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Neurogenic Bowel

  1. Disease/Disorder:
    Definition

    Neurogenic bowel (NB) is the impairment of the gastrointestinal and anorectal function from a lesion in the nervous system, resulting in failure to evacuate the bowel (fecal constipation, fecal impaction) or failure to contain stool (fecal incontinence). Nervous system lesions above the conus medullaris result in upper motor NB.  Lesions at or below the level of the conus medullaris result in lower motor NB.

    Etiology

    NB is common in spinal cord injury (SCI), brain injury, stroke, spina bifida, amyotrophic lateral sclerosis, multiple sclerosis, sacral nerve injuries and diabetes mellitus, among others. 

    Epidemiology including risk factors and primary prevention

    ​The prevalence of constipation in North America has been estimated between 12 and 19%.1 Fecal incontinence and fecal impaction occur in 0.3-5% of the general population.2 It has been reported that 95% of patients with SCI required at least one therapeutic procedure to initiate defecation.1 Approximately 33% of multiple sclerosis, 25% of stroke, and 37% of Parkinson’s disease patients suffer from constipation or difficulty with defecation. Fecal incontinence occurs in about 25% and 15% of multiple sclerosis and stroke patients, respectively.3

    Patho-anatomy/physiology

    The type of dysfunction occurring depends on the level of the lesion (Table 1). With an upper motor neuron (UMN) or hyper-reflexic bowel, there is increased colonic wall and anal tone. There is loss of voluntary control of the external anal sphincter (EAS), thus allowing the sphincter to stay tight and retain stool. Stool propulsion and reflex coordination still occur as the nerve connections between the spinal cord and colon remain intact. UMN bowel produces constipation and fecal retention. The gastrocolic reflex remains active for some patients and can be helpful in bowel management. 4-6 With a lower motor neuron (LMN) bowel or areflexic bowel, there is no spinal cord mediated peristalsis; there is slow stool propulsion; and the EAS is denervated. This type of injury produces constipation and incontinence due the laxity of the EAS.


    Table 1 - Features of Upper Motor Neuron (UMN) versus Lower Motor Neuron (LMN) Bowel Dysfunction
    UMN LMN
    Constipation and fecal retention Constipation and incontinence
    Anal area appears normal. Flattened scalloped appearance of anal area
    Normal or increase anal sphincter tone Reduced anal sphincter tone
    Reflex defecation is present. Absent reflex defecation
    Anocutaneous and bulbocavernosus reflexes are present or increased. Anocutaneous and bulbocavernosus reflexes are absent or decreased.
    Target stool consistency is soft formed. Target stool consistency is firm but not hard.
      Prone to rectal prolapse
    Bowel care every 1-3 days is recommended. Daily bowel care is recommended to avoid fecal incontinence.
    Use rectal suppositories to promote peristalsis and evacuation. Rectal suppositories are not usually effective.
    Digital stimulation can be used to assist in evacuation. Digital stimulation is not effective; manual evacuation may be necessary.
    Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
    1. New onset/acute: After SCI, there is temporary loss or depression of all or most reflex activity below the level of the lesion, which may last hours to weeks (spinal shock). During this time period, there is less reflex-mediated defecation.4 Studies on the natural history of NB in other populations are lacking.
    2. Subacute: In SCI, once spinal shock has resolved, a bowel program can be initiated. The underlying pathophysiology (UMN vs. LMN) will determine the interventions to be used (Table 1).
    3. Chronic/stable: During this time period, treatment continues using an appropriate bowel program. Hemorrhoids can develop if high pressures are present due to hard stool passage. In LMN bowel, chronic passage of large hard stools can result in rectal prolapse with an overstretched, non-competent sphincter.2
    4. Pre-terminal: N/A
    Specific secondary or associated conditions and complications

    Complications due to neurogenic bowel include, but are not limited to, ileus, gastroesophageal reflux disease (GERD), autonomic dysreflexia (AD), pain, distention, nausea, anorexia, impaction, constipation, diarrhea, delayed evacuation, and unplanned evacuation. An appropriate bowel program should minimize or eliminate complications.4

  2. Essentials of Assessment
    History

    This should include pre-injury gastrointestinal function and medical conditions, current bowel program, current symptoms including abdominal distention, respiratory compromise, early satiety, nausea, evacuation difficulty, unplanned evacuations, rectal bleeding, diarrhea, constipation and pain. History should also include defecation or bowel care frequency and medication use. Daily fluid intake, diet (amount of fiber intake and calorie frequency), activity level, components of bowel care and characteristics (amount, consistency, presence of blood) of the stool should also be explored.4

    Physical examination

    The patient physical examination should be performed at onset and annually thereafter in stable situations. The examination should include complete abdominal assessment, rectal examination, assessment of anal sphincter tone, and elicitation of anocutaneous and bulbocavernosus reflexes to determine if the patient has UMN or LMN bowel. 4, 6, 7

    Functional assessment

    Assessment should include ability to learn and/or to direct others with a bowel program, sitting tolerance, sitting balance, upper limb strength and proprioception, upper limb function, spasticity, transfer skills, actual and potential risks to skin, home accessibility, and equipment needs. This assessment should occur for both the patient and caregiver. 2

    Laboratory studies

    Annual stool testing for occult blood should occur for patients over the age of 50. For patients experiencing diarrhea of unknown etiology, stool examination for fecal leukocytes, clostridium difficile toxin, and ova and parasites may be helpful in searching for a diagnosis.4, 6, 7

    Imaging

    Fecal retention and megacolon are common diagnoses in patients with neurogenic bowel, thus flat plate x-ray of the abdomen may be warranted in patients with obstipation or constipation. After age 50, colonoscopies, sigmoidoscopies, double-contrast barium enemas or computerized tomographic (CT) colonography (virtual colonoscopy) should be performed every 5-10 years (depending on the test).4, 6

    Supplemental assessment tools

    A dietary record and bowel care record can be useful to determine appropriate diet and bowel program changes. Bowel care record should include position, stimulation method, assistive techniques, time to results, and stool properties (amount, color, consistency).4 In cases where further tests are necessary to elucidate the reasons for bowel dysfunction anal endosonography, barium enemas, serial radiographs after ingestion of radiopaque beads, kymography, and electromyography of perineal muscles can be useful in characterizing dysfunction.

    Environmental

    The home environment should be evaluated, and appropriate adaptive equipment for bowel care should be prescribed. Commonly, shower chairs with seats designed to allow access to the perineal area are necessary. The equipment should be inspected and fit assessed to avoid pressure ulcers related to equipment.4, 7

    Social role and social support system

    The patient’s and caregiver’s knowledge and performance of, and confidence in, the recommended bowel management program should be assessed at each follow-up appointment.

  3. Rehabilitation Management and Treatments
    Available or current treatment guidelines

    Clinical Practice guidelines are available for SCI patients only from the Consortium of Spinal Cord medicine.2 The goals of an effective bowel program are to provide predictable and effective elimination and reduce evacuation problems and gastrointestinal complaints. The design of a bowel program should take into account attendant care, personal goals, life schedules, role obligations of the individual, and self-rated quality of life. In order to prevent complications, a bowel program should be initiated early and should be scheduled at the same time of the day to establish a habit-forming response. Thirty minutes prior to bowel care, food or liquids may need to be ingested to stimulate the gastrocolic response. Bowel care should be scheduled on average once every two days to prevent chronic colorectal overdistention. Frequency of bowel care will be dependent on amount and type of intake, activity, type of impairment, and pre-injury patterns of elimination.4-6 A summary of bowel care agents can be found elsewhere.8

    At different disease stages
    1. New onset/acute: Treatment options are available based on the pathophysiology:
      1. Reflexic bowel (UMN): Initial bowel care should consist of a chemical stimulant onto the rectal mucosa. After waiting for the stimulant to activate, the patient is placed in an upright or side-lying position and digital stimulation is performed until evacuation occurs. The goal for stool consistency is soft formed, allowing easy evacuation with rectal stimulation.4, 7
      2. Areflexic bowel (LMN): Initial bowel care should consist of upright or side-lying position, performing gentle Valsalva maneuvers and/or manual evacuation until the rectum is stool free. The goal for stool consistency is firm formed stool that can be retained between bowel care sessions and allow easy manual evacuation. 4, 7
    2. Subacute: At this stage diet, fluids, and activity help attain and maintain appropriate stool consistency. It is important to make changes to a bowel program systematically changing one factor at a time (diet, fluids, activity, schedule, position, rectal stimulant medications, mechanical stimulation, assistive techniques, or oral medications). To prevent hard stools, the individual should increase their fluid intake to assist with colonic transit time. Initially, an individual should consume only 15 grams of fiber daily and increase gradually to avoid bloating. Oral agents are also used in conjunction with diet and exercise to promote bowel evacuation. The 3-2-1 method is commonly used: stool softener three times a day, senna twice a day, and one enema. This method can be used long term or modified to meet the individual needs of the patient. Surgical measures such as colostomies and ileostomies should only be considered after conservative alternatives to alleviate complications have been exhausted. 4, 6
    3. Chronic/stable: Monitoring of diet and fluid intake should continue. Medication changes and aging can have an impact on well established bowel programs. The American Cancer Society guidelines for early detection of colon cancer should be followed starting at age 50.9These include a yearly test to detect malignancy (most commonly fecal occult blood test) and a test to detect polyps or malignancy every 5-10 years (most commonly colonoscopy).9
    4. Pre-terminal or end of life care: N/A
    Patient & family education

    This is essential. As described in previous sections, there should be understanding of the different types of neurogenic bowel and the bowel programs that are required to achieve proper care. Social and emotional support should be available to help manage actual or potential disabilities associated with neurogenic bowel. The Consortium for Spinal Cord Medicine Consumer Guideline on Neurogenic Bowel is a great resource for patients and families (even when SCI is not the underlying etiology).10

    Emerging/unique Interventions

    Appropriate neurogenic bowel management will result in regular evacuation that is predictable and at acceptable times without the occurrence of accidents (unplanned evacuation). Bowel management should become a part of the patient’s daily routine and determining if bowel dysfunction is I interfering with daily life should be evaluated as part of outcome measures.4, 5

  4. Cutting edge/emerging and unique concepts and practice
    Cutting edge concepts and practice

    Resolving fecal impaction using pulsed irrigation evacuation is being explored. This consists of pulses of warm tap water administered rectally, allowing intermittent irrigation that allows rehydration of feces, promoting peristalsis, and assisting in breaking up impaction. Efficacy of this procedure requires further study.4

  5. Gaps in the evidence-based knowledge
    Gaps in the evidence-based knowledge
    ​Not applicable at this time.
    References
    1. Higgins PD, Johanson JF. Epidemiology of constipation in North America: A systematic review. American Journal of Gastroenterology. 2004;99:750-759.
    2. Steins SA, King JC. Neurogenic bowel: Dysfunction and rehabilitation. In: Braddom RL, ed, Physical Medicine and Rehabilitation. Vol 1. 3rd ed. Philadelphia, PA: Saunders; 2006:637-650.
    3. Preziosi G, Emmanuel A. Neurogenic bowel dysfunction: Pathophysiology, clinical manifestations and treatment. Expert review of gastroenterology & hepatology. 2009;3(4):417-423.
    4. Consortium for Spinal Cord Medicine. Clinical practice guidelines: neurogenic bowel management in adults with spinal cord injury. Journal of Spinal Cord Medicine 1998;21:248-293.
    5. Spinal Cord Injury Centres of the United Kingdom and Ireland. Guidelines for management of neurogenic bowel dysfunction after spinal cord injury.http://www.rcn.org.uk/__data/assets/pdf_file/0019/253036/CV453N_full_doc.pdf. Accessed May 1, 2011.
    6. Linsenmeyer TA, Stone JM, Steins SA. Neurogenic Bowel. In: Delisa J. Physical Medicine and Rehabilitation: Principles and Practice, Volume 2, 4th edition, Philadelphia, PA: Lippincott Williams & Wilkins; 2005:1641.
    7. Stiens S, Goetz L, Strayer J. Neurogenic bowel dysfunction: Evaluation and adaptive management. In: O'Young B, Young M, Stiens S, eds. Physical Medicine and Rehabilitation Secrets. 4th ed. Philadelphia, PA: Mosby Elsevier; 2008:531-538.
    8. Appendix 4 ; Bowel Care Medications. In: Gonzalez-Fernandez M, Friedman JD, eds. Physical Medicine and Rehabilitation Pocket Companion. Vol 1. 1st ed. New York, NY: Demos; 2011:326-3279. American Cancer Society. Americal Cancer Society guidelines for the early detection of cancer. http://www.cancer.org/healthy/findcancerearly/cancerscreeningguidelines/american-cancer-society-guidelines-for-the-early-detection-of-cancer. Accessed May 1, 2011.
    9. Consortium for Spinal Cord Medicine. Neurogenic bowel: what you should know. http://www.scicpg.org/cpg_cons_pdf/BWLC.pdf. Accessed May 1, 2011.
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