Infected thoracoabdominal aortic aneurysm related to an implanted long-term arterial catheter for chemotherapy: a case report

A 78-year-old Japanese male presented to the emergency department of our hospital with low back pain on exertion for 1 week. The pain was described as dull and gradually worsens. Although the location was near the thoracolumbar spine, he denied radiation of the pain to any parts of the body. Severity of pain using a numerical rating scale was 10/10 at the day of admission. The character and intensity of the pain were not affected by changes in physical movement or by rest. He denied any other symptoms such as fever, nausea, dysuria, hematuria, abdominal pain, and leg numbness during his clinical course.

He had a past medical history of rectal cancer with liver metastasis and had undergone surgery and chemotherapy. At the time of diagnosis, rectal cancer was stage IV (TNM classification of malignant tumors; T3N2M1), grade 3, and was revealed to be adenocarcinoma during histopathology. Liver metastasis affected segments 3 and 6. He underwent low anterior resection of the rectum and resection of the affected liver segments. He then underwent chemotherapy using fluorouracil that was arterially infused through a catheter inserted into the femoral artery and implanted into the hepatic artery through the celiac artery. He initially had good response to treatment but 2 years after diagnosis, he had a recurrence of liver metastasis. He underwent partial resection of segment 6 of the liver and was followed by chemotherapy using FOLFOX6 + bevacizumab protocol instead of arterial infusion. After finishing chemotherapy, he achieved complete remission 11 years after initial diagnosis. As a result of the possibility of another recurrence, the catheter remained in place without being replaced. His other past medical history was hypertension and he remained on amlodipine 5 mg daily and imidapril 5 mg daily. Social history revealed that he had smoked approximately 10 cigarettes a day for 50 years and drank alcohol occasionally. Family and environmental history was unremarkable. His employment history was an office worker, but he retired at the age of 60 and has not worked since then.

On the day of admission, his blood pressure was 171/75 mmHg, heart rate was 67 bpm, SpO₂ 97% at ambient room air, and body temperature was 36.6 °C. He denied abdominal pain, and pain or numbness in the lower extremities. General appearance was not in acute distress. There was no conjunctiva pallor or icterus. Respiratory sounds were clear to auscultation bilaterally and there were no wheezes or crackles. Cardiovascular examination revealed normal S1 and S2. There was no S3, S4, or murmurs. Abdominal examination revealed a flat and soft abdomen with audible bowel sounds. There was no bruit. There was no abdominal tenderness or hepatosplenomegaly. There was no spinal tenderness or costovertebral angle tenderness on percussion. There was no edema of his lower extremities. There was no joint swelling bilaterally at the wrists, ankles, and knees. General physical examinations revealed no abnormalities. His neurologic examination 2 to 12 were intact. There were no abnormalities with sensation and strength throughout with normal reflexes. Although laboratory analysis revealed normal results for complete blood count, electrolyte level, creatinine level, liver function, and coagulation test, levels of beta-d-glucan were slightly elevated at 24 pg/mL (reference value, < 20 pg/mL) (Table 1). Urinalysis was negative for proteinuria, pyuria, and hematuria (Table 1). Blood culture of aerobic and anaerobic bacteria including fungi and urine culture were all negative (Table 1). Transthoracic echocardiography revealed no valve vegetation, no valve regurgitation, no stenosis, and a normal ejection fraction. Computed tomography (CT) of the chest and abdomen revealed an irregularly shaped aortic aneurysm measuring 45 × 33 mm at the origin of the celiac artery and a partially expanded common hepatic artery with disproportionate fat stranding; no extravasation was observed using contrast enhancement (Fig. 1). There was a high possibility that the aortic aneurysm was infected because it was at the site of the catheter that was inserted for the femoral artery via the common hepatic artery. The patient was diagnosed with impending rupture of acute thoracoabdominal aortic aneurysm and was admitted to the intensive care unit of our hospital. Graft replacement was performed for the thoracoabdominal aortic aneurysm, and the implanted catheter was removed during surgery and tested for culture. Pus was discharged from the aortic aneurysm wall incision and collected with swab for culture. The cultures of both the removed catheter and the pus of the aneurysm revealed Escherichia coli, Serratia marcescens, Eikenella corrodens, Streptococcus anginosus, α-Streptococcus, and Candida glabrata. The reported antimicrobial sensitivities of these organisms are shown in Table 2. Antimicrobial susceptibilities were determined by the disk diffusion method, and the results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results of pathology examination of the wall tissue of the aneurysm were compatible with those of the infected aneurysm cultures because the former showed infiltration of neutrophils mainly in the small blood vessels around the adventitia and infiltration of neutrophils, lymphocytes, and plasma cells in the media of the blood vessels (Fig. 2). On the basis of these findings, a diagnosis of catheter-related thoracoabdominal infected aortic aneurysm was made.

On the day of admission, antibiotics therapy was considered for implanted catheter-related infection. The patient was administered a combination of vancomycin 1.0 g intravenously every 12 hours, piperacillin/tazobactam 4.5 g every 6 hours, and micafungin 150 mg every 24 hours until all culture results were confirmed for a week at first. After determination of the drug susceptibilities of all strains, these antibiotics were found to be suitable and were continued. Although the thoracoabdominal aneurysm was resected and pus was drained, antibiotics were administered for 6 weeks in consideration of infection of the perivascular area from the celiac artery to the hepatic artery. His symptoms and laboratory test results improved after surgery and administration of antibiotics. The patient was discharged on day 45, and no recurrence of infected aortic aneurysm was observed on subsequent follow-up CTs as an outpatient for 1 year.