Two cases of infected atherosclerotic aneurysms and a comparison with infective endocarditis

Infective Native Extracranial Carotid Artery Aneurysms: A Systematic Review

BACKGROUND

Infective native extracranial carotid artery aneurysms are rare, and their management is variable due to a lack of evidence assessing outcomes.

METHODS

We performed a systematic literature review following PRISMA guidelines to identify all reported cases of infective native extracranial carotid artery aneurysms between January 1970 and March 2021.

RESULTS

This study identified 193 infective native aneurysms of the extracranial carotid artery from 154 sources. Patients were predominantly male (71.4%), and age ranged from 6 months to 89 years old. The most common presenting features were a neck mass and fever, but also included hemorrhage, respiratory distress, and neurological symptoms. Most aneurysms were located in the internal carotid artery (47.4%). Staphylococcus (23.3%) was the most commonly identified causative pathogen, followed by Mycobacterium tuberculosis (20.9%). Most appeared to become infected by direct local spread. Treatment strategies involved open surgical methods in 101 cases and an endovascular approach in 41 cases. In 4 cases, a hybrid method involving concurrent endovascular and open surgical management was undertaken. In 5 cases, there was antibiotic treatment alone. In the open surgery-treated group, the complication rate was 20.8% compared to 13.2% in the endovascular group. Mortality rate was 5.6%.

CONCLUSIONS

Our review identified 193 cases of infective native extracranial carotid artery aneurysms. Direct local spread of a staphylococcus infection was the commonest cause. Endovascular management was associated with fewer early complications than open surgical management.

Molecular diagnosis and characterization of a culture-negative mycotic aneurysm due to ST54 Haemophilus influenzae type b with PBP 3 alterations

Mycotic aneurysm is a rare but life-threatening disease that warrants an integrated therapeutic approach involving surgical intervention and prolonged antibiotic use. However, the causative organisms are often unidentified because antibiotics started empirically render blood and tissue cultures negative. Molecular diagnosis has been reported to be useful in such culture-negative cases. We report a case of a culture-negative mycotic aortic aneurysm due to Haemophilus influenzae, diagnosed by direct 16S rRNA polymerase chain reaction (PCR) and sequencing of the resected aneurysm tissue. PCR for serotype revealed type b, and PCR and sequencing of the ftsI gene revealed alterations in penicillin-binding protein 3, suggesting resistance to ampicillin. Multilocus sequence typing demonstrated that the isolate belonged to sequence type 54.

Mycotic aortic aneurysm caused by haemophilus influenzae group F

BACKGROUND

Haemophilus influenzae is a rare cause of mycotic aortic aneurysm. We present a case of H. influenzae mycotic aortic aneurysm, which was complicated by prior endovascular stent-graft placement at another facility.

METHODS

A 58 year-old man was treated by endograft placement for a presumed penetrating aortic ulcer after having symptoms of abdominal pain and malaise for one month. He presented to our institution 11 days after endograft placement with septic physiology. Repeat computed tomography angiogram demonstrated an inflammatory mass around the distal aorta and right common iliac artery, which had an associated contained rupture.

RESULTS

The patient was treated using intravenous antibiotics, axillo-bifemoral bypass followed by endograft explantation and aortic and iliac ligation. Intraoperative cultures grew Haemophilus influenzae, serotype f.

CONCLUSIONS

Aortic endografts have been successfully used for treatment of selected mycotic aneurysms, generally after adequate treatment of the primary infection with intravenous antibiotics. This case demonstrates the unfavorable natural history of endograft placement in an unsuspected mycotic aneurysm. A high index of suspicion for possible aortic infection should be maintained for patients with systemic symptoms and unusual aortic pathology prior to choosing endovascular repair.

Descending thoracic aortitis due to Haemophilus influenzae: a case report and literature review

Aortitis due to Haemophilus influenzae especially involving the descending thoracic aorta is rarely encountered. We present a case and literature review concerning Haemophilus influenzae aortitis. This article serves to enhance the awareness of this extremely rare disease.