Late Infectious Complication After Exclusion of Popliteal Artery Aneurysm by Ligation and Venous Bypass

We present a case of a late infection of a popliteal artery aneurysm (PAA) 8 years after ligation and repair with a venous bypass graft. The patient presented with fever and a progressive painful swelling in the popliteal fossa. CT-angiography and MRI showed a large abscess in the region of the excluded PAA. Bacterial culture showed a Streptococcus Milleri. Repeated drainage and prolonged antibiotic therapy were necessary to cure the infection. On final exploration the abscess corresponded with the ligated aneurysm which was still fed by small vessels in the aneurysm wall, suggesting the thrombus in the aneurysm was infected via a bacteremia. The patient's recovery after repeated drainage of the infection and complete exclusion of the aneurysm was complicated by a transient superficial peroneal nerve paralysis.