Paeds: Constipation

Question 1

Normal bowel movements

Answer 1

‘Normal frequency’ of defaecation is highly variable and varies with age. Average of four stools a day.

Question 2

Definition:

Answer 2

Infrequent passage of dry, hardened faeces often accompanied by straining or pain. May be abdominal pain which waxes and wanes with passage of stool or overflow soiling

Question 3

Idiopathic

Answer 3

Commonest due to a combination of:
- Low fibre diet
- Lack of mobility and exercise
Poor colonic motility (55% have a positive family history)

Question 4

Gastrointestinal

Answer 4

Hirschsprungs disease
Anal disease (infection, stenosis, ectopic, fissure, hypertonic sphincter)
Partial intestinal obstruction
Food hypersensitivity
Coaliac disease

Question 5

Non-gastrointestinal

Answer 5

• Hypothyroidism
• Hypercalcaemia
• Neurological disease e.g. spinal disease
• Chronic dehydration e.g. diabetes insipidus
• Drugs e.g. opiates and anticholinergics
  Sexual abuse

Question 6

Presentation:

Answer 6

1. Straining and/or infrequent stools
2. Anal pain on defeacation
3. Fresh rectal bleeding (anal fissure)
4. Abdominal pain
5. Anorexia
6. Involuntary soiling or spurious diarrhoea (liquid faeces passess around solid impaction
7. Flatulence
8. Reduced growth
9. Abdomial distension
10. Palpable abdominal or rectal faecal masses, usually indentible
11. Anal fissure
12. Abnormal anal tone – only if anal stenosis is suspected

Question 7

Investigations: Usually not necessary. If an organic cause is suspected, consider:

Answer 7

• FBC
• coeliac antibody screen
• TFTs
• serum Calcium
• RAST testing
• AXR
• Bowel transits studies (older child)
• Rectal biopsy (for hirschsprung’s disease
• Anal manometry
• Spinal imaging (neurological cause)

Question 8

Note:

Answer 8

May be precipitated by dehydration or reduced fluid intake or an anal fissure causing pain.
Progression:

Question 9

Progression:

Answer 9

Long-standing constipation, the rectum becomes over distended, with a subsequent loss of feeling the need to defecate.

Question 10

Dietary advice

Answer 10

• Increase oral fluid intake
• Natural laxatives e.g. fruit juice
  Behavioural measures: toilet foot rests, 5 min toilet time after meals; star charts and rewards for child passing stool; re

Question 11

Progression of management

Answer 11

• Regular oral faecal softerners e.g. Movicol, lactulose or sodium docusate will aid disimpaction
• Oral stimulant laxatives e.g. senna, sodium picosulphate may ne required
• Consider treatment of anal fissure with topical anaesthetic (2% lidocaine ointment) to reduce pain and remove voluntary inhibition to defaecate.
• Oral magnesium citrate, magnesium phosphate or large volume polyethylene glycol (PEG) electrolyte solution bowel clean out (may require NG admin for rapid infusion
• Enemas e.g. Micralax or phosphate enemas, only fi no response to intensive treatment with above
  Hospital admin for manual evac

Question 12

Disimpaction

Answer 12

a. Achieved using a disimpaction regimen of stool softeners, initially with a macrogol laxative e.g. polyethylene glycol + electrolytes (Movicol Oaediatric Plain)
b. If unsuccessful a stimulant laxative e.g. senna or sodium picosulphate

Question 13

Maintenance

Answer 13

Polyethylene glycol (with or without stimulant laxative) 
Dose should be reduced over a period of months in response to improvement in stool consistency and frequency.

Question 14

Failure to pass meconium within 24h of life

Answer 14

Hirschsprung disease

Question 15

Failure to thrive/growth failure

Answer 15

Hypothyroidism, coeliac disease, other causes

Question 16

Gross abdominal distension

Answer 16

Hirschsprungs disease or other gastrointestinal hysmotility

Question 17

Abnormal lower limb neurology or deformity e.g. talipes or secondary urinary incontinence

Answer 17

Lumbrosacral pathology

Question 18

Sacral dimple above natal cleft, over the spine – naevus, hairy patch, central pit, or discoloured skin

Answer 18

Spina bifida occulta

Question 19

Abnormal appearance/position/patency of anus

Answer 19

Abnormal anorectal anatomy

Question 20

Perianal bruising or multiple dissures

Answer 20

Sexual abuse

Question 21

Perianal fistulae, abscesses or fissures

Answer 21

Perianal Crohn disease

Question 22

Prognosis:

Answer 22

Cured by an enthusiastic and sympathetic paediatrician with complete evacuation of any stool masses, maintaining soft stools and defecation training.