The Pediatric Surgery Service: Pediatric Abdominal Pain and Constipation
By Gregg Ford, M.D., and Rita Snavely, RN, FNP

“Abdominal pain” in a child is one of the more common complaints leading to evaluation by a health care provider. The etiology of such pain is usually clinically quite obvious; occasionally the source of abdominal pain may be subtle and elusive. In a two-year review of all children (0-18 years of age) admitted to St. John's Hospital for evaluation of abdominal pain only 6 percent were found to have a surgical disease. The more common causes of the pain were gastroenteritis, dehydration, pneumonia, and constipation.

Gastroenteritis, dehydration and pneumonia are self-limited conditions which resolve with fluid resuscitation and occasional antibiotics for some pneumonias. Conversely, the pain of constipation in children tends to be persistent, may present as a non-descript discomfort, may follow other illnesses, and/or may be a child’s reaction to a dysfunctional social environment. Constipation can be quite frustrating to treat for the patient, their families, and the health provider. Constipation will tend to recur if the etiology is not understood and/or if not adequately managed. 

Most, 80-85 percent, of constipation is functional in nature. These problems tend to be self-limited, are relatively easily treated, and usually have a clear precipitating cause. Once these children are satisfactorily treated they do not require further diagnostic evaluation for organic causes of constipation. Many of these children present in a seasonal manner. In the fall and spring we commonly see children who have had a viral illness, have become relatively dehydrated and then have become constipated. We also see a fair number of children with constipation just before the school year is about to begin. Many of these children admit to being anxious about beginning the school year and being in a new social situation. Frequently, a constipated child will be living in a broken home, in a home in which the parents argue or have substance addictions, or where the children are subject to abuse. 

The family will often indicate that the child is having a bowel movement daily, sometimes even “diarrhea,” but on clinical examination stool is easily palpated throughout the left colon. Some families are adamant that “there is no way my child is constipated.”  An abdominal plane X-ray usually shows stool throughout the entire colon. We spend a great deal of time discussing the apparent paradoxes with the family. “How can there be constipation when he/she is having loose stools?”  We explain that the colon is attempting to rid itself of the fecal load. The rectum generates a fair amount of mucus which may be construed as diarrhea.  We are often confronted with the question “he/she just can’t have constipation, we have never heard of constipation causing pain, and the pain is really severe." 

We explain that the nervous innervation of the gastrointestinal tract is a bit different than the rest of the body. We explain to the parents that we could actually incise someone’s colon while they are awake and they would not feel pain, but, if we were to stretch that same intestine then the patient would feel some of the worst pain possible.  We explain that that is exactly what happens when an infant has colic. The infant swallows quite a bit of air, that air gets into the intestine, the intestine is stretched and the child screams out in pain. In the case of constipation, we explain that the intestine is nothing but a tube going from the mouth to the anus. 

When that tube is blocked up with fecal matter then swallowed air cannot pass normally. That air stretches the intestine and the child feels pain, sometimes a lot of pain. Most families find these explanations quite satisfactory. We will often send the patient for a plane abdominal film, then review the film with the family. Stool is quite easy to see on a film. We explain that the stool should be in the area of the rectosigmoid colon and we can often point out stool that extends around the entire colon to the level of the appendix. We find this exercise to be very educational for the family and enhances their understanding of the magnitude of the problem. 

Almost all children with these types of constipation can be managed with a bowel clean out and a functional constipation maintenance regime. 

Consideration of organic causes of constipation may be considered in those children who chronically fail catharsis and a bowel management program, or in those children who clinically may have other problems which typically lead to constipation. As an example, these would include children who have been constipated since birth and may very well have Hirschprung’s disease. Other causes of organic constipation include electrolyte imbalance, thyroid disease, lead intoxication, or cystic fibrosis.

We have developed a protocol for the evaluation and systematic management of pediatric patients with constipation. We have found this protocol to be well received in the primary care setting. We begin with a basic evaluation followed by a progressive treatment regimen for functional constipation. If the patient is refractory, then management is intensified and consideration is given to evaluation for organic constipation.

PROTOCOL FOR MANAGEMENT OF CHILDREN WITH FUNCTIONAL CONSTIPATION

The patient with constipation most commonly will have a functional problem.  Although consideration should be given to other causes of constipation, the usual patient will respond to catharsis and not require further evaluation.  For the routine-type patient we proceed in a stepwise manner from disimpaction, to early maintenance programs, to prolonged bowel regimen (if required).  The details of those steps are as follows:

DISIMPACTION

Disimpaction is required if there is a large amount of stool present (identified by physical examination or on abdominal radiograph). This may be done by oral or rectal medication and may require a combination of methods:

Children <2 years old:

Oral medications:

• Trial of prune or other laxative-type juice may be sufficient

• *Mineral oil (> 1 year old): 15-30ml/year of age

• Polyethylene glycol (PEG 3350) 0.75grams/kg/day up to 2 grams/kg/day

Rectal medications:

• Glycerin suppository (these come in infant through adult sizes)

• Bisacodyl suppository (1/2 of a 10mg suppository).

Children >2 years old:

Oral medications:

• GoLightly (polyethylene glycol-electrolyte solution)-20 to  60ml/kg/day (up to 1 gallon). 

• Polyethylene glycol (PEG 3350 powder is the same ingredient as in GoLightly) may be given in large doses than for maintenance or for Disimpaction if preferred over GoLightly

• *Mineral oil: 15-30ml/year of age up to 240ml/day

Rectal medications

• Fleets phosphate enema—6ml/kg (up to 135ml)

• A mineral oil enema may be needed first if the stool is hard

• Bisacodyl suppository (10mg)

EARLY MAINTENANCE

Children <2 years old:

Oral medications:

• Lactulose - 1-3ml/kg/day (may be divided for BID dosing)

• Corn syrup - 5-10ml up to every formula or juice bottle

• Maltsupex - 5-10ml once or twice a day in formula or juice

• *Mineral oil (> 1 year old) - 15-30ml/year of age/day

• Polyethylene glycol (PEG 3350) 0.75gm/kg/day to 2 grams/kg/day with flavored liquid, formula, or juice

Rectal medication

• Occasional glycerin suppository

Children >2 years old:

Oral medications

• Polyethylene glycol (PEG 3350) up to 2 grams/ kg/day (usually ½  to 1 capful in a flavored liquid once or twice a day. Adolescents may require larger dose

• Lactulose - 1-3ml/kg/day (dose can be divided for BID dosing

• Milk of Magnesia--- (2-5 years) 1-3 teaspoons daily (> 5 years) 1-2 tablespoons 1-2 times daily

• *Mineral oil: 15-30ml/year of age/day up to 240ml

Rectal medications:

• Fleets phosphate enema (6ml/kg up to 135ml) every 3 days if no stool using other medications

• *Mineral oil may be given with chocolate syrup, chocolate milk, or other flavored fluids, and is usually better tolerated if cold. Although vitamin deficiencies have not been well documented with chronic therapy, if a multivitamin is given, it should be given at a different time of day.

We also formally document a patient’s progress with the following chart. Some patients will respond well to one modality and not others (e.g. mineral oil vs glycerin vs Dulcolax, etc). We have found that those children with future recurrent problems tend to respond well to previous successful modalities.  This chart allows us to keep track of treatment success/failures for each patient

FUNCTIONAL CONSTIPATION PROTOCOL
MEDICATIONS AND TREATMENTS

MAINTENANCE THERAPY

Once a normal stooling pattern is achieved:

• Diet counseling, if appropriate

• Behavioral counseling, if appropriate

• Decrease dosage of medication as diet improves (as long as able to maintain normal stooling pattern). Stimulant laxatives may be necessary for short periods of time if constipation relapse occurs.

• Follow up includes frequent office visits with evaluation of progress and adjustments of medications and diet. Initially this usually requires weekly visits, then biweekly, and then monthly visits with phone contact as needed until stable.

Once the diagnosis of functional constipation is made it is imperative that the treating provider stress to the family that successful outcome requires family support.  Initial treatment includes family education of the pathogenesis and behavioral aspects of the constipation and the importance of adherence to a bowel program.

EVALUATION AND REFERRAL OF PATIENTS WITH CHRONIC CONSTIPATION

Some patients will persist with their constipation, 15-20% of cases.  Many of these patients may have medical causes of altered colonic motility, some will have surgical causes.  Our protocol evaluation is successful in identifying the most common chronic conditions and helps direct subsequent referral.  We begin with a battery of laboratory evaluations to include:

• Plain abdominal X-ray- This is our first step. Occasionally children will have a huge fecal mass that will require manual disimpaction. This film should be reviewed by the treating physician.  Often radiograph readings will not include comments as to fecal volume or load.

If the X-ray is unremarkable, we then proceed with:

• FT4, TSH for thyroid dysfunction

• Serum electrolytes (Basic Metabolic Panel)

• Serum Calcium (often included in the Basic Metabolic Panel)

• Sweat Chloride to survey for cystic fibrosis. If suspicion is high then we will often send a serum Cystic Fibrosis DNA probe

• Celiac disease antibodies

If these evaluations are unremarkable, then invasive evaluation may be indicated.  Those evaluations include:

• Unprepped barium enema to survey for Hirschprung’s disease.  Note that a Barium enema is probably not helpful in infants or toddlers. The enema looks for a transition zone in the colon which requires some time to develop. In smaller children with strong consideration of Hirschprung’s disease (congenital colonic aganglionosis) a rectal biopsy is much more sensitive and specific.

• Rectal biopsy

• Colonoscopy if there is clinical indication of possible inflammatory changes

• U/S or MRI of lumbosacral spine to search for intraspinal problems such as tethered cord, tumors, or sacral agenesis.  These studies are best directed by the referred specialist.  Some prefer one modality over others.

We have found that most children with symptomatic constipation can be evaluated and managed using this diagnostic and treatment regimen. Referral to a pediatric gastroenterologist is appropriate for those children with truly refractory constipation and a negative workup for organic causes of constipation. Many of these children will require long-term follow-up. 

Pediatric gastroenterology services are provided through St. John's Children’s Specialty outreach clinic in Springfield.  In the refractory patient, we are also happy to participate in evaluation for surgical causes of constipation. Pediatric surgery services are provided through St. John’s Clinic-General and Specialty Surgery-Fremont in Springfield. Contact information for these St. John’s Children’s Hospital clinics is listed below. 

• E. Gregg Ford, M.D., Pediatric Surgery
  St. John's Clinic-General and Specialty Surgery-Fremont
  1965 S. Fremont Suite 100
  Springfield, MO 65804
  417-820-3800
   

• St. John's Clinic-Gastroenterology
  1965 S. Fremont Suite 100
  Springfield, MO 65804
  417-820-2226

Sources

Baker, S., Liptak, G., Colletti, R., Croffie, J., DiLorenzo, C., Ector, W., & Nurko, S.  North American Society for Pediatric Gastroenterology and Nutrition. Constipation in infants and children: Algorithm for evaluation and treatment of constipation. [Endorsed by the American Academy of Pediatrics].

Bell, E. & Wall, G.  (2004). Pediatric Constipation therapy using guidelines and polyethylene glycol 3350.

Roberts, C.  MD. Pediatric Gastroenterology, Children’s Mercy Hospitals & Clinics. Kansas City, Missouri.

Pashankar, D., Loening-Baucke, V., & Bishop, W. (2003). Safety of polyethylene glycol 3350 for the treatment of chronic constipation in children.