Abdominal Abscess

Overview

An abdominal abscess is a pocket of pus that collects inside the abdomen. Pus is a mixture of dead tissue, white blood cells, and bacteria, and the body walls it off to try to contain an infection. The abscess can sit among the loops of bowel, against an organ such as the liver or spleen, or in a corner of the abdominal cavity.

An abscess often develops after an organ becomes infected or bursts, after abdominal surgery, or because of inflammatory bowel disease or other infections. Because the infection is sealed off, antibiotics alone frequently cannot clear it, and the pus usually has to be drained. Left untreated, an abdominal abscess can spread infection and become life-threatening.

Symptoms

Symptoms can develop gradually or come on quickly, and they often reflect both the infection and its location.

• Abdominal pain or tenderness, sometimes localized to one area
• Fever, chills, and sweats
• Nausea, vomiting, or loss of appetite
• A general feeling of being unwell or fatigued
• A swollen or distended abdomen
• Changes in bowel habits

Warning signs that the infection is spreading include high fever, a rapid heartbeat, confusion, very low blood pressure, and severe pain. These suggest the infection may be entering the bloodstream and need emergency care.

Causes

An abdominal abscess forms when bacteria are released into the abdominal cavity and the body walls off the infection. Common causes include:

• Burst or inflamed organs: A ruptured appendix, inflamed diverticula, or perforated bowel can spill bacteria into the abdomen.
• After surgery: Abscesses can form following abdominal operations, especially if there is a leak.
• Inflammatory and infectious bowel disease: Crohn's disease and severe infections can lead to abscesses.
• Gallbladder, pancreas, or liver infection: Severe infections of these organs can produce abscesses.
• Injury: Trauma to the abdomen that damages organs.

Risk Factors

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

Diagnosis

Diagnosis combines examination, blood tests, and imaging to find and locate the abscess:

• Physical examination: Checking for tenderness, swelling, and fever.
• Blood tests: A raised white blood cell count and inflammatory markers point to infection.
• CT scan: The most reliable way to find an abdominal abscess, define its size, and plan drainage.
• Ultrasound: Useful for some locations and to guide drainage.

Imaging also helps identify the underlying cause, such as a burst appendix or diverticulitis, so it can be treated as well.

Treatment

Treatment usually requires removing the pus as well as treating the infection.

• Drainage: Most abscesses are drained, often with a thin tube placed through the skin under CT or ultrasound guidance; some need surgery.
• Antibiotics: Given to control the infection, though they work best once the pus is drained.
• Treating the cause: The underlying problem, such as a burst appendix or diverticulitis, is addressed, sometimes with surgery.
• Supportive care: Fluids, pain relief, and monitoring, especially if the infection has spread.

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

Prevention

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

When to See a Doctor

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

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.