Anoscopy 

Patients may present to the outpatient or emergency department setting with various anorectal conditions. Professionalism is especially warranted in these cases because of the nature of the examination. As part of the initial evaluation, obtain a complete history of the present illness, perform a physical examination of the abdomen, and perform a visual inspection of the anus and perineum. The next step, if necessary, is a digital rectal examination (DRE). If the data obtained from the external visualization and digital rectal examination are insufficient to make a definitive diagnosis, an anoscopy may be performed to visualize the anus, anal canal, and internal sphincter.^[1]

• To visually investigate anorectal conditions for which a digital rectal examination does not provide sufficient diagnostic information
• To obtain information on conditions such as internal hemorrhoids or disruption and other pathology of the rectal mucosa, or to examine for anorectal mass or foreign body in the anal canal
• To obtain samples for cytology as a screening method for anal squamous lesions,^{[2, 3, 4]} particularly in high-risk patients with human immunodeficiency virus infection^[5]

• Anoscopy should not be performed on an imperforate anus
• Caution should be exercised on patients with recent anal or rectal surgery

Most patients do not require analgesia for anoscopy.

• Topical anesthesia with 2% lidocaine jelly may be inserted into the anal canal at least 10 minutes prior to insertion of the anoscope.
• If necessary, intravenous medications such as opiates (eg, morphine sulfate) or benzodiazepines (eg, lorazepam, diazepam, midazolam) may be administered for analgesia and light sedation.
• In some situations, consider intravenous procedural sedation via local protocol with agents such as fentanyl, midazolam, propofol, ketamine, or etomidate. Such situations include the following:

  • The patient could not tolerate anoscopy despite topical medication and administration of initial intravenous medications.
  • Initial attempts at foreign body removal with medication as described above were not successful and further attempts are indicated in the current venue.
• For complicated cases in which the anatomy is distorted, the patient cannot tolerate the procedure, or the attempt at foreign body removal was unsuccessful, referral to a specialist for an examination under anesthesia or admission to the hospital is indicated.

• Lubricating jelly or lidocaine jelly (See image below.)Standard lubricating jelly.
• Sterile or nonsterile gloves
• Paper towels or tissue paper
• Disposable sheet
• Light source (if not already built in to the anoscope)
• Anoscope (several different devices pictured below)Stainless steel anoscope. Image courtesy of Welch Allyn. Disposable anoscope with integrated light source. Image courtesy of Welch Allyn. Plastic disposable anoscope with obturator in place. Plastic disposable anoscope with obturator removed.

• The patient can be placed in various positions to facilitate insertion of the anoscope.

  • The most common position is the lateral decubitus position with the contralateral (top) leg flexed at the knee and the hip.
  • The patient may also be placed in the knee-shoulder position or prone position.

1. Prior to an anoscopy, visually inspect the area and then perform a digital rectal examination to investigate for bleeding or an obvious mass. A digital rectal examination can also help to localize pain prior to the procedure.
2. In some cases, it may be beneficial to clear the rectum of stool. An enema may also be administered in cases of obstipation to help clear the rectal vault prior to the procedure.
3. When using an anoscope with an obturator, ensure that the obturator of the anoscope is completely inserted.
4. Generously lubricate the anoscope with standard lubricating jelly or lidocaine jelly.
5. Introduce the anoscope gently and advance it slowly with a slight side-to-side twisting motion while the patient bears down. If resistance due to contraction of the external anal sphincter is significant, constant pressure on the anoscope eventually fatigues the muscles and permits insertion.
6. Maintain pressure over the obturator with the thumb during insertion to keep the obturator from slipping out. To avoid pinching the anal mucosa, completely remove the anoscope and reinsert the device if the obturator slips or falls out during insertion. Some anoscope models have small tabs at the operator end of the device. These tabs should be aligned along the rostral to caudal axis of the patient to allow complete insertion of the device.
7. Once the anoscope is completely inserted, remove the obturator.
8. As the anoscope is slowly withdrawn, the anal mucosa can be visualized over the entire circumference of the canal. Any debris or blood can be swabbed for analysis, if desired.
9. As the instrument is withdrawn at the anal verge, spasm of the external sphincter may lead to rapid expulsion. Firm counterpressure prevents expulsion. Reinsertion may be required for adequate visualization of the anal verge.

• Perform a digital rectal examination prior to anoscopy to check for pain, bleeding, or mass obstruction.
• If the obturator falls out during insertion, remove the entire anoscope prior to reinsertion to prevent pinching the anal mucosa.
• At the last stage of withdrawal, apply firm counterpressure to prevent rapid expulsion of the anoscope due to spasm of the external sphincter.

Anoscopy is a relatively safe procedure.

• The most common complication is minor irritation of the local mucosa, which can lead to some bleeding.
• To avoid contamination, do not reuse multi-use anoscopes without proper sterilization. Dispose of single-use devices after use.