Epiploic appendagitis

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 Epiploic appendagitis

1. Definition

Epiploic appendagitis (EA) is a benign, self-limiting inflammatory condition involving one or more epiploic appendages—small, fat-filled, peritoneal outpouchings arranged along the anti-mesenteric border of the colon. It results from either torsion or spontaneous venous thrombosis of an epiploic appendage, leading to ischemia and sterile fat necrosis. Though clinically it can mimic acute abdominal emergencies like appendicitis or diverticulitis, EA is usually managed conservatively.

2. Etiology and Causes

EA occurs due to a compromise of the blood supply to an epiploic appendage. The primary causes include:

A. Torsion of the epiploic appendage (Primary Epiploic Appendagitis)

  • Most common cause.
  • A long pedicle or sudden motion may lead to rotation and vascular compromise.
  • Results in venous outflow obstruction, congestion, ischemia, and localized inflammation.

B. Spontaneous Venous Thrombosis

  • Without torsion, occlusion of the draining vein can still lead to ischemia and necrosis.

C. Secondary Inflammation (Secondary Epiploic Appendagitis)

  • Adjacent inflammatory processes, such as diverticulitis, appendicitis, or pancreatitis, may secondarily inflame epiploic appendages.

3. Pathogenesis

Each epiploic appendage is supplied by a small end-artery and drained by a single vein. These appendages are:

  • 0.5–5 cm in length.
  • Number about 50–100, distributed from the cecum to the rectosigmoid junction.

Mechanism:

  1. Torsion or venous thrombosis occurs.
  2. This leads to vascular compromise, primarily venous outflow obstruction.
  3. Ischemic infarction and sterile fat necrosis follow.
  4. Local peritoneal inflammation results.
  5. A fibrinous exudate may cause adherence to adjacent structures or form a fibrous capsule in chronic stages.

4. Epidemiology

  • Incidence: Uncertain but likely underdiagnosed, as many cases are mistaken for diverticulitis or appendicitis.
  • Age: Typically presents between 20–50 years of age.
  • Gender: Slight male predominance.
  • Risk factors:
    • Obesity (increased fat content of appendages).
    • Sudden physical activity or trauma (torsion risk).
    • Hernias (strangulation of appendages).
    • Recent abdominal surgery or colonoscopy.

5. Clinical Symptoms

Although benign and self-limiting, EA often mimics more severe conditions due to acute, localized abdominal pain.

Key Features:

  • Onset: Sudden, non-radiating localized pain.
  • Location: Commonly in the left lower quadrant (LLQ) (sigmoid colon) or right lower quadrant (RLQ) (cecum).
  • Severity: Moderate to severe; sharp or stabbing.
  • Associated symptoms:
    • No or minimal fever.
    • No significant gastrointestinal symptoms.
    • Rarely nausea or anorexia.
    • No rebound tenderness or guarding usually.

Physical Exam:

  • Localized tenderness.
  • No peritoneal signs.
  • Normal bowel sounds.

6. Imaging Findings

CT Imaging (Gold Standard)


  • CT scan with contrast is diagnostic in >90% of cases.

Classic Findings:

  • Oval-shaped fat-density lesion (1.5–3.5 cm) adjacent to the colon.
  • Surrounded by hyperattenuating rim ("hyperattenuating ring sign").
  • Often with a central high-density dot (representing a thrombosed vein).
  • Adjacent colonic wall: normal or mildly thickened.
  • Surrounding fat stranding is disproportionate to the small size of the lesion.
  • No significant lymphadenopathy.

CT Distribution:

  • Sigmoid colon (most common).
  • Cecum, ascending colon, transverse colon.

Ultrasound (less sensitive, operator-dependent)


  • Non-compressible, hyperechoic mass adjacent to the colon.
  • No central vascularity on Doppler.

MRI


  • Used infrequently.
  • T1: hyperintense fatty lesion with surrounding hypointense rim.
  • T2: hypointense rim with adjacent fat stranding.

7. Differential Diagnosis

EA must be differentiated from other causes of acute abdominal pain, including:

Left Lower Quadrant Pain:

  • Acute diverticulitis
  • Omental infarction
  • Colonic neoplasm

Right Lower Quadrant Pain:

  • Acute appendicitis
  • Cecal diverticulitis
  • Crohn’s disease
  • Mesenteric adenitis

Others:

  • Strangulated hernia
  • Meckel’s diverticulitis
  • Epiploic appendage torsion in inguinal hernia

8. Treatment

EA is a self-limiting condition and is almost always managed non-surgically.

Conservative Management:

  • NSAIDs: Ibuprofen, ketorolac for pain control.
  • Rest and supportive care.
  • No need for antibiotics unless secondary infection is suspected.
  • No role for surgery unless complications arise.

Indications for Surgery (Rare):

  • Persistent or worsening symptoms beyond 7–10 days.
  • Development of abscess or peritonitis (very rare).
  • Diagnostic uncertainty (laparoscopic exploration).

9. Prognosis

  • Excellent prognosis.
  • Most symptoms resolve within 3–14 days.
  • No long-term sequelae.
  • Recurrence is rare but reported in <5% of cases.
  • No increased risk of malignancy or chronic bowel disease.

10. Key Points for Clinicians

  • Avoid misdiagnosis as appendicitis or diverticulitis, especially to prevent unnecessary antibiotics or surgery.
  • CT imaging is crucial: Characteristic features help in accurate diagnosis.
  • Education is essential: Patients should be reassured about the benign nature.
  • Clinicians must include EA in the differential for localized, non-systemic, acute abdominal pain in adults.

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Case study: A 28-Year-Old Woman with Left Lower Quadrant Abdominal Pain  
Epiploic Appendagitis

History and Imaging Findings

  1. A 28-year-old woman with a known history of asthma presented with persistent pain in the left lower quadrant of the abdomen following a meal.

  2. She reported no fever, chills, nausea, vomiting, constipation, or rectal bleeding.

  3. She stated that she had experienced loose stools before the onset of pain; however, those symptoms subsequently resolved.

  4. A computed tomography (CT) scan was performed for further evaluation.


Quiz

  1. Which of the following is least appropriate to include in the differential diagnosis of left lower quadrant (LLQ) abdominal pain?
     (1) Diverticulitis
     (2) Omental infarction
     (3) Epiploic appendagitis
     (4) Nephrolithiasis
     (5) Pyelonephritis

Explanation: Pyelonephritis typically presents with flank pain rather than localized LLQ pain. The other choices are more likely to present with pain in the left lower quadrant.

  1. What is the most likely diagnosis in this patient?
     (1) Small bowel obstruction
     (2) Diverticulitis
     (3) Colitis
     (4) Nephrolithiasis
     (5) Epiploic appendagitis
     (6) Ulcerative colitis flare

Explanation: The presence of an oval area of fat attenuation with surrounding inflammatory soft tissue stranding on imaging is most consistent with epiploic appendagitis.

  1. What is the most appropriate treatment for this patient?
     (1) Ciprofloxacin and metronidazole
     (2) Meropenem
     (3) Non-steroidal anti-inflammatory drugs (NSAIDs)
     (4) Exploratory laparotomy and surgical resection
     (5) None of the above

Explanation: Epiploic appendagitis is a self-limiting condition that typically does not require antibiotics or surgical intervention. NSAIDs are the treatment of choice to help manage inflammation and pain.

Findings and Diagnosis
The CT images demonstrate an oval fat-density lesion adjacent to the sigmoid colon, surrounded by inflammatory changes. These findings are characteristic of epiploic appendagitis.

Findings
There is no evidence of bowel obstruction or diverticulitis. CT imaging reveals an ovoid fat-attenuation lesion with surrounding soft tissue stranding and mild adjacent fat infiltration anterior to the distal descending colon. These findings are consistent with epiploic appendagitis.

Differential Diagnosis

  • Colitis

  • Omental infarction

  • Gastroenteritis

  • Epiploic appendagitis

  • Diverticulitis

Diagnosis:
Epiploic appendagitis

Discussion

Epiploic Appendagitis

Epidemiology and Pathogenesis

Epiploic appendagitis is a relatively uncommon condition, most frequently seen in obese patients between the ages of 20 and 50. It is identified in approximately 1.3% of patients presenting with acute abdominal pain.

This condition arises from inflammation of the epiploic appendages, which are small, fat-filled, serosal outpouchings arranged along the colon, most commonly located near the sigmoid colon and the cecum. Due to their pedunculated shape and limited vascular supply, these structures are prone to torsion or venous thrombosis, leading to localized ischemia and subsequent inflammation.

Clinical Presentation

Symptoms typically consist of sharp, localized, non-migratory pain in the left or right lower quadrant of the abdomen. Focal tenderness is common, often with rebound tenderness but without guarding or rigidity. Notably, the absence of systemic symptoms such as high fever, nausea, vomiting, anorexia, or significant changes in bowel habits helps distinguish epiploic appendagitis from other causes of acute abdomen, such as appendicitis, cholecystitis, or diverticulitis.

Imaging Findings

CT Imaging:
On CT, the most characteristic finding is a 2–3 cm oval fat-density lesion adjacent to the colonic wall, usually in the pericolic region, surrounded by inflammatory fat stranding. The lesion often displays a hyperattenuating rim (the "hyperattenuating ring sign"). The adjacent bowel wall is usually of normal thickness, and there may be mild peritoneal thickening. A central high-density dot may also be seen within the lesion, representing a thrombosed vessel — a finding considered highly suggestive of epiploic appendagitis.

Ultrasound:
Placing the transducer over the point of maximal tenderness typically reveals a non-compressible, hyperechoic, oval mass with no internal vascularity, surrounded by a hypoechoic rim. The adjacent bowel wall is generally normal in thickness, and ascites is usually absent.

Treatment

Treatment of epiploic appendagitis is conservative, primarily involving non-steroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation control. The condition is self-limiting and typically resolves within several days to weeks without the need for antibiotics or surgical intervention.

References

(1)     Acute epiploic appendagitis: Radiologic and clinical features of 12 patients. Int J Surg Case Rep. 2016;28:219-222. doi:10.1016/j.ijscr.2016.09.015

(2)     Gaillard F. Epiploic appendagitis. Radiopaedia.org. Published June 1, 2022. https://radiopaedia.org/articles/epiploic-appendagitis.


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