At presentation he was found to be haemodynamically stable with a temperature of 37.9 °C. No obvious source of infection was found on clinical examination. He had a normal full blood count and renal function with only slightly deranged liver function tests.
Chest radiography and abdominal ultrasound scan were unremarkable. An echocardiogram did not identify any valve vegetations or atrial thrombus. Protein electrophoresis revealed a diffuse hypergammaglobinaemia.
He was discharged after undergoing a bone marrow biopsy. Three blood cultures during his admission were negative and the bone marrow aspirate and trephine biopsy were normal. He was booked for an outpatient CT chest, abdomen and pelvis.
The following day he attended A&E with a short history of haematuria and left sided loin pain. His white cell count and renal function were normal. A CT KUB showed no evidence of renal tract calcification or ureteric dilatation. However there was loss of definition around the lower aorta with increased density in the periaortic fat. The aorta was not dilated and the appearances suggested an inflammatory process.
Contrast enhanced CT showed an abnormality in the left psoas muscle and the adjacent soft tissue around the distal end of the aortic bifurcation. The appearances were suggestive of a psoas abscess. There was also a focal dilatation of the distal aorta just proximal to the bifurcation with a small amount of surrounding soft tissue suspicious of aortitis ().
Dilated distal aortitis.
He was initially treated empirically with intravenous vancomycin which was subsequently changed to meropenem on advice from the Microbiologists. His symptoms rapidly settled with normalisation of his temperature and inflammatory markers.
A CT aortogram 12 days later showed deterioration with aneurysm formation of the distal aorta. The inflammatory collection within the left ilio-psoas muscle had however resolved ().
Distal abdominal aortic aneurysm.
After two weeks of intravenous antibiotic treatment, given the radiological evidence of a weakened, dilating aortic wall, he underwent repair of his distal aorta.
At operation two separate saccular aneurysms were identified just above the aortic bifurcation. The left side was a pseudo-aneurysm with complete loss of the posterior aortic wall. Both aneurysms were full of fresh thrombus with a moderate amount of laminar thrombus within the more proximal infra-renal aorta. Both iliac arteries were soft and disease free.
All intra-luminal thrombus and aortic wall was sent for microscopy, culture and sensitivity. The aortic wall was excised leaving a posterior strip which was covered with an omental pedicle. The bifurcation was replaced with a rifampicin soaked Dacron bifurcation graft with end to end anastomosis to the infra-renal aorta and both common iliac arteries (). After completing the anastomoses the graft was wrapped with a second omental pedicle.
Prosthetic bifurcation graft with omental pedicle.
He made a good post-operative recovery and was discharged home two weeks later on oral antibiotics for a further two months. Tissue cultures proved to be sterile.
On review he is asymptomatic with normal inflammatory markers and a CT scan seven months post procedure shows no evidence of infection or inflammation.