Epiploic Appendagitis

Epiploic appendagitis is inflammation and ischemia of an epiploic appendage, a fat-filled peritoneal pouch (1 to 2 cm thick, 2 to 5 cm long) on the serosal surface of the colon that is supplied by one or two end arteries and drained by a tortuous vein. Primary torsion or spontaneous venous thrombosis of the appendage causes ischemic necrosis and local peritoneal inflammation. Secondary forms follow adjacent diverticulitis, appendicitis or cholecystitis.

It is an uncommon cause of acute abdominal pain (about 1% of suspected diverticulitis and 0.3 to 1% of suspected appendicitis), and often unrecognized. Peak age is 20 to 50 years, with a slight male predominance. Obesity and hernia are risk factors. Sites: the sigmoid colon (about 60%), the descending colon, the ileocecal region and the transverse colon.

The disorder is self-limiting, with resolution in 1 to 2 weeks. Complications are rare: adhesions causing obstruction, intraperitoneal loose body (calcified appendage), abscess, and peritonitis. Recurrence occurs in 3 to 4%.

• Acute, localized, non-migratory sharp pain, usually in the left or right lower quadrant, without marked nausea, vomiting or anorexia
• A localized tender point, sometimes a palpable mass, and rebound over the site
• Normal temperature, normal or minimally raised white cell count and CRP
• Pain that worsens on coughing or on position change
• Red flags: fever with a high white cell count, generalized peritonitis, hemodynamic instability, and bowel obstruction

1. CT with intravenous contrast: an ovoid, fat-attenuation lesion (1.5 to 3.5 cm) adjacent to the antimesenteric surface of the colon, with a thin hyperattenuating rim (the inflamed visceral peritoneum), a central hyperattenuating dot (the thrombosed vessel, the "central dot sign"), and surrounding fat stranding. The colon wall is normal or mildly thickened.
2. Ultrasound: a non-compressible, hyperechoic ovoid mass at the point of maximum tenderness, with absent Doppler flow.
3. Blood tests: white cell count, CRP and urinalysis, to exclude other diagnoses.
4. Colonoscopy at 6 to 8 weeks when there is diagnostic doubt or a mass lesion.

Differentials: acute diverticulitis, acute appendicitis, omental infarction, mesenteric panniculitis, Crohn disease, ovarian torsion, ureteric colic, cholecystitis, colon cancer.

Conservative care (the standard)

• Reassurance and outpatient management when the CT diagnosis is clear.
• Ibuprofen 400 mg orally every 8 hours with food for 7 to 10 days (avoid in peptic ulcer disease, renal impairment, heart failure and anticoagulation), with paracetamol 1 g orally every 6 hours (maximum 4 g a day) as adjunct.
• Children: ibuprofen 10 mg/kg orally every 8 hours and paracetamol 15 mg/kg orally every 6 hours.
• No antibiotics, as the disease is sterile.
• Early return to normal diet and activity, with resolution of pain within 1 to 2 weeks.
• Follow-up CT is unnecessary when the patient recovers.

Surgery (laparoscopic ligation and excision of the appendage)

• Recurrent or persistent pain beyond 3 weeks, doubt about diagnosis, obstruction, abscess or suspected torsion in a large appendage.
• Cefazolin 2 g IV before incision (children 30 mg/kg).
• Ligate the pedicle at the base with absorbable suture and remove the appendage, with inspection of the colon.
• Discharge within 24 hours.

Complications of surgery: wound infection, adhesions and rarely colonic injury.

Counsel on the benign course, on avoiding unnecessary admission and antibiotics, and on returning for fever or worsening pain. Recurrence risk is low.