Case 1: Diagnostic Testing

Here are the results of the initial diagnostic testing

Choose the 3 diagnostic tests that would be most appropriate to obtain next
Excellent choice! Patient has bloody diarrhea with labs showing anemia, thrombocytosis, presence of fecal leucocytes and raised fecal calprotectin, which are all concerning for inflammatory bowel disease. Colonoscopy will allow for mucosal inspection and tissue sampling to help confirm the diagnosis and characterize extent and severity.
CT angiography
This isn’t an appropriate next test. While it can reveal intestinal wall thickening or masses, it does not eliminate the need for a colonoscopy and will expose the patient to radiation unnecessarily. If the clinical suspicion for right sided isolated ischemia was high, then a CT angiography would have been indicated. Try again!
MR enterography
This isn’t an appropriate next test. If a diagnosis of inflammatory bowel disease is confirmed on colonoscopy, and if features of Crohns disease are noted (skipped pattern, terminal ileal involvement, rectal sparing) then a MRE would be useful at that juncture to rule out small bowel disease. Try again!
This isn’t an appropriate next test. Serologic markers such as perinuclear antineutrophil cytoplasmic antibodies (pANCAs) may be found in up to 70% of patients with ulcerative colitis (UC), and combination of negative anti–Saccharomyces cerevisiaeantibodies (ASCA) with elevated pANCA levels have been proposed to facilitate establishing a diagnosis of UC. However since the pooled sensitivity of antibody testing for diagnosis of UC is low, the guidelines recommend against serologic antibody testing to establish or rule out a diagnosis of UC.
Iron studies
Excellent choice! Given the patient’s chronic blood loss anemia it is important to obtain iron studies and initiate repletion as needed
Erythrocyte sedimentation rate and C reactive protein
Reasonable choice! These inflammatory markers will not help confirm a diagnosis, but their levels can be trended to ascertain IBD response to therapy.

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