Fecal Incontinence and Constipation Flashcards
How does true fecal incontinence differ from pseudoincontinence?
True fecal incontinence must be distinguished from pseudoincontinence.
Children with true fecal incontinence include some surgical patients with ARM, those with HD, and those with spinal problems, either congenital or acquired, because they lack a key anatomic element required for voluntary bowel movements.
Patients with pseudoincontinence have all the physiologic capabilities necessary for bowel control, but still soil. Their problem usually results from severe constipation (encopresis) and sometimes from hypermotility.
In addition, despite being anatomically normal, they may have significant psychological, behavioral, and/or intellectual deficiencies that severely curtail their ability to develop and maintain bowel control.
Patients with true fecal incontinence require an artificial way to be kept clean. This regimen is termed bowel management and involves a daily enema that can be given retrograde via the rectum, or antegrade via a Malone procedure or cecostomy.
Patients with pseudoincontinence, on the other hand, require an effective medical regimen for treatment of either constipation or loose stools. This involves getting the stool to the right consistency so they can have a bowel movement that they voluntarily control.
Understanding this significant distinction is the key to deciding the correct bowel treatment.
Fecal continence depends on which four main factors?
(1) voluntary sphincter muscles
(2) anal canal sensation
(3) colonic motility
(4) the intellectual and psychological capacity to achieve continence
What comprises a constipating diet?
Banana
Apple
Rice
Pretzels
Tea
Potato
Jelly (not jam)
Baked bread
White pasta with no sauce
Boiled meat, chicken, fish
Children with loose stools have an overactive colon. Most of the time, they do not have a rectal reservoir.
This means that, even when an enema is able to clean their colon, new stool passes quickly.
To prevent this, a constipating diet, bulking agents (e.g., water-soluble fibers), and/or medications (e.g., loperamide) are used to slow the colon.
Eliminating foods that loosen bowel movements (fried food, dairy products, sugary drinks, fruits, vegetables, spices, fruit juice, chocolate) will help the colon move more slowly.
What are the key steps to bowel management?
1) Perform a contrast enema with Water soluble material (not barium).
It is very important to obtain a postevacuation film. This contrast study shows the type of colon that is present: dilated and constipated or nondilated with a tendency toward loose stools. The enema volume and type can be estimated from this study.
The bowel management program is then implemented according to the patient’s type of colon and the results evaluated daily. Changes in the volume and content of the enema are made until the colon is successfully cleaned. An abdominal radiograph obtained every day after the enema is invaluable in determining whether the colon is empty.
There are different types of solutions that can be used for enemas. Saline can be obtained from a pharmacy or can be prepared at home using clean water and salt (0.9% saline can be made by adding 1.5 teaspoons of salt to 1000 mL of water).
Saline enemas are combined with stimulants (glycerine and soap) to make the enema more effective. The saline enema (range: 350–750 mL) can be mixed with glycerin (range: 10–40 mL), soap (range: 10–40 mL), and/or bisacodyl.
The daily enema should result in a bowel movement within 45 minutes, followed by 24 hours of complete cleanliness. If the chosen enema is not sufficient to clean the colon (as demonstrated by the daily radiograph), or if the child keeps soiling, the child requires a more voluminous or concentrated enema. If the ascending or transverse colon is full of stool, the volume needs to be increased. If the descending colon, sigmoid, or rectum contain stool, the amount of stimulant needs to be increased. Administering the enema with a balloon catheter helps prevent enema leakage. The “right” enema is the one that can empty the child’s colon and allow the child to stay clean for the next 24 hours. The particular enema is individualized to each patient through trial and error.
2) Start the child on a very strict diet until clean for 24h, for 2-3 days in a row.
Children with loose stools have an overactive colon. Most of the time, they do not have a rectal reservoir. This means that, even when an enema is able to clean their colon, new stool passes quickly. To prevent this, a constipating diet, bulking agents (e.g., water-soluble fibers), and/or medications (e.g., loperamide) are used to slow the colon. Eliminating foods that loosen bowel movements will help the colon move more slowly.
3) Supplement treatment with loperamide in divided doses, and water-soluble fiber or pectin.
Most children respond to this aggressive m ment within 1–2 weeks. The child should remain on a strict diet until clean for 24 hours for 2–3 days in a row.
They can then choose one new food every 2–3 days and observe the effect of this new food on colonic activity.
If the child soils after eating a newly introduced food, that food should be eliminated from the diet.
Over several months, the most liberal diet possible should be sought. If the child remains clean with a liberal diet, the dose of the medication can be gradually reduced to the lowest effective dose to keep the child clean for 24h.
How is fecal impaction managed In younger, good prognosis ARM patients?
Fecal impaction is a stressful event resulting from retained stool for several days or weeks, cramping abdominal pain, and sometimes tenesmus.
First, the impaction needs to be removed with enemas and colonic irrigations to clean the megarectosigmoid. However, manual disimpaction also may be necessary.
Then, once the colon is clean, the constipation is treated with large doses of stimulant laxatives.
Stool softeners should be avoided as they only soften the stool. They do not help it be evacuated, and the colon remains full.
The dosage of the laxative is increased daily until the right amount is reached to completely empty the colon each day.
A good bowel movement pattern is sought: one or two well-formed stools per day.
Water-soluble fiber is added, which provides stool bulk and makes the laxative more efficient.
This is extremely important in ARM because children lack the ability to feel liquid stool due to the absence of a functional anal canal. It is in this group that the combination of stimulant laxatives and water-soluble fiber to create solid stool (which can be sensed and evacuated) is essential to effective toilet training.
How is fecal impaction managed for older children with ARM and good potential for bowel control?
In older children with ARM and good potential for bowel control, laxative treatment may not be the best first-line treatment option.
Over the age of 6 years, we have found it very difficult to get children clean by starting with laxatives.
In this group who have been soiling all their lives, often with a very dilated rectosigmoid, a period of treatment with enemas (usually at least 6 months) may be necessary before attempting laxatives.
We have found that this period of being clean helps the children understand what being clean feels like and also leads to a less dilated rectosigmoid at the time of starting laxatives.
How are children with severe megarectosigmoid, suffering from
overflow pseudoincontinence (ie, requiring enormous amounts of laxatives for emptying) managed?
If medical treatment proves to be difficult because the child has a severe megarectosigmoid and requires an enormous amount of laxatives to empty, the surgeon can offer a segmental resection of the colon (see Fig. 36.9), which, when combined with an antegrade enema option (Fig. 36.10), facilitates the patient to be clean right after the operation.
Then a laxative trial can be started 6–12 months later.
In ARM it is important to preserve the rectum in patients with potential for bowel control when doing a segmental sigmoid resection. The surgeon should be very careful to preserve the blood supply to the rectum at this time, remembering that the marginal and hemorrhoidal vessels will often have been divided at the time of the colostomy and subsequent pull-through.
After the resection, the amount of laxatives required to treat these children can be significantly reduced or even eliminated.
Before performing this operation, it is important to confirm that the child is definitely suffering from overflow pseudoincontinence rather than true fecal incontinence with constipation. Failure to make this distinction may lead to an operation in which a fecally incontinent and constipated child is changed to one with a tendency to have loose stool, which will make the patient’s condition much more difficult to manage.
How is severe constipation treated among patients with ARM and HD, with good potential for bowel control?
Patients with ARM or HD and severe constipation, but the potential for bowel control, require an aggressive laxative regimen. Drugs that are designed to increase the colon’s motility (containing senna or bisacodyl) are best when compared with medications that are only stool softeners. Softening of the stool without improving the colonic motility makes the patient worse, because they no longer have control with soft stool, whereas they do reasonably well with solid stool that allows them to feel rectal distention. This is a common misconception, and the switch from stool softener to laxative usually makes an enormous difference.
In many cases, the laxative regimen that works best uses the same medications that have been tried previously but were unsuccessful. Almost always, the patient previously received a lower dose than what was really needed. Success is based on starting with a radiographically clean colon and adapting the laxative dosage to the patient’s response. The response is monitored daily with an abdominal radiograph with the laxative dose adjusted as needed. The colon must be emptied with an enema whenever 24 hours has passed without a bowel movement.
Disimpaction The disimpaction process is a vital and often neglected step. This includes the administration of enemas several times a day until the patient is clean (confirmed radiologically). The contrast enema using water-soluble material not only shows the anatomy, but also is a helpful tool for cleaning the colon. If the patient remains impacted, he or she should receive a balanced electrolyte solution via a nasogastric tube in the hospital. If this is unsuccessful, a manual disimpaction under anesthesia is usually necessary.
Determining the Laxative Requirement Once the patient has been disimpacted, a specific amount of a senna-based laxative (predicted from the contrast study) is started. An empiric dose is given, and the patient is observed for the next 24 hours. If the patient does not have a bowel movement in the 24 hours after taking the laxative, it means the laxative dose was not strong enough and should be increased. An enema is also required to remove the stool produced during the previous 24 hours. Stool in these extremely constipated patients should never remain in the rectosigmoid for more than 24 hours.
The routine of increasing the amount of laxatives and giving an enema, if needed, is continued every night until the child has a voluntary bowel movement and empties the colon completely. Ideally, this routine is checked with a daily radiograph. Each day that the patient has a bowel movement, a radiograph should confirm that the bowel movement was effective, meaning that the patient completely emptied the rectosigmoid. If the patient passed stool but did not empty completely, the dose of laxative should be increased. If the patient passed stool and successfully emptied the colon, that laxative dose should be continued on a daily basis. If the patient passed multiple stools
and the abdominal film is clear, then the laxative dose can be reduced slightly. If the stools are loose but the colon is empty, more bulking fiber should be added.
It is important to remember that patients may have laxative requirements that are much larger than the manufacturer’s recommendation. Occasionally, in the process of increasing the amount of laxatives, patients throw up, feel nauseated, or cramp with the medication before reaching any positive effect. In these patients, a different medication can be tried. Some patients vomit all kinds of laxatives and are unable to reach the amount of laxative that produces a bowel movement that empties the colon. Others empty but have significant symptoms from the laxatives. Such patients are considered medically unmanageable and are candidates for operative intervention.
When should surgery be offered among patients with functional constipation?
Surgery should be offered only after a child has undergone an intensive week-long bowel management regimen with the goal of finding a medical regimen that works for the individual child. This approach improves compliance, increases the likelihood of success, and makes many intractable patients manageable.
Medical treatments include stimulant laxatives, which are effective at generating HAPCs that result in a recognizable urge to defecate, and more effective stool evacuation bowel movements.
Their site of action is the colon, and the onset of action is usually 6–10 hours. Senna and bisacodyl are the best stimulant laxatives.
After a laxative trial, it is possible to medically manage the majority of patients referred for a surgical evaluation due to poor response to medical management. Unfortunately, this is a very small fraction of patients with FC.
In a small percentage of patients considered to have truly failed medical management, operative intervention can be considered. However, before proceeding further, it is advisable that these patients have a sophisticated motility evaluation to help guide the next steps of treatment.
The inability to reliably empty the colon with laxatives is not an indication for surgery, but it is an important predictor.
The next step is to start enemas. Enemas can be given either rectally or via an antegrade route, which requires access to the colon. Although there is no evidence that antegrade enemas are more effective than rectal enemas, there are many patients for whom rectal enemas present major compliance issues.
The enema program may be a temporizing measure before proceeding to operation. If the team caring for the patient is not able to empty the colon effectively with an enema program, which may be manifested by ongoing soiling, distention, abdominal pain, and failure to thrive, surgery becomes an option to help improve the patient’s quality of life.
In addition, patients who have withholding behavior or obstructive stooling may be candidates for botulinum toxin (Botox) injection to treat IAS achalasia.
What operative procedures can be used for the treatment of FC?
(1) anal and pelvic floor procedures
(2) antegrade enema procedures (Malone antegrade colonic enema/antegrade colonic enema [MACE/ACE])
(3) colonic resections and rectal operations
(4) stoma formation, and
(5) sacral nerve stimulation
Among patients with FC, what are the indications for anal and pelvic floor procedures?
Anal and pelvic floor procedures: Included in this group are anal dilation, IAS myectomy, and Botox injection of both the IAS and EAS.
This category has the only two RCTS in the field. The first RCT compared the effect of anal dilation and placebo in patients with FC and found there to be no difference. A second RCT found no difference in outcome between IAS myectomy and Botox injection of the IAS.
Botox injection, which causes relaxation of both the IAS in the treatment of IAS achalasia and the EAS in the treatment of EAS dyssynergia, has been shown to significantly improve stooling patterns in EAS dyssynergia.
Botox injection has the added benefit of being temporary with no long-term side effects.
Myectomy should not be used due to the risk of permanent incontinence.
Among patients with FC, what are the indications for surgical techniques for antegrade colonic irrigation?
Surgical techniques to provide antegrade colonic irrigation:
There is one prospective study in the literature and 24 other published studies, all of which are level 4 or 5 evidence describing the use of antegrade enema procedures in an FC patient. There is no uniformity in the indications for the procedure, preoperative testing, postoperative outcomes, or even the details of the technique.
Complications (including pain at catheterization, skin excoriation, stoma leakage, and stoma stenosis) are widely reported and range from 5–80% in reported series.
Antegrade enema options are very effective at helping patients regain their autonomy with their enema program.
The colon can be washed out in an antegrade fashion either via a cecostomy or a Malone appendicostomy.
The difference between the two is mostly patient preference, although obesity can limit the ability to perform an appendicostomy.
To perform an appendicostomy, the appendix is brought to the umbilicus or right lower quadrant and a valve is created in the cecum to prevent stool leakage out onto the skin. The site can be cannulated at the time of the flush.
A cecostomy requires a plastic tube to be present in the skin at all times, but avoids the 5–10% stricture rate seen in an appendicostomy.
Some patients benefit greatly from antegrade enemas, which often are used as a temporary measure until laxatives can be tried again.
In contrast, some patients fail to empty with a flush, and these are the patients for whom a better prediction of outcome using motility studies is needed.
Among patients with FC, what are indications for colonic resections and rectal operations?
Colonic resections and rectal operations:
The literature for colonic resections is limited. All studies are retrospective and level 4 and 5 evidence. There are 10 studies in the literature, representing a total of only 83 patients.
Fortunately, the preoperative workup for these patients is far more uniform. The vast majority of patients (90%) underwent contrast enemas, and about 70% of them underwent colonic manometry prior to colon resection.
The main indications for operation were failure of medical management and the presence of a megarectosigmoid.
A wide range of procedures are performed in this patient group. Colonic resections are the most commonly reported. However various pull-through type procedures (with removal of the rectum) and J-pouches, have also been reported with variable results.
The goal of all these procedures is to remove the dilated, redundant, and dysmotile colon, with some or all of the rectum, but maintain the patient’s continence.
There have been early reports describing a combination of a colonic resection with antegrade enemas in patients with soiling, which has showed promising results.
Among patients with FC, what are the indications for stoma formation?
Stoma formation:
Temporary ileostomies are sometimes required for younger children with failure to thrive and diffuse dysmotility on colonic manometry.
These patients should be distinguished from patients with small bowel pseudo-obstruction based on the fact that the dysmotility is confined to the colon.
Almost half of the patients are able to have their stoma reversed later because of colonic recovery with good outcomes.
The decision to close these stomas is largely based on improvement in colonic motility, which occurs after a period of diversion (1–2 years), and confirmed by repeat manometry.
Stomas are not benign procedures, however, with complication rates reported between 5 and 40%.
Sadly, stomas are sometimes performed in desperation in patients in whom a laxative regimen or segmental colonic resection might have been successful.
Among patients with FC, what are indications for sacral nerve stimulation?
Sacral nerve stimulation:
Sacral nerve stimulation (SNS) stimulates the anterior ramus of sacral nerve roots 3 and 4 through surgically implanted electrodes connected to a pulse generator that is placed subcutaneously in the lateral buttock.
It has largely been used for the treatment of fecal and urinary incontinence, and to a lesser degree for constipation.
Although recent retrospective studies have shown some promise for the treatment of constipation in children, larger prospective trials will be needed to truly understand how SNS works in the treatment of childhood FC and which specific patients might benefit.
A patient suffering from faecal incontinence was born with imperforate anus, three sacral vertebrae missing, a flat perineum and a mislocated rectum. The Hypaque enema shows a moderate megasigmoid. The best treatment is:
A bowel management consisting of enemas, no special diet and no medication
B bowel management consisting of enemas and laxatives
C permanent colostomy
D gracilis muscle transposition
E bowel management consisting of enemas and loperamide.
A
When instituting bowel management with enemas, the water-soluble contrast enema can help determine if the colon is dilated (hypomotile) or non-dilated (hypermotile).
In patients with a dilated rectosigmoid, the bowel is hypomotile, and will retain stool until washed out by the daily enema.
In patients with a previous resection of the rectosigmoid, the bowel is hypermotile, and usually requires agents to slow down bowel transit.
Without these agents, the patient will soil between enemas.
SPSE 1
