Neurological bowel disease

Damage to the central nervous system (brain and spinal cord) impacts on the function of the large bowel, the colon, and on the ability to maintain bowel continence.

The term neurogenic bowel describes the loss of nervous control which prevents the bowel from functioning correctly. Stool transit through the bowel may be slowed down which places the individual at risk of constipation. And the sensory and motor control of the ano-rectum may be impaired leaving the individual with reduced or absent voluntary control of the defaecation process, and incontinent of faeces.

The combination of impaired continence and risk of severe constipation is termed neurogenic bowel dysfunction (NBD). Without intervention the individual may become incontinent of faeces and chronically constipated.

Causes of neurogenic bowel

Central nervous system (CNS) diseases or injury which can cause a neurogenic bowel are:

• Spinal cord injury
• Cauda equina
• Spina bifida, myelomeningocele, the most serious form of spina bifida
• Multiple sclerosis (MS)
• Parkinson’s
• Stroke
• Cerebral palsy
• Diabetes mellitus

Damage to the spinal cord and brain interrupts the neural pathways and the outcome to the individual will depend on the location and severity of the damage.

The neurogenic function may be reflex, areflexic or mixed – to identify the correct treatment you need to understand how these manifest and the types of problem experienced.

NBD results from loss of normal sensory or motor control and may encompass both the upper and the lower gastrointestinal (GI) tract. Quality of life is greatly affected and patients often find their symptoms to be socially disabling.

The type of neurogenic bowel is determined by the level of the damage in the spinal cord.

• A Reflex bowel occurs when damage is above T12
• A Flaccid or Areflexic bowel occurs when the damage is below T12

Clinical practice point. An understanding of this is important when making decisions on bowel management.

Types of NBD

• Autonomic dysreflexia – this occurs with spinal cord injury at T6 or above
• Reflex bowel dysfunction – lesions above T12/L1. The reflexes are intact and can be stimulated to prompt defaecation
• Flaccid or Areflexic bowel dysfunction – lesions T12/L1 and below. There are no sacral arc reflexes that can be stimulated to cause bowel movements