Meckel's Diverticulum on Ultrasound: Differential Diagnosis with Appendicitis and Intussusception
Clinical Context
Heterotopia refers to the displacement of an organ from its normal anatomical location. Inflammation of Meckel's diverticulum (diverticulitis) can mimic appendicitis; therefore, during appendectomy, the ileum should be inspected for Meckel's diverticulum, and if found, it should be removed along with the appendix. In adults, Meckel's diverticulitis may present with intestinal obstruction, rectal bleeding, or diverticular inflammation. Acute appendicitis and acute Meckel's diverticulitis may be clinically indistinguishable.
Ultrasound Appearance of Meckel's Diverticulum
The wall of Meckel's diverticulum consists of mucous, muscular, and serous layers. According to the literature, Meckel's diverticulitis is characterized by the following features: loop pattern of the structure, along with clinical symptoms—rectal bleeding and tenderness. The key feature in differentiation from appendicitis is the absence of association with the cecum (no association with cecum).
Differential Diagnosis with Appendicitis
Diagnosis of even classic appendicitis is complicated by the fact that many conditions present with a similar clinical picture of acute abdomen. The differential diagnosis, in addition to Meckel's diverticulitis, includes: acute gastroenteritis, mesenteric lymphadenitis in children, ruptured ectopic pregnancy, mittelschmerz, regional enteritis, right-sided ovarian torsion.
| Feature | Acute Appendicitis | Meckel's Diverticulitis |
|---|---|---|
| Association with cecum | Appendix originates from the cecum | No association with the cecum |
| Shape | Tubular, blind-ending structure with bowel signature | Loop pattern |
| Diameter | Maximum outer diameter of normal appendix up to 6 mm; in appendicitis—diameter increase | [requires clarification] |
| Compressibility | Non-compressible; thickened muscular wall | [requires clarification] |
| Clinical presentation | Pain in right lower quadrant, McBurney's point tenderness, fever, nausea/vomiting, leukocytosis | Rectal bleeding, tenderness; may be asymptomatic |
Features of Normal and Inflamed Appendix
The normal appendix can sometimes be visualized with graded compression; the maximum outer diameter of a normal appendix is up to 6 mm. In appendicitis, the following findings are noted: thickened muscular wall, increased appendiceal diameter, absence of peristalsis, inability to compress, increased blood flow on Doppler, and variable echogenicity (anechoic, hypoechoic, or complex). On transvaginal ultrasound, appendicitis appears as a tubular, blind-ending structure with bowel signature adjacent to the ovary; periappendiceal fluid and peritoneal enhancement confirm the diagnosis.
Intussusception
Specific ultrasound criteria for intussusception are not provided in the available source fragments. [requires clarification]
Practical Conclusion
The main differential landmark on ultrasound is tracing the association of the structure with the cecum: the appendix originates from the cecum, whereas Meckel's diverticulum has no association with the cecum. When clinical differentiation between acute appendicitis and acute Meckel's diverticulitis is not possible, intraoperative inspection of the ileum is mandatory.
Frequently asked questions
How can Meckel's diverticulum be distinguished from the appendix on ultrasound?
The key feature is the absence of association of Meckel's diverticulum with the cecum (no association with cecum), whereas the appendix originates from the cecum. Diverticulitis is characterized by a loop pattern.
What layers comprise the wall of Meckel's diverticulum?
The wall of Meckel's diverticulum consists of mucous, muscular, and serous layers.
What is the normal diameter of the appendix on ultrasound?
The maximum outer diameter of a normal appendix can be up to 6 mm.
Can Meckel's diverticulitis be clinically distinguished from appendicitis?
No, acute appendicitis and acute Meckel's diverticulitis may be clinically indistinguishable. Therefore, during appendectomy, the ileum is inspected for Meckel's diverticulum.
What are the ultrasound features characteristic of acute appendicitis?
Thickened muscular wall, increased appendiceal diameter, absence of peristalsis, inability to compress, increased blood flow on Doppler; echogenicity is variable—anechoic, hypoechoic, or complex.