An abscess is a localized collection of pus, a thick fluid composed of dead white blood cells, bacteria, and tissue debris. This pocket forms as the body’s immune system attempts to contain a bacterial infection. When this occurs in the upper abdomen, near the stomach, it is referred to as a gastric or abdominal abscess, and it represents a serious medical issue. The infection needs prompt medical attention because, if left untreated, the abscess can expand, rupture, and potentially lead to a life-threatening systemic infection called sepsis.
Defining Gastric and Abdominal Abscesses
An abdominal abscess is a confined accumulation of infected fluid and pus within the abdominal cavity, often walled off by surrounding organs and inflammatory tissue. When discussing the stomach region, it is helpful to distinguish between two types based on their anatomical location.
The first is an intramural gastric abscess, an extremely rare condition where pus collects directly within the wall of the stomach itself. The bactericidal effect of stomach acid naturally protects the inner lining, making this type of abscess uncommon.
The second, and far more common type, is an abscess located near the stomach in the surrounding abdominal space, often termed a perigastric or subphrenic abscess. These are localized collections that form in the peritoneal cavity, the space between the abdominal organs. The body attempts to isolate the infection by forming an inflammatory barrier. These abscesses frequently settle in dependent areas, such as beneath the diaphragm (subphrenic) or behind the stomach in the lesser sac.
Underlying Causes and Risk Factors
The formation of an abscess in the upper abdomen is typically the result of a process that allows bacteria, usually from the gastrointestinal tract, to escape into the sterile abdominal cavity. One significant cause is the perforation of a hollow organ, such as a peptic ulcer that eats through the stomach or duodenum wall. This event spills highly concentrated bacteria and digestive contents into the surrounding space, overwhelming the local defenses.
Complications following abdominal surgery are another major source, especially after procedures involving the stomach, intestines, or gallbladder. A leak at a surgical connection site, known as an anastomotic leak, can allow intestinal bacteria to seed the abdominal space. Inflammatory conditions also raise the risk, as diseases like pancreatitis or severe diverticulitis can cause infection to spread beyond the original organ. Furthermore, severe abdominal trauma can compromise tissue integrity and introduce bacteria into the area.
Recognising the Signs
The symptoms of an abscess in the stomach area can be non-specific, often mimicking other less serious conditions, but they warrant immediate medical evaluation. A persistent and elevated fever, often accompanied by chills, is one of the most consistent signs of a deep-seated infection.
Patients typically experience localized abdominal pain, which can be dull or sharp, and is often confined to the upper abdomen near the abscess site. This pain may worsen with movement, coughing, or deep breaths, signaling inflammation of the surrounding peritoneal lining. Other common indications include nausea, vomiting, and a loss of appetite, which occur because inflammation disrupts normal digestive function. General feelings of weakness and overall malaise also frequently accompany the localized symptoms.
Diagnosis and Medical Management
Confirming the presence of an abdominal abscess begins with laboratory tests to identify signs of infection. A complete blood count typically reveals an elevated white blood cell count, indicating the immune system is actively fighting a bacterial invader. Blood tests also check for elevated inflammatory markers, such as C-reactive protein.
Imaging studies are necessary to precisely locate and characterize the abscess. A contrast-enhanced Computed Tomography (CT) scan is the most reliable method for visualizing the abscess, providing detailed cross-sectional images of the fluid collection. Ultrasound may also be used to quickly identify fluid pockets.
The definitive medical management involves a two-pronged approach: antibiotics and drainage. Aggressive, broad-spectrum antibiotic therapy is initiated immediately to control the infection and prevent its spread. However, antibiotics alone are often insufficient because the thick wall of the abscess limits their penetration into the core of the pus.
The pus must be physically removed through drainage. Percutaneous drainage (PCD) is the preferred, minimally invasive technique, where a catheter is inserted through the skin into the abscess using imaging guidance, such as CT or ultrasound. This drain remains in place for days or weeks to allow the pus to continually drain out. If the abscess is difficult to access safely or if an underlying issue requires repair, open surgical drainage may be necessary.