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Beyond appendicitis: ultrasound findings of acute bowel pathology
Beyond appendicitis: ultrasound findings of acute bowel pathology
REVIEWED BY | Marilyn Zelesco ASA SIG: General
REFERENCE | Jihee Choe, Jeremy Wortman, Aya Michaels, Asha Sarma, Urvi Fulwadhva, Aaron Sodickson Emergency Radiology (2019) 26:307–317
WHY THE ARTICLE WAS PUBLISHED
Bowel pathology is a common unexpected finding on routine abdominal and pelvic ultrasound. However, imaging staff are often unfamiliar with the ultrasound appearances of the gastrointestinal tract due to underutilisation of ultrasound for bowel investigations. This article reviewed basic ultrasound technique for bowel evaluation, ultrasound appearances of normal bowel and of common acute bowel pathologies.
INTRODUCTORY TEXT
The article introduced the reader to the concept that acute abdominal pain accounts for 8% of all emergency department presentations. Many of these will be due to underlying acute gut pathology. As ultrasound is often a first-line modality for investigation of acute abdominal pain, sonographers need to be familiar with characteristic features of abnormal bowel, such as wall thickening, decreased motility, absence of luminal content, and a fluid-filled distended lumen, all of which can be well demonstrated on ultrasound. However, a considered approach is required.
The article presents a comprehensive section on baseline bowel ultrasound technique, as well as a section on general bowel ultrasound principles and sonographic criteria. These general principles and criteria are well presented in a summation table that addresses wall stratification, wall thickness, luminal diameter, peristalsis, compressibility, vascularity and the involvement of adjacent fat.
CORE TEXT
The core text commences with consideration of the role of ultrasound in the diagnosis of acute appendicitis, including diagnostic pitfalls. The article then considers the role of ultrasound in infectious and pseudomembranous colitis. The article highlights that because the colonic wall is not well visualised sonographically, thickened wall almost always raises the suspicion for underlying colitis. Typhlitis is also discussed as it is a common presentation for neutropenic patients and those with other immunosuppressive disorders. The role of ultrasound in diverticulosis and diverticulitis (including Meckel’s diverticulitis) is covered, as well as potential complications such as obstruction, free air, abscess or fistula formation.
A large section of text addresses the exacerbation of Crohn’s disease – covering inflammation, fissures and fistulae, as well as strictures. Although there are findings in Crohn’s that demonstrate overlap with other diseases, the likelihood increases when the sonographer finds a segmental, circumferential bowel wall thickening that affects the terminal ileum along with evidence of complications such as abscess or fistula.
The authors then address bowel malignancy, lymphoma and colonic cancer as all of these may present as an acute finding.
The final section addresses characteristic features of small bowel obstruction on ultrasound, with an overall sensitivity of > 95% and accuracy of > 80% respectively. The authors highlight that the presence of free fluid between the small bowel loops suggests worsening mechanical small bowel obstruction and the need for surgical management.
RELEVANCE TO CLINICAL PRACTICE
Many sonographers/radiologists limit the use of abdominal and pelvic ultrasound to solid organs. However, ultrasound can be a valuable tool for the assessment of gut in the acute abdomen. This article familiarises the sonographer with basic normal and abnormal sonographic criteria – both static and dynamic assessment.
