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Anorectal Abscess and Anal Fistula


Anorectal abscess and anal fistula are conditions that often occur together. An anal fistula is an abnormal tunnel from the anus or rectum to the skin or another organ. It usually forms when there is an anorectal abscess. An anorectal abscess is a collection of pus from an infection in the anus or rectum.


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You may be given the following medicines:

  • Antibiotics: This medicine is given to help treat or prevent an infection caused by bacteria.
  • Pain medicine: Healthcare providers may give you medicine to take away or decrease your pain.
    • Do not wait until the pain is severe to ask for your medicine. Tell healthcare providers if your pain does not decrease. The medicine may not work as well at controlling your pain if you wait too long to take it.
    • Pain medicine can make you dizzy or sleepy. Prevent falls by calling for help when you want to get out of bed.
  • Stool softeners: This medicine makes it easier for you to have a bowel movement. You may need this medicine to treat or prevent constipation.


You may have any of the following:

  • Anoscopy: A clear lotion is put onto a short plastic or metal tube. The tube is then gently pushed into your anus and up the rectum. Your healthcare provider can also take samples of bowel movement to be sent to a lab for tests.
  • Fistulography: This is a type of x-ray that may show how deep the fistula is and where it started. A probe or catheter (tube) will be inserted into the opening of the fistula. A dye may be put into the fistula tract (pathway) before the x-ray to make it show up better.
  • Magnetic resonance imaging test: This test is also called an MRI. It uses magnetic waves to look at your intestine. This will help healthcare providers check how long the fistula is. You will need to lie still during an MRI. Never enter the MRI room with any metal objects. This can cause serious injury.
  • Sigmoidoscopy: A sigmoidoscopy test looks for changes in your intestinal (bowel) wall that may be caused by a disease or condition. This test may also help find the cause of bleeding or pain. A long, thin tube with a tiny camera on the end is put through your anus into your rectum (rear-end). It also goes to the part of your intestine called the sigmoid. Healthcare providers will look for problems in your rectum and lower colon. A small amount of tissue may be taken from the intestine wall and sent for tests. Follow your healthcare provider's instructions for what to do before, during and after the test.
  • Transanal ultrasound: This is a test that looks inside your rectum to check for a large fistula. A small tube is placed into your anus. Sound waves are used to show pictures of your organs and tissues on a monitor. Hydrogen peroxide may be injected into the tract of the fistula before the test.


  • Incision and drainage: Your healthcare provider may break the abscess to drain the pus. This is done by making an incision in or near the affected area. Sometimes, a catheter (tube) may be put in place for some time to allow the remaining pus to drain.
  • Surgery: You may need to have surgery to drain a very large abscess. If you have a fistula, surgery may be done to open and clean up the fistula tract. This may be left open until it heals on its own.


Surgery used to treat an anorectal abscess or anal fistula may cause you to bleed too much. You may get another infection from the surgery. A fistula may form after treatment of the abscess. Surgery to treat a fistula may injure other body parts, including the sphincter muscles. This may lead to problems with controlling bowel movements. If left untreated, the infection may spread to other parts of your body and make you very sick. If an abscess is not treated, it may also return.


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Learn more about Anorectal Abscess and Anal Fistula (Inpatient Care)

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