Synopsis
Match colonoscopy, flexible sigmoidoscopy or CT colonography to the anatomical question, need for tissue or therapy, procedural risk and bowel-preparation feasibility, then close any incomplete examination.
- Choose the test by anatomical reach, need for biopsy or therapy, patient fitness and preparation feasibility.
- Colonoscopy examines mucosa throughout the colon and permits biopsy or polypectomy when complete and well prepared.
- Flexible sigmoidoscopy assesses distal bowel only and cannot exclude right-sided disease.
Key red flags
Severe abdominal pain, peritonism, haemodynamic instability or suspected perforation after endoscopy or CT colonography requires urgent assessment rather than routine post-procedure advice.
Investigation priorities
directly inspect the whole colonic mucosa and obtain biopsy or provide endoscopic therapy
Management branches
A frail 79-year-old with iron-deficiency anaemia needs assessment of the whole colon. Previous sedation caused respiratory compromise, so the team must compare CT colonography with carefully planned colonoscopy and explain downstream biopsy needs.
- Define that the diagnostic target is the entire colon because iron-deficiency anaemia can arise from proximal disease; a flexible sigmoidoscopy would leave that target incompletely assessed.
- Review prior respiratory compromise, current fitness, renal function, bowel-preparation safety and whether likely lesions would require immediate biopsy or polypectomy.