causes of septic pyonephrosis and prompt response would be the mainstay treatment.