Introduction

Inflammatory bowel disease (IBD) is an immune-mediated condition resulting from inappropriate inflammation in response to intestinal microbes and environmental factors in a genetically susceptible host. Disruptions in the gut bacteria coupled with a weakened intestinal barrier lead to a dysregulated, chronic immune response that presents in a spectrum of conditions, the most common being Crohn’s Disease (CD) and Ulcerative Colitis (UC). Both conditions present with significant discomfort and a reduction in quality of life due to the persistent inflammation. Individuals commonly present with a range of symptoms including tenesmus, discomfort, fatigue, abdominal pain and diarrhoea.^1,2

Tenesmus is defined as the frequent urge to pass stool even if your bowels are already empty. It may involve straining, pain and cramping. The severity of tenesmus varies between different people, with some experiencing no pain and others experiencing pain and bleeding. It significantly affects quality of life due to the frustrations of making frequent bathroom trips.³

What are Crohn's disease and ulcerative colitis?

CD is characterised by chronic inflammation at any part of the gastrointestinal tract, though it most frequently occurs in the distal ileum and the colon. It presents with discontinuous, patchy inflammation through all the layers of the intestinal wall as well as deep ulcers. Although the rectum is usually spared, complications such as fistulas and abscesses are common.¹ 

UC typically presents with inflammation in the colon and the rectum, and is usually restricted to the surface layer of the intestine. Mucosal inflammation leads to oedema, ulceration and bleeding. Approximately 15% of those with UC have pancolitis, a condition where inflammation affects the entire colon.¹ 

Although tenesmus may occur in both CD and UC, it is more common in UC.¹ 

How does tenesmus arise?

Rectal inflammation and hypersensitivity

Tenesmus can be caused by inflammation of the colon. Mucosal inflammation is driven by inappropriate host immune responses to intestinal microbes, gastrointestinal infections or disturbances in colonic motility. This leads to the characteristic chronic inflammatory cascade with infiltrating immune cells, nerve activation and the release of inflammatory mediators.⁴ 

Studies have suggested that rectal hypersensitivity is present in IBD during active inflammatory stages, through a combination of central and peripheral mechanisms. There is a sensitising effect of inflammation on neurons, which leads to disrupted motility and abnormal contractions. The neuroplastic changes in the enteric nervous system cause persistent rectal dysfunction even after inflammation subsides.^5,6

An increase in rectal sensation also lowers the threshold for rectal urgency, meaning that the urge to defecate is earlier or more persistent. Rectal sensation is triggered by poor rectal distensibility and compliance, which refers to the ability of the rectum to stretch and accommodate stool. This can lead to the persistent or false urge to defecate despite the rectum being empty or containing small amounts of stool, triggering tenesmus.⁶

Ulceration and oedema

The presence of ulcers and oedema are characteristic features of both CD and UC. Ulcers are sores that can occur in the lining of the digestive tract, producing blood and pus, while oedema refers to the swelling and fluid build-up within the intestinal wall.^1,7

In UC, mucosal ulcers, oedema, and congestion can disrupt rectal sensation and reflexes, triggering the persistent urge to defecate. The irritation from ulcers can also lead to pain and bleeding.⁸ 

Fibrosis and strictures 

Fibrosis and strictures are common features of CD that develop over time and may contribute to tenesmus. Chronic inflammation seen in IBD leads to dysregulated wound healing and can therefore lead to tissue damage and scarring in the intestinal wall, known as fibrosis. The scarred tissue can then lead to strictures, which are an abnormal narrowing of the bowel wall. The stiffer bowel wall in combination with narrowing in parts of the rectum may obstruct stool passage and can lead to the sensation of incomplete evacuation and straining. Fibrosis also reduces the flexibility of the colon, which impairs the movement of stool through the intestine and can lead to obstruction and constipation. Studies have shown that those with a form of IBD have reduced ability of the intestine to stretch compared to non-IBD controls.^2,9,10

What does tenesmus feel like?

Tenesmus is a clinical sign that is associated with diseases such as IBD. It can be uncomfortable, frustrating, and painful in many cases. Although the symptoms vary between individuals, tenesmus usually presents with the following signs:^1,2

• Pain and cramping in the rectum and abdominal regions
• Straining, which can be involuntary
• Frequently feeling the need to pass stool
• Urgency to pass small amounts of stool
• Feeling the sensation of incomplete evacuation
• Blood and/or mucus in stool

How do you diagnose tenesmus in IBD?

Tenesmus itself is a sign of an underlying condition, such as IBD. Therefore, identifying the condition is the first line of defence against tenesmus. Doctors may consider the following tests:^1,11

• Clinical evaluation to assess stool frequency, urgency, pain, rectal swelling and bleeding 
• Stool sample analysis to check for blood, mucus or pathogens in the stool
• Blood tests to check for markers of inflammation
• Colonoscopy to examine the rectal and colonic mucosa for inflammation, ulceration, erosions and strictures 
• Cross-sectional imaging studies to detect inflammation, fibrosis and strictures
• Histological investigations to detect inflammatory infiltration

How do you treat tenesmus?

Treatment of tenesmus in the context of IBD focuses on reducing pain and inflammation as well as addressing the underlying condition and associated structural complications. Treatment also depends on the frequency and severity of the symptoms. 

Lifestyle interventions

Lifestyle adaptations such as physical activity have been shown to boost immune responses and reduce the release of proinflammatory mediators. The reduction in inflammation may contribute to less rectal irritation, a common feature of tenesmus. Staying physically active is also suggested to reduce stress and anxiety, which may help support muscle relaxation and prevent frequent urges.^12,13

Bowel training may help alleviate the symptoms of tenesmus. This could include teaching your body to have regular bowel movements by going to the toilet at specific times of the day to reduce unpredictability. Pelvic floor muscle training is also recommended as they have been shown to have benefits in those with impaired evacuation. The pelvic floor muscles support the bowel and play a role in controlling defecation by coordinating rectal relaxation and contraction of the anal sphincters.¹³

Dietary changes can also support the symptoms of tenesmus depending on the cause. High-fibre diets improve the symptoms of both CD and UC by promoting the softening of stool, which may help it pass more easily, and should be considered in cases where constipation is common. However, those with strictures or blockages in the colon may experience worsened tenesmus with high-fibre diets, and therefore dietary changes should be considered on a case-by-case basis.^14,15

Medical interventions

In general, the first step to manage tenesmus through medical treatment aims to reduce pain and inflammation through anti-inflammatory medications and immunosuppressants. These include aminosalicylates and short-term use of corticosteroids.¹ 

Biologics are a class of targeted therapy against chemical messengers or mediators involved in ameliorating the chronic inflammatory state in IBD. Clinical trials have been successful, with biologics being used in both UC and CD to reduce disease progression. Antibiotics can also be considered in the case where tenesmus has been caused by an acute infection.^1,16

Summary 

Inflammatory bowel disease is an immune-mediated condition that normally presents as either ulcerative colitis or Crohn’s disease. It is caused by inappropriate, chronic inflammation in the gastrointestinal tract in response to intestinal microbes. Tenesmus is a common clinical sign associated with inflammatory bowel disease and is characterised by the frequent, sometimes painful, urge to pass stool despite empty bowels. Tenesmus is proposed to arise due to rectal inflammation and hypersensitivity, the presence of ulcerations and oedema, and fibrosis and strictures. Although symptoms vary between individuals, tenesmus is usually uncomfortable and frustrating. Diagnosis and treatment of tenesmus focus on the underlying condition, in which tests are conducted to identify inflammation or structural changes in the bowel, while medical interventions focus on suppressing the chronic inflammatory response. Lifestyle interventions may also be considered to improve one's quality of life.