Fecal Impaction – Causes, Symptoms, Complications, Treatments

What is impacted feces?

Feces are stored within the large intestine before being expelled through the rectum and anus during the act of defecation. Sometimes, the feces within the lower regions of the large intestine (sigmoid colon and rectum) may become dry and hard. Such hard, dry and large masses of stool within the lower bowels are referred to as impacted feces or impacted stools.

Impacted stool is hard to pass out. Therefore, fecal impaction causes a blockage in the large intestine that prevents normal bowel movements. Impacted feces may extend upwards as far as the sigmoid colon, forming hard, stone-like masses known as fecaloma or fecalith. Impacted stool may also lead to aggravation of other disorders of the large intestine, such as diverticula.

How does stool become impacted?

The most common cause of fecal impaction is chronic constipation. Long-standing constipation causes an increase in the transit time of feces through the colon. This allows more water to be reabsorbed from the colonic contents, leading to accumulation of dry and hard feces. Accumulation of impacted stool further slows down the movement of feces and causes an impacted bowel.

A partial or complete obstruction of the colon occurs, which leads to backing up of the colonic contents. The walls of the colon expand and stretch in the region before the blockade. This could lead to the formation of a distended colon (technically referred to as a megacolon).

Left untreated, fecal impaction can lead to serious complications. The backflow of gastrointestinal contents may even reach parts of the small intestine. Blood flow to the distended megacolon may get affected, leading to ischemic bowel disease. Accumulation of feces in the colon may facilitate onset of infections, which can spread rapidly to other parts of the abdominal cavity. This may be fatal if emergency treatment is not started. In some cases, the impacted feces may become too hard to be evacuated through the rectum.

It is important to note that not all cases of constipation result in fecal impaction. In fact, fecal impaction is a rare complication of chronic constipation. It is seen mostly under special circumstances, such as in bedridden patients, elderly people, and in those who overuse certain medications. However, it is a serious complication of constipation that needs to be treated promptly.

Read more on complications of constipation.

Signs and Symptoms of Fecal Impaction

In the initial stages of fecal impaction, no specific signs and symptoms may occur to signal the presence of impacted stool. Since chronic constipation is the most common reason for fecal impaction, the affected individuals may notice only constipation in the initial stages. There may be intermittent episodes of bowel incontinence due to paradoxical overflow diarrhea.

Stools may also become very thin (pencil-thin stools). However, due to the stretching capacity of the bowels, one may not notice any symptoms other than constipation in the early stages of fecal impaction. As the process of fecal impaction continues, the following signs and symptoms may appear:

  • Paradoxical diarrhea (watery stool) may occur along with constipation as the watery contents of the bowel flow around the obstruction caused by impacted feces.
  • Bowel movements may become painful.
  • Excessive straining may occur during bowel movements. Only small amount of feces may be passed out despite the excessive straining.
  • Fecal incontinence may occur.
  • Rectal bleeding may occur and fresh blood may be seen in the feces.
  • Bloating and pain in the abdominal region may also occur.

Apart from the above mentioned signs and symptoms, the patient may also display general symptoms such as malaise, restlessness, loss of appetite, nausea and vomiting. When fecal impaction has progressed enough to affect the upper gastrointestinal region, the following signs and symptoms may arise:

  • Nausea and vomiting
  • Indigestion
  • Malaise or a general feeling of being unwell
  • Severe pain in the abdominal region
  • Loss of appetite
  • Urinary tract infections.

These signs and symptoms may precede onset of further complications.

Causes of Fecal Impaction

Fecal impaction is most commonly associated with chronic and severe constipation. However, not all cases of severe and chronic constipation lead to fecal impaction. Other factors may be required to precipitate fecal impaction in constipated individuals.

For example, overuse of certain drugs (such as antidiarrheals, anticholinergics, painkillers and narcotics) may cause fecal impaction in a person who is suffering from chronic and severe constipation. The risk of fecal impaction is also higher in the elderly, and in sedentary or bedridden patients.

Severe constipation can cause a number of other bowel disorders. Both partial and complete obstruction of the bowels is possible, even without fecal impaction. Therefore, the term “impacted bowel” could also be used to refer to conditions other than fecal impaction that may cause partial or complete obstruction of the bowels. Blockage of the intestine can occur in both the small intestine and the large intestine.

The contents within the human intestine are mostly semi-solid or liquid in nature. Reabsorption of water from the colonic contents solidifies the feces. This solidification of feces typically occurs in the descending and sigmoid colon. Chronic constipation, accompanied by other risk factors, causes the stools to become drier and harder than normal. Fecal impaction in these cases prevents the normal evacuation of the solid feces through defecation.

Read more on blocked colon.

Complications of Fecal Impaction

Fecal impaction, if left untreated, can cause serious complications. One of the complications of untreated fecal impaction is megacolon. This condition is characterized by an abnormal dilation of the colon due to accumulated solid feces. Fecal impaction can also cause damage to the lining of the walls of the colon. This can adversely affect the motility of the colon. Blood flow to the walls of the colon may also get affected, leading to ischemic bowel disease.

Treatments for Fecal Impaction

Fecal impaction needs to be treated quickly to restore normal bowel movements and prevent further complications. The following are the common treatment options for fecal impaction:

  • Medication: Medications to soften the stool can help in treating fecal impaction. Examples of such medications include bulking agents and laxatives. However, the use of laxatives may cause an increase in abdominal cramps and vomiting.
  • Changes in diet: Dietary changes may help provide relief from constipation that is often associated with fecal impaction. An increase in water intake and daily physical activity may also help.
  • Enema: Impacted feces may be removed through daily enemas. At the very least, daily enemas may prevent further growth of impacted feces.
  • Manual removal of impacted feces: When the above measures fail to provide relief, impacted stool may be broken down and removed manually through the anus. However, this procedure should only be performed by a trained medical professional. Otherwise, there is a high risk of injury to the bowels.
  • Surgery: Surgery is usually not required for the treatment of fecal impaction.

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