Abscess and Fluid Drainage

Using image guidance to place drainage tubes

An abscess is an area where pus has accumulated due to an infection, or sometimes due to a foreign material in the body. Abscesses can form anywhere in the body and are a natural response that serves to isolate bacteria or other infectious agents. The puss that collects is a mixture of dead white blood cells and other fluids that result from the immune reaction to the infection.

Drawing off built-up fluid is an essential part of healing.

Sometimes draining the fluid within an abscess can help the healing process, and sometimes this step can be a critically important one in containing an infection. Interventional radiologists can drain abscesses wherever they occur. As with biopsies, they normally perform this step by inserting needles through the skin and guiding the positioning of these needles with various types of imaging, sometimes followed by insertion of a catheter to draw fluid out. (If indicated, a drainage catheter may be placed at the same time that a needle aspiration is performed.) Ultrasound and CT are common forms of imaging used for this purpose. Various forms of angiography may also be employed. Interventionalists sometimes insert a tube and leave it in place temporarily to drain the abscess.

In addition, such drainage techniques may also be required to remove other types of accumulation of body liquids in pockets or areas where congestion, blood, or fluid from serum may collect. Abscesses and fluid accumulations may result from injury, from exposure to bacteria or parasites, from complications of surgery, or from chronic processes such as inflammatory conditions or organ disease.   Fluid accumulations can be life threatening, as in cases were they compromise the function of organs and create organ failure, especially as regards the heart and lungs.

Types of drainage provided by interventional radiologists include:

• chest tube (tube thoracostomy, typically to drain fluid from around the lungs or heart, due to surgery or injury to the chest, an infection in the chest, congestive heart failure, lung problems, or chemotherapy for lung cancer);

• ascites drainage (placement of a catheter or port in the abdomen or pelvis to remove fluid);

• transrectal or transvaginal abscess drainage (accessing abscesses through the vagina or rectum, to drain deep pelvic areas).

The procedures are usually require only local anesthesia and sometimes sedation, and can normally be performed on an outpatient basis. Patients with tube placement may be required to remain in a prone position for several hours while the tube drains fluid into a collection bag. Other patients may be required to maintain the tube-and-bag drainage from weeks or months to continue or complete the drainage.

The fluid material removed is usually sent to the pathology lab for analysis. The team will often combine drainage with antibiotic therapy, and this treatment can be effective in resolving an abscess within a few days. (Sometimes the specialist may also inject a scarring agent into the abscess cavity through the drainage catheter to decrease the likelihood of fluid accumulating in the area again.)  Without these procedures, patients would often have to undergo surgery to achieve drainage of these areas.