Endovascular treatment of thoracic aortic pseudoaneurysm due to brucellosis: a rare case report

Brucellosis is a zoonotic infection that most commonly occurs in Middle Eastern, Mediterranean, and East Asian countries. Nearly 200 cases are reported every year in Italy, [1] and nearly 4000 cases are reported every year in China, with more than half of the cases occurring in the northeast and northern regions, including the inner Mongolia autonomous region and Heilongjiang and Jilin provinces. The reservoir hosts include sheep, cattle, and swine, and transmission from sheep is the most common way of contraction in China [2]. Humans become infected with the disease through ingestion of contaminated milk products or meat or through direct contact via the mucous membranes. Certain professions, such as breeder, butcher, dairyman, and kitchen employee, are associated with an increased risk of contracting the disease [2]. The main clinical presentations include undulant fever, night sweats, and joint pain in the acute stage [3]. These symptoms as well as joint damage, tendon contracture, meningitis, orchitis, and epididymitis are all very common in the chronic stage. Meanwhile, damage to the cardiovascular, digestive, and respiratory systems is occasionally observed. More than 75% of deaths related to brucellosis occurred due to endocarditis [3, 4]. Pseudoaneurysms in peripheral arteries have been reported in a few cases, [5–7] but there has been no report of the occurrence of a thoracic aortic pseudoaneurysm secondary to brucellosis. Here, we describe a rare case of a brucellosis-induced thoracic aortic pseudoaneurysm and discuss the treatment procedure applied for this patient.

Brucella can infect endothelial cells and induce a severe inflammatory response, leading to possible cardiovascular complications. In the inflammatory response, the pathogenic mechanism is suggested to involve endothelial activation in response to brucella infection, with upregulation of adhesion molecules and secretion of proinflammatory chemokines [8]. Vascular complications of brucellosis are rare, but include aneurysm in the peripheral arteries (aorta, brachial, tibioperoneal, mesenteric, and cerebral arteries) and venous and arterial thrombosis with or without underlying endocarditis [9–15]. Although rare, such vascular complications are so deadly they are the primary cause of death related to brucellosis. Pseudoaneurysm secondary to brucellosis is extremely rare in the peripheral arteries, but it is a very severe and dangerous complication [5–7]. In other case studies, it has been reported that mycotic pseudoaneurysm usually is due to trauma to the arterial wall with subsequent contamination [6, 16–21]. The arterial segment might be disrupted when an invasive infection is able to directly lodge in the artery or the vasa vasorum, especially with an intimal defect in the arterial wall such as an arteriosclerotic plaque [6, 19, 20]. In our case, the arteriosclerotic plaques were on CTA imaging.(Fig. 1 ) Due to the arteriosclerotic plaques and damage to the arterial endothelium, the medial layer was exposed to the bloodstream. Based on the physiological and pathological processes, brucella can easily destroy and even penetrate the arterial wall.

Generally, most cases of thoracic aortic pseudoaneurysms in the hospital settings occur following thoracic aortic surgery or trauma and are associated with high mortality rates [22]. Thus, urgent treatment of the thoracic aorta pseudoaneurysm is needed. Compared with open surgery, the endovascular treatment is more likely to minimize the operative wound, hospital stay, and peri-operative mortality [23]. In view of these factors, we performed the minimally invasive operation of implanting a coated stent graft and achieved an ideal outcome in our case. Management of Brucella-induced pseudoaneurysm involves resection of the affected artery and endovascular stenting together with long-term anti-brucellosis treatment. Despite the known hepatotoxicity, neurotoxicity, and reproductive toxicity, rifampin, doxycycline, and streptomycin are the basic drugs used for anti-brucellosis treatment clinically. Without a normative anti-brucellosis treatment, the patient would be more likely to suffer a poor prognosis [24].

In conclusion, the present case may be the first reported case of Brucella-induced thoracic aortic pseudoaneurysm and was successfully managed by endovascular treatment. However, this case has some limitations: 1. the follow-up time was ony 6.5 months; 2. the Brucella-infected arterial wall and tissue were not removed; and 3. the diagnosis was based on a serological test (SAT) and imaging examination (CTA) without pathological analysis. Thus, a case series study is needed to facilitate a systematic diagnosis and formulate treatment recommendations for thoracic aortic pseudoaneurysm caused by brucellosis.