An abscess is a serious medical condition indicating a localized, contained infection within the abdominal cavity. While the term “stomach abscess” is commonly used, the condition most often refers to an intra-abdominal abscess, which is a collection of infected material located near the stomach or within the wider abdominal space. This collection of pus requires swift medical intervention to resolve the underlying bacterial infection.
What is an Abdominal Abscess
An abscess is a pocket of pus and infected fluid that develops when the immune system attempts to isolate a bacterial infection by forming a wall of inflamed tissue around it. This infected material contains dead white blood cells, bacteria, and tissue debris. The bacteria responsible often originate from the gut, such as Escherichia coli (E. coli), since the gastrointestinal tract is a major source of contamination.
The collection of pus is usually found in the spaces surrounding the organs, rather than strictly within the stomach wall itself. These intra-abdominal abscesses can form in various locations, including the subphrenic space (below the diaphragm), the pelvis, or interloop spaces between the small intestines. If left untreated, the bacteria can multiply, potentially spreading the infection and leading to life-threatening conditions like sepsis.
Recognizing the Signs and Underlying Causes
The symptoms of an intra-abdominal abscess vary based on the specific location and size of the infected pocket. Persistent or worsening abdominal pain is a primary symptom, which may be localized to the area of the abscess or feel more diffuse. A high fever, often accompanied by chills, is another strong indicator of a contained infection.
Patients frequently experience nausea, vomiting, and a loss of appetite, which can lead to weight loss. An abscess located near the diaphragm (subphrenic) may produce symptoms like shoulder pain, chest pain, or a nonproductive cough due to irritation of nearby structures. Pelvic abscesses, located lower in the abdomen, can cause changes in bowel movements, rectal tenderness, or an urgent need to urinate.
These abscesses are almost always secondary to a preceding event or medical condition that allowed bacteria to escape into the abdominal cavity. The causes are often linked to a break in the integrity of the gastrointestinal tract, allowing normal gut flora to contaminate the sterile abdominal space. Common underlying causes include the rupture or perforation of an organ, such as a perforated appendix, a perforated ulcer, or a ruptured diverticulum from diverticulitis.
Post-surgical complications are a frequent cause, particularly after abdominal surgeries where a leak from an intestinal connection (anastomosis) allows contents to spill into the abdomen. Trauma, such as a penetrating injury to the abdomen, can also introduce bacteria and lead to abscess formation. Conditions like Crohn’s disease or pancreatitis, which cause intense inflammation, may also precede the development of an abscess. The time between the initial event and abscess formation can be days to weeks.
Medical Confirmation and Treatment
Diagnosing an intra-abdominal abscess begins with clinical suspicion, especially in a patient with recent abdominal surgery, trauma, or a history of an inflammatory condition. Laboratory tests, such as a complete blood count, typically show an elevated white blood cell (WBC) count, indicating a systemic immune response. Blood cultures may also be taken to identify the specific bacteria causing the infection.
Imaging studies are the definitive way to confirm the presence and exact location of the pus collection. A computed tomography (CT) scan of the abdomen is the most useful diagnostic tool because it provides detailed images that clearly differentiate the pus-filled pocket from surrounding tissues. Ultrasound may also be used, but the CT scan remains the gold standard for full localization.
Treatment relies on two main therapeutic pillars: physical drainage and antibiotic therapy. Drainage is considered the primary intervention because antibiotics alone often struggle to penetrate the thick wall of the abscess and the infected material within. The most common method is percutaneous drainage, where a small catheter is inserted through the skin into the abscess cavity under the guidance of a CT scan or ultrasound.
The catheter allows the pus to be removed and the infected space to be flushed, providing immediate relief and source control. Broad-spectrum antibiotics are started immediately to combat the polymicrobial infection, often before the specific bacteria are identified. The antibiotic regimen is then tailored based on the culture results from the drained pus to effectively clear any remaining infection. Surgical drainage may be necessary if the abscess is complex, contains thick debris, or is in a location that is inaccessible to a percutaneous catheter.