Meckel Diverticulum Surgery Workup

Updated: Sep 24, 2019
  • Author: Mark V Mazziotti, MD; Chief Editor: Harsh Grewal, MD, FACS, FAAP  more...
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Workup

Laboratory Studies

A complete blood count (CBC) is helpful. In patients with a bleeding Meckel diverticulum, assessment of the hemoglobin level is critical. This helps guide transfusion therapy and should be repeated following transfusion to ensure that the hemoglobin level has adequately risen. This test is also important in the assessment of the patient with Meckel diverticulitis. An increased white blood cell (WBC) count and a left shift can support the diagnosis.

In patients with vomiting due to bowel obstruction, electrolyte abnormalities are common. Serum levels of sodium, potassium, chloride, carbon dioxide, blood urea nitrogen (BUN), and creatinine should be obtained. Studies are repeated as abnormalities are corrected.

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Imaging Studies

Technetium-99m pertechnetate radioisotope scanning

Also known as the Meckel scan, this study is important for evaluating Meckel diverticula that contain ectopic gastric mucosa, which readily takes up the isotope. [4] A Foley catheter can be placed to drain the bladder and reduce signal intensity from this area. Because the false-negative result rate may approach 2%, pentagastrin (to stimulate uptake of the radioisotope), histamine blockers (to inhibit secretion of the pertechnetate once it is taken up), and glucagon (to inhibit peristalsis and thereby decrease washout of the pertechnetate) may be used to increase the sensitivity of the test. (See the image below.)

Test of choice for bleeding Meckel diverticulum is Test of choice for bleeding Meckel diverticulum is technetium-99m pertechnetate isotope scan (Meckel scan). It concentrates isotope in ectopic gastric mucosa, with sensitivity of 85% and specificity of 95%. In this scan, isotope is seen in stomach and bladder (normal), with radiotracer signal in midabdomen, suggesting presence of Meckel diverticulum with ectopic gastric mucosa. Image courtesy of Jaime Shalkow, MD.

If the clinical index of suspicion for Meckel diverticulum is high but the Meckel scan is negative or equivocal, repeat scintigraphy may be useful. [5]

Several groups have reported that diagnostic laparoscopy should replace Meckel scanning in the assessment of patients with anemia who have lower gastrointestinal (GI) bleeding because it has a sensitivity of 60%. [6, 7]

Plain abdominal radiography

In patients with a Meckel diverticulum that causes bowel obstruction, plain radiography is needed and may reveal dilated bowel loops with air-fluid levels and a paucity of distal gas. In a protracted clinical course, perforation may occur, and free air may be seen on upright radiographs.

Ultrasonography

Many centers use ultrasonography (US) in the evaluation of abdominal pain. If the patient has Meckel diverticulitis, a thickened noncompressible tubular structure may be seen. These are many of the same criteria that are used to confirm the diagnosis of appendicitis by means of US. This modality is also helpful in assessing patients with persistent umbilical drainage. Structures such as fistulous tracts and persistent cysts may be readily identified by means of US.

Computed tomography

In many centers, abdominal-pelvic computed tomography (CT) is the radiologic test of choice if abdominal pain is present. In patients with Meckel diverticulitis, an inflammatory mass with peridiverticular stranding may be observed. Multidetector CT (MDCT) is helpful in cases of complicated Meckel diverticulum. [8]

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Procedures

Some patients have an unusual presentation and adjunctive assessment results that do not clearly lead to a particular diagnosis. In patients who have continued abdominal pain, laparoscopy may be useful. Laparoscopy has the advantage of being a minimally invasive approach to establish the diagnosis of intra-abdominal pathology. Laparoscopy can also be the primary form of treatment in various disorders.

Double-balloon enteroscopy and capsule endoscopy are additional modalities that may aid in the diagnosis of a Meckel diverticulum prior to surgery. [9, 10, 11, 12]

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Histologic Findings

A Meckel diverticulum is a true diverticulum, containing all four layers of the bowel wall. Ectopic tissue is frequently found within a Meckel diverticulum, most frequently gastric mucosa or pancreatic tissue. The remainder of the diverticulum lining is typical ileal mucosa.

Occasionally, a Meckel diverticulum may contain cancer. The tumors most likely to affect these diverticula are neuroendocrine tumors. These tumors are rare, but when present, they are often associated with nodal metastases and liver metastases. They are optimally managed with small-bowel resection with regional lymphadenectomy and debulking of liver metastases where feasible. [13]

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