Constipation

Question 1

Define constipation

Answer 1

The infrequent passage of dry, hardened faeces often accompanied by strain or pain and bleeding associated with hard stools

Question 2

How does constipation present?

Answer 2

1. Abdominal pain - waxes and wanes with passage of stool
2. Overflow soiling
3. Dehydration
4. Decreased fluid intake
5. Painful anal fissure
6. Problems with toilet training
7. Refusal
8. Anxieties about opening bowels at school or in unfamiliar toilets

*3-8 = precipitating factors

Question 3

How will the child appear on exam?

Answer 3

• Well child
• Normal growth
• Abdomen SNT
• Back and perianal area = normal position and appearance
• Soft faecal mass may be palpable in abdomen

Question 4

List the primary underlying causes of constipation

Answer 4

1. Hirschsprung disease
2. Lower spinal cord problems
3. Anorectal abnormalities
4. Hypothyroidism
5. Coeliac disease
6. Hypercalcaemia

Question 5

List the red flag symptoms/signs

Answer 5

1. Failure to pass meconium in first 24hrs of life (Hirschsprung)
2. Faltering growth/growth failure (hypothyroidism, coeliac, other)
3. Gross abdominal distension (Hirschsprung, other GI dysmotility)
4. Abnormal lower limb neurology or deformity (lumbosacral pathology)
5. Sacral dimple (spina bifida occulta)
6. Abnormal appearance/position/patency of anus (abnormal anorectal anatomy)
7. Perianal bruising or multiple fissures (sexual abuse)
8. Perianal fistulae, abscesses or fissures (perianal Crohn’s disease)

Question 6

How do we manage long standing constipation?

Answer 6

1. Disimpaction regime = polyethylene glycol 3350+electrolytes +/-stimulant laxative
2. Explain to parents that soiling is involuntary
3. Disimpaction followed by maintenance dose that is gradually decreased over a period of at least 6mths
4. Dietary interventions = balanced dieat and increase fluid
5. Behavioural interventions = sit on toilet after every meal to utilise physiologic gastrocolic reflex; can also make bathroom more inviting place
6. Occasionally will need surgical evacuation under GA

• Relapse is common - treat early and aggressively
• Most common reason for treatment failure is underuse

Question 7

Define Hirschsprung’s disease

Answer 7

Absence of ganglion cells from the myenteric and submucosal plexuses of part of the large bowel results in a narrow, contracted segment which extends from rectum for variable distance

Question 8

How does Hirschsprung’s disease present?

Answer 8

1. During neonatal period
2. Failure to pass meconium in first 24hrs of life
3. Abdominal distension
4. Bile stained vomiting

Question 9

What is observed on rectal examination in Hirschsprung’s disease?

Answer 9

1. Narrowed segment

2. Gush of liquid stool and flatus on withdrawal of finger

Question 10

How can Hirschsprung’s disease present in later childhood?

Answer 10

1. Chronic constipation
2. Abdominal distension
3. No soiling
4. Growth failure

Question 11

What investigations should be performed if HD is suspected?

Answer 11

1. Suction rectal biopsy - absence of ganglion cells and presence of large, acetylcholinesterase positive nerve trunks
2. Anorectal manometry
3. Barium studies

*2-3 useful for surgery

Question 12

How is HD managed?

Answer 12

Surgically:

- Initial colostomy followed by anastomosing normally innervated bowel to anus