Tenesmus

Tenesmus is a spurious feeling of the need to evacuate the bowels, with little or no stool passed. Tenesmus may be constant or intermittent, and is usually accompanied by pain, cramping and involuntary straining efforts. It can be a temporary and transient problem related to constipation. The term rectal tenesmus is sometimes used to differentiate from vesical tenesmus, which is an overwhelming desire to empty the bladder.

There are a number of possible causes of tenesmus but the commonest is inflammatory bowel disease. Causes include:

• Crohn's disease
• Ulcerative colitis
• Ano-rectal abscess
• Infective colitis
• Colo-rectal tumours, especially polyps
• Radiation proctitis; this may follow irradiation for tumours of other sites such as bladder tumours, cervical carcinoma and prostatic tumours
• Irritable bowel syndrome
• Thrombosed haemorrhoids
• Endometriosis; can affect the rectum and cause pain and tenesmus

There are a number of questions that will help to elucidate the problem:

• When did the problem start? Is it recent or has it been going on for a while?
• Is there a constant urge to empty the bowels or is the feeling intermittent?
• How much tends to be passed?
• Is there abdominal pain? If so, where?
• Is there a great urge to strain?
• Is there diarrhoea or vomiting?
• Is any blood passed?
• Has the patient eaten anything unusual or been somewhere where there is a risk that the food may produce gastroenteritis?
• Have any family or close friends had similar problems?
• Are there any medical problems?

Examination

Abdominal examination should be performed followed by both digital rectal examination and proctoscopy. There may be faecal impaction, a large polyp or very congested and inflamed mucosa.

• If the cause of the problem is not apparent, full blood count, ESR and C-reactive protein may indicate an underlying inflammatory condition.
• Sigmoidoscopy and even colonoscopy may be required.
• Plain abdominal x-ray may be of value.

Management will depend on the cause:

• Where the problem is constipation, simple measures such as increasing dietary fibre may help. Lactulose syrup can reduce tenesmus in the constipated elderly.¹
• Malignancy requires appropriate intervention. In advanced rectal carcinoma, radiotherapy can relieve tenesmus.²
• Endometriosis affecting the rectum may be treated medically or surgically, including laparoscopic colo-rectal resection.³
• A thrombosed pile requires incision and evacuation.
• In distal ulcerative colitis, topical aminosalicylates act more effectively and rapidly to induce and maintain remission than their oral preparations or topical steroids.⁴ Rarely ulcerative proctitis is refractory to topical therapy and systemic corticosteroids, antibiotics, immunomodulators, or surgery is required.
• Modern radiotherapy techniques reduce the risk of radiation proctitis and usually it responds to conservative management but intervention is required if symptoms persist. These may include topical formalin application, endoscopic argon plasma coagulation, hyperbaric oxygen therapy and surgical intervention.⁵
• Tenesmus can be a significant problem in advanced colo-rectal carcinoma. Morphine is usually satisfactory. Where this fails methadone may be successful and possibly causes less constipation.⁶ Where pharmacological treatment has failed, lumbar sympathectomy gives good results that appear to persist and with few problems.⁷