What is a mycotic (fungal) aneurysm?

From the Guidelines

Treatment of a mycotic aneurysm should prioritize in situ reconstruction, as it offers a more versatile approach with fewer long-term complications, higher patency rates, and a lower recurrent infection rate compared to extra-anatomic reconstruction or endovascular device repair. When considering management options for a mycotic aneurysm, several factors must be taken into account, including the location of the aneurysm, the presence of gross purulence, and the patient's overall health status 1.

Key Considerations

• The location of the mycotic aneurysm is crucial in determining the best course of treatment, with thoracic, suprarenal, infrarenal, or visceral locations being more suitable for in situ reconstruction 1.
• Extra-anatomic reconstruction may be considered for infrarenal locations with gross purulence, psoas or retroperitoneal dosing, vertebral osteomyelitis, inadequate response to antibiotic therapy, or selected aortoenteric fistulae, but it is associated with a higher risk of stump blowout, reinfection, and limb ischemia 1.
• Endovascular device repair may be used as a bridge procedure for patients with hemodynamic instability, uncontrolled bleeding, rupture, or impending rupture, but it is associated with higher long-term morbidity and mortality due to persistent infections and device infections 1.

Management Approach

• Antibiotic therapy should be initiated promptly, with broad-spectrum coverage such as vancomycin and ceftriaxone, adjusted based on blood culture results, and continued for at least 6 weeks.
• Surgical management should involve resection of the infected aneurysm, debridement of surrounding infected tissue, and revascularization through bypass grafting or in-situ reconstruction.
• In situ reconstruction using polyester grafts, rifampin-soaked or silver-coated, is a viable option for emergency surgery, with fewer long-term complications and higher patency rates compared to extra-anatomic reconstruction 1.

From the Research

Definition and Causes of Mycotic Aneurysm

• Mycotic aneurysm is a focal dilation of an infected arterial wall 2
• It can be caused by bacterial, fungal, or viral infection 3
• The incidence of mycotic aneurysms is rare but carries a significant mortality risk 3

Clinical Presentation

• Patients with mycotic aneurysms can have wide-ranging clinical presentations depending on the site of the aneurysm 3
• Common presentations include nausea and vomiting, abdominal pain, fever, and chest or back pain 4, 3
• Some patients may also present with hemodynamic instability, gastrointestinal bleeding, or hemothorax 4

Diagnosis and Treatment

• Diagnosis of mycotic aneurysm can be challenging due to its rarity and variable clinical presentations 2, 5
• Treatment options include open surgical repair, endovascular repair, and antibiotic therapy 4, 6, 5
• The choice of treatment depends on the location and character of the aneurysm, as well as the clinical status of the patient 5

Outcomes and Prognosis

• Mycotic aneurysms have a high mortality rate, especially if left untreated or if treatment is delayed 4, 3
• The presence of certain bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), can be associated with a poor prognosis 4
• Endovascular repair may be a reasonable short-term management option for patients with hemodynamic instability or high surgical risk, but it may not be a durable treatment option in the long term 6