Rupture of a Salmonella-infected iliac aneurysm: A case report

ACHAIKI IATRIKI | 2021; 40(2):111–114

Case Report

Ioannis Ntouvas1, Chrysanthi Papageorgopoulou2, Konstantinos Nikolakopoulos2, Polyzois Tsantrizos2, Spyros Papadoulas2, Stavros Kakkos2


1General Hospital of Patras ‘’St. Andrew’’, Patras, Greece
2Department of Vascular Surgery, University of Patras Medical School, Patras, Greece

Received: 18 Sep 2020; Accepted: 06 May 2021

Corresponding author: Ioannis Ntouvas, D. Gounari 187, Patras, 26331, Tel: +30 26936188344, E-mail: ntouvas@gmail.com

Key words: Infected aneurysm, rupture femo-femoral by-pass, Salmonella

 


Abstract

Infected aneurysms of the abdominal aorta and iliac arteries, are a rare entity with high morbidity and mortality due to sepsis and the possibility of rupture. Salmonella is one of the most common causes of these aneurysms. Although some cases of endovascular treatment have been reported, open repair remains the gold standard treatment. Antibiotics have a complementary but significant role in the treatment of infected aneurysms. We present the rare case of a 62-year-old man with a rupture of a Salmonella infected iliac aneurysm. The patient, was operated successfully with complete excision of aneurysmal sac, debridement of the surrounding infected tissue and arterial revascularization via femo-femoral bypass.

Introduction

Infected abdominal aneurysm is a rare entity with high mortality. It is caused by degeneration of arterial wall of either bacterial or fungal infection. Its incidence is 0,65%-2% of all aortic aneurysms [1]. Salmonella is one of the most common and well-recognized organisms that is implicated in this serious condition. Additionally, Salmonella is the only organism that causes infected aneurysm from a food-born source. In this article, we report the case of a patient that was operated due to the rupture of a Salmonella infected iliac aneurysm.

Case

A 62-year-old man heavy smoker, with a history of insulin dependent diabetes mellitus, hypertension and a coronary angioplasty 8 months ago, was referred to the Emergency Department of our hospital on hypovolemic shock. On physical examination, he was tachycardic and hypotensive with blood pressure 80/40 mmHg and approximately 110 – 120bpm. He also suffered from a sudden-onset profound paralysis on his left lower extremity. Blood tests revealed the following: Hemoglobin 9,1 gr/dl, WBC 26.000 /mm3, CRP 27mg/L. After resuscitation and stabilization, the patient underwent a Computed Tomography (CT) scan. A left iliac aneurysm rupture was detected (fig.1). It is remarkable that ten days ago the patient had visited a general practitioner, due to a back pain combined with fever, and was prescribed a medication for urinary tract infection.

Figure 1. Left iliac aneurysm rupture.

The patient was immediately taken to the operating room. A middle line laparatomy was performed and a large retroperitoneal hematoma at the left side of the abdomen was revealed. After the aorta, right common iliac and left external iliac artery clamping, the hematoma was evacuated. The cause of the hematoma was the rupture of a pseudo-aneurysm at the left common iliac artery near the bifurcation. The sac of the aneurysm and part of the common, external and internal iliac artery were resected following debridement of the surrounding tissue and ligature of these arteries. After closing the abdomen, we proceeded to a femo-femoral bypass with a PTFE graft (fig 2). Specimens were sent for histopathology and culture-sensitivity. At the end of the operation, the patient had pulses on both legs and he was admitted to the Intensive Care Unit. Postoperative recovery was complicated by an iliac femoral vein thrombosis. Paralysis of the left leg remained, probably due to chronic ischemia of the sciatic nerve by the pressure of the hematoma. Magnetic resonance imaging (MRI) on the 10th postoperative day detected osteomyelitis of the ilium. Specimens culture yielded Salmonella that was multi-sensitive. During hospitalization, the patient received ciprofloxacin and clindamycin. He was discharged on the 22th postoperative day, receiving ciprofloxacin and amoxicillin-clavulanic acid twice daily for 6 months based on cultures’ results. Six months post-operatively, the patient has no laboratory sign of infection according to either biological tests or MRI findings with a significant improvement at the mobility of his left lower extremity.

Figure 2. MRI, Femo-femoral by Pass with PTFE.

Discussion

The term mycotic was coined by Osler and was used in his Gulstonian lectures in 1885 to describe multiple aortic aneurysms laden with fungal vegetations in a patient with bacterial endocarditis. Currently, the bibliography term has changed to “infected”. The most common cause of infected aneurysms is Staphylococcus aureus, followed by Salmonella [2] which is a genus of rod-shaped (bacillus) gram -negative bacteria of the Enterobacteriaceae family. Gastroenteritis is the dominant clinical manifestation of this infection. However, approximately 5% of Salmonella infected patients develop bacteremia [3]. Salmonella has the ability to invade normal arterial intima and cause endothelial infection in the presence of atherosclerosis [4]. As a consequence, the arterial wall is digested and a pseudo aneurysm is formed. The arteries of diabetic patients (especially the aorta and iliac arteries) are likely to be affected by Salmonella because of the increased incidence of atherosclerosis and intimal damage as well as the reduced immune response. The clinical picture of aortitis consists of fever, back pain, and/or abdominal pain. In one study, that includes patients with Salmonella bacteremia, 25% of those that were older than 50 years-old, developed an endothelial infection [5]. Salmonella-related aneurysms are known to have a fast disease progression with the risk of early rupture [6]. The recurrence of Salmonella infection is possible due to intracellular survival [7].

CT scan with contrast enhancement is considered to be the method of choice to diagnose mycotic aneurysms. Early changes of aortitis, preceding aneurysm formation, include: an irregular arterial wall, periaortic edema, a periaortic soft-tissue mass, and periaortic gas. Periaortic edema can appear as fat stranding or a hypoattenuating concentric rim at CT [8].

The gold standard treatment of infected aneurysm according to the recent guidelines of ESVS (European Society of Vascular Surgery) remains open surgery with surgical resection of the infected artery and surrounding tissues followed by either an extra-anatomic bypass (EABG) or in situ interposition graft (ISB) and a long-term antibiotic therapy [9]. An alternative option either as a permanent or as a bridge therapy is the EVAR (EndoVascular Aneurysm Repair). Patients’ mortality treated non-surgically is about 70–90% [10]. In a published review including 57 cases during the last ten years, for Salmonella mycotic aneurysms only, mortality rates were 21.43% and 7.14 % for open and endovascular treatment, with recurrence rates of infection 0% and 17.85%, respectively. There is no mention for the long-term mortality in this study. In the majority of studies, the short-term rates of mortality in open surgery were 20% – 40% [11]. In a German single-center study, the 5-year survival rate was 35% [12]. Generally, reports on long-term outcome after open repair are scarce. Additionally, there is a debate over the use of in situ interposition graft (ISB) instead of extra-anatomic bypass (EABG). Some authors report similar results between the two methods [13]. In contrary, there are a lot of studies with higher infection rates in ISB. Certainly, EVAR is another option that recently gains a lot of ground. In a European multicenter retrospective study [14] that included only aortic infected aneurysms, the 1-month survival rate was 91% and the 120-month survival was 41%; however, only 19% of deaths, according to the study were due to infection. The recurrence or persistence of infection remains a big issue for EVAR treatment despite the promising results. Hence, it is suggested only for patients with co-morbidities. On the other hand, there is no consensus on the length of antibiotic therapy. According to some authors, there is a tendency to prescribe antibiotic therapy for at least 6 weeks. However, because of the possibility of recurrence during the first 6 to 12 months, a long-term antibiotic therapy for 6 months to 1 year or even lifelong is under consideration [15].

Conclusions

Infected aneurysms due to Salmonella infections constitute a therapeutic challenge with extremely high morbidity and mortality. Excision of the aneurysmatic sac and surrounding infected tissues followed by revascularization remains the treatment of choice. The alternative option, only for patients with co-morbidities, is endovascular treatment. Antibiotic therapy should be continued for a long time, probably for six months to one year due to the tendency of recurrence.

Conflict of interest disclosure

None to declare.

Declaration of funding sources

None to declare.

Author contributions

I. Ntouvas and C. Papageorgopoulou wrote the manuscript; K. Nikolakopoulos, P. Tsantrizos, S. Papadoulas and S. Kakkos were involved in patient management.

References

1. Reddy DJ, Shepard AD, Evans JR, Wright DJ, Smith RF, Ernst CB. Management of infected aortoiliac aneurysms. Arch Surg. 1991;126(7):873-8.
2. Pirvu A, Bouchet C, Garibotti FM, Haupert S, Sessa C. Mycotic aneurysm of the internal carotid artery. Ann Vasc Surg. 2013; 27(6):826-30.
3. Fernandez GM, Aguado JM, Arribas A, Lumbreras C, de Gorgolas M. The spectrum of cardiovascular infections due to Salmonella enterica: a review of clinical features and factors determining outcome. Medicine (Baltimore). 2004;83(2):123-38.
4. Meerkin D, Yinnon AM, Munter RG, Shemesh C, Hiller N, Abraham AS. Salmonella mycotic aneurysm of the aortic arch: case report and review. Clin Infect Dis. 1995;21(3):523-8.
5. Cohen SS, O’Brien TF, Schoenbaum S, Medeiros AA. The risk of endothelial infection in adults with Salmonella bacteremia. Ann Intern Med. 1978;89(6):931-2.
6. Hsu RB, Chen RJ, Wang SS, Chu SH. Infected aortic aneurysms: clinical outcome and risk factor analysis. J Vasc Surg. 2004;40(1):30-5.
7. Chen PL, Tsai LM, Kan CD, Ko WC. Is 2 weeks of antibiotic therapy enough to treat elderly patients with nontyphoid Salmonella bacteremia? A case report of fatal endovascular infection. J Microbiol Immunol Infect. 2014;47(4): 350-3.
8. MacedoTA, Stanson AW, Oderich GS, Johnson CM, Panneton JM, Tie ML. Infected aortic aneurysms: imaging findings. Radiology. 2004;231(1):250-7.
9. Wanhainen A, Verzini F, Van Herzeele I, Allaire E, Bown M, Cohnert T, et al. Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms. Eur J Vasc Endovasc Surg. 2019;57(1): 8-93.
10. Knouse MC, Madeira RG, Celani VJ. Pseudomonas aeruginosa causing a right carotid artery mycotic aneurysm after a dental extraction procedure. Mayo Clin Proc. 2002;77(10): 1125-30.
11. Yiqun Guo, Yu Bai, Chunxia Yang, Peng Wang and Li Gu. Mycotic aneurysm due to Salmonella species: clinical experiences and review of the literature. Braz J Med Biol Res. 2018 Jun 25;51(9):e6864.
12. Müller BT, Wegener OR, Grabitz K, Pillny M, Thomas L, Sandmann W. Mycotic aneurysms of the thoracic and abdominal aorta and iliac arteries: experience with anatomic and extra-anatomic repair in 33 cases. J Vasc Surg. 2001;33(1):106-13.
13. Lee CH, Hsieh HC, Ko PJ. In situ versus extra-anatomical reconstruction for primary infected infra-renal abdominal aortic aneurysms. J Vasc Surg. 2011;54(1): 64-70.
14. Sorelius K, Mani K, Bjorck M, Sedivy P, Wahlgren CM, Taylor P, et al. Endovascular treatment of mycotic aortic aneurysms: a European multicenter study. Circulation. 2014;130(24): 2136-42.
15. Clough RE, Black SA, Lyons OT, Zayed HA, Bell RE, Carrell T, et al. Is endovascular repair of mycotic aortic aneurysms a durable treatment option? Eur J Vasc Endovasc Surg. 2009;37(4):407-12.