Constipation is the state in which bowel movements are infrequent and the stool is hard and difficult to pass.
The effects are purely local in the lower bowel. These local effects may eventually lead to serious disturbance.
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The younger the child, the more likely it is that the problem is due to an organic cause.
It is important to exclude Hirschprung’s disease. In this condition a segment of the bowel does not relax to allow the passage of stools because the nerve supply is absent.
The commonest cause of abnormal infrequent defecation in infancy is underfeeding.
The treatment is the treatment of the cause.
A distinction must be made between soiling and encopresis.
Soiling is the involuntary passage of small amounts of stool, and results from chronic constipation.
Encopresis is the passage of normal stools at inappropriate occasions. It generally results from inadequate training or severe emotional disorder.
What is constipation?
Constipation is the state in which bowel movements are infrequent and the stool is hard and difficult to pass. The average baby passes three to six stools per day in the neo-natal period, one to two stools per day at one year and one per day or every other day in the pre-school years. Nevertheless, normal bowel frequency varies widely: some breastfed infants have a bowel action of normal consistency only once every three or four days and older children may be equally infrequent, yet pass normal stools.
What are the harmful effects of infrequent defecation? The myth of serious toxic effects caused by un-passed stools has long been discounted, though it derived from what the medical profession taught generations ago. The effects are purely local in the lower bowel. Nevertheless, the local effects, minor in their beginnings, may eventually lead to serious disturbance in some children.
Constipation of recent onset
Absence of defecation may be due to acute intestinal obstruction, in which case the presenting features are likely to be abdominal pain, vomiting and shock. This article does not discuss the causes of acute obstruction, but will focus on the mundane and less glamorous chronic variety.
Constipation in infancy
Although the vast majority of children presenting with constipation have no serious underlying pathology, the younger the child, the more likely it is that the problem is due to an organic cause. It is particularly important to exclude Hirschsprung’s disease.
Some organic causes of constipation
Hirschprung’s Disease
Anorectal anomalies
Cystic fibrosis
Metabolic and endocrine:
Hypothyroidism
Hypercalcaemia
Hypokalaemia
Renal failure
Toxic:
Lead poisoning
Spinal cord lesion
Cerebral palsy
Hirschsprung’s disease
In this condition a segment of the bowel, usually the recto-sigmoid junction, has no nerve supply, and does not relax to allow the passage of stools. The condition is present at birth.
In the early months, diarrhoea or infrequent passage of stools or even complete obstruction may occur. The child may be under-sized and the appetite poor. Abdominal distension is often seen. On rectal examination there may be no particular resistance to the examining finger and the rectum contains no faeces. Soiling is extremely rare.
A Barium enema shows a narrow segment usually in the rectum or sigmoid colon but occasionally higher up in the intestine. Removal of the abnormal segment by an abdomino-perineal operation gives excellent results.
Notes on causes of constipation in infancy
The commonest cause of abnormal infrequent defecation in infancy is underfeeding. Underfeeding, whether on breast or bottle, in the first month or two of life may lead to the passage of small, semi-liquid, dark-green stools.
Constipation may result from insufficient fluid intake, especially during a feverish illness,
or else to a change in feed or routine. Casein-containing milk formulae are more likely to constipate than the low-casein varieties.
Nevertheless, hard stools may be passed by infants who are well-nourished and evidently getting all the food they need. In these infants the process of absorption of water may be unduly active.
Straining to pass a hard stool may result in abrasion to the anus – an acute fissure-in-ano - and the stool will then often show a small streak of fresh blood. The pain on defecation results in further retention. If the fissure is not recognised and treated, it can become chronic. Severe faecal loading in the older child often has its origin in such an incident in infancy.
How is it treated?
The treatment of infrequent defecation in infancy is the treatment of the cause.
The breastfeeding infant with an infrequent bowel pattern needs no treatment.
Underfeeding should be rectified.
In infants under four months on formula feeds, an increase in fluids between feeds is often all that is required.
Over four months, the introduction of cereal and fibre in the form of sieved vegetables and unsweetened stewed fruits is beneficial.
A fissure-in-ano should be treated by the application of an ointment containing a topical anaesthetic, such as lignocane, to the anus. It should also be inserted gently into the anal canal with the little finger. This should be done three times a day, and if possible, just before a stool is passed.
A stool softener such as lactulose or sorbitol is also helpful.
If the stools remain hard and infrequent, then a safe and helpful measure is the use of senna tablets or granules at night for a limited period.
Avoid all preparations containing phenolphthalein, castor oil or cascara. Phenolphthalein and cascara can damage the colon and induce dependency. Castor oil contains ricin, which is carcinogenic. Medicinal paraffin affects absorption of fat-soluble vitamins.
Constipation in older children
The origins of constipation in older children are often difficult to pinpoint and several factors may initially have been involved:
Loss of appetite during an acute illness
The prescription of constipating medications for diarrhoea
Pain from an anal fissure
A stressful life event
Having to rise early and travel long distances to school in the morning
The need to use a cold and often unhygienic outside toilet; or filthy toilet facilities at school
Over-rigid management by parents determined to see their child toilet-trained at an early age.
Retained faeces become hard and painful to expel and as they build up, the rectum gradually becomes distended, reducing rectal sensation and thus diminishing the urge to defecate. There is frequently over-flow soiling caused by fluid stool and mucus passing around the hard faeces and staining the child’s underwear.
The child may be smelly and become the butt of jokes at school. This can have profound effects on well-being and self-esteem. Parents or teachers may adopt a punitive approach towards the child and compound an already unfortunate situation.
A special problem is that of chronic constipation in children with mental handicap and neurological disabilities such as cerebral palsy or spinal cord abnormalities.
Chronic constipation should be suspected when abdominal and rectal examinations show palpable faeces, confirmed by straight abdominal radiographs showing faecal content that may fill the entire colon. Gross distension of the bowel is not commonly seen.
Children with chronic faecal loading are often misdiagnosed as having chronic diarrhoea, non-specific abdominal pain or psychological encopresis. It has also been shown that constipation can cause reversible urinary tract abnormalities that may result in urinary tract infection and incontinence.
How is it treated?
Clearing the bowel:
The colon and rectum must be evacuated using repeated Microlax® (5ml) or Fleet® (62ml) enemas.
In advanced cases the administration by mouth of large volumes of a balanced electrolyte polyethylene glycol solution such as Golytely® is helpful.
The diet should be carefully adjusted to include more fibre– bran containing cereals, brown or whole-wheat bread, vegetables, and more fruit and fluid intake.
In addition, bulk laxatives should be given – such as Metamucil® (psyllium), or Fibogel® (ispaghula) - and continued for several months.
If this form of laxative is insufficient, it should be complemented with a stool softener (lactulose) or bowel stimulant (senna tablets or granules, one to three tablets or teaspoons at night for three to six weeks).
Encouraging a regular bowel habit:
A child should be encouraged to use the toilet at a fixed time every day and rewarded for doing so (behaviour modification). Punitive measures and harsh discipline are often at the root of the problem and parents need to be advised about this.
Faecal soiling and encopresis
As distinct from the faecal soiling or overflow incontinence in chronically constipated children just described, encopresis is the passage of stools at inappropriate occasions. Encopresis generally results from inadequate training or severe emotional disorder.
Inadequate training
Some children will have had continuous encopresis from infancy. The family is generally disorganised and chaotic, the caregiver will have made no serious attempt to train the child and the care may be cold and uninterested. These children respond well to a proper training programme, warmth and encouragement.
Underlying emotional disturbance
Encopresis can reflect a poor parent-child relationship, often of long standing, and often associated with other psychiatric problems. This symptom nearly always indicates that the child and parents need expert psychological assessment and help without delay. This will include behavioural (star chart) and individual psychotherapy, and parental counselling and family therapy to modify attitudes and hostile interactions.
Lastly, it should be borne in mind that faecal soiling may occasionally be a manifestation of sexual abuse.
Laxatives for use in children
Bulk laxatives
Bran and other vegetable fibres are best
Metamucil® (psyllium), ½ to 1 sachet daily
Fybogel® (ispaghula), ½ to 1 sachet daily
Contact laxatives
Senokot® (senna), 1 to 3 tabs at night
Osmotically active laxatives
Magnesium hydroxide, 2.5 to 5.0 ml daily (suitable for young infants)
Duphalac® (lactulose), 2.5 to 15 ml daily
Golyteley® (balanced electrolyte polyethylene glycol solution), 1 sachet in 1 litre of water: 20-25 ml/kg/hour
Avoid all preparations containing phenolphthalein, castor oil or cascara.
(Written by Prof M. A. Kibel, University of Cape Town)
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