Impacted Bowel – Causes and Symptoms of Colon Stool Impaction

What is an impacted bowel?

The term impacted bowel is used commonly to refer to a condition known as fecal impaction. This is usually a consequence of severe and long standing constipation where the feces forms a hard, dry mass and fills up the rectum. It can sometimes extend up as high as the sigmoid colon. This impacted feces form a stone-like mass that is known as a fecolith or fecaloma. It may also aggravate other large bowel disorders like diverticula when it collects in the outpouchings.

An impacted bowel causes a partial or complete obstruction which leads to the colonic contents backing up. As the condition progresses, especially if left untreated, the backflow of gastrointestinal contents can extend to the small intestine. The colon stretches significantly just proximal to the blockage and expands – this distended colon is known as a megacolon. The normal motility in this area is compromised due to the distension further aggravating the constipation as fecal contents, even when broken up, cannot be evacuated from the rectum.

The danger lies with rare complications like ischemic bowel disease as the blood flow to the distended colon (megacolon) is compromised.  Infection may arise and quickly spread throughout the abdominal cavity. Without emergency medical care, it can be fatal. However, an impacted bowel is NOT a common complication of constipation. It is rarely seen except in the overuse of certain medication, the elderly and bedridden patients.

Causes of an Impacted Bowel

Although the term impacted bowel is used to refer to fecal impaction, as a general term it can also be ascribed to other conditions leading to partial or complete bowel obstruction. This may arise from the small intestine (blocked bowel) or large intestine (blocked colon).

Proximal to the descending colon, the gastrointestinal contents are fluid to semi-solid and only with a significant obstruction will its passage be affected. In the descending and sigmoid colon, the contents become more solid to form the typical firm feces. With fecal impaction, the feces may enter the rectum but is not evacuated as would occur with normal defecation. Water absorption causes the feces to become dry and hard further compounding the impaction.

The various causes of constipation need to be considered for preventing further episodes. It is however more likely to occur with severe constipation.

Symptoms of an Impacted Bowel

The capacity of the human bowel coupled with its ability to stretch often means that a person will not notice any specific symptoms of fecal impaction at the outset. Constipation is present and usually ongoing, with patients reporting episodes of bowel incontinence as a result of paradoxical overflow diarrhea. More attentive patients and those with only partial obstruction will report a pencil-thin stool. Fecal impaction, however, may occur in the absence of any of these symptoms other than constipation alone.

Other symptoms of an impacted bowel includes :

  • Excessive straining with the passage of little or no stool
  • Painful bowel movements
  • Rectal bleeding

Upper gastrointestinal symptoms or generalized symptoms should be monitored closely. It usually arises as the condition has progressed further and is possibly bordering on the onset of complications. These symptoms include :

  • Indigestion
  • Nausea and vomiting
  • Lack of appetite
  • General feeling of being unwell
  • Severe abdominal pain
  • Urinary tract infections

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