Imaging Inflammation and Infection in the Gastrointestinal Tract

A variety of seemingly non-specific symptoms manifest within the gastrointestinal (GI) tract, particularly in the colon, in response to inflammation, infection, or a combination thereof. Differentiation between symptom sources can often be achieved using various radiologic studies. Although it is not possible to provide a comprehensive survey of imaging gastrointestinal GI tract infections in a single article, the purpose of this review is to survey several topics on imaging of GI tract inflammation and infections. The review discusses such modalities as computed tomography, positron emission tomography, ultrasound, endoscopy, and magnetic resonance imaging while looking at up-an-coming technologies that could improve diagnoses and patient comfort. The discussion is accomplished through examining a combination of organ-based and organism-based approaches, with accompanying selected case examples. Specific focus is placed on the bacterial infections caused by Shigella spp., Escherichia coli, Clostridium difficile, Salmonella, and inflammatory conditions of diverticulitis and irritable bowel disease. These infectious and inflammatory diseases and their detection via molecular imaging will be compared including the appropriate differential diagnostic considerations.

Sonographic findings in Shigella colitis

We present a case of colitis caused by Shigella sonnei in which abdominal sonography helped in the early diagnosis, leading to successful conservative management. Sonography showed diffuse wall thickening and layer stratification in the descending and sigmoid colon. Although Shigella colitis is relatively rare, the possibility must be considered when patients have diffuse wall thickening with distinct layer stratification in the left colon.

Salmonella- and Shigella-induced ileitis: CT findings in four patients

PURPOSE

The purpose of this study is to describe and illustrate the CT appearance of four cases of acute terminal ileitis induced by nontyphoidal Salmonella and Shigella infection and to review the radiographic and endoscopic findings of these entities.

METHOD

The medical records, CT examinations, and small bowel examinations of three patients with Salmonella ileitis and one patient with Shigella ileitis were retrospectively reviewed. CT examinations were done in four patients, colonoscopy in three patients, and small bowel examinations in two patients. Stool cultures established the diagnosis of nontyphoidal Salmonella enteritis in three patients and Shigella enteritis in one patient. The patients' symptoms and clinical findings resolved promptly following supportive therapy and appropriate antibiotic therapy.

RESULTS

CT showed slight circumferential and homogeneous thickening of the terminal ileum over a segment of 10-15 cm in patients with Salmonella ileitis. Associated mild thickening of the wall of the colon was present in addition. Small bowel examination performed in one patient revealed a spastic terminal ileum with thickened mucosal folds. Colonoscopy revealed acute colitis involving the colon diffusely in one case, but sparing the distal 50 cm of the colon in one case. CT showed more pronounced thickening of the terminal ileum and a target configuration in the patient with Shigella ileitis. Small bowel examination revealed narrowing, irregular contour, several large nodular defects (thumbprinting), and a severely ulcerated mucosa affecting the terminal ileum. Colonoscopy revealed a normal colon and large ulcerations with fibropurulent exudate in the terminal ileum.

CONCLUSION

In patients with severe Salmonella or Shigella infections or persistent and/or confusing clinical presentations, CT can play a complementary but important role in the initial diagnostic evaluation. It avoids clinical mismanagement, circumvents unnecessary invasive procedures, and contributes to the efficient workup and therapy in this group of individuals.