From the Guidelines
When approaching mild colitis on CT as a GI fellow, the initial step should be to correlate the radiologic findings with the patient's clinical presentation and consider further diagnostic testing such as flexible sigmoidoscopy or colonoscopy with biopsies to confirm the diagnosis. The patient's clinical presentation, including symptoms, medical history, and laboratory values, should be thoroughly evaluated. A thorough history focusing on symptom duration, stool characteristics, abdominal pain, and risk factors for infectious colitis should be obtained. Perform a physical examination and order laboratory tests including CBC, CRP, ESR, stool studies for infectious pathogens, and Clostridioides difficile testing, as these can help guide the diagnosis and management of colitis 1. Consideration of the potential benefits and limitations of CT scans in evaluating colitis is crucial, and according to the ACR Appropriateness Criteria, CT is the most useful examination for patients with suspected colonic diverticulitis due to its high diagnostic accuracy and ability to identify alternative diagnoses and complications 1. However, for mild colitis, the use of IV contrast material may not be necessary, and unenhanced CT or radiation dose-reduced contrast-enhanced CT can be considered, especially in patients with contraindications to IV contrast material 1. The approach to managing mild colitis should be guided by the underlying etiology, which may include inflammatory bowel disease, infection, ischemia, or medication effects, and treatment should be tailored accordingly. Some key points to consider in the management of mild colitis include:
- Initiating treatment with 5-aminosalicylates like mesalamine for mild ulcerative colitis
- Considering budesonide for mild Crohn's colitis
- Treating the underlying pathogen with appropriate antibiotics for infectious colitis
- Scheduling follow-up within 2-4 weeks to assess response to therapy and adjust treatment if needed. It is essential to prioritize the patient's clinical presentation and tailor the diagnostic and therapeutic approach accordingly, rather than relying solely on CT findings.
From the Research
Approach to Mild Colitis on CT as a GI Fellow
- When approaching mild colitis on CT, it is essential to consider the clinical presentation, endoscopic findings, histology, and the absence of alternative diagnoses 2.
- The hallmark CT finding of ulcerative colitis (UC) is mural thickening with a mean wall thickness of 8 mm, as opposed to a 2-3 mm mean wall thickness of the normal colon 2.
- Abdominal computed tomographic (CT) scanning is the preferred initial radiographic imaging study in UC patients with acute abdominal symptoms 2.
Diagnosis and Treatment
- Ileocolonoscopy with biopsy is the only way to make a definitive diagnosis of UC 2.
- The classical histological changes in UC include decreased crypt density, crypt architectural distortion, irregular mucosal surface and heavy diffuse transmucosal inflammation, in the absence of genuine granulomas 2.
- Mesalamine is a 5-aminosalicylic acid compound that is the first-line therapy to induce and maintain clinical remission in patients with mild-to-moderate UC 3, 4.
- For patients who are refractory to mesalamine or have more severe disease, steroids, azathioprine/mercaptopurine, cyclosporine, or infliximab may be used to induce and/or maintain remission 4.
Considerations for Specific Patient Populations
- Microscopic colitis (MC) is an inflammatory disease of the colon and a common cause of chronic watery diarrhea, predominantly in older patients 5.
- The approach to treatment of MC is similar for both lymphocytic colitis and collagenous colitis and should be guided by the severity of the patient's symptoms 5.
- In patients with infectious colitis, the management depends upon establishment of cause, and most forms of infectious colitis are treatable with antimicrobials 6.