Epiploic appendagitis (EA) is a condition causing acute abdominal pain due to the inflammation of small, fat-filled pouches called epiploic appendages, which are attached to the outside of the large intestine. Although their function is not fully understood, this inflammation is typically benign and self-limiting. EA is relatively rare and is often mistaken for more serious causes of abdominal discomfort, such as appendicitis or diverticulitis.
The Immediate Cause of Inflammation
The root of epiploic appendagitis is a mechanical event that cuts off the blood supply to one of the appendages. These appendages are small, finger-like projections of adipose tissue (fat) attached to the outer wall of the colon by a narrow stalk containing blood vessels. Most people have between 50 and 100 of these structures distributed along the large intestine, particularly on the sigmoid colon and the cecum.
The primary mechanism leading to inflammation is torsion, which is the twisting of the appendage on its vascular stalk. This twisting obstructs blood flow, causing ischemia (a lack of oxygen) within the fatty tissue. The resulting tissue death (necrosis) triggers a localized inflammatory response, which causes the severe pain.
A secondary, less common cause is spontaneous venous thrombosis, where a blood clot forms within the small draining vein of the appendage. This clot blocks blood outflow, causing congestion and leading to the same ischemic injury and subsequent inflammation. Regardless of the trigger, the result is a sterile inflammation confined to the appendage, distinguishing it from infectious conditions like bacterial diverticulitis.
Predisposing Factors
While inflammation is caused by a mechanical event, certain factors increase susceptibility to epiploic appendagitis. It is most frequently diagnosed in adults aged 20 to 50, with a slight predominance in males. The presence of excess abdominal adipose tissue is a significant factor, as obesity or a high body mass index (BMI) can increase the size and number of epiploic appendages, making them more prone to twisting.
Any activity causing a sudden, intense change in intra-abdominal pressure can also increase the risk of torsion. This includes strenuous physical exertion or intense exercise, which may precipitate the twisting of an appendage on its stalk. Rapid changes in weight, whether gain or loss, may also alter the anatomy of the appendages, predisposing them to injury. Additionally, other abdominal inflammatory conditions, such as diverticulosis, are sometimes associated with EA development.
Recognizing the Signs and Diagnosis
Symptoms typically begin with the sudden onset of acute, non-migratory abdominal pain highly localized to one spot. Since the majority of appendages are on the sigmoid colon, pain often occurs in the left lower quadrant, mimicking acute diverticulitis. If inflammation occurs near the cecum, the pain is felt in the right lower quadrant and may be mistaken for acute appendicitis.
A distinguishing feature is the absence of systemic symptoms common in other abdominal infections. Patients typically do not have a fever, and laboratory tests often show normal or only mildly elevated white blood cell counts. The pain is constant and worsened by movement, coughing, or deep breathing. Physical examination usually reveals only localized tenderness without the rebound tenderness associated with widespread peritoneal irritation.
A definitive diagnosis relies heavily on medical imaging, with a Computed Tomography (CT) scan of the abdomen being the gold standard. The CT scan is essential for ruling out more serious conditions and confirming the benign nature of the inflammation. The characteristic finding is a small, oval-shaped lesion of fat density, usually measuring 1.5 to 3.5 centimeters, located adjacent to the colon wall. This fatty lesion is often surrounded by a thin, bright rim, known as the “hyperattenuating ring sign,” representing the inflamed lining. Sometimes, a tiny high-density spot, or “central dot sign,” is visible within the lesion, indicating the thrombosed central vein.
Managing the Condition and Outlook
Treatment for epiploic appendagitis is almost always conservative, as the condition is self-limiting and resolves without aggressive intervention. The primary goal is to control localized pain and inflammation while the body naturally resolves the injured tissue. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are highly effective for pain management because the underlying pathology is sterile inflammation.
Since the condition is not caused by a bacterial infection, antibiotics are unnecessary and avoided. Patients are typically managed on an outpatient basis and advised to limit strenuous activity until symptoms subside. The inflammatory process resolves as the infarcted appendage tissue is absorbed by the body, usually within a few days to two weeks. Full recovery without long-term consequences is the expected outcome. Surgery is reserved only for extremely rare cases where the diagnosis is uncertain or complications, such as bowel obstruction, are suspected.