Intra-abdominal abscesses -- either single or multiple -- are infected pockets of fluid (collections of pus) that occur within the abdominal cavity.

Intra-abdominal abscesses can be caused by a ruptured appendix, ruptured diverticula, intestinal parasitism (Entamoeba histolytica), and other conditions.

Risk factors for intra-abdominal abscesses include any history of abdominal infectious processes such as appendicitis, diverticulitis, perforated ulcer disease, or any operation that involves contamination of the abdominal cavity, foreign bodies or dead tissue.

Depending on the location, patients with intra-abdominal abscess may have fever and chills, abdominal pain and distention, weakness, anorexia (lack of appetite), nausea, and occasionally vomiting, rectal tenderness and fullness, or diarrhea.

The white blood cell count may be elevated on a complete blood count test. A CT scan of the abdomen will usually reveal an intra-abdominal abscess. In addition, after a CT scan, a needle may be placed through the skin into the abscess cavity to confirm diagnosis and treat the abscess. Liver function tests, abdominal x-ray, and sonogram may also be helpful in diagnosing abscess.

Sometimes laparotomy (opening of the abdomen, which is done under general anesthesia) may be necessary for diagnosis.

Treatment of an intra-abdominal abscess requires intravenous antibiotic therapy and drainage. Drainage involves placing a needle through the skin in the abscess cavity, usually under radiological (x-ray) guidance. The drain is then left in place for days or weeks until the abscess resolves.

Occasionally, abscesses cannot be safely accessed this way. In such cases, an operation is necessary. An incision is made in the abdomen under general anesthesia (the patient is unconscious and pain-free). The abscess cavity is drained and washed. A drain is left in the abscess cavity, which remains in place until the infection resolves.

Whatever the drainage approach, it is important to identify and address the underlying condition that caused the abscess.

The outlook depends on the original cause of the abscess and the degree of infection present. Generally, drainage is successful in treating localized intra-abdominal abscesses.

Complications include recurrent abscesses, spontaneous rupture of an abscess, and occasionally, spread of the infection to the blood stream and widespread infection.

Call your physician for any severe abdominal pain, fevers, nausea, vomiting, or changes in bowel habits.