Blocked Rectum – Causes of a Rectal Blockage

The rectum and the anus constitute the terminal parts of the gastrointestinal tract. Before defecation, the feces are temporarily stored within the rectum. A blockage in the rectum (like a blockage in any other part of the gastrointestinal tract) can adversely affect the movement of stool, resulting in constipation. If the blockage in the rectum is not treated, the condition may become serious and lead to tears in the walls of the intestine.

Although a blocked rectum is characterized by constipation, one should not infer that all cases of constipation are caused by a blocked rectum. In most cases, the exact cause of constipation remains unknown. Dietary factors (such as low-fiber diet and limited water intake) and lifestyle factors (such as sedentary work) are thought to contribute to the occurrence of constipation. In addition, constipation may also occur in a variety of other conditions that are not linked to any blockage in the gut.

Symptoms of a Blocked Rectum

Blockage in the rectum is usually a partial blockage. A complete blockage in the rectum is a rare occurrence. A partially blocked rectum may not be accompanied by any alarming signs and symptoms. This may lead to missed diagnosis, especially in the early stages of the condition. Over time, the signs and symptoms may become more prominent. The following are some of the signs and symptoms that may be present in case of a blocked rectum:

  • Constipation: As mentioned previously, a blockage in any part of the gut (including the rectum) typically causes constipation. The feces within the gut become dry and hard. This causes considerable discomfort during defecation.
  • Tenesmus: A blocked rectum hampers the proper emptying of the bowels. This results in a constant urge to pass stool even after defecation. This urge to pass stool due a feeling of incomplete bowel emptying is technically referred to as tenesmus.
  • Pain: Individuals suffering from a blocked rectum may experience discomfort, burning sensation or pain in the rectum. They may also experience a sensation of fullness in the rectum.
  • Fecal incontinence: The liquid contents of the feces may flow around the blockage in the rectum and seep out of the anus, causing fecal incontinence.
  • Bloody stools: Mucus and blood may also be present in the stools.
  • Pencil-thin stools: Stools that pass out may have a pencil-thin appearance on account of being squeezed out through a narrow space around the blockage in the rectum.

Depending on the underlying cause of the rectal blockage, there may also be other signs and symptoms.

Causes of Rectal Blockage

Blockage in the rectum could occur due to many different causes, such as hard feces, presence of foreign bodies, abnormal growths, and strictures. The blockage can either be partial or complete. This results in varying degrees of impairment in the movement of feces through the rectum and the anus.

Fecal impaction

Fecal impaction refers to solidification of feces inside the intestine, resulting in a hard mass of stool that is difficult to pass out during defecation. Chronic constipation is the most frequent cause of fecal impaction. Some amount of liquid feces may pass out in this condition since the watery content of the feces can make its way around the impacted stool. Left untreated, fecal impaction could result in serious complications arising from decreased blood flow to the intestine.

Read more on fecal impaction.

Intestinal polyps

Polyps are benign abnormal growths. Within the large intestine, polyps are more likely to form in the sigmoid colon and the rectum, thereby causing obstruction in these places. Even though most polyps are benign, some can become malignant (cancerous).

Foreign bodies

The presence of any foreign body within the rectum can lead to a blocked rectum. Foreign bodies that may get lodged in the rectum include objects inserted intentionally through the anus (like suppositories). Fecal impaction may further worsen the condition by making it more difficult for the foreign body to be expelled out.


Hemorrhoids (also known as piles) refer to a swelling of the veins within the rectum and the anus. The swelling is usually caused by inflammation. When the swelling of the veins is significant enough, blockage of the rectum can occur. Defecation in such a condition becomes very painful. Constipation may ensue, leading to further complications like impacted stool.

Read more on hemorrhoids.

Compression of the rectum

Tissues and organs that lie in the vicinity of the rectum can also contribute to a blocked rectum by compressing the rectum. For example, enlargement of the uterus (due to uterine fibroids) and the prostate gland (due to hypertrophy) can cause compression and blockage of rectum. Cancers of the uterus and the prostate gland can also cause partial compression and blockage of the rectum.


The term “strictures” refers to narrowing of any passage within the body. Narrowing of the region where the rectum and the anus meet (anorectal stricture) can lead to a blockage in the rectum. Anorectal strictures can be due to compression caused by nearby organs, formation of scar tissues after an injury, or anatomical abnormalities in this region of the gut.

Anatomical abnormalities

Abnormalities in the structure, orientation, and position of the bowels can contribute to a blocked rectum. Examples of conditions that can cause such abnormalities include abdominal hernia and twisted bowels. In abdominal hernia, a part of the bowel gets trapped within the abdominal wall, which leads to impaired bowel movements.


A false or pseudo-obstruction of the bowels is caused by a malfunction of the nerves and muscles in some segment of the bowel. This causes the affected portion of the bowel to expand. Movement of content within the expanded part of the intestine ceases due to lack of muscular contractions. Such a condition is technically referred to as Ogilvie syndrome or acute pseudo-obstruction (abbreviated as ACPO). The term “pseudo” refers to the fact that there is no real obstruction to the passage of feces. Pseudo-obstruction can lead to fatal complications if left untreated.

Colorectal cancer

Colorectal cancer is very serious condition that can lead to blocked rectum, rectal bleeding, changes in bowel habits, fatigue and weight loss. It is one of the most lethal cancers. Without prompt treatment, colorectal cancer can turn fatal within a short time.

Diagnosis and Treatment

Diagnosis of a blocked rectum should be done by a medical professional. Abdominal X-ray, barium X-ray, colonoscopy, MRI, and CT scans are some of the diagnostic investigations that may be performed. If an abnormal growth is found to cause a blockage, a biopsy may be done to know the nature of the growth. Since a blocked rectum can be caused by many different conditions, the actual treatment needs to be decided on a case-by-case basis. The results of the diagnostic investigations would determine the course of treatment chosen.

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