Bowel Management in Spinal Cord Injury

Original Editor - Naomi O'Reilly

Top Contributors - Redisha Jakibanjar, Naomi O'Reilly, Kim Jackson, Anas Mohamed, Arnold Fredrick D'Souza, Admin and Lucinda hampton  

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Introduction

Neurogenic bowel dysfunction is characterized by alteration in normal bowel function due to the lack of nervous control. The clinical symptoms of neurogenic bowel may vary. Some clinical symptoms are bloating, constipation, abdominal pain, incontinence.

The symptoms of neurogenic bladder in Spinal Cord Injury(SCI) can be broadly divided into two headings:

• Upper Motor Neuron (UMN) bowel syndrome
• Lower Motor Neuron (LMN) bowel syndrome

Upper Motor Neuron (UMN) Bowel Syndrome, occurring in a spinal cord injury above the conus medullaris results in a hyperreflexic bowel, characterized by an increased colonic wall and anal tones, with disrupted voluntary external anal sphincter(EAS) control. The nerve connections between the spinal cord and colon remain intact so, sphincter remains tight, thereby promoting retention of stool and there is preserved reflex coordination and stool propulsion. Hence, UMN Bowel Syndrome is associated with constipation and fecal retention at least in part due to external anal sphincter activity.

Lower Motor Neuron (LMN) Bowel Syndrome, occurring in a spinal cord injury at the conus medullaris or cauda equina results in an areflexic bowel, characterized by loss of spinal cord-mediated peristalsis and slow stool propulsion with an atonic external anal sphincter. Typically associated with constipation and a significant risk of incontinence due to flaccid paralysis of the external anal sphincter and reduced motor control of levator ani. 

The three main implications of disruption to the motor, sensory, and autonomic pathways post spinal cord injury on bowel function are an inability to:

1. feel when the bowel is full
2. voluntarily control muscles to defecate
3. voluntarily contract muscles to prevent defecating

Neurogenic bowel dysfunction can have different neuropathological patterns in people with SCI. They are:

• Pattern A: This pattern is seen in patients with SCI level above T7 and is characterized by loss of voluntary abdominal muscle contraction but preserved sacral spinal reflexes. Patients with this pattern have a moderate delay in Colonic transit time (CTT), absence of anal relaxation during the defecatory maneuver, and decreased intraabdominal pressure which causes very frequent constipation with significant defecatory difficulty and infrequent incontinence.
• Pattern B: Patients with SCI below T7 and who have preserved both voluntary control of abdominal muscles and preserved sacral reflexes fall under this pattern. Patients with pattern B have a moderate delay in CTT, have increased intra-abdominal pressure and increased anal resistance during the defecatory maneuver, presence of external anal sphincter contraction when intraabdominal pressure increases, and during rectal distension. So, they have frequent constipation, significant defecatory difficulty ad not very frequent incontinence.
• Pattern C: Patients with SCI·below T7 and who have voluntary control of abdominal muscles and absent sacral reflexes belong to this pattern. They have frequent constipation, less difficulty during defecation, and have a high chance of incontinence due to severe delay in CTT, increased intraabdominal pressure, absence of anal resistance during the defecatory maneuver, and absence of EAS contraction when intraabdominal pressure increases and during renal distension.

Consequences of Neurogenic Bowel Dysfunction(NBD)

People with NBD commonly have the following consequences in life:

• Loss of independence
• Feeling of embarrassment
• Social isolation (restrictions in social life)
• Decreased quality of life

Management of NBD

Bowel management will be successful only when the assessment is properly done, diagnosis is accurate and the treatment is individualized. The history-taking should include:

• Previous bowel and bladder habits and the findings should be related to current situations
• Premorbid bowel history which includes daily fluid intake, diet (fiber, meal frequency, spice preferences, amounts), bowel movements (frequency, duration, difficulties), stool (consistency, color, mucus, blood), medications

Non-Pharmacological management

This method of management includes multifaceted programs, use of suppositories, dietary fibre, reflex Stimulation of the GI tract, abdominal massage, assistive devices, irrigation techniques, functional electrical and magnetic stimulation of skeletal muscles.

Successful bowel management is multi-dimensional and needs to be specific to each individual requiring careful assessment for accurate diagnoses and prescription of treatments for bowel management following spinal cord injury, recognising that completeness of injury also has a significant impact on bowel function.Key strategies for bowel management include a high-fibre diet although further research to examine the optimal level, adequate fluid intake and a regular routine for bowel evacuation, which may incorporate digital stimulation or manual evacuation. Transanal irrigation is also now seen as a promising technique to reduce constipation and fecal incontinence. Prokinetic agents such as cisapride, prucalopride, metoclopramide, neostigmine, and fampridine are supported by strong evidence for the treatment of chronic constipation in individuals with a spinal cord injury in those where conservative management is not effective. 

Bowel Management Options	Considerations for Appropriate Bowel Management Options
High Fibre Diet	Presence or Absence of Bowel Reflexes Complete Lesions below the conus medullaris have loss of bowel reflexes, Complete Lesions above the conus medullaris do not have loss of bowel reflexes Hand Function Patients’ Preference Other Complex Factors
Adequate Fluid Intake
Regular Bowel Emptying Routine
Digital Stimulation Bowel Reflexes
Medication Oral e.g. Bowel Softeners Rectal e.g. Enemas