Intra-abdominal Abscess

Overview

An intra-abdominal abscess is a pocket of pus that collects inside the abdominal cavity. When bacteria escape into the abdomen, the body tries to contain the infection by walling it off, forming an abscess. These collections can sit between loops of bowel, beneath the diaphragm, in the pelvis, or against organs such as the liver, spleen, or pancreas.

Because the pus is sealed off from the bloodstream, antibiotics alone often cannot clear an abscess, and the collection usually has to be drained. An untreated intra-abdominal abscess can enlarge, spread infection, and lead to widespread infection of the abdomen or bloodstream, so prompt diagnosis and treatment are important.

Symptoms

Symptoms can build up over days and depend partly on where the abscess sits.

• Abdominal pain or tenderness, sometimes focused in one area
• Fever, chills, and night sweats
• Nausea, vomiting, or loss of appetite
• Feeling generally unwell, tired, or run down
• A swollen abdomen or a tender lump
• Shoulder-tip pain or hiccups if the abscess sits under the diaphragm

Warning signs of spreading infection include high fever, a rapid heartbeat, confusion, fainting, and very low blood pressure. These suggest the infection may be entering the bloodstream and require emergency care.

Causes

An intra-abdominal abscess forms when bacteria reach the abdominal cavity and the body walls off the infection. Common sources include:

• Perforated organs: A burst appendix, perforated bowel, or inflamed diverticula can release bacteria.
• After surgery: Abscesses can develop following abdominal operations, especially with a leak.
• Inflammatory bowel disease: Crohn's disease can lead to abscesses.
• Organ infections: Severe infection of the gallbladder, pancreas, or liver.
• Injury: Trauma that damages abdominal organs.

Risk Factors

• Recent abdominal surgery
• A perforated organ such as a burst appendix
• Diverticulitis or inflammatory bowel disease
• Diabetes or a weakened immune system
• Severe pancreatitis or gallbladder infection
• Abdominal injury

Diagnosis

Doctors confirm and locate the abscess with a combination of tests:

• Examination: Checking for tenderness, swelling, and fever.
• Blood tests: A raised white blood cell count and inflammatory markers indicate infection.
• CT scan: The most reliable test to find an abscess, define its size and location, and plan drainage.
• Ultrasound: Helpful for certain locations and to guide drainage at the bedside.

Imaging also helps reveal the underlying cause so that it can be treated alongside the abscess.

Treatment

Treatment combines removing the pus with treating the infection and its cause.

• Drainage: Most abscesses are drained with a thin tube placed through the skin under CT or ultrasound guidance; some need surgical drainage.
• Antibiotics: Used to control the infection, working best once the pus has been drained.
• Treating the cause: Addressing the source, such as a burst appendix or diverticulitis, often with surgery.
• Supportive care: Fluids, pain relief, and close monitoring, particularly if the infection has spread.

With timely drainage and antibiotics, most people recover well, though recovery time depends on the cause and overall health.

Prevention

• Seek prompt care for severe abdominal pain so conditions like appendicitis are treated early
• Follow post-operative instructions and report fever or worsening pain after surgery
• Manage diverticulitis and inflammatory bowel disease
• Keep diabetes well controlled
• Complete prescribed antibiotic courses

When to See a Doctor

See a doctor promptly for abdominal pain with fever, chills, or a general feeling of being unwell, especially after recent abdominal surgery or a known infection. Seek emergency care if you have severe or rapidly worsening abdominal pain, high fever, a racing heart, confusion, fainting, or a rigid, very tender abdomen, as these can signal a spreading, life-threatening infection.

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine. Intra-abdominal abscess.
2. Mayo Clinic. Diverticulitis - Symptoms and causes.
3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Appendicitis.
4. Centers for Disease Control and Prevention (CDC). Sepsis.