Meckel diverticulitis: Do not forget the rule of twos

A 33-year-old male with a history of appendectomy arrived at the emergency department (ED) with progressive abdominal pain. The abdominal imaging (X-ray and ultrasound) and blood tests were normal, resulting in discharging the patient with conservative treatment. 72 hours later the patient came back due to persistence of symptoms. A new laboratory analysis highlights elevated CRP 24.25 mg/dL (normal, 0-0,5 mg/dL) and Leukocytes 13.1 x 10E9/L (normal, 4.8-10.8 x 10E9/L).

The patient underwent an abdominal ultrasound that showed a longitudinal section a hypoechoic tubular sac surrounded by increased echogenicity of the neighbouring fatty tissue (white arrows) near the ileum (Figure 1, A-B). For better characterization, an abdominal CT was performed (Figure 2, A-B: enhanced abdominal CT coronal reconstruction and Figure 3, A-D: enhanced abdominal CT axial and coronal reconstructions with maximum intensity projection and volume rendering MIP/VRT).

Contrast-enhanced abdominal CT showed a collection in the right flank with alimentary content of 28x26 mm, dependent on middle ileum loop, suggestive of Meckel diverticulum. Accompanied by marked inflammatory involvement of the adjacent mesenteric fat, free fluid, and gas at the edge of the diverticulum, probably due to focal discontinuity and contained perforation. Moderate thickening of the wall of the ileum loops near the diverticulum and retrograde bowel dilatation due to ileus secondary to the inflammatory involvement are observed, as well as small reactive lymphadenopathy in the root of the mesentery(Figure 3, A-D: VRT reconstruction). There was no signs of acute diverticular bleeding. Arterial and venous vascular branches were patent. There was no pneumoperitoneum.

Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract. It results from an incomplete obliteration of the vitelline duct leading to the formation of a true diverticulum arising from the antimesenteric border, usually within 40-100 cm of the ileocecal valve [1, 2].

Most described clinical risk factors for Meckel diverticulitis are [3]: age less than 50 years old, male, diverticulum length greater than 2 cm and presence of histologically abnormal tissue inside the diverticulum.

The rule of twos (2) is the classic description of the essential features of Meckel diverticulum:

• occurs in approximately 2% of the population with a male-to-female ratio of 2:1
• it is found approximately 2 feet from the ileocecal valve,
• and it is approximately 2 inches long. Approximately 2% of patients develop a complication over their lifetime, typically before the age of 2. Symptomatic Meckel diverticula most often contain both (2) native intestinal and heterotopic gastric mucosa.

Meckel diverticulum may be discovered incidentally from evaluation of an unrelated pathology. When symptomatic, it may present with abdominal pain or symptoms that resembles gastrointestinal bleeding or bowel obstruction.

Complications of Meckel diverticulum [4, 5]:

• Bleeding: most common presentation in children.
• Intestinal obstruction: most common presentation in adults, second most common in children.
• Diverticulitis (our case): represent the 20% of symptomatic Meckel diverticulum [6].
• Perforation and tumours (very rare).

Different imaging methods may be used to evaluate the presence of Meckel diverticulum or possible complications:

• Ultrasound: useful as initial approach (for children) especially when complication are suspected (showing findings that mimics appendicitis), but is not the most sensitive technique.
• Computed tomography (CT): study of choice for the acute abdomen presentation on emergency room, showing classically a blinded pouch with fluid or mixed content on the antimesenteric border of the terminal ileum (abdominal midline).

CT findings of Meckel diverticulitis varies from a blind pouch that generally contained fluid and air or particulate material, with no oral contrast within the lumen of the visualized diverticula, with almost always mural enhancement [7]. The majority are localized near the midline or in the right lower quadrant. An attachment to the umbilicus in CT has been described as a helpful diagnostic sign [8].

Emergency surgery was performed with a periumbilical approach, locating de diverticulum sac in the antimesenteric edge at 100 cm proximal to the ileocecal junction [9]. The diverticulum had a contained focal perforation (Figure 4 A-C).