Mycotic aneurysm
A mycotic aneurysm is a rare medical condition characterized by bacterial infection of an artery wall, leading to dilation and the formation of an infectious mass. This condition most commonly affects the femoral artery and the thoracic and abdominal aortas, although it can occur in any artery. The term "mycotic" may suggest a fungal origin, but bacterial pathogens, such as Streptococcus pneumoniae, Staphylococcus aureus, and Salmonella species, are the primary culprits. Risk factors include existing health conditions like cancer, diabetes, and immunosuppression, as well as older age and invasive procedures.
Symptoms of a mycotic aneurysm can vary widely, including fever, pain in affected areas, and in severe cases, bleeding. Diagnosis typically involves a combination of symptom assessment, blood tests, and imaging techniques such as CT scans and echocardiography. Treatment strategies generally include antibiotic therapy and surgical intervention to remove infected tissue and repair the artery. While there are no preventive measures for mycotic aneurysms, reducing the risk of Salmonella infections may decrease the likelihood of developing this condition. Overall, timely diagnosis and treatment are crucial for improving outcomes in individuals affected by mycotic aneurysms.
Mycotic aneurysm
- ANATOMY OR SYSTEM AFFECTED: Arteries, blood, cardiovascular system, circulatory system, heart
Definition
A mycotic aneurysm is a rare condition in which bacteria infect the wall of an artery and cause dilation of the artery and a mass of infectious material. Pieces of this mass can break off and travel to other parts of the body where they can colonize a new site or interfere with blood flow. A mycotic aneurysm is more likely in an artery. It can occur in any artery in the body, although it is most common in the femoral artery and the thoracic and abdominal aortas. In rare instances, a mycotic aneurysm is preceded by infective endocarditis or valvular heart disease.
Causes
Although the term “mycotic” implies a fungal infection, most mycotic aneurysms are caused by bacteria. Some of the organisms that can cause a mycotic aneurysm are Streptococcus pneumoniae, S. viridans, Staphylococcus aureus, and Salmonella species. Often, the mycotic aneurysm develops at a tear in an artery caused by atherosclerosis.
Risk Factors
Persons living with existing health issues are more likely to develop a mycotic aneurysm. These health issues include cancer, liver cirrhosis, systemic lupus erythematosus, acquired immunodeficiency syndrome, inflammatory bowel disease, and diabetes. Higher risk is also associated with older age, immunosuppressive therapy or glucocorticoid therapy, and intravenous drug abuse. Pre-existing cardiovascular conditions, invasive procedures, and prosthetic devices may also increase risk.
Symptoms
The symptoms of a mycotic aneurysm vary according to their size and their site. If the site of the mycotic aneurysm is bleeding, there will be additional symptoms. The symptoms include fever; abdominal, thigh, neck, or arm pain; palpable mass; nausea; weakness; and fatigue. If the mycotic aneurysm is in the arteries of the brain, the symptoms will be headache, seizures, bleeding into the brain, and nausea and vomiting.
Screening and Diagnosis
There is no routine screening for a mycotic aneurysm. The diagnosis is based on the symptoms, on increased white blood cells, and on diagnostic imaging. Testing includes blood cell count (CBC), transesophageal echocardiography, color Doppler echocardiography, angiography, computed tomography (CT) scan, and magnetic resonance imaging (MRI). The imaging focuses on the area that is painful or where there is a mass.
Treatment and Therapy
The treatment for mycotic aneurysms is antibiotics and surgery. The antibiotics used will depend on the bacteria involved. If the bacterium has not been identified, antibiotics will be chosen based on the likely bacteria. A brain mycotic aneurysm sometimes requires the aneurysm be blocked off with tiny metal coils to prevent rupture. This endovascular treatment has grown in popularity and may be used for mycotic aneurysms in other areas of the body as well.
Mycotic aneurysms require surgery to remove the infective debris and to replace or bypass the damaged artery. Sometimes, cardiac valve replacement is required too. A combination of the listed treatments is likely used to treat mycotic aneurysms.
Prevention and Outcomes
There is no way to prevent a mycotic aneurysm. It is thought that avoiding Salmonella infections of the gastrointestinal tract can decrease the likelihood of contracting a Salmonella infection, including a mycotic aneurysm, in other parts of the body. Salmonella infections are contracted by contact with infected chickens, pigs, and eggs.
Bibliography
Ahsan, Humera, et al. “Cerebral Fungal Infection with Mycotic Aneurysm of Basilar Artery and Subarachnoid Haemorrhage.” Singapore Medical Journal, vol. 50, no. 1, 2009, pp. E22-25. https://ecommons.aku.edu/cgi/viewcontent.cgi?article=1054&context=pakistan‗fhs‗mc‗radiol. Accessed 20 Nov. 2024.
Hoffman, Gary S., and Cornelia M. Weyland, eds. Inflammatory Diseases of Blood Vessels. Marcel Dekker, 2002.
Majeed, Hafsa. “Mycotic Aneurysm - StatPearls.” NCBI, 10 July 2023, www.ncbi.nlm.nih.gov/books/NBK560736. Accessed 18 Nov. 2024.
“Pseudoaneurysm and Mycotic Aneurysm.” Frankel Cardiovascular Center, www.umcvc.org/conditions-treatments/pseudoaneurysm-and-mycotic-aneurysm. Accessed 18 Nov. 2024.