What Is Rectal Tenesmus?

Sensation of Being Unable to Empty the Bowel

sitting on toilet constipation pain

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Tenesmus is a medical term used to describe the sensation of being unable to empty your bowel after having defecated. When used on its own, the word tenesmus typically refers to the bowel and rectum. By contrast, the sensation of being unable to empty your bladder after urination is referred to as vesicle tenesmus.

Tenesmus is primarily associated with inflammatory bowel diseases, both infectious and non-infectious. The diagnosis of the underlying cause may involve a stool culture, blood tests, colonoscopy, or a biopsy. Pain medications and antispasmodics may be prescribed to help alleviate symptoms while the underlying cause is being treated.

Symptoms

Symptoms of tenesmus may be constant or intermittent and will usually be accompanied by pain, cramping, and involuntary straining. Depending on the underlying cause, there may also be gas, bloating, or rectal itching. Rectal discharge and bleeding are also common, either caused by excessive straining or an inflammatory condition which compromises colorectal tissues.

Urgent care should be sought if tenesmus is accompanied by high fever (over 100.4 F), chills, severe bleeding, nausea, vomiting, or fainting.

Causes

While the cause of tenesmus is not well understood, it is believed that inflammation of the bowel may stimulate both somatic nerve fibers that instigate physical sensations and autonomic nerve fibers which modulate smooth muscle contractions. Overstimulation of these nerves may not only make it feel as if there is residue inside the bowel, it can trigger contractions that we recognize as the onset of a bowel movement.

Severe diarrhea or constipation can also cause the scarring of bowel tissue. It this happens, it not only makes passing a stool more difficult, it can make it feel as if there is more in the bowel than there actually is. Localized sores or growths can do the same.

There are numerous conditions that can trigger tenesmus, including:

Tenesmus can affect people who have undergone radiation therapy for cervical cancer, rectal cancer, prostate cancer, or colon cancer (a condition referred to as radiation proctitis).

Diagnosis

Tenesmus is not a medical condition but rather a symptom of a condition. As such, your doctor will want to uncover the underlying cause by first reviewing your medical history, family history, and current symptoms. This would likely include questions about your bowel habits, diet, and lifestyle.

Based on the diagnostic clues, your doctor will want to perform tests to explore the more likely causes while excluding potentially serious ones. This may involve:

Treatment 

While tenesmus is typically resolved by treating the underlying condition, other treatments may be prescribed to help ease the symptoms. These may include:

On occasion, methadone may be prescribed to alleviate intractable rectal pain associated with advanced colorectal cancer.

Tenesmus is largely unresponsive to opioids drugs. Benzodiazepines and phenothiazines, traditionally used to treat tenesmus, have little clinical evidence to support their use.

A Word From Verywell

While it may be embarrassing to discuss tenesmus with your doctor, doing so is important as it may be the sign of a medical condition in need of treatment. This is especially true if the symptom is persistent, worsening, or accompanied by bleeding, tarry stools, narrow stools, weight loss, fever, vomiting, or the inability to defecate.

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