Managing functional constipation in children

Question 1

What are the Rome III diagnostic criteria for functional constipation?

Answer 1

Must include two or more of the following in a child with a developmental age of at least four years, with insufficient criteria for the diagnosis of irritable bowel syndrome:

1. Two or fewer defecations in the toilet per week.
2. At least one episode of fecal incontinence per week.
3. History of retentive posturing or excessive volitional stool retention.
4. History of painful or hard bowel movements.
5. Presence of a large fecal mass in the rectum.
6. History of large diameter stools that may obstruct the toilet.

Question 2

What is an examples of a brief description of the mechanism of functional constipation?

Answer 2

When stool enters the normal rectum, the involuntary smooth muscle of the internal anal sphincter is relaxed. The urge to defecate is signaled when the stool reaches the external anal sphincter. If the child voluntarily relaxes the external sphincter appropriately, the rectum is evacuated. If, however, the child tightens the external sphincter and the gluteal muscles, the fecal mass is pushed back in the rectal vault and the urge to defecate subsides. Parents will likely recognize examples of these characteristic withholding behaviours: squatting, rocking, stiff walking on tiptoes, crossing the legs or sitting with heels pressed against the perineum. Withholding leads to stretching of the rectum and lower colon, and retention of stool. The longer the stool remains in the rectum, the more water is removed and the harder the stool becomes, to the point of impaction. Involuntary overflow soiling then occurs around this mass of impacted stool.

Question 3

What transition periods are particularly prone to functional constipation?

Answer 3

1. Time of toilet learning

2. During start of school

Question 4

What is fecal impaction?

Answer 4

identified by the presence of a large and hard mass in the abdomen or dilated vault filled with stool on rectal examination, and often substantiated by a history of overflow incontinence.

Question 5

What are the recommendations for disimpaction?

Answer 5

1. PEG 3350 1-1.5g/kg/day (max 100g/day) x 3d
2. Daily enemas x 6d
3. High dose mineral oil
4. Digital disimpaction cannot be recommended and may have harmful effects

Question 6

What are some medications to treat pediatric constipation and their side effects?

Answer 6

1. Lactulose - flatulence, abdominal cramps
2. Milk of magnesia - magnesium poisoning (infants), in OD hyperMg, hypoPO4, and secondary hypoCa
3. PEG - limited SE, occ. abdominal pain, bloating, loose BM
4. PEG-lyte - nausea, bloating, abdominal cramps, emesis and anal irritation
5. Mineral oil –> lipid pneumonia if aspirated
6. Senna –> idiosyncratic hepatitis, melanosis coli, hypertrophic osteoarthropathy, analgesic nephropathy
7. Bisacodyl –> abdominal cramping, nausea, diarrhea, rare proctitis
8. Docusate sodium - abdominal pain, cramping, diarrhea
9. Glycerine suppositories - none
10. Phosphate enemas - risk of mechanical trauma to rectal wall, abdominal distension or vomiting, hyperPO4, hypoCa

Question 7

What are the recommendations re: behavioral modification?

Answer 7

1. Scheduled toilet sitting for 3-10min daily to BID
2. Sit with footstool to support legs
3. Praise and reward for stooling and behavior of toilet sitting
4. Keep stool dairy
5. Regular physical activity

Question 8

What are the recommendations re: dietary modification?

Answer 8

1. Recommend balanced diet including whole grains, fruits, and vegetables
2. Carbohydrates esp. sorbitol found in prune, pear, and apple juice can incrase freq. and water contant in stol
3. Recommend fibre intake 0.5g/kg/day (to max 35g/day)

Question 9

What are the recommendations re: constipation in infants?

Answer 9

1. Mineral oil contraindicated due to aspiration risk
2. Lactulose and glycerine suppositories can be used
3. PEG 0.8g/kg/day is safe and effective in infants <18mo

Question 10

When should referral to gastroenterologist occur?

Answer 10

Consultation with a gastroenterologist should be sought when adequate therapeutic measures fail or there is a concern that organic disease exists

Question 11

What are the summary of recommendations?

Answer 11

1. A thorough history and physical examination are required to rule out organic causes of constipation.
2. Investigations (laboratory and radiography) are seldom required.
3. Education is critical at the initial visit and should be regularly reinforced at subsequent visits.
4. Disimpaction can be achieved with either oral or rectal medication.
5. A balanced and varied diet with requisite fibre intake is recommended.
6. Behavioural management should be used in conjunction with medication therapy.
7. PEG 3350 is a safe, effective and well-tolerated long-term treatment for constipation.
8. Regular follow-up is very important.
9. Referral to a gastroenterologist should be made in refractory cases or when there is a suspicion of organic disease.