Aortoenteric Fistula Definition, Symptoms, Causes, Treatment

Aortoenteric Fistula Definition, Symptoms, Causes, Treatment

Aortoenteric Fistula Definition

Aortoenteric fistulae, often known as AEF for short, are aberrant connections that can form between the gastrointestinal tract and the aorta or major arterial branches of the aorta in patients who have or have not undergone previous aortic surgery. Surgery is the only truly effective treatment for patients with this diagnosis due to their poor prognosis.

The aorta is the body’s largest artery. It is loaded with oxygen-rich blood that is pumped throughout the body, and it originates in the left ventricle of the heart, which is the primary chamber that is responsible for pumping blood out of the heart. A tube-like, abnormal connection between two body components is known as a fistula. An Aortoenteric Fistula is the medical term for a connection that forms between the aorta and a loop of the bowel that is located close to the aorta.

There are two distinct varieties of AEF, and they are as follows:

  • When an untreated chronic aortic aneurysm affects or destroys the aorta and bowel tissue, this is referred to as primary.
  • Inflammation from a previous aortic graft surgery near a section of the bowel causes the secondary type of AEF. This is the more prevalent type of AEF than primary AEF.

Aortoenteric Fistula Symptoms

Aortoenteric fistula, often known as AEF, is an extremely uncommon condition that has the potential to be fatal. In clinical practice, Aortoenteric Fistula (AEF), an uncommon cause of gastrointestinal bleeding, is frequently misdiagnosed. The common symptoms of this condition include bleeding in the gastrointestinal tract, pain in the abdomen and back, loss of weight, anorexia, and fever. A small amount of hematemesis can also occur as a “herald bleed” in some patients. CT scans are mostly used for the diagnosis of a fistula and they also detect if there is an abscess or infection in the abdomen. 

Aortoenteric Fistula Definition, Symptoms, Causes, Treatment

Aortoenteric Fistula Causes

Aortoenteric fistulas (AEFs) are either caused by primary or secondary causes. Initial fistula development is caused by a combination of frictional mechanical forces and aortic inflammation. In primary cases, aneurysm formation is the most prevalent cause of mechanical thinning of the aorta and enteral outermost layers because they rub together with each subsequent heart pulsation and gastrointestinal peristalsis, respectively. This mechanical breakdown can also be caused by or made worse by foreign bodies and tumors. Several etiologies, including sepsis, syphilis, mycotic aneurysms, salmonella, and tuberculosis, are also linked to inflammation that can worsen this nearby erosion.

Secondary AEFs develop after open or endovascular aortic surgical intervention, most commonly after the installation of synthetic aortic graft material. Mechanical friction between the graft material and the adjacent enteral tract mostly causes erosion if soft tissue is not present. The development of a fistula, sepsis and graft infection can quickly exacerbate this erosion as enteral bacteria move into the bloodstream and seed the graft. Most AEFs form in one place, but there are also reports of more than one fistula at the same time. The most frequent location for the development of an AEF is the duodenum, namely the third and fourth segments where the aorta and duodenum are most closely connected.

Aortoenteric Fistula Treatment

The treatment of an AEF is dependent on a prompt diagnosis and an aggressive surgical approach. Initial hemodynamic support and ongoing resuscitation are needed to best prepare the patient for the operating room. When AEF is diagnosed, blood cultures need to be taken, and broad-spectrum antibiotics must be started before being narrowed after specific microbial growth. If Clostridium Septicum is found in cultures, a colonoscopy is usually performed to look for cancer. Basic lifesaving procedures need to be carried out in the event of persistent bleeding, such as reversing anticoagulation and administering fresh frozen plasma plasma, platelets and  red blood cells in an equal 1:1:1 ratio.

The only treatment that is successful in curing Aortoenteric fistula is emergency surgery. Aortoenteric fistulas and abdominal infections are detected by CT scans. It is also possible to use endovascular repair, and studies have demonstrated positive results in this area. To prevent infection and minimize inflammation, patients are mostly given broad-spectrum antibiotics after surgery.

Surgical care is carried out either through a classic invasive open technique, such as a laparotomy with or without thoracotomy or through a less invasive endovascular aorta repair (EVAR).

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