Constipation
An approach to symptom management to guide decision-making in the management of patients with life-threatening illness
Appropriate assessment to identify cause and severity of symptoms
Explanation to patient and family at all stages
Institute non-pharmacological interventions
Prescribe appropriate first-line treatment
Consider adjuvant/second-line treatment
At all stages of management consider
Definition
Passage of small hard stools passed infrequently and with difficulty.
Appropriate assessment to identify cause and severity of symptoms
Associated symptoms : Flatulence, abdominal pain, bloating.
Symptoms of complications: Anorexia, overflow diarrhoea, confusion, nausea and vomiting, urinary dysfunction
Investigations are rarely needed. Abdominal x-rays may be done to differentiate between intestinal obstruction and constipation. Abdominal examination and PR are vital
Causes
| Diminished food and fibre intake; old age, anorexia, oral candidiasis Inactivity - lack of exercise Dehydration - vomiting, fever, poor fluid intake Weakness - too weak, inability to reach toilet when urged to defecate Lack of privacy Positioning - best to sit upright not to be lying on bedpan | Side effects of drugs including: Opioids (morphine, codeine), cyclizine, NSAIDS, anti cholinergics, (hyoscrine), some antidepressants (amitriptyline), anticonvulsants, iron tablets. Hypokalaemia, hypercalcaemia, spinal cord compression. Haemorrhoids, Anal fissure. Endocrine dysfunction, hypothyroidism Idiopathic |
Explanation to patient and family at all stages
Explain goals of treatment i.e. soft bowel movement every 3 days or less, not necessarily a DAILY bowel movement.
(If more than 3 days pass without a bowel movement, notify palliative care provider) Educate patient and family re need for bowel movement despite minimal intake of food. If the patient is on any opioid (weak/strong), it is essential that laxatives be used on a daily basis irrespective of bowel movement
Correct reversible factors
- Review medication
- Treat GIT disorder, hypercalcaemia, correct metabolic disorder
Institute non-pharmacological interventions
Anticipate this common problem, enquire about bowel function regularly, encourage increase in fluid intake if possible, encourage increased mobility, avoid bedpans, provide toilet privacy and adjust toilet seat if necessary.
Increased fibre intake of benefit in early disease (i.e. patient with normal oral intake) but may not be appropriate in patients with advanced disease and poor appetite/reduced oral intake of food
Prescribe appropriate first-line treatment
The aim of laxative therapy is comfortable defecation. They are divided into three groups:
- Bulking agents
- Stool softeners
- Stimulants
Bulking agents need to be taken with large volumes of water and are not effective for severe constipation and are not appropriate for routine use in palliative care particularly when the disease is far advanced and the patient is debilitated.
- Choose a combination of a stool softener and a stimulant laxative
- Stool softener – lactulose 15ml bd po/30mg d po, Sorbitol 15ml bd po/30mg d po
- Stimulant laxative – Senna 2-4 tabs nocte po, Bisacodyl 2 tabs nocte po
- A cost effective combination is magnesium hydroxide and liquid paraffin combination in 3:1 ratio
Softening laxatives
| Mode of action | Usual dose range | Comments | |
| Lactulose | Osmotic agent: (retains water in gut lumen) | 15-40 mls BD-TDS | Active in the small bowel. Latency of action 1-2 days C/I: too sweet, flatulence, bloating |
| Magnesium Sulphate | Osmotic agent | 2-4g daily | Acts throughout the bowel. Latency of action 1-6 hr(dose dependent) |
| liquid paraffin | Lubricant | -- | Increases water retention, does soften stools. Latency 1-3 days C/I: weak contact stimulant |
| Glycerine Suppositories | Lubricant | 1-3PRN | may also have an irritant action that provokes expulsion of stools |
Stimulant laxatives
| Mode of Action | Dose range | Comments | |
| Senna | All these stimulant laxative have the same actions. Stimulation of myenteric nerves Increased gut mobility Soften motion by reduced absorption of water from gut | 7.5-30mg bd | Anthraquinone family |
| Bisacodyl sodium picosulphate tablets | Cause colonic peristalsis | 10-20mg bd 5-50mg bd | Polyphenolic family Latency of action 6-12 hr |
| Bisacodyl sodium picosulphate suppositories | Cause colonic peristalsis. Rapid action of 1 hour | 10-20mg | Latency of action 1 hour C/I: Colic |
Consider adjuvant/second-line treatment
Many patients may need a combination of laxatives. Most patients prefer oral to rectal laxatives. Have an approach to the choice between rectal and oral laxatives and between softeners and stimulant drugs
- NB: Continue with first line drug therapy
- If no bowel movement for 3 days or patient very uncomfortable before 3 days do PR. If rectum empty, exclude bowel obstruction, increase dose of first-line laxatives
- If rectum full: hard stool - glycerine suppositories, or Olive oil/Arachis oil/ Sunflower oil retention enema (+/- 100ml PR),
- Soft stool - bisacodyl suppositories, if no result give sodium phosphate enema or sorbitol micro-enema
- If no result refer for manual removal under sedation Midazolam 15mg IV, or warm saline rectal lavage
Points to remember
- Colostomies are managed in the same way.
- Paraplegic patients may require manual evacuation or rectal suppositories routinely every third day.
- Diarrhoea may be as a complication of constipation
- Be aware of faecal impaction.
- Severe constipation occasionally presents with symptoms of intestinal obstruction.
- A laxative should always be started with opioid analgesia unless diarrhoea is a pre- existing problem.
- If intestinal obstruction is a possibility – use only laxatives with a predominantly softening action e.g. lactulose, sorbitol to avoid colic.
- If there is rectal impaction with hard faeces, soften the faecal mass using glycerine suppositories, or an oil enema retained overnight. If spontaneous evacuation remains impossible, a manual evacuation may be necessary.
- If there is rectal loading with soft faeces, a peristaltic stimulant e.g. senna will be effective.
- If there is little or no stool in rectum – use a stimulant/softener combination.
- Constipation in AIDS is usually drug induced.
Review assessment and management regularly to attain regular comfortable bowel movement.
At all stages of management consider
- Involvement of interdisciplinary team, including dietician
- Referral to appropriate service/more experienced clinician