An area of increased attenuation within the mesenteric fat in the right upper quadrant surrounding an area of diminished attenuation was noted, arising from the transverse colon (Figures 3 and 4).
The findings were consistent with a diagnosis of epiploic appendagitis. The epiploic appendages (variably termed "appendices epiploicae") are pedunculated adipose projections from the serosal surface of the colon. They appear in the fifth month of fetal life, and each appendage contains a venule and one or two arterioles branching off of the vasa recta.[1,2] They are multiple (up to 100) and form two rows that parallel the anterior and posterior taenia coli and run from the cecum to the rectosigmoid junction; they are most prominent along the descending and sigmoid colon.[1,3]
Each epiploic appendage is approximately 1-2 cm thick and 0.5-5 cm in length,[1,4] with an average length of 3 cm (although appendages as long as 15 cm have been reported). They are frequently found in association with colonic diverticula and are only visible on diagnostic imaging when surrounded by inflammatory fluid.
The term "primary epiploic appendagitis" is reserved for cases resulting from spontaneous torsion, thrombosis, ischemia, or inflammation of an epiploic appendage.[1,2,3] Two central factors contribute to the appendages' propensity for torsion, followed by ischemia and/or infarction: They are freely mobile and they have a limited blood supply, consisting of two narrow end arteries and one tortuous vein passing through a narrow pedicle base.
The sequence of clinical events is similar to that of appendicitis—namely, an obstruction of some sort, followed by ischemia, thrombosis, and, finally, necrosis. The signs of torsion and necrosis are rarely seen during laparotomy.
Secondary epiploic appendagitis is caused by inflammation that extends from adjacent structures (as in diverticulitis, appendicitis, or cholecystitis).[2,3]
Vesalius was the first to recognize the appendices epiploicae in 1543, but their potential significance was not recognized until 1853, when Virchow proposed that their detachment may be a source of loose intraperitoneal bodies.[5,7,8] These loose appendages may calcify and may be later seen as incidental findings on diagnostic imaging or laparoscopy; when found reattached to intraperitoneal organs, these epiploic appendages are known as "parasitized appendices epiploicae."
The exact role of these appendages is not known, although there are various plausible theories as to their function. Epiploic appendages may protect and cushion the colon, like a small omentum; they may act as a blood depository during colonic vessel contraction; they may store fat; and they may even have a role in absorption and the immune response.[1,9,10] They are also used in surgery to protect suture lines and close perforations.
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Cite this: Noah Gudel, Lisa M. Rock. Gastro Case Challenge: Excruciating Abdominal Pain in a Woman Taking Benzodiazepines and Narcotics - Medscape - Dec 07, 2022.