Introduction to Constipation
Constipation is a clinical condition in which a person has uncomfortable or infrequent bowel movements and/or passage of hard stools.
Generally, a person is considered to be constipated when bowel movements result in passage of small amounts of hard, dry stool, usually fewer than three times a week.
Causes of Constipation
- Inadequate fibre in diet (simple constipation)
- Drugs e.g. tricyclic antidepressants, narcotic analgesics, (atropine, codeine, morphine, disopyramide) etc
- Diseases of the anus, rectum and colon e.g. fissures, haemorrhoids, cancer
- Irritable bowel syndrome
- Metabolic diseases e.g. hypothyroidism, hypercalcaemia
- Ignoring the urge to defecate e.g. due to immobility
- Lazy bowel from chronic laxative use including ‘herbal’ preparations
- Lack of exercise
- Dehydration and starvation (particularly in children)
Other Causes
- Gastrointestinal obstruction
- Anal fissure and other painful perianal lesions
- Carcinoma of the rectum and sigmoid colon
- Foreign body in the gut
- Pelvic mass e.g. fibroid, foetus
- Aganglionic and acquired megacolon
- Pseudo-bowel obstruction (Ogilvie syndrome) following immobility from any cause
Symptoms of Constipation
- Dry, hard and/or lumpy stools
- Abdominal bloating
- Excessive flatulence.
- Fewer than three bowel movements a week.
- Difficult or painful defecation
- A possible stomach ache or cramps.
- A feeling of incomplete bowels emptying after a movement.
Complications of Constipation
- Megacolon
- Anal fissures/tears
- Haemorrhoids
- Rectal bleeding
Diagnosis
- Stool examination including microscopy.
- Proctoscopy/sigmoidoscopy.
- Barium enema
- Serum hormonal levels e.g. thyroxine, triiodotyronine, thyroid stimulating hormone to exclude hypothyroidism
Treatment objectives of Constipation
- Identify and eliminate cause(s)
- Evacuate hard faecal matter
Where to use laxatives in Constipation
Laxatives are to be used in situations where straining will exacerbate pre-existing medical/surgical conditions. The conditions are:
- Angina
- Risk of rectal bleeding
- Increased risk of anal tear
Other conditions that will necessitate the use of laxatives include the following:
- In drug-induced constipation
- When it is needed to clear the alimentary tract before surgery or radiological procedures
Non-drug treatment for Constipation
- Avoid precipitants
- Eat high fibre diet (including fruits and vegetables).
- Take adequate fluid
- Megacolon: Saline enema
- Surgical: resection of large bowel
Drug treatment
A. Management of Constipation in Adults
1st Line Treatment
Evidence Rating: [C]
- Bisacodyl, oral, 10-20 mg at night
Or
- Senna, oral, 15-30 mg at bedtime (maximum 70-100 mg daily). Doses above 70 mg should be divided 12 hourly
Or
- Lactulose, oral, 15-30 ml daily until response, then 10-20 ml daily
2nd Line Treatment
Evidence Rating: [C]
- Bisacodyl, rectal, 10 mg in the morning
Or
- Glycerol suppositories, rectal, 4 g at night
Or
- Liquid paraffin, oral, 10-30 ml at night
Or
Milk of Magnesia, oral, 5-10 ml in a glass of water, 12-24 hourly
B. Management of Constipation in Children
1st Line Treatment
Evidence Rating: [C]
Lactulose, oral,
- 10-18 years: 15 ml 12 hourly
- 5-10 years: 10 ml 12 hourly
- 1-5 years: 5 ml 12 hourly
- < 1 year: 2.5 ml 12 hourly
Or
Glycerol suppositories, rectal,
- 2-5 years: 2 g at night
- < 1 year: 1 g at night
Or
Bisacodyl, rectal,
- > 10 years: 5 mg in the morning
- < 10 years: on medical advice only
Or
Senna, oral,
- 6-12 years: 5-40 ml at bedtime
- 2-6 years: 2.5-20 ml at bedtime.
Caution
- Do not use magnesium salts in patients with impaired renal function
- Laxatives should generally be avoided. Most times these drugs are needed for only a few days
- In children, laxatives should be prescribed by a healthcare professional experienced in the management of constipation in children.
Referral Criteria
The following categories of patients should be referred to a surgeon:
- Patients with absent bowel sounds, vomiting or not passing flatus
- Cases resistant to medical treatment
- Any suspected surgical cause
References
- John Hopkins Medicine: Constipation
- Cleveland Clinic: Constipation