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Mycotic abdominal aortic aneurysm caused by Borrelia afzelii: a case report
Magne Torsteinsen1, Hans-Johnny Schjeldrup Nilsen2, Jan Kristian Damås3,4
1Department of Vascular Surgery, St. Olavs Hospital, Trondheim, Norway. magne.torsteinsen@stolav.no.
Background:
Inflammatory aneurysms and mycotic aneurysms make up a minority of abdominal aortic aneurysms. Mainly autoimmune mechanisms are proposed in the pathogenesis of inflammatory aneurysms, and it is not routine to check for infectious agents as disease culprits.
Case Presentation:
A 58-year-old European male with complaints of abdominal and back pain for 8 weeks was admitted after a semi-urgent computed tomography scan revealed an 85 mm inflammatory abdominal aortic aneurysm. The patient had normal vital signs, slightly elevated inflammatory markers, and mild anemia on admission. Clinical examination revealed a tender pulsating mass in his abdomen. His clinical condition was interpreted as impending rupture and urgent repair of the aneurysm was deemed necessary. Due to the patient's relatively young age and aneurysm neck morphology, open aortic repair was preferred. Preoperatively, the aneurysm appeared inflamed, with fibrous wall thickening and perianeurysmal adhesions. Aneurysm wall biopsies were sent to histopathological and microbiological diagnostics. Routine cultures were negative, but 16S rRNA gene real-time polymerase chain reaction was positive and Borrelia afzelii was identified by DNA sequencing of the polymerase chain reaction product. B. afzelii was also identified by sequencing the polymerase chain reaction product of a Borrelia-specific groEL target. Immunoglobulin G and M anti-Borrelia antibodies were present on serological analysis. Histopathological analysis displayed loss of normal aortic wall structure and diffuse infiltration of lymphocytes and plasma cells. The patient had an uneventful recovery and was discharged after 1 week to a regional rehabilitation facility. Though the patient fares clinically well and inflammatory markers had normalized, antimicrobial treatment with doxycycline continues at 3 months follow-up due to remaining radiologic signs of inflammation.
Conclusions:
Borrelia infection in the setting of acute aortic pathology is a rare entity. To our knowledge, this is the first case report to demonstrate a mycotic abdominal aortic aneurysm as a rare manifestation of Lyme disease. Aortic wall biopsies and real-time polymerase chain reaction analysis of the specimen were essential for accurate diagnosis. This finding may contribute to the understanding of the etiology of inflammatory aneurysmal disease and abdominal aneurysms in general.
Insights
This study reports a rare case of a mycotic abdominal aortic aneurysm caused by Borrelia infection, a manifestation of Lyme disease. Early diagnosis using molecular techniques on aortic biopsies was crucial for identifying this rare cause of inflammatory aneurysms.
Area of Science:
- Cardiovascular Medicine
- Infectious Diseases
- Medical Diagnostics
Background:
- Inflammatory and mycotic aneurysms are uncommon types of abdominal aortic aneurysms.
- Autoimmune mechanisms are typically implicated in inflammatory aneurysms, often overlooking infectious causes.
Observation:
- A 58-year-old male presented with symptoms suggestive of an impending ruptured abdominal aortic aneurysm.
- Computed tomography revealed an 85 mm inflammatory abdominal aortic aneurysm.
- Initial cultures were negative, but molecular analysis of aortic biopsies identified Borrelia afzelii.
Findings:
- Real-time polymerase chain reaction (PCR) and DNA sequencing confirmed Borrelia afzelii in aortic wall biopsies.
- Serological tests showed the presence of anti-Borrelia antibodies (IgG and IgM).
- Histopathology revealed significant aortic wall damage and inflammatory cell infiltration.
Implications:
- This case highlights Borrelia infection as a potential cause of mycotic abdominal aortic aneurysms, a rare manifestation of Lyme disease.
- Aortic wall biopsy with molecular analysis (PCR) is essential for diagnosing such rare infectious etiologies.
- This finding may broaden the understanding of inflammatory aneurysmal disease and abdominal aortic aneurysms.
