The diagnostic yield of lower endoscopy plus biopsy in nonbloody diarrhea

Patients presenting with diarrhea frequently undergo lower endoscopy plus biopsy as part of their diagnostic evaluation. The diagnostic yield of this approach has not been systematically evaluated.

To evaluate the diagnostic yield of endoscopy and biopsy in the investigation of nonbloody diarrhea, we performed a retrospective analysis using the endoscopy unit database of a tertiary care university hospital over a 3-year period. The database was searched for cases in which colonoscopy was performed for the single indication of diarrhea. The endoscopic findings and initial biopsy reports were extracted from a chart review, and each clinician was interviewed for the patient's current clinical diagnosis. The clinical diagnoses were compared with the endoscopy and biopsy results to determine whether the tests had contributed to making the clinical diagnoses.

Three hundred six patients were identified. One hundred one were excluded for standardized predefined exclusion criteria, leaving 205 evaluable patients, of whom 77 had flexible sigmoidoscopy and 128 had colonoscopy. Eighteen percent had specific clinical diagnoses facilitated by endoscopy and/or biopsy. Endoscopy and biopsy results were normal in 74% of cases. In 8% of the cases either the endoscopy or biopsy findings were inconsistent with the final clinical diagnoses.

Endoscopy and biopsy are important diagnostic tools in the evaluation of patients with nonbloody diarrhea, leading to a specific diagnosis in nearly one fifth of cases.