Mycotic aneurysms: a critical diagnosis in the emergency setting

Rupture of Mycotic Abdominal Aortic Aneurysm as a Result of Incompletely Treated Multiple Peripheral Mycotic Aneurysms

Background: A mycotic aortic aneurysm is a rare type of aortic aneurysm that can have disastrous outcomes. Most mycotic aneurysms originate from infectious sources, such as trauma, vegetation in the heart, and adjacent infectious sources. If a mycotic aneurysm is diagnosed, it should be treated simultaneously with the primary source of the infection. Case Summary: Treatment was performed for a mycotic aneurysm of the brachial artery that occurred suddenly during treatment for a fever for which the primary source of infection had not been confirmed. The workup revealed that a mycotic aneurysm of the brachial artery was the cause of the fever, followed by aneurysms in the abdomen and lower extremities and even vegetation in the heart that was not initially present. The patient declined to undergo treatment for personal reasons. After 5 months, it was revealed that the abdominal aortic aneurysm, which was initially considered normal aorta, was ruptured; however, the aneurysm was successfully treated. Conclusions: A peripheral mycotic aneurysm may be associated with multiple aneurysms. Appropriate diagnosis and complete treatments are necessary to prevent fatal consequences.

Aortic calcification correlates with pseudoaneurysm or penetrating aortic ulcer of different etiologies

Chronic risk factors for pseudoaneurysm (PSA) or penetrating aortic ulcer (PAU) have not been fully clarified. This study aims to evaluate the association of aortic calcification with PSA or PAU of different etiologies. Totally 77 pseudoaneurysms, 80 PAU, and 160 healthy controls (HCs) were retrospectively included, of which 30 were infected, 34 were immunological, and 93 were atherosclerotic etiologies. The aortic calcification status, position of aortic tears/ulcers, and risk factors for disease or acute aortic syndrome (AAS) were identified. Atherosclerotic patients aged more than 65 and infective patients aged more than 60 had significantly higher calcification scores. The immunological group had a lower level of calcification in the infrarenal aorta. For patients of infective or atherosclerotic etiology, 60% (18/30) and 60.22% (56/93) of the tears/ulcers occurred at the aortic parts with the highest level of calcification. Patients with longitudinal calcification exceeding 1/3 of the aortic arch had an increased risk of acquiring diseases (OR = 13.231). The presence of longitudinal calcification of the descending aorta or cross-sectional calcification of the infrarenal aorta increased the risks of acquiring diseases (OR = 8.484 and 8.804). After adjusting for age, longitudinal calcification of the descending aorta exceeding 1/3 length was found to be associated with AAS (OR = 4.662). Tears/ulcers of pseudoaneurysm and PAU were both generally found at the part of the aorta with most calcification. Distinct aorta calcification characteristics were observed for lesions of different etiologies. Longitudinal thoracic and cross-sectional infrarenal abdominal aortic calcification increased the risk of acquiring diseases, and descending aortic calcification was associated with symptomatic patients.

Contained Rupture of a Small Mycotic Abdominal Aneurysm in a Patient With Infective Endocarditis

A contained ruptured mycotic abdominal aneurysm is one of the complications of infective endocarditis. It is a complication that physicians should entertain when patients with infective endocarditis present with a complaint of back pain. This case report aims to increase the awareness of the possibility of a rupture of a small size abdominal mycotic aneurysm. This is a 36-year-old female with a history of intravenous (IV) drug use and infective endocarditis secondary to methicillin-sensitive Staphylococcus aureus presented with acute right-sided lower back pain. Work-up revealed a contained ruptured 2.5 cm mycotic abdominal aneurysm. She had an open surgical repair of the abdominal aorta followed by a mitral valve replacement a week later and she was discharged home on antibiotics and an anticoagulant. Untreated, a mycotic aneurysm can expand quickly and has a higher likelihood of rupturing as compared to an atherosclerotic abdominal aortic aneurysm. A contained ruptured mycotic abdominal aneurysm can lead to a dramatic hemodynamic compromise when it becomes uncontained, hence it is prudent that it is acted after it is diagnosed. Most authors recommend prompt surgery for all patients irrespective of the size of the aneurysm. Younger age is a factor to consider in choosing a repair approach despite the complications associated with both open surgical and endovascular repair.

Rapidly Growing Aneurysm with Ulcer-like Projection Complicated with Bacteroides ovatus Bacteremia

The incidence of anaerobic bacteremia has been increasing over the past several decades. Further, antibiotic resistance in Bacteroides is a pertinent issue. A 76-year-old man was brought to our hospital with complaints of fever, chills, and abdominal pain. Empiric antibiotics induced minimal relief. The blood culture was positive for multi-drug resistant Bacteroides ovatus. Our patient developed a periaortic abscess in the abdominal aorta and a thoracic aortic aneurysm with ulcer-like projection (ULP), which rapidly increased in size. He was transferred to the tertiary medical institution for surgical drainage. This case suggests that bacteremia can exacerbate aneurysms with ulcerative lesions. Anaerobic bacteremia is a possible differential diagnosis when periaortic abscess formation is present. Early surgical consultation and appropriate antibiotic selection are crucial in anaerobic bacteremia treatment.

Streptococcus pneumoniae as a Cause of Mycotic and Infected Aneurysms in Patients without Respiratory Features: Challenging Diagnoses Aided by 16S PCR

BACKGROUND

Streptococcus pneumoniae is considered a rare cause of mycotic aneurysms. The microbiological diagnosis of mycotic aneurysms can be difficult, and many patients have negative blood culture results.

METHODS

We describe a series of four consecutive cases of mycotic aneurysms caused by S. pneumoniae with no respiratory features or extravascular septic foci. In two patients with negative blood culture results, 16S PCR was used for the diagnosis of S. pneumoniae infection.

RESULTS

Four men with mycotic aneurysms affecting the aorta, axillary, and popliteal arteries caused by S. pneumoniae presented to our center between 2015 and 2016. All were treated with at least one month of intravenous antibiotics, followed by at least 4 weeks of oral antibiotics. Two were additionally managed using endovascular surgical techniques, and one underwent an open surgical repair. The fourth patient presented with bilateral popliteal aneurysms, one of which ruptured and was managed using surgical ligation and bypass, whereas the other side subsequently ruptured and was repaired endovascularly. Three of the four patients are currently off antibiotics and considered cured, while one died of an unrelated cause.

CONCLUSIONS

S. pneumoniae should be considered a potential causative agent of mycotic aneurysms. Diagnosis can be confirmed using 16S PCR, especially in patients where peripheral blood cultures are uninformative.