From the Guidelines
Sigmoidoscopy is associated with a low risk of serious side effects, including 0.5 bleeding events per 10,000 procedures and 0.2 perforations per 10,000 procedures, as reported in a 2021 study published in JAMA 1. The most common side effects of sigmoidoscopy are typically mild and temporary, including bloating, gas, and abdominal discomfort due to the air introduced into the colon during the examination. Some patients may experience minor rectal bleeding, especially if biopsies were taken or polyps were removed. More serious but rare side effects include perforation and significant bleeding requiring intervention. Infection is also a rare complication. If you experience severe abdominal pain, significant rectal bleeding, fever, or persistent symptoms after a sigmoidoscopy, you should seek immediate medical attention. To minimize discomfort, follow your doctor's post-procedure instructions carefully, which may include avoiding certain activities for 24 hours and gradually returning to your normal diet. The procedure itself is performed with minimal sedation or none at all, which contributes to its generally good safety profile compared to more invasive procedures, as supported by a 2021 study published in JAMA 1. Key points to consider when evaluating the safety of sigmoidoscopy include:
- The risk of serious side effects is low, with rates of bleeding and perforation reported as 0.5 and 0.2 per 10,000 procedures, respectively 1.
- The procedure is generally well-tolerated, with most side effects being mild and temporary.
- Rare but serious complications, such as infection and significant bleeding, can occur, and patients should be aware of the signs and symptoms to watch for.
- The safety profile of sigmoidoscopy compares favorably to more invasive procedures, such as colonoscopy, which has higher rates of bleeding and perforation 1.
From the Research
Sigmoidoscopy Side Effects
- The most common post-procedural complaints after sigmoidoscopy are abdominal distension and pain 2
- People mentioning pain or bowel distension following preparation are more likely to report severe pain after sigmoidoscopy (OR, 2.13; 95% CI 1.52-2.97) 2
- The 30-day hospitalization rate after sigmoidoscopy is similar to that after total colonoscopy and fecal immunochemical test 2
- Sigmoidoscopy can be safely performed after recent colonic surgery, but clinicians should use discretion and only perform it for clinically important indications 3
- Intra-operative flexible sigmoidoscopy can be used to assess anastomotic integrity and bleeding after restorative colorectal resection, and refashioning the anastomosis after formal takedown can obviate the risk of leakage 4
Comparison with Other Procedures
- Total colonoscopy has a higher proportion of people complaining of serious reactions following bowel preparation (OR, 5.17; 95% CI 3.70-7.24) and reporting severe pain immediately after the exam (OR, 1.86; 95% CI 1.47-2.34) compared to sigmoidoscopy 2
- New low-volume polyethylene glycol preparations have been developed to improve patient compliance and tolerability for bowel cleansing prior to colonoscopy, and have been shown to be as effective as split-dose 4-L polyethylene glycol regimens 5, 6
Safety and Efficacy
- Sigmoidoscopy has been shown to be safe and effective in diagnosing and treating various colonic conditions, including rectal bleeding, distal colonic obstruction, and colon cancer 3
- The overall anastomotic leak rate after sigmoidoscopy has been reported to be 2.1% 4
- Intra-operative flexible sigmoidoscopy can help identify anastomotic leaks and bleeding, allowing for prompt intervention and reducing the risk of postoperative complications 4