A fecal impaction is a large lump of dry, hard stool that remains stuck in the rectum. It is most often seen in patients with long-term constipation.
Impaction of the bowels
Causes, incidence, and risk factors
Constipation is when you are not passing stool as often as you normally do. Your stool becomes hard and dry, and it is difficult to pass.
Fecal impaction is often seen in people who have had constipation for a long time and have been using laxatives. Impaction is even more likely when the laxatives are stopped suddenly. The muscles of the intestines forget how to move stool or feces on their own.
Persons at risk for chronic constipation and fecal impaction include those who:
- Do not move around much and spend most of their time in a chair or bed
- Have diseases of the brain or nervous system that damage the nerves that go to the muscles of the intestines
Certain drugs slow the passage of stool through the bowels:
- Anticholinergics, which affect the interaction between nerves and muscles of the bowel
- Medicines used to treat diarrhea, if they are taken too often
- Narcotic pain medication, such as methadone and codeine
Common symptoms include:
- Abdominal cramping and bloating
- Leakage of liquid or sudden episodes of watery diarrhea in someone who has chronic constipation
- Rectal bleeding
- Small, semi-formed stools
- Straining when trying to pass stools
Other possible symptoms include:
- Bladder pressure or loss of bladder control
- Lower back pain
- Rapid heartbeat or light-headedness from straining to pass stool
Signs and tests
The health care provider will examine your stomach area and rectum. The rectal exam will reveal a hard mass of stool in the rectum.
If there has been a recent change in your bowel habits, your doctor may recommend a colonoscopy to evaluate for colon or rectal cancer.
Treating a fecal impaction involves removing the impacted stool. After that, measures are taken to prevent future fecal impactions.
Often a warm mineral oil enema is used to soften and lubricate the stool. However, enemas alone are usually not enough to remove a large, hardened impaction.
The mass may have to be broken up by hand. This is called manual removal:
- A health care provider will need to insert one or two fingers into the rectum and slowly break up the mass into smaller pieces so that it can come out.
- This process must be done in small steps to avoid causing injury to the rectum.
- Suppositories inserted into the rectum may be given between attempts to help clear the stool.
Surgery is rarely needed to treat a fecal impaction. An overly widened colon (megacolon) or complete blockage of the bowel may require emergency removal of the impaction.
Almost anyone who has had a fecal impaction will need a bowel retraining program. Your doctor and a specially trained nurse or therapist will:
- Take a detailed history of your diet, bowel patterns, laxative use, medications, and medical problems
- Examine you carefully
- Recommend changes in your diet, how to use laxatives and stool softeners, special exercises, lifestyle changes, and other special techniques to retrain your bowel
- Follow you closely to make sure the program works for you
With treatment, the outcome is good.
- Tear (ulceration) of the rectal tissue
- Tissue death (necrosis) or rectal tissue injury
Calling your health care provider
Tell your health care provider if you are experiencing chronic diarrhea or fecal incontinence after a long period of constipation. Also notify your health care provider if you are experiencing any of the following symptoms:
Lembo AJ, Ullman SP. Constipation. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 18.
Nelson H. Diseases of the rectum and anus. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 148.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; George F Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.