Endothelial infection is a recognized complication of Salmonella bacteremia, especially in elderly patients with diabetes mellitus. Mycotic aneurysms usually involve the abdominal aorta and may involve the iliac arteries.1,2 The clinical presentation of mycotic aneurysm secondary to Salmonella is classic (fever, back pain, and/or abdominal pain) but nonspecific. Such aneurysms are associated with high morbidity and mortality. We present a case of aortic mycotic aneurysm due to Salmonella and outline the therapeutic options.
Case ReportA 71-year-old man known to have coronary artery disease, diabetes mellitus and hypertension, was admitted for management of Salmonella bacteremia. A week prior to admission, the patient had developed fever, chills and rigors, and had been treated symptomatically. Blood cultures that were taken grew Salmonella non-typhi group D four days later, and oral azithromycin was prescribed. The patient continued to have fever and chills, and was hence admitted for further evaluation.On examination, his temperature was 38°C, and there was no palpable lymphadenopathy. Chest and heart examination was unremarkable and no murmur was detected. The abdomen was soft and lax with no palpable masses. Laboratory investigations revealed a WBC of 15x10 9 /L with 60% polymorphonuclear cells, hemoglobin of 7.44 mmol/L (12 g/dL), and platelets of 656x10 9 /L. ESR was 110 and C-reactive-protein (CRP) was 22.6. Initial blood cultures one week prior to admission and those on admission were positive for S. nontyphi group D. Ceftriaxone was started intravenously. The patient complained of back pain and continued to have a low-grade fever. MRI of the spine revealed spondylolithiasis at L5-S1 and a hemangioma at LI with no herniation of the disc. A bone scan was negative, however, gallium-67 scan revealed a focal area of accumulation of the radio-tracer at the region of L4-5 area. CT scan of the abdomen revealed an aneurysmal dilatation of the abdominal aorta, extending from below the origin of the renal arteries down to the iliac bifurcation. The aneurysm demonstrated an extraluminal leakage beyond the calcified wall (Figure 1). The patient underwent successful resection and grafting of the abdominal aortic aneurysm using a straight 14 mm Gore-Tex graft. Intraoperatively, the small bowel was adherent to the site of the aortic aneurysm and was technically difficult to separate from the aneurysm, hence the native aortic tissue was left in place. Intraoperative Gram's stain of the aneurysmal wall showed many WBCs but no organisms, and the cultures subsequently were negative. A repeat CT scan one week postoperatively showed no leak from the aorta. The CRP decreased to 12.6 and ESR to 64. The patient received IV ceftriaxone for a total of 38 days, and a two-month course of oral Ciprofloxacin. On follow-up, the CRP was <0.3 and ESR was 9. At one-year follow-up, the patient was asymptomatic with negative blood cultures and good anatomic results on CT scan.
DiscussionIn 1885, Osier described mycotic aneurysm in associati...