What is a Mycotic Aneurysm?

A mycotic aneurysm is an aneurysm that becomes infected as a result of bacterial or fungal accumulation in the bloodstream. It can also be a pre-existing aneurysm that becomes infected. Mycotic aneurysms are a common complication of bacterial or infective endocarditis, a condition in which a heart vessel becomes infected due to bacteria in the bloodstream. This type of aneurysm commonly occurs within the thoracic aorta, but it may also occur in the arteries of the neck, arm, thigh and abdomen.

Individuals with heart disease or heart valve conditions are at the highest risk of getting a mycotic aneurysm, especially if they have artificial heart valves. Intravenous, or IV, drug users are another high-risk group for mycotic aneurysms because of the higher likelihood of contracting the staphylococcus bacteria in the bloodstream, which can travel to the heart. Some dental procedures can expose a patient to bacteria that can infect the arteries and walls of the heart, which is why patients are asked to notify the dentist of any heart conditions prior to having dental work done.

Symptoms of a mycotic aneurysm include pain the neck, arm or abdomen. Fever, fatigue, nausea and weakness can also occur. As with any type of aneurysm, a rupture can be fatal. Signs of a possible rupture include high blood pressure, elevated heart rate and light-headedness. Upon prompt medical attention, a computed tomography, or CT, scan and ultrasound are performed to determine the location, size and extent of the aneurysm and to determine the most effective course of treatment.

Treatment of a mycotic aneurysm can be risky. Antibiotics to fight infection are administered for a period of four to six weeks. Serial angiography may be used to track the effectiveness of the antibiotics. While medication may appear to shrink a mycotic aneurysm, there is still a possibility that it will grow, and new ones may form.

Surgery is a necessity in most cases. Depending on the location, degree of infection and the state of the patient’s immune system, extraanatomic reconstruction or in-situ endovascular reconstruction may be performed—the former is more common than the latter. Extraanatomic reconstruction requires multiple operations involving aortal or arterial litigation, excision of the infected tissue and extraanatomic bypass grafting through a non-infected plane.

Endovascular in-situ reconstruction is considered when extraanatomic reconstruction is too risky due to a mycotic aneurysm being too close to the heart, like in an ascending aorta. This procedure involves in-situ insertion of an aortic conduit homograph composed of cryopreserved aortic tissue. In-situ reconstruction has received more attention in recent years because of its reduced postoperative infection rates and improved survival rates.

Typically, the only way to prevent a mycotic aneurysm is to closely monitor the underlying conditions that may cause one to develop. Although mycotic aneurysms are potentially fatal, recovery is possible. Recurring or constant pain that does not go away or gets worse, a spike in blood pressure or heart rate that does not slow down at rest or a fever lasting longer than five to seven days are symptoms that should not be ignored.