Imagine feeling the constant and urgent need to use the bathroom, even when there is nothing to pass. This symptom is known as tenesmus, which has its roots in disorders of the digestive tract like Crohn’s disease, irritable bowel syndrome, or colorectal tumours. However, although it is rarely considered, neurological conditions can also play a part in causing this symptom. 

Neurological conditions can interfere with the nerve signals that control bowel function, leading to symptoms like tenesmus. Disorders such as multiple sclerosis, spinal cord injuries, Parkinson’s disease, and autonomic neuropathy can all contribute to the development of this condition. This is because they can disrupt the nerve pathways responsible for coordinating defecation. Though tenesmus is not a diagnostic marker of these disorders, understanding the underlying neurological causes is crucial in tenesmus management and treatment. 

Read on to learn more about the key neurological conditions linked to tenesmus and how this symptom can be managed. 

Introduction

Tenesmus is a symptom in which you feel like you need to go to the toilet to empty your bowels or bladder when they are empty or have been emptied recently. You may feel the urge to go to the bathroom frequently but cannot, or feel like you haven’t finished defecating. This results in pain and straining and is often associated with disorders of the gastrointestinal tract. However, the neurological origins of this disorder should also be considered, as neurons play a big role in the signalling events leading to correct emptying of the bladder and bowels. Therefore, understanding the neurological conditions leading to tenesmus is essential for its diagnosis and treatment or management. 

Neurological control of bowel and bladder function

Whilst it may seem purely instinctive, the process of defecation is orchestrated by various systems working together in the body. These different systems, including neuronal circuits, are responsible for coordinating events like sensations and motor control of the perineal region. Disruptions of nerves along these pathways can give rise to symptoms like tenesmus.   

The role of the central nervous system

The central nervous system is composed of the brain and spinal cord, and is considered the processing centre of the body. The central nervous system is not usually implicated in digestive tract disorders, as those usually occur from faults in neuronal wiring of the peripheral nervous system. However, there are some parts of the brain and spinal cord which can play a role in defecation, and hence may affect the symptoms of tenesmus. 

The role of the peripheral nervous system

The digestive system is usually linked to the enteric nervous system, a part of the peripheral nervous system. The enteric nervous system is a complex system of over 100 million neurons, which line the entire digestive tract to ensure everything runs smoothly. This system converses using signals with the central nervous system, linking the digestive system with cognition and emotion. 

Neurological conditions associated with tenesmus

Multiple sclerosis 

Multiple sclerosis is a condition which affects the brain’s control over muscle movement. This leads to difficulties with movement, coordination, and balance, and can therefore affect the digestive tract. Whilst a lot of patients preserve their normal urges to defecate, some experience digestive tract symptoms like tenesmus, in which the control over defecation urge isreduced, lost, or becomes very sudden regardless of actual needs. This can result in abdominal pain and an increased severity of symptoms like muscle spasticity.²

Spinal cord disorders

The spine is the epicentre of a multitude of neurons that play a part in various bodily functions, including digestion. Spinal cord injuries and inflammation can disrupt signalling between neurons, thus disrupting the processes that they are associated with. Tenesmus can occur due to:^3,4,5

• Spinal cord injury
• Herniated discs
• Transverse myelitis, inflammation of a part of the spinal cord

Stroke

Stroke, a condition in which the blood supply to part of the brain is interrupted, can have significant effects on the digestive tract. There are currently limited studies looking at the effects of stroke on bowel dysfunction; however, stroke can lead to symptoms like tenesmus depending on which part of the brain is affected.⁶ 

Parkinson’s disease

In Parkinson’s disease, parts of the brain become damaged and die prematurely. This mainly affects movement and coordination and can then progress to psychiatric symptoms like dementia. As Parkinson’s disease impacts muscle control, it can lead to many problems with urinating and defecation. Tenesmus is usually associated with the initial stages of the disease, affecting around a fifth of early-stage Parkinson’s disease patients.⁷

Cauda equina syndrome

Cauda equina syndrome is a condition in which the nerves at the tail-end of the spine are compressed. The causes of cauda equina syndrome range from spinal cord injury to tumours and infections. The neurons responsible for the control of bladder and bowel movements are compressed. Hence, cauda equina syndrome can lead to tenesmus in both the bowels and the bladder.⁸

Autonomic neuropathy

Autonomic neuropathy refers to the damage or inflammation of peripheral nerves (outside of the brain and spinal cord). It can be caused by:

• Diabetes
• Excessive alcohol consumption
• Low levels of certain vitamins
• Guillain-Barré syndrome 
• Disorders of the immune system, such as arthritis, lupus, or coeliac disease 
• Certain medications, for example, certain chemotherapies

Autonomic neuropathy is sometimes associated with tenesmus and other disorders of the gastrointestinal tract.⁹

Other neurological disorders

Other than the causes discussed above, any neurological condition which affects the muscles responsible for defecation can cause tenesmus. Alternative neurological disorders that can lead to tenesmus include:

• Amyotrophic lateral sclerosis (ALS)¹⁰
• Huntington’s disease¹¹ 

Diagnosis and evaluation

Tenesmus is a symptom, so it is usually diagnosed with the disorder causing it. If the cause of tenesmus is unknown, the doctor may order tests for underlying inflammation, possible causes, and diagnosis. These include:

• Blood tests
  • Full blood count 
  • Erythrocyte sedimentation rate
  • C-reactive protein 
• Sigmoidoscopy, and in rarer cases, colonoscopy
• Abdominal x-ray

While tenesmus may be a sign or a symptom of neurological conditions, it is not used as a primary diagnostic marker. These neurological conditions are diagnosed independently, with tenesmus being a distressing byproduct of the neurological dysfunction and not the main focus of treatment. 

Treatment approaches

Tenesmus does not have a pharmacological “cure”. Instead, to ease the discomfort of the condition, the underlying cause must be addressed, and the associated symptoms should be managed. Although research on the management of tenesmus is limited, certain things may help alleviate the discomfort associated with tenesmus, which include:

• Dietary changes: increasing fibre intake if the problem is constipation
• Local anaesthetic as an enema treatment to relieve pain
• Implementing a toilet routine with correct toilet posture
• Pelvic floor exercises

Summary

Tenesmus is a distressing condition that can significantly impact one’s quality of life. It is characterised by the feeling that you have not fully emptied the bowels or bladder after going to the bathroom, which can lead to complications like pain and discomfort in the region. While tenesmus is commonly associated with disorders of the gastrointestinal tract, its neurological origins should not be overlooked. The intricate network of the central and peripheral nervous systems plays a crucial role in bowel function. Disruptions of these networks associated with conditions like multiple sclerosis, spinal cord disorders, Parkinson’s disease and autonomic neuropathy can lead to tenesmus. Tenesmus is not a diagnostic criterion in these neurological disorders, but rather a symptom, and requires careful evaluation, diagnosis and management. Treatment should focus on the underlying neurological causes. Discomfort caused by tenesmus can be managed by lifestyle changes, physical therapy, and symptom-specific interventions like local pain relief and the implementation of toilet routines.