When a Psoas Abscess Is No Longer an Abscess: Computed Tomography Angiography in Detection of Type I Endoleak with Aorto-Psoas Fistula After Endovascular Aortic Repair

Abstract

Introduction: Aorto-psoas fistulas resulting from infected stent grafts are rare but carry high mortality rates. This case report highlights the critical necessity of distinguishing between a simple abscess and a vascular fistula in patients with prior aortic interventions to prevent catastrophic procedural complications. Case Presentation: An 84-year-old man with a history of lung cancer and prior endovascular aneurysm repair (EVAR) performed 5 years ago presented to the emergency department with severe low back pain. He had a known history of persistent spondylodiscitis and psoas abscess diagnosed 4 months ago, for which he had undergone multiple drainages. The initial admission assessment suggested a recurrent abscess, and percutaneous drainage was arranged. However, the patient's condition rapidly deteriorated with sudden shock and massive gastrointestinal bleeding. An emergency arterial-phase computed tomography angiography (CTA) was performed during resuscitation. The CTA demonstrated contrast medium leakage from the proximal edge of the stent graft, establishing a Type Ia endoleak with fistulous communication to the psoas abscess and the duodenum. Consequently, the contraindicated drainage was withheld. Due to the catastrophic hemorrhage and hemodynamic collapse, the patient died shortly after the diagnosis. Conclusion: This case underscores the necessity of routine contrast-enhanced CTA prior to any image-guided drainage in patients with prior aortic stent grafts. Early identification via CTA is essential to modify management strategies and avoid iatrogenic hemorrhage