Rectal Tenesmus Symptoms, Causes, and Treatment

The Sensation of Being Unable to Empty the Bowel

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Tenesmus is a medical term used to describe the sensation of being unable to empty your bowel after you have already defecated. Tenesmus is commonly associated with inflammatory bowel disease (IBD), but may also be caused by conditions such as hemorrhoids, infections, and cancer.

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The diagnosis may involve a stool culture, blood tests, colonoscopy, or a biopsy to identify the underlying cause. Pain medications and antispasmodics may be prescribed to help alleviate symptoms while the underlying cause is being treated.


Symptoms of tenesmus may be constant or intermittent, but usually involve some or all of the following:

  • Rectal pain
  • Gas
  • Bloating
  • Cramping
  • Itching
  • Rectal discharge
  • Rectal bleeding
  • Involuntary straining

When to Call a Healthcare Provider

Seek medical care right away if you experience tenesmus accompanied by a high fever (over 100.4 F), chills, severe rectal bleeding, nausea, vomiting, or fainting.


The cause of tenesmus is not well understood, but it is believed that inflammation or irritation may stimulate somatic nerves (that transmit physical sensations) and autonomic nerves (that modulate smooth muscle contractions) in the bowel.

Overstimulation of these nerves can make it feel as if there is residue within the bowel and can trigger the contractions that we recognize as the onset of a bowel movement.

In addition, severe diarrhea or constipation can also cause scarring of bowel tissues. If this happens, it makes passing stools more difficult, and it can feel as if there is more in the bowel than there actually is. Sores or growths around the rectum or in the colon can do the same.

Numerous conditions can trigger tenesmus, including:

Radiation proctitis can develop and cause tenesmus after radiation therapy for cervical cancer, rectal cancer, prostate cancer, or colon cancer.


Tenesmus is not a medical condition, but rather a symptom of a condition. As such, your healthcare provider will search for the underlying cause by reviewing your medical history, family history, and current symptoms. This will likely include questions about your bowel habits, diet, and lifestyle.

Based on these diagnostic clues, your healthcare provider will do further testing to identify the reason for your symptoms.

Physical Exam

The physical exam is essential to the diagnosis of tenesmus. It helps your healthcare provider see if there is any inflammation or abnormalities around the rectum, tenderness or pain in the abdomen, or signs of a sexually transmitted infection.

The procedure may involve a digital rectal exam (DRE). This involves the insertion of a gloved finger into the anus to check for hemorrhoids, blood, mucus discharge, infection, or abnormal growths.

Lab Tests

After the physical exam, your healthcare provider will commonly order a battery of blood and stool tests to help narrow down the causes.

These may include:

Imaging Studies

Before proceeding to more invasive procedures, your healthcare provider may order imaging tests to help visualize your digestive tract.

These may include:


If colorectal cancer is suspected or an anomaly is spotted on imaging studies, your healthcare provider may refer you to a gastroenterologist, who might proceed with a minimally invasive endoscopic procedure.

Test you might have include:

  • Colonoscopy: A procedure using a flexible scope, called a colonoscope, to examine the entire colon
  • Sigmoidoscopy: A version of colonoscopy limited to the lower part of the colon, the sigmoid colon
  • Colon biopsy: Performed during a colonoscopy or sigmoidoscopy to obtain a sample of tissue for evaluation

If colorectal cancer is the cause of tenesmus, the only test that can definitively confirm the diagnosis is a biopsy. Blood tests and imaging studies can support the diagnosis, but they cannot diagnose the disease.


Tenesmus tends to improve once the underlying cause is identified and treated. Because the causes of tenesmus are so diverse, so are the treatments. Below are the treatments used to treat tenesmus in each condition.

Cause Treatment Options
Celiac disease Gluten-free diet
Constipation Laxatives and stool softeners
  High-fiber diet
Diarrhea Antidiarrheals like Imodium (loperamide)
Colorectal cancer Opioid drugs for advanced cancer
  Endoscopic laser treatment
Crohn's disease and Ulcerative Colitis Corticosteroids like prednisone
  Immunosuppressants like methotrexate
  Aminosalicylates like Colazal (balsalazide)
  TNF blockers like Humira (adalimumab)
  Antibiotics like Flagyl (metronidazole)
Diverticular disease High-fiber diet
  Oral or intravenous antibiotics
Gastroenteritis Antibiotics (if the cause is bacterial)
  Antiparastic drugs (if the cause is parasitic)
IBS High-fiber diet 
  Antispasmodics like Levsin (hyoscyamine)
  Anti-diarrheals or laxatives, as needed
  Tricyclic antidepressants like amitriptyline 
Ischemic colitis Antibiotics
  Surgery, if blood flow obstruction is severe
Pelvic floor disorders Stool softeners
  Physical therapy
  Percutaneous tibial nerve stimulation (PTNS)
Prolapsed hemorrhoid Rubber band ligation
Rectal abscess Surgical drainage
  Antibiotics, including penicillin
Rectocele Kegel exercises
  Intravaginal pessary
STDs Antibiotics (varies by infection)

A Word From Verywell

While you may feel uncomfortable discussing tenesmus with your healthcare provider, it is important to do so. 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. None of these symptoms should ever be dismissed or ignored.

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