The Lactobacillus Strikes Back: Peroneal Mycotic Pseudoaneurysm

Purpose: Peroneal artery pseudoaneurysms are a rare clinical entity typically caused by trauma or iatrogenic injury. There are currently no guidelines describing the optimal management of peripheral mycotic pseudoaneurysms. We present the case of a man presenting with leg pain caused by an expanding peroneal artery pseudoaneurysm as the presentation of infective endocarditis caused by Lactobacillus rhamnosus (typically found in probiotic drinks). To our knowledge, this is the first report on L. rhamnosus causing a peripheral mycotic pseudoaneurysm.

Materials and Methods: A 71-year-old man presented with a 1-week history of right calf pain and swelling. He felt generally unwell with fevers and chills. He denied any recent history of trauma or precipitating factors. An ultrasound scan was performed to exclude venous thrombosis but identified a pseudoaneurysm of the peroneal artery. Dedicated vascular ultrasonography demonstrated a pseudoaneurysm neck 3.6 mm wide and 3.5 mm in length. This was confirmed by computed tomography angiography. Peripheral blood cultures subsequently grew L. rhamnosus. Echocardiography demonstrated vegetations on his aortic valve with moderate to severe aortic regurgitation. The pseudoaneurysm was accessed using a Progreat catheter, and a 6.5- × 12-mm microvascular plug was deployed across the neck of the pseudoaneurysm, with a good result on completion angiogram. Follow-up ultrasound scan 6 weeks after the procedure demonstrated successful occlusion of the pseudoaneurysm.

Results: Peroneal pseudoaneurysms are rare and uncommonly caused by infection but should raise suspicion for a proximal embolic source. In the management of crural pseudoaneurysms, multiple endovascular interventions have been described, including coil embolization, covered stent insertion, and a combination of techniques. These risk endograft infection but appear to be a durable option with comparable outcomes to open surgical repair. We opted for a microvascular plug rather than coil embolization because of the short section of the peroneal artery feeding the pseudoaneurysm and the associated risk of occluding the posterior tibial artery.

Conclusions: L. rhamnosus may cause peripheral mycotic pseudoaneurysms. Vascular surgeons should be aware of infective endocarditis presenting with peripheral embolization and infection, which may initially present similar to deep vein thrombosis. There is no consensus on the best approach to peripheral mycotic pseudoaneurysms, but microvascular plug embolization may be a durable approach.