Persistent constipation (refractory constipation) in children

What is refractory constipation?

We do not have an agreed definition for refractory constipation among physicians. However, refractory constipation is typically associated with symptoms that last for months to years.

What kind of investigations are required for refractory constipation?

Experts in the field have a collection of tests and investigations that help them reach the correct diagnosis and the right treatment.

What are the optional tests in cases of refractory constipation?

Contrasts enemas to assess the structure of the large intestine
This is a relatively simple test in which a contrast enema is carried out while taking a series of x-rays. The images produced allow for the assessment of the structure of the lower part of the gastrointestinal tract – the rectum and the large intestine. The images help understand whether there are areas that are narrow or dilated, and this test is the initial workup for constipation. In addition, the enema helps empty out the gastrointestinal tract, which is a desired side effect. In other words, it has both a diagnostic and therapeutic role.

Gastrointestinal transit tests

These are tests that are more sophisticated and include:

Marker tests

This is a relatively simple test that gives us an initial understanding of a child’s gastrointestinal function. The patient is asked to swallow a capsule with small plastic rings that do not get absorbed and are not broken down in the gastrointestinal tract. The capsule is broken down following swallowing and then the rings spread in the stomach and advance together with the contents of the stomach through the gastrointestinal tract. A simple abdominal x-ray is performed 5 days later. When looking at the x-ray, the physician is able to see whether the rings are still in the gastrointestinal tract and if so, where they are located. If most of them are not visible in the tract anymore, then refractory constipation is unlikely, and different types of investigations should be carried out. If most of the rings are still in the large intestine, their exact location is assessed. If most of them are visible at the end of the large intestine, this leads the physician to suspect a disorder in relaxation of the sphincters and allows management to be tailored to the problem. Despite this test not being very accurate, and not confirming the diagnosis, it still provides us with an initial idea of where the problem is likely to be and allows us to advance the investigations and management.

SmartPill

This is a sophisticated product that can measure the pressures in the gastrointestinal tract, to recognize the region of the tract and to measure the transit times. At the beginning, when it was first launched, this product seemed promising. However, little research was done to assess its performance and therefore the use of this pill was stopped about a year ago.

Testing pressures in the gastrointestinal tract (manometry)

This is a test that is done in centers that specialize in gastrointestinal motility disorders. The two main tests that are carried out in manometry tests are:

Ano-rectal manometry

This is a test that is carried out when the child is awake and it assesses the anorectal sphincters. There are two types of sphincters in the anus – the upper one is the internal sphincter, and the lower one is the external sphincter. The internal sphincter is involuntary, and it opens and closes without our active control. However, we have control of the lower sphincter, and this is what allows us to choose when to pass stool. It remains ‘overactive’ when we are restraining to hold stool in. During this short exam, a thin tube containing sensors is inserted into the anus and the response of the sphincters to a balloon distension, which mimics stool, is assessed. The test allows us to receive comprehensive information about the function of the sphincters, the pressures in the them and their response to balloon distension. The test also helps us learn about the synchronization between the gastrointestinal tract and the muscles when stool is passed. Additionally, the test allows us to rule out Hirschsprung disease, which is a disease that causes constipation due to a disorder in the innervation of the gastrointestinal tract.

Colonic manometry

This is a more complex test that is done in cases of severe constipation. Its purpose is to assess the activity of the large intestine. First, a clean out of the gastrointestinal tract is carried out (similar to what is done prior to a colonoscopy) and then, during a colonoscopy a catheter containing lots of pressure sensors is inserted into the large intestine and left there for the duration of the test. This catheter is connected to a device that measures the different pressures in the large intestine over the span of a few hours. This test allows us to assess whether the large intestine is working properly, its response to food and medication, and if there is a problem, it also helps us detect the specific area in the large intestine that is not working properly. It helps us choose the correct management.

How is refractory constipation treated?

The first step, which is just as important as any pharmacological treatment, is to go over the entire medial history from the start. It is important to truly understand when the first signs and symptoms of constipation started, when the symptoms worsened and when they improved. To try and understand what kind of treatment has already been trialed, what was helpful and what was not. It is important to understand what is concerning the patient the most – the abdominal pain? The incontinence? The social implications? And to really address these concerns. The next step is to set goals for the treatment together with the patient and to discuss the length of treatment required.
The treatment of refractory constipation takes a very long time, but it is important to keep in mind that in most cases we are able to provide the child and family significant relief.

Pharmacological treatment for refractory constipation in children

The first line of treatment typically relies on stool softeners. The most common treatment in this group of medications is polyethylene glycol (such as restorolax or peg). This substance leads to an increase in the volume of water in the large intestine and by doing so causes stools to become more watery. I am aware that most children who have come this far have already tried this treatment and failed.
The next line of treatment includes a wide variety of options, including fibers that soften stools, stimulant drugs that activate the large intestine and cause synchronized contractions to advance the stool content, and more.
The newest line of treatment includes several new medications that have only been recently introduced into the pediatric market: one group of drugs is the secretagogues that cause increased fluid secretion into the tract in an active manner. Research assessing the effects of these drugs are presently being done and published and following many years where we haven’t had any new drugs in the market, this is a meaningful development.
Another medication that is becoming more popular is prucalopride, its main advantage is its relatively selectivity to the entire gastrointestinal tract, and not only the large intestine, and that is why it is beneficial in the treatment of children who have several different affected regions in their intestines.

Rectal therapies for refractory constipation in children

Many times, the source of the constipation is the lower part of the gastrointestinal tract. Sometimes, it is a result of severe restraining habits and other times it is because of a lack of synchronization between the different muscles during defecation. These situations cause the rectum to dilate (the lower part of the tract). This dilatation causes damage to the muscles of the gastrointestinal tract and makes it harder to contract and worsens the condition. The dilated rectum is also the main reason for incontinence in children with severe constipation. The most effective way to empty the rectum in these children is with the use of rectal therapies, such as enemas and suppositories.
Because these therapies are “invasive”, there is an ongoing debate among healthcare professionals about their regular use. Some believe that because they are highly effective, they should be used frequently, despite their inconvenience. They believe that their use helps shorten therapy. Others try to avoid them because they believe they can cause further “trauma”, beyond the one that these children with severe constipation already experience, and they reserve these therapies to exceptionally severe cases.
There are many different products out there, but in children we try to avoid products that contain phosphate – a substance that is associated with mineral imbalance in the blood, and it is therefore important to stick to enemas that are made for children.
The volume of the enema may vary as well. There are enemas with smaller volumes but there are also enemas with larger volumes, containing content that is tailored to the child’s weight and condition.
Contrary to what is thought, many children agree to enemas and sometimes actually positively anticipate them because of the relief they feel after the enema.

‘Clean-out’ of the gastrointestinal tract

Cleaning out the tract is a procedure in which a large amount of laxatives are taken. Cleanouts are known to most of us as the cleanout performed prior to a colonoscopy, where the purpose is to completely empty out the large intestine. This procedure requires drinking a substance that causes lots of stools to be passed in a relatively short amount of time. During the cleanout it is very important to drink lots of fluids to prevent dehydration. In refractory constipation, a cleanout is sometimes performed in the early stages of diagnosis, to allow the child to get a good start and give the other pharmacological treatment a good chance to work. Sometimes the cleanout is performed on a monthly basis, or a weekly basis, as part of the management plan that is individualized to the patient.

Sacral nerve stimulation

In severe cases, where pharmacological treatment does not lead to improvement, or in cases where there is improvement following enemas and the child is unable to cope without enemas, there is another treatment option – sacral nerve stimulation implant device. This is a treatment that belongs to the neurostimulation field – stimulation of nerves. The device does not act on the muscles of the large intestine, but rather on the nerves that innervate the intestine at the spinal cord level.
Contrary to cardiac pacemakers, which cause regular contractions in the heart, the sacral stimulation device does not cause direct contractions in the large intestine but induces activity in the gastrointestinal nerves.
The implantation of the device is carried out in a surgery that is considered relatively simple, where several electrodes are placed in the lower part of the spinal cord. They are first connected to an external device for a temporary period of time to assess their efficacy.
If, after the trial period, there is an improvement in the constipation, the device is implanted permanently under the skin, in a simple surgical procedure.
Research has shown that the sacral stimulators mainly improve episodes of incontinence. In addition, it is important to keep in mind that sacral stimulators also work on children with urinary incontinence, therefore for children that have combined constipation as well as stool and urinary incontinence, this device should be considered.

Pelvic floor physiotherapy

Physiotherapy of the pelvic floor plays a major role in the success of the treatment. The process of emptying the gastrointestinal system is complex and requires synchrony between several different systems. Certain muscles need to contract while other need to relax and it all needs to happen in perfect synchrony.
Throughout a series of physiotherapy sessions by a physiotherapist that specialises in pelvic floor treatment, the child learns how to strengthen their core muscles, be aware of when the body is signalling the need to pass tools, as well as to learn the correct habits of sitting on the toilet: from the right timing to the correct posture. Some of these therapies are combined with biofeedback in which the child learns with the help of play, to relax certain muscles and contract others.

Emotional therapy

Chronic constipation becomes the entire household’s problem. Many times, there is a behavioural component that results from trauma, anxiety, fear or other complexities associated with going to the toilet. A previously painful experience causes the child to avoid going to the toilet and worsens the constipation even more, causing the stools to become harder, leading to the leaking of stool and a vicious cycle, that feeds itself.
An emotional therapist can guide the child and their parents and get to the source of the problem. They help the entire family deal with the situation in the best way possible and points out what should be emphasized, what should be ignored and most importantly, provides the family with tools to cope with the condition.

In summary, this is not a simple chapter because it is discusses the really severe, refractory cases. But even in these severe cases that lead to significant implications to quality of life, and despite repeated failed treatments, we still have a variety of available therapies. Finally, it is important to keep in mind that most children will either heal or improve significantly in the long-run.