This article reviews the developmental considerations involved in helping the family of a child with spina bifida who needs to achieve bowel continence. Strategies for success based on an algorithm are interwoven throughout the discussion. The current medications and techniques used at the developmentally appropriate times designed for optimal success are presented.
This article reviews the developmental considerations involved in helping the family of a child with spina bifida who needs to achieve bowel continence. Strategies for success based on an algorithm are interwoven throughout the discussion. The current medications and techniques used at the developmentally appropriate times designed for optimal success are presented.
Overview
A hallmark in every young family’s life is toilet training and eliminating diapers. Parents of a newborn with spina bifida have no idea what to expect or how to parent an infant with a disability. Lack of knowledge can lead to anxiety and a crisis of confidence in the parent.
Toilet training is a watershed event in a young family’s life. Bowel continence is a critically important aspect of adaptive function with enormous implications for the future. Bowel accidents are embarrassing and lead to social isolation, affecting peer relations and social success. They affect the work environment and may be a barrier to employment. Incontinence may have a lasting impact on friendships and intimacy.
Research has identified several issues related to incontinence in adults, including the decreased participation due to the time programs take, a sense of helplessness when the program did not work, the shame when asking others for assistance, and the social isolation if accidents occurred. Adults with spina bifida have felt the loss of the pediatric clinic, with no identified resource for assistance in the adult health care community.
Quality-of-life (QOL) studies have attempted to evaluate the impact of achieving continence in a person’s life. Adults and teenagers with spina bifida have a lower health-related QOL score than matched controls. The effect of urinary versus fecal continence on QOL was difficult to separate. Surgical intervention, although effective in achieving continence, did not affect the health-related QOL. The developmental age when bowel continence was acquired has not been evaluated in relation to its impact on the QOL of the teenager/adult with spina bifida. Regardless, continence is clearly one important aspect of health-related QOL in those with spina bifida.
Pathophysiology of the neurogenic bowel
Bowel movements occur through the combined activity of colonic motility, rectal storage, and elimination. The neurologic innervations of the colon include the sympathetic nervous system from T10 through L2 (inhibitory impulses in the colon and rectum), the parasympathetic system from S2 through S4 (stimulatory innervation to the descending colon and rectum), and the enteric nervous system contained in the intestinal wall regulating colorectal motility.
Liquid feces enter the ascending colon and move through the colon by contractions and mixing of the contents. This promotes absorption of water to form solid stool as it passes through the descending colon. The rectum’s main function is to store feces, and it requires the ability to be relaxed until a certain amount of stool has filled the rectal vault. The internal sphincter remains closed through inhibitory impulses and has brief moments of relaxation, releasing gas. The internal sphincter relaxes (parasympathetic response) as the rectal vault reaches a certain volume and stool begins to move through it. The external sphincter’s parasympathetic stimulation controls the stools’ passage or containment. The neurogenic bowel has one or more of these components interrupted.
In children with spina bifida, most lesions are above the S2 level, resulting in a neurogenic bowel. Colonic motility is not related to level of lesion or mobility and is prolonged as compared with controls. Slow colonic transit is related to symptoms of constipation and fecal impaction. The inability to sense impending bowel movements or to “hold it” results in fecal incontinence.
Pathophysiology of the neurogenic bowel
Bowel movements occur through the combined activity of colonic motility, rectal storage, and elimination. The neurologic innervations of the colon include the sympathetic nervous system from T10 through L2 (inhibitory impulses in the colon and rectum), the parasympathetic system from S2 through S4 (stimulatory innervation to the descending colon and rectum), and the enteric nervous system contained in the intestinal wall regulating colorectal motility.
Liquid feces enter the ascending colon and move through the colon by contractions and mixing of the contents. This promotes absorption of water to form solid stool as it passes through the descending colon. The rectum’s main function is to store feces, and it requires the ability to be relaxed until a certain amount of stool has filled the rectal vault. The internal sphincter remains closed through inhibitory impulses and has brief moments of relaxation, releasing gas. The internal sphincter relaxes (parasympathetic response) as the rectal vault reaches a certain volume and stool begins to move through it. The external sphincter’s parasympathetic stimulation controls the stools’ passage or containment. The neurogenic bowel has one or more of these components interrupted.
In children with spina bifida, most lesions are above the S2 level, resulting in a neurogenic bowel. Colonic motility is not related to level of lesion or mobility and is prolonged as compared with controls. Slow colonic transit is related to symptoms of constipation and fecal impaction. The inability to sense impending bowel movements or to “hold it” results in fecal incontinence.
Developmental aspects of bowel control
Infants have several stools throughout a 24-hour period. Stools are seedy, loose, and soft until solid food is introduced. The frequency decreases to 1 to 2 stools per day as babies approach their first birthday. At about 18 months of age, the stool becomes more formed. At 2 years, the child becomes more aware of having had a stool. Toilet training ensues as the toddler becomes aware of impending stools and chooses to use the toilet or not. By age 4 years, most children are toilet trained and cleaning themselves.
Infants with spina bifida tend to experience constipation as solid foods are introduced. Prevention of constipation is helpful in later development of a continence program. Lack of rectal awareness and lack of sensation in the perineal/buttock area results in stool remaining in the diaper until odor brings attention to its presence. Cleaning and changing remain in the parental domain as the child enters school. Continence programs need to begin at the developmentally appropriate age, to assist children with spina bifida in reaching similar developmental milestones to their unaffected peers.
Types of bowel continence programs
Dietary
Fluid and fiber remains the foundation for prevention of constipation and treatment of continence. The intake amount is determined by age and weight. In infants, fluid and baby fruits are key. In older children, fiber is added through cereals, fruits, vegetables, and breads/grains. Parents are taught to read labels to identify higher-fiber foods. Whole-grain products, introduced before low-fiber refined products, can be well-accepted by children as they grow. Fluid goals are determined by weight in children younger than 10 years. For those older than 10 years, 64 ounces a day is the basic goal. Fiber goals are based on the age plus 5 to 10 (3 years + 5 = 8 g of fiber a day). Children with spina bifida have a Chiari II malformation and may exhibit dysphagia demonstrated by low fluid volumes and difficulty with food textures. Evaluation and intervention with dietary and oral motor therapy may be helpful.
Dietary triggers that cause an unexpected or loose stool need to be identified as the child is introduced to new foods. Chocolate and spicy and greasy foods can cause loose stools. Foods that contain corn or high-fructose corn syrup are especially implicated in causing loose or unexpected stools. Some children are more sensitive than others. Any child that has not had formed stools needs to have a diet history taken to identify possible food triggers.
Medications
Oral medications are used to promote a soft formed stool that is in the rectal vault at the time planned by the family/teenager for a bowel movement. Osmotic and bulk laxatives are effective in keeping the stool soft and formed when diet and liquids are not enough. A stimulant laxative, such as senna, strengthens colonic motility, enabling the stool to be in the rectal vault 6 hours (typically) after ingestion and providing predictability for elimination. When used with a suppository or enema program, individuals can be continent ( Table 1 ).
| Common Use | Medications | Actions | Dose | Comments |
|---|---|---|---|---|
| Maintenance Oral | Lactulose | Poorly absorbed sugar with osmotic effect | Infant: 2.5–10 mL/d Child: 7.5 mL/d | Gas and bloating can be common side effects |
| Senna (8.6 mg/5 ml = 1 tab) Pedia-Lax senna (1 strip = 8.6 mg senna) | Stimulant laxative Grape-flavored quick-dissolving strips | Infant: 1.25–2.5 mL/d 1–5 y: 2.5–10 mL/d >6 y: 5–15 mL/d | Produces peristalsis; works usually in 6 h from ingestion | |
| Psyllium- (Perdiem, Fiberall) | Bulk laxative | Titrate | May cause bloating; must take with plenty of water to avoid intestinal obstruction | |
| Polycarbophil (Fibercon, Equalactin, Konsyl) | Bulk laxative | Titrate | Synthetic fiber resistant to bacterial degradation = less bloating; helpful in regulating fluid excess in bowel | |
| Guar gum (Benefiber) | Bulk laxative | 1 scoop = 3 g fiber; increase as needed every 3 days | Taste-free, grit-free; does not thicken or alter taste or texture of food | |
| Polyethylene glycol 3350 (MiraLax) | Osmotic laxative | 0.8 g/kg once/d | Not as effective in neurogenic bowel; difficult to time; can cause gas bloating and nausea | |
| Metoclopramide (Reglan) | Motility agent-gastro/colonic | 0.1–0.2 mg/kg 2–3 times/d | Decreases time stool sits in colon and prevents constipation | |
| Erythromycin | Motility agent-gastro/colonic | 2–3 mg/kg/dose 3 times/d | Decreases time stool sits in colon |
Suppositories
Suppository programs are designed to produce a bowel movement within a few minutes of insertion. Liquid glycerin, liquid glycerin with docusate (mini-enema), and bisacodyl in a wax or water-soluble base are currently available ( Table 2 ). The liquid suppositories require holding the external sphincter shut after the liquid is inserted for a few minutes to stimulate emptying. In the author’s clinical experience, this is easier for a parent to do with a baby or toddler but difficult for an older child to do independently while sitting on the toilet.
| Common Use | Medications | Actions | Dose | Comments |
|---|---|---|---|---|
| Maintenance Rectal | Docusate (Enemeez [4 mL of docusate, glycerin, polyethylene glycol]) | Stimulant | Contents of 1 mini enema; If added to transanal or MACE irrigation solution may add 1–2 | Difficult to hold in with incompetent external sphincter—does not support independence Assist in speed of emptying; administration technique supports independence |
| Bisacodyl-rectal suppository (Magic Bullet [bisacodyl in water base]) | Stimulant | 1 suppository inserted on toilet | Can be done independently; works in 5–10 min |
The bisacodyl suppository needs to be inserted through the internal anal sphincter and not into stool. The wax-based suppository is difficult to time and may work in 15 or 45 minutes. The water-based suppository works in about 5 minutes and is easy for a school-aged child or teenager to insert on the toilet and have a bowel movement in 5 to 10 minutes.
Difficulties arise with either suppository if there is low rectal tone. The anal canal has loose tissue, making it challenging to insert the suppository (liquid or solid) through the loose tissue to the internal anal sphincter and rectal vault. A clue to the problem is a parent reporting that no suppository works, an indicator for use of the cone enema.
Enema Programs
Cone enemas (transanal) use a colostomy irrigation system, which administers 1 to 2 cups of tap water while sitting on the toilet. The cone acts as a plug to keep the water inside. It produces significant rectal distention and, once removed, results in a bowel movement being completed in 20 minutes. These enemas are very effective and can be used independently by teenagers with sacral level 1 to lumbar level 1 spina bifida (sitting balance is important).
The antegrade continence enema (ACE) or Malone antegrade continence enema (MACE) is a surgical intervention that creates a continent channel at the ascending colon near the cecum. Tap water with or without other stimulants is run through, flushing out the entire colon. The MACE can be used independently by older school-aged children and teenagers. The time can be problematic, taking an average of 53 minutes. There can be “wash out” failure allowing for the water to move around the stool and not push the stool with it. Long-term follow-up indicates a 40% dropout rate in adulthood, which may be related to the lack of support in maintaining a bowel management program in the transition to adult care. Stomal stenosis may occur, requiring surgical revision. Despite many of these concerns, there remains a high degree of contentment.
A variation on this is the placement of a tube such as the Chait Trapdoor (Cook, Bloomington, IN, USA), which is similar to a gastrostomy (g-) tube (has a balloon on the tube end that is inserted into the stomach) but has a coil on the end inserted into the ascending colon to anchor it. The Chait Trapdoor is opened to insert a catheter and run the solution through the colon. The Chait Trapdoor can be done through interventional radiology as opposed to a surgery needed to create the continent stoma.
The left antegrade continent enema is a continent channel created in the left abdomen into the descending colon and acts like antegrade cone, eliminating the stool in the descending colon. The average transit time is 31 minutes and requires less solution to be instilled. The occurrence of stomal stenosis is 50% less than with the ACE.
Colostomies are not currently used unless there is a malformation of the rectum. They can be effective for some families, providing a measure of control and eventual independence.
There are no published reports on the use of the sacral nerve stimulator in the spina bifida or pediatric population, but it may have some future possibilities. The sacral nerve stimulator has electrodes implanted into the S2-4 anterior nerve roots, which are controlled by an external transmitter to stimulate the anal-rectal area so that evacuation occurs. The sacral nerve stimulator has been used and evaluated in adults with spinal cord injury. The results in this population indicate an improvement in constipation, increased defecation frequency, reduced defecation time, reduction in the number of medications required previously, and high degree of patient satisfaction.
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