An intra-abdominal abscess is an infected pocket of fluid and pus located inside the belly area (abdominal cavity). There may be more than one abscess.

An intra-abdominal abscess can be caused by a ruptured appendix, ruptured diverticula, a parasite infection in the intestines (Entamoeba histolytica), or other condition.

Risk factors include a history of appendicitis, diverticulitis, perforated ulcer disease, or any surgery that may have infected the abdominal cavity.

Depending on the location, symptoms may include:

• Abdominal pain and distention
• Chills
• Diarrhea
• Fever
• Lack of appetite
• Nausea
• Rectal tenderness and fullness
• Vomiting
• Weakness

A complete blood count may show a higher-than-normal white blood count.

A CT scan of the abdomen will usually reveal an intra-abdominal abscess. After the CT scan is done, a needle may be placed through the skin into the abscess cavity to confirm the diagnosis and treat the abscess.

Other tests may include:

• Abdominal x-ray
• Liver function tests,
• Ultrasound of the belly area

Sometimes surgery called a laparotomy may be needed to diagnose this condition.

Treatment of an intra-abdominal abscess requires antibiotics (given by an IV) and drainage. Drainage involves placing a needle through the skin in the abscess, usually under x-ray guidance. The drain is then left in place for days or weeks until the abscess goes away.

Occasionally, abscesses cannot be safely drained this way. In such cases, surgery must be done while the patient is under general anesthesia (unconscious and pain-free). A cut is made in the belly area (abdomen), and the abscess is drained and cleaned. A drain is left in the abscess cavity, and remains in place until the infection goes away.

It is always important to identify and treated the cause of the abscess.

The outlook depends on the original cause of the abscess and how bad the infection is. Generally, drainage is successful in treating intra-abdominal abscesses that have not spread.

Complications include:

• Return of the abscess
• Rupture of an abscess
• Spread of the infection to the bloodstream
• Widespread infection

Call your doctor if you have severe abdominal pain, fevers, nausea, vomiting, or changes in bowel habits.

Fry RD, Mahmoud N, Maron J, Ross HM, Rombeau J. Colon and Rectum. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. St. Louis, Mo: WB Saunders; 2008:chap.50.

Marrero F, Qadeer MA, Lashner BA. Severe complications of inflammatory bowel disease. Med Clin North Am. May 2008; 92(3): 671-86, ix.