Chapter 27 — Anorectal Trauma and Foreign Bodies

This chapter covers anorectal injury and retained foreign bodies from causes other than sexual assault, which is covered separately in Chapter 23. It includes accidental injury, impalement, and self-inserted objects. This chapter covers presentation, examination, investigations, and management, including how to recognise a perforation. This is the same pattern used for every disease chapter in this manual.

27.1 What Is Anorectal Trauma and Foreign Bodies

Anorectal trauma means injury to the anal canal, rectum, or surrounding tissue. It can be accidental, or it can result from a foreign body.

A foreign body is any object retained in the rectum or anal canal. Objects reach this area for many reasons. These include recreational insertion, accidental insertion, and retained medical devices.

Approach every patient without judgement. Follow the same principle described in Chapter 23. A calm, non-judgemental manner encourages an honest history, which is essential for safe treatment.

27.2 Why It Happens

Accidental trauma can follow a fall onto a sharp or pointed object, an impalement injury. It can also follow an industrial accident, a road traffic accident with an associated pelvic fracture, or injury during a medical procedure such as an enema or endoscopy.

A foreign body may be inserted recreationally. It may also be inserted or retained for other reasons. These include concealment of an object, or a repeated pattern of behaviour that may benefit from psychological assessment, described in Section 27.9.

A retained medical device, such as a thermometer or an enema tip, is another recognised cause.

27.3 Classification

Trauma may be penetrating, from a sharp object, or blunt, from a fall or impact.

Injury severity ranges widely. A superficial injury affects only the perianal skin or soft tissue. A more severe injury involves the sphincter complex directly. The most severe injury causes a full- thickness perforation of the rectal wall, with a genuine risk of contamination of the abdominal cavity.

A foreign body may be low-lying, within reach of the examining finger, or high-lying, above the rectosigmoid junction. A high-lying object is harder to retrieve, and carries a higher risk of injury during removal.

27.4 Presentation

Follow the history-taking method described in Chapter 2.

Pain is common, and can be severe, particularly after an impalement injury.

Bleeding may be present, ranging from minor to significant.

Take an honest, detailed history of how the injury happened, or how the object was inserted. This history guides both the urgency and the method of treatment.

Ask specifically whether the patient has already attempted to remove the object themselves. This attempt can itself cause further injury, and changes the assessment needed.

Ask about fever, abdominal pain, and abdominal distension. These symptoms suggest a possible perforation, described fully in Section 27.6, and need urgent attention.

A patient may delay presentation out of embarrassment. This delay does not change the urgency of assessment once the patient presents.

27.5 Examination

Assess the whole patient first, not only the anorectal area. Check for signs of shock, including a fast heart rate and low blood pressure, particularly after a significant injury.

Examine the abdomen carefully. Abdominal tenderness, distension, or rigidity are concerning signs of possible perforation.

Follow the local anorectal sequence described in Chapter 3, once the general assessment is complete.

Inspection, described in Chapter 4, assesses the extent of visible injury, and may show a foreign body at or near the anal verge.

Digital rectal examination, described in Chapter 5, should be gentle. Do not attempt a digital examination if a sharp object is suspected. This risks pushing the object deeper, or causing additional injury. Proceed instead to imaging, described in Section 27.7.

Do not attempt blind removal of a foreign body in the clinic or emergency department if it is high-lying, sharp, or fragile. This risks incomplete removal, further injury, or the object breaking apart. Examination under anaesthesia is the safer approach in this situation.

27.6 Assessment for Perforation

A full-thickness injury to the rectal wall allows bowel contents to enter the abdominal cavity. This is a genuine surgical emergency.

During abdominal examination, look for peritonism: tenderness with guarding and rigidity.

Fever and a fast heart rate both raise concern for perforation and early sepsis.

Urgent imaging, described in Section 27.7, is needed whenever perforation is suspected. Do not delay this assessment.

A confirmed or strongly suspected perforation needs urgent surgical involvement, often without delay.

27.7 Investigations

A plain X-ray can show a radio-opaque foreign body, and can also show free air under the diaphragm, which indicates perforation.

A CT scan gives a more detailed assessment. It is essential whenever perforation is suspected, and is also useful for locating a high-lying foreign body precisely before any attempt at removal.

Examination under anaesthesia allows a full, pain-free assessment, and safe removal of a foreign body that cannot be assessed or removed safely in clinic.

27.8 Principles of Management

Resuscitate the patient first if there are signs of shock or significant blood loss, before proceeding to definitive local treatment.

A low-lying, blunt foreign body can often be removed manually, or with simple instruments, in the clinic or emergency department, with adequate local anaesthesia or sedation.

A high-lying, sharp, or fragile object is more safely removed under general anaesthesia, described in Section 27.5, rather than attempted blindly.

After any foreign body removal, check the rectal wall carefully. Proctoscopy or sigmoidoscopy, described in Chapter 6, confirms there is no residual injury or perforation from the object or its removal.

A sphincter injury identified during assessment is repaired following the same principles described in Chapters 21 and 22.

A confirmed perforation needs urgent surgical repair. This often needs a temporary defunctioning stoma to protect the repair, in the same way described for other severe anorectal injuries in this manual.

Antibiotic cover is appropriate whenever contamination is possible, given the risk of infection from bowel contents.

27.9 Special Situations

Suspected concealment of an object, sometimes for the purpose of smuggling, needs careful, sensitive assessment. Imaging is important, since a concealed packet at risk of rupture can cause serious, sometimes life-threatening, contamination or toxicity. Appropriate coordination with other services may be needed, handled with the same sensitivity as every other patient in this chapter.

A patient with repeated episodes of self-inserted objects may benefit from a compassionate psychological assessment, offered supportively rather than punitively.

Trauma associated with a pelvic fracture needs coordinated assessment with the wider trauma team, since the anorectal injury is only one part of a more complex picture.

27.10 Complications

Perforation and peritonitis, described in Section 27.6.

Sphincter injury, with the risk of later incontinence, described in Chapter 20.

Infection or abscess formation at the site of injury.

Fistula formation, developing during healing.

Significant psychological distress, which deserves the same attention as the physical injury itself.

27.11 Common Mistakes to Avoid

Attempting blind removal of a foreign body without first assessing its position, shape, and risk, particularly when it is high-lying or sharp.

Focusing only on the local anorectal findings, and missing signs of perforation elsewhere in the abdomen.

Approaching the patient with judgement, which discourages an honest history and delays safe treatment.

Failing to check the rectal wall after foreign body removal, and missing a resulting injury.

Delaying imaging when perforation is a genuine possibility.

27.12 Recording and Follow-Up

Record the mechanism of injury, the examination findings, and the treatment given. For example: "Low-lying foreign body, removed manually under local anaesthesia. Proctoscopy after removal shows an intact rectal wall, no bleeding. No signs of perforation." Arrange follow-up to confirm healing, and to offer psychological support where appropriate.

27.13 Why This Chapter Matters

Anorectal trauma and foreign bodies need calm, careful assessment, not judgement. Checking for perforation, avoiding blind removal of a high-risk object, and confirming the rectal wall is intact afterward together protect the patient from a missed, serious injury. The next chapter turns to the anorectal manifestations of systemic and inflammatory bowel disease.