Introduction
Computed tomography (CT) is a common modality used to assess patients who present acutely with gastrointestinal symptoms.1 The term colitis refers to the thickening of the colonic wall 2 and is often described in CT reports. Causes of colitis are commonly classified into infectious, inflammatory and ischaemic colitis.3 Although there are some radiological features that are helpful in suggesting a specific diagnosis,4 determining the underlying aetiology of colitis often requires correlation with clinical history, laboratory results including stool cultures and endoscopic evaluation.1 There is currently limited literature on the prevalence of the different aetiologies in patients with colitis reported on CT.3 Identification of the underlying aetiology allows for specific management of patients as treatment options differ depending on the underlying cause.
Aims & Methods
The aim of this study is to identify the aetiology of colitis in patients with reported colitis on CT imaging.
A retrospective review of CT reports and patient case notes was performed. A text search through our radiology system (CRIS) was used to identify patients with CT reported colitis during their inpatient admission. Patients with known Inflammatory bowel disease (IBD), colorectal cancer as well as outpatient CT reports were excluded. Following identification of our patient cohort, we reviewed their clinical notes as well as laboratory, stool and endoscopic results to determine the underlying aetiology of their colitis.
Results
A total of 138 patients with colitis reported on CT imaging were included. 98 patients (71.0%) had a stool culture sent during their admission whilst 83 patients (60.1%) underwent endoscopic evaluation with a flexible sigmoidoscopy (n=49, 59.0%) or colonoscopy (n=34, 41.0%). In 35 patients (42.2%) there were no significant abnormalities found endoscopically.
74 patients (53.6%) were thought to have infectious colitis with main pathogens including Campylobacter spp. in 19 patients (25.7%), Clostridiodes difficile in 11 patients (14.9%) and Salmonella spp. in 1 patient (1.4%). 4 patients (5.4%) had endoscopic features of infectious colitis. 39 patients (52.7%) patients were suspected to have infective colitis from clinical history and laboratory results.
25 patients (18.1%) had ischaemic colitis either confirmed endoscopically (n=11, 44.0%) or through clinical history and CT features (n=14, 56.0%). Endoscopically, 6 patients (4.3%) had features compatible with IBD, 2 patients (1.4%) with lymphocytic colitis and 1 patient (0.7%) with an adenocarcinoma. 15 patients (10.9%) had diverticulosis.
C-reactive protein (CRP) was higher in patients with infectious colitis (mean of 141.4 mg/L) and lower in patient with ischaemic colitis (mean of 108.6 mg/L). Albumin and haemoglobin levels were highest in those with infectious colitis (mean of 33.4 g/L and 135.5g/L respectively) and lowest in patients with IBD (mean of 26.8 g/L and 108.5g/L respectively).
Conclusion
CT reported colitis was of infectious aetiology in 53.6% of patients, ischaemic in 18.1% and inflammatory in 4.3%. Laboratory results such as haemoglobin and albumin levels can be helpful in determining aetiology. Despite CT features suggestive of colitis, 42.2% of endoscopic evaluation revealed no significant abnormality. CT findings of colitis should therefore be correlated with clinical history, stool results and endoscopic evaluation when determining the underlying aetiology.
References
1 Thoeni, R.F. and Cello, J.P., 2006. CT imaging of colitis. Radiology, 240(3), pp.623-638.
2 Moraitis, D., Singh, P., Jayadevan, R. and Cayten, C.G., 2006. Colonic wall thickening on computed tomography scan and clinical correlation. Does it suggest the presence of an underlying neoplasia?. The American Surgeon, 72(3), pp.269-271.
3 Meyer, J., Schrenzel, J., Balaphas, A., Delaune, V., Abbas, M., Morel, P., Puppa, G., Rubbia-Brandt, L., Bichard, P., Frossard, J.L. and Toso, C., 2022. Mapping of etiologies of computed tomography-proven acute colitis: a prospective cohort study. Scientific Reports, 12(1), p.9730.
4 Philpotts, L.E., Heiken, J.P., Westcott, M.A. and Gore, R.M., 1994. Colitis: use of CT findings in differential diagnosis. Radiology, 190(2), pp.445-449.