Teaching Case

An 89-year-old woman presented with a 2-day history of generalized abdominal pain, vomits and fever. She denied bowel habits changes. Her past history was relevant for a gastric ulcer. She was alergic to penicilin. At physical examination, only abdominal tenderness was noted. Blood tests revealed mild leukocytosis and elevation of C-reactive protein.

Abdominal ultrasound (Fig. 1) detected concentric regular wall thickening (11 mm) along 7 cm of longitudinal extension of a bowel loop located in the right iliac fossa, associated with increased echogenicity of the adjacent fat. The ileocecal appendix wasn't confidently identified.

Subsequent abdominal CT (Fig. 2) revealed a 4.5 cm long diverticulum in the pelvic distal ileum with thickened wall and a calcified image at its neck. There was also adjacent fat stranding and a fluid collection with thickened and enhancing wall, consistent with an abscess, near the diverticulum's tip.  These findings were suggestive of Meckel diverticulitis secondary to obstruction caused by a enterolith, complicated with perforation and abscess formation. Additionally, there was also wall thickening and stratification of a relatively long segment of the adjacent small bowel, probably due to contiguous extension of the inflammatory changes. A small volume of peritoneal fluid was seen on the pelvis (Fig. 3). Ileocecal appendix was remarkable (Fig. 4).

Meckel’s diverticulum (MD) is a true diverticulum of the small bowel, secondary to incomplete obliteration of the fetal omphalo-mesenteric duct. It represents the most common gastrointestinal tract congenital anomaly, present in about 2% of population. [1-4]

It is typically located on anti-mesenteric border, within 100 cm from the ileocecal valve. 90% measure 1 to 10 cm and about 50% harbour heterotopic mucosa (mostly gastric/pancreatic). Sometimes a fibrous band connects it to the mesentery or umbilicus, unlike urachal duct cysts (connected to the bladder’s dome). [3-6]

Most cases remain asymptomatic until incidentally found intraoperatively or diagnostic imaging. Less frequently (mostly in children), it may present with symptomatic complications. [1,4,5]

The risk of developing symptoms is higher in younger age <50, male sex, size > 2 cm and abnormal histology or ectopic tissue. Complication rate ranges from 4 to 16% and decreases with age. [6,7] Hemorrhage is more frequent in children, whereas obstruction and diverticulitis are the most common complications in adults. [5,7,8].

Obstruction may be caused by intussusception of an inverted MD, volvulus, strangulation by a fibrous band, postinflammatory adhesions/strictures, incarceration in an inguinal hernia and rarely by foreign objects, enteroliths or tumours. [2,5,9] Progressive inflammation may result in perforation. [10]

The estimated prevalence of enterolithiasis in patients with MD is 3%-10%, most prevalent in males. Risk factors to their formation include delayed diagnosis, small intestinal lining (as opposed to gastric mucosa in which decreased pH prevents calcium salt precipitation), alkaline environment, neck oedema/inflammation, and focal nidus formation. [11]

Preoperative diagnosis of complicated MD may be challenging given the overlapping clinical and imaging features of other inflammatory abdominal conditions. [3]

Computed tomography is the imaging modality of choice to diagnose Meckel’s diverticulitis, preferably with intravenous and oral contrast. The diverticulum appears as a blind-ending rounded or tubular pouch usually filled with air and fluid or particulate material, communicating with the adjacent small bowel. Other findings include mesenteric inflammatory changes and rarely foreign bodies, enteroliths or neoplasms. [1,4,5,8] Enteroliths’ size range from 1 to 5 cm in diameter and 89% are peripherally calcified with radiolucent centres. [11]  Free intraperitoneal air suggests perforation. [2]

Ultrasonographic findings are usually unspecific and include a fluid-distended thick-walled diverticular structure with the typical gut signature and connected to a small-bowel loop. It may also reveal segmental thickening of the adjacent bowel’s wall, invagination and abscess. [2,9]

Plain radiography may reveal signs of bowel obstruction or perforation. [9]

Other imaging studies include technetium-99m pertechnetate scan (useful in doubtful cases, although specific to ectopic gastric mucosa), angiography (in acute/unexplained gastrointestinal bleeding), enteroscopy and endoscopic capsule. [3-5,8] Exploratory laparoscopic surgery is another reported diagnostic tool. [10]

Mortality reaches 6% in symptomatic patients and is higher in elderly patients with complications [10]. Therefore, timely diagnosis and treatment are vital.

The treatment of choice for the symptomatic MD is surgical resection, either diverticulectomy or segmental ileal resection, the latter preferred in cases of severe inflammation, perforation or neoplasm. [3,8] When asymptomatic, several authors favour excision in patients with a higher risk of developing symptoms. [3]

Our patient was submitted to laparoscopic segmental enterectomy. Pathology confirmed perforated MD lined by enteric mucosa with areas of inflammation, without metaplasia or dysplasia. No complications occurred during the postoperative follow-up period and the patient was discharged within 10 days.

Take-Home Message

Clinical and imaging findings of complicated Meckel’s diverticulum overlap those of other acute conditions of the abdomen. Being rare in adults, a high index of suspicion is necessary to allow early detection and timely adequate management.

Written informed patient consent for publication has been obtained.