An intra-abdominal abscess can develop from a wide variety of causes that lead to an infection of the peritoneal cavity (peritonitis) due to :
- Direct spread from abdominal organs
- Perforation of abdominal organs
- Perforation of peptic ulcer
- Perforation of the colon (perforated bowel)
- Perforation of diverticulitis
- Rupture of an abscess in abdominal organs into the peritoneal cavity
- Rupture of abscess in appendix, spleen and liver, gangrenous gall bladder, gangrene of intestine
- Penetrating abdominal injury
- Post-operative infection
An intra-abdominal abscess usually affects patients with predisposing diseases of the abdominal organs. It may also develops after abdominal surgery or infection of the abdominal cavity (peritonitis). The type and the number of organisms associated with an abscess vary with the affected organ that leads to the formation of an intra-abdominal abscess. An abscess resulting from upper gastrointestinal tract perforations cause less severe sepsis compared to the perforations in the lower gastrointestinal tract. The microorganisms in the upper part of gastrointestinal tract are fewer in number and include only a few varieties like streptococci and a few gram negative bacilli. The lower part of thegastrointestinal tract has large number of microorganisms belonging to a wide variety of species.
Microorganisms that Cause Intra-Abdominal Abscesses
An intra-abdominal abscess is usually associated with a mixture of microorganisms. It includes organisms like aerobic bacteria (Escherichia coli, Klebsiella and Proteus species), and anaerobic bacteria (Bacteriodes, Clostridium species) which are normally found in the intestines. Fungi, like the Candida species, may cause an abscess in some patients who have been on prolonged antibiotic treatment. Protozoa like amoeba may be found in intra-abdominal abscess resulting in association with rupture of amoebic liver abscess. Peritoneal infections resulting from penetrating injuries of abdomen may lead to bacteria that are naturally found on the skin causing the abscess.
Pelvic abscess which follows pelvic inflammatory disease (infections seen in reproductive organs of women) can be associated with gonococci (gonorrhea causing bacteria), anaerobic bacteria or sometimes Chlamydia.
Signs and Symptoms of an Intra-Abdominal Abscess
Most patients with intra-abdominal abscess suffer from persistent abdominal pain and tenderness over the area where the abscess is collected. There may also be episodes of high fever with sweating. Vomiting and a loss of appetite may also be part of the clinical presentation with weight loss in long standing cases. At times there can be only vague symptoms like gastrointestinal dysfunction and fever.
Sometimes the symptoms in patients with an intra-abdominal abscess following abdominal surgery may be masked. This could be a result of pain-killers (analgesics) and antibiotics that are administered post-operatively. The pain and fever associated with an abscess may be palliated by analgesics while antibiotic use can partially suppress the infection. The symptoms may suddenly become evident after discontinuing the medication.
Some of the symptoms are specific to the location of the abscess. With a subphrenic abscess, patients may experience persistent hiccups, shoulder pain or certain lung complications like a pleural effusion (fluid around the lungs) or pleuritis. A pelvic abscess can lead to frequent diarrhea, or ineffective painful straining during bowel movements (tenesmus).
Occasionally, patients with a deep seated abscess patients may only have some supportive findings like a raised white blood cell (WBC) count and bacteria may be detected blood at times.