Constipation in Cancer Patients
Constipation is the commonest preventable problems of patients with advanced cancer. Some causes of constipation are specific to cancer patients. Always anticipate and prevent it by regular monitoring, attention to the environment, concurrent administration of laxatives with opioids and regular review. Because some causes are reversible, always try to find out the cause. Digital rectal examination provides much information about the type and the cause of constipation that are important for deciding the approach to treatment. A stepwise approach is adopted in the use of laxatives. Combination of oral stool softeners and contact stimulants with morning use of suppository or enema are effective in most cases. Lactulose and bulk laxatives are inappropriate in patients who have limited intake of fluid.
It is the commonest preventable problem which affects 75-80% of patients with advanced cancer.1 It causes much suffering which must be treated aggressively if established. Apart from the usual causes of constipation in non-cancer patients, there are causes that are specific to cancer patients.
Table 1 shows the causes of constipation more specific to cancer patients and their management or prevention.
Many drugs used for cancer patients are constipating. Opioid receptors are present in the gut. Constipation caused by opioids is caused by direct contact of these receptors which leads to less muscle activity and less secretion production.6
Dehydration, reduced food and fibre consumption and inactivity predispose the patient to constipation. Painful anal conditions, fear of diarrhoea or incontinence, lack of privacy and difficulty in using bedpan or toilet facilities make the patient hold back the faeces until really necessary.
Patients who do not eat any food can still produce faeces which are composed of bacteria and epithelial cells of the gut. Patients with partial intestinal obstruction can still pass flatus and faeces.
Hypercalcaemia is not uncommon in cancer patients, especially in those with myeloma or bone secondaries from breast and kidney cancers. Constipation is a common feature of hypercalcaemia.
Neurological deficits can disturb the motor function of the gut and control of anal sphincter leading to constipation. They also cause immobility, impairing the patient’s ability to answer to the call of defaecation.
Abdominal pain can be present, but most patients with constipation do not have pain. Some may complain of rectal pain or discomfort. There can be no urge to defaecation in colonic inertia or neurological deficit. The only complaint may be quite non-specific such as malaise, anorexia, bloating, nausea and vomiting. They may even present as urinary retention, bowel obstruction, restlessness or confusion especially in elderly patients. Paradoxically, it can present as diarrhoea. Rectal discharge or spurious diarrhoea in constipation or intestinal obstruction are caused by bacterial liquefication of faecal material, increased mucus production and liquid faeces seeping past faecal lumps.
Always try to find the causes, many of which are reversible.
Most patients may complain of constipation. However, some patients may not complain of it unless being asked about it. So, always ask for bowel function, not only about frequency,7 but also the quantity and consistency of faeces.8 Regular review of bowel function is essential because established constipation may be very distressful and refractory to treatment. Table two shows the questions to be asked in history taking.
Table 2: History to be taken about constipation
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Usual bowel habit Nature of cancer Current medication Previous intervention - bowel resection or radiotherapy Severity of constipation – frequency, quantity & consistency Duration of constipation Any feeling of the need for defaecation yes – indicates hard stool or obstruction no – suggests colonic inertia Nature of faeces: hard, soft or spurious diarrhoea. Pain on defaecation Presence of blood in the faeces suggests tumour as a cause or haemorrhoid as a consequence of constipation Symptoms of gastrointestinal problems abdominal pain and distension, nausea and vomiting Symptoms of hypercalcaemia nausea and vomiting, polydipsia, polyuria, dehydration, confusion, clouding of consciousness. Symptoms of depression Fear about toileting – history of soiling, any holding back |
Look for signs of dehydration such as dry mouth and skin turgor. However, dry mouth is quite common in cancer patients and may not indicate dehydration.
On examining the abdomen, look for mass along the whole length of colon especially in the left iliac fossa. Faeces can be identified as non-tender, relatively mobile mass which can be indented with pressure. Also look for signs of intestinal obstruction.
Always do a digital rectal examination if a patient complains of constipation or diarrhoea. Table 3 shows the possible findings of digital rectal examination and their interpretations.
Table 3: Possible findings of digital rectal examination and their interpretations.
|
Findings |
Interpretation |
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· Empty and collapsed rectum |
· No impaction |
|
· Empty and ballooned rectum |
· High impaction |
|
· Loaded rectum with hard faeces |
· Impaction |
|
· Loaded rectum with soft faeces |
· Lack of muscular activity |
|
· Painful anal or rectal condition |
· Painful condition may be the cause |
|
· Local tumour infiltration |
· Tumour may be the cause |
|
· Reduced sensation, normal anal tone and reflex |
· Spinal cord pathology |
|
· Reduced or absent anal tone and reflex, sensory loss over sacral dermatome. |
· Sacral nerve or root pathology |
Examine the spine and the neurological condition of the lower limbs for signs of spinal cord compression or lumbosacral nerves involvement.
Assess the psychological state of the patient for any confusion, depression and level of consciousness. Also assess the psychological state of the family, their concerns, problems and ability to cope.
Few patients need investigation. Sometimes plain abdominal x-ray may be done to help making diagnosis.7,9 Presence of loaded gut may indicate impaction. Gas distension with fluid level may indicate intestinal obstruction. However, faecal retention throughout the colon may be due to a gradual organic obstruction and extensive gas distension may hide faecal material.
If hypercalcaemia is suspected from the clinical features, serum calcium level, corrected with albumin level, must be done because hypercalcaemia is reversible.
It is vital to prevent constipation by anticipating it, asking for it and regular review.
Get nursing service involved as early as possible. Record everyday in the ‘bowel book’ the times, amount, consistency, colour of every bowel motion and difficulty in passing the motion.
Always prescribe laxative with opioid, even if patient is having normal bowel motion. For patients who have no problem taking fluid, encourage them to take more fibre in the form of fruit, vegetable, bran, fibre supplement or fibre supplement with laxative such as Normacol Plus. Avoid this if the patient’s fluid intake is limited. Avoid also osmotic laxative such as lactulose if patient’s fluid intake is limited.
Opioids reduce bowel secretion and motility. Docusate (Coloxyl) with senna is a good laxative for this purpose. Docusate, a stool softener, promotes water, sodium, and chloride secretion in the jejunum and colon.10 It also stimulates gut motility in high dose.12 Senna, apart from stimulating gut motility, also increases water secretion and electrolytes. Titrate the dosage of laxative against the effect. It is not proportional to the dose of narcotic being consumed.11 However, if the dose of senna is too high, the patient may experience cramps and diarrhoea, with risk of dehydration and electrolyte imbalance.13 A higher docusate to senna ratio, one to two extra docusate 120mg cap/day, is preferred in opioid induced constipation patients who experience abdominal cramp with a high dose of Coloxyl with senna.
Give oral stimulant laxatives once daily at bedtime because the onset of effect is 6-12 hours later which matches with the massive peristalsis on waking up in the morning. If the dosage is too high for one administration, give at most twice a day.
The goal of prevention is that the patient can have a comfortable bowel motion everyday. If the oral laxative fails to open the bowel, give an additional Microlax enema or bisacodyl suppository preferably in the morning to clear the bowel out before a correct dose of oral laxative has been reached to prevent constipation. It is more uncomfortable for the patient and more difficult to treat established constipation.
Table 5 shows my favourite stepwise approach on using laxatives. Other alternative approaches using lactulose, danthron or bisacodyl may be preferred by other doctors. If the result of oral laxative is unsatisfactory, wait for two days before going to the next step. If the narcotic was increased during that period, increase the laxative as well.
Table 5: Stepwise approach on using laxatives
|
Day 1-2 |
Docusate (Coloxyl) with Senna 2 tablets bd. |
|
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or Bekunis Senna 20mg 1-2 tablets nocte |
|
|
|
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Day 3-4 |
Microlax enema or glycerine suppository 1 stat, then |
|
|
Docusate with senna 3 bd |
|
|
|
|
Day 5-6 |
Microlax enema 1 stat +/- glycerine suppository, then |
|
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Docusate with Senna 3 bd + Liquid Paraffin (Agarol) 10ml nocte + Senokot granule 1-2 tsp nocte. |
|
|
|
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Day 7-8 |
Microlax enema 1 stat +/- glycerine suppository, then |
|
|
Docusate with Senna 3 bd + liquid paraffin 15ml nocte + Senokot granule 2 tsp nocte. |
|
|
|
|
Day 9-10 |
Docusate enema 200-500ml stat* +/- glycerine suppository, then |
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Glycerine supp alternate days +/- |
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Coloxyl enemas 200-500ml weekly to twice weekly prn. |
* Dilute Coloxyl Enema Concentrate 1 in 24. As retention enema, use 100-150ml and as evacuant enema use 300-500ml.
If the patient has a tumour of the gut with a risk of obstruction, use pure stool softener, docusate 50mg 8-12 tablets a day, or 120mg 4-6 tablets daily. Avoid non-digestible food and ensure adequate fluid intake. Paraplegic patients with loss of sensation at anus tend to have faecal incontinence. They should take less fibre to avoid soiling and have a rectal clearance 2-3 times a week. Lactulose should be avoided in those who have a limited fluid intake. It also causes gas formation with uncomfortable and embarrassing flatus.
Apart from the pharmaceutical effects, suppositories work by stimulating recto-colonic reflex. Glycerine suppository works by softening faeces and it is a mild stimulant. Bisacodyl (Dulcolax) suppository, being a contact laxative, is more effective than glycerine suppository.14 Coloxyl suppository, which contains docusate and bisacodyl, is both a stool softener and a contact laxative. To be effective, make sure that the suppository is not embedded in the faeces. They are best used in the morning to match with the diurnal massive peristalsis.
Like suppositories, they are best used in the morning. Microlax enema is more effective than bisacodyl suppository and is simple to use because of its small volume. It takes 15 to 30 minutes to work.
Coloxyl retention enema comes in a concentrated solution and has to be diluted by 1 in 24 before use.
Perform a digital rectal examination. Table 3 shows the interpretation of the different findings on digital examination. If it is full of hard faeces, give a glycerine suppository, bisacodyl suppository or Microlax enema 1 stat or a combination of bisacodyl and glycerine suppository. Very big hard faeces can be softened with oil retention enema. Twenty to 100 ml of either olive oil or arachis (peanut) oil can be administered in the evening deep into rectum with a syringe and butterfly tubing with needle cut away. It can be retained overnight. Bisacodyl suppository is then used in the next morning. If the rectum is empty and high impaction is suspected, the olive oil can be administer higher up through a Foley catheter.
Large ‘rocks’ of stool need manual removal. It is a very uncomfortable procedure. The patient must be sedated beforehand. Appropriate medication include oral morphine solution 5mg and lorazepam 1mg one hour beforehand, or morphine 3-5mg sc and midazolam 2-5mg subcutaneous injection 30 minutes beforehand for those who cannot tolerate oral medication. Other suitable pre-medications are sublingual buprenorphine (Tamgesic), short acting opioid and nitrous oxide inhalation (Entonox).
If the rectum is full of soft faeces, give a glycerine suppository or a bisacodyl suppository or Microlax enema stat. If ineffective, dilute 10ml Coloxyl enema concentrate in 240ml water and give over 10-20 minutes. Repeat next day if necessary. The bowel motion can then be maintained with docusate with senna.
If the rectum is empty, the patient needs bulk laxation, plenty of water and stimulant laxative. Empty ballooned rectum indicates high impaction. Olive oil enema 20-40ml can be given and followed by high coloxyl enema 12 hours later. He may need a strong laxative to push the faeces down if there is no sign of obstruction.
After bowel function has been restored, maintain with daily oral laxative as suggested above in the section of prevention. For patients who have refractory constipation, consider use of alternative opioids such as tramadol, oxycodone and fentanyl.
It has been shown that oral naloxone and methylnaltrexone are not absorbed and they block the action of opioids on the receptors in the gut. They can reverse opioid induced constipation. For naloxone, the dose is 7-20% of the 24 hour morphine dose. The maximum initial individual dose is 5mg.15,16
During the initial phase of spinal cord compression, spinal shock causes paralytic ileus followed by spastic bowel with hypertonic anal sphincter. The constipation can be treated with adequate fibre and fluid, oral laxative and rectal suppository. Because the sacral reflex is intact, rectal stimulation by the suppository increases peristalsis and relaxation of anal sphincter. The stool may be soft, so docusate and paraffin are not appropriate
If there is no sacral reflex such as in the case of pelvic nerve or nerve root damage, rectal stimulation is useless. The anal sphincter is flaccid and peristalsis is reduced. The bowel can be made to open by straining and abdominal massage. Cholinesterase inhibitors, such as bethanechol 10-30mg, 8hrly or neostigmine 25mg eight hourly can be tried to stimulate peristalsis.17,18
It is very sweet and is found unpleasant by some patients especially those with nausea. It causes flatulence, bloating, discomfort or even cramps. The patient needs to increase water intake to as much as drinking a litre of fluid in an hour that may be impossible in some patients with advanced cancer.12
Ill people have small appetites and they tend to eat a diet low in fibre. It has been shown that individuals with severe constipation are not fibre deficient and their gut function responds poorly to added fibre.19 Fibre increases stool mass but has no propulsive activity. It also needs more water to function which may be impossible in some patients. The patient’s diet should contain normal amount of fibre, but not excessive.
Lubricants
Liquid paraffin in long term use can cause intestinal mucosal damage. Aspiration on vomiting leads to pneumonitis. There can also be troublesome seepage. Therefore, it is not to be administered at night or to debilitated patients.
If there are few symptoms of constipation during the terminal phase, laxative can be discontinued. If the patient feels the urge to defaecate or has pain or diarrhoea with incontinence secondary to faecal impaction, suppository or enema can be given.
1. Cartwright A, Hockey L, Anderson JL, Life before death, London:Routledge & Kegan Paul, 1973:23.
2. Wald A, Constipation in elderly patients: pathogenesis and management. Drugs Ageing, 1993; 3:220-31.
3. Bruera E, Chadwick S, Fox R, Hanson J, MacDonald N, Study of cardiovascular autonomic insufficiency in advanced cancer patients. Cancer Treatment Rep., 1986;70:997-1002.
4. Bruera E, MacDonald N, Cartz Z, Hooper R, Lentle B, Chronic nausea and anorexia in advanced cancer patients: the possible role for autonomic dysfunction. 1987; 2:19-21.
5. Muller-Lissner SA, Treatment of chronic constipation with cisapride and placebo. Gut, 1987; 28:1033-8
6. Manara L, Bianchetti A, The central and peripheral influences of opioids on gastrointestinal propulsion. Ann. Rev. Pharmacol. Toxicol, 1985; 25:249-73
7. Bruera E, Suarez-Almazor M, Velasco A, Bertolino M, Donald SM, Hanson J. The assessment of constipation in terminal cancer patients admitted to a palliative care unit a retrospective review. J of Pain and Symptom Management, 1994; 9(8):515-9
8. Sykes N. Methods of assessment of bowel function in patients with advanced cancer. Palliat Med., 1990; 4:287-92
9. Smith R, Lewis S. The relationship between digital rectal examination and abdominal radiographs in elderly patients. Age Ageing 1990; 19(2):142-3.
10. Mariarty KJ, Fairclough PD, Clark ML, Dawson AM, Inhibition of glucose and water absorption in the human jejunum by dioctyl sodium sulphosuccinate: a prostaglandin-mediated phenomenon? Gut, 1982; 23:A443.
11. Brunton LL, Laxatives. In: Gilman AG, Goodman LS, Rall TW, Murd F, eds. The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan, 1985:994-1003.
12. Woodruff R, Palliative Medicine, 2nd edition, Melbourne: Asperula Pty Ltd, 1996:180.
13. Muller-Lissner SA, Adverse effects of laxatives: fact and fiction. Pharmacology, 1993; 47(suppl 1):138-45.
14. Mandel L, Silinsky J, Bisacodyl (Dulcolax): an evacuant suppository. A controlled therapeutic trial in chronically ill and geriatric patients. Canadian Medical Association Journal, 1960; 83:384-7.
15. Sykes N. An investigation of the ability of oral naloxone to correct opioid-related constipation in patients with advanced cancer. Palliative Medicine 1996; 10(2):135-44.
16. Sykes NP, Oral naloxone in opioid-associated constipation. Lancet, 1991; 337:1475.
17. Woodruff R, Palliative Medicine, 2nd edition, Melbourne: Asperula Pty Ltd, 1996:182.
18. Woodruff R, Symptom Control in Advanced Cancer, Melbourne: Asperula Pty Ltd., 1997:33.
19. Mumford SP, Can high fibre diets improve the bowel function in patients on radiotherapy ward? Cited in: Twycross RG, Lack SA, Central of Alimentary Symptoms in Far Advanced Cancer. Edinburgh: Churchill Livingstone, 1986:183.
1. Always anticipate and prevent constipation by regular review and concurrent use of laxatives with opioids.
2. Constipation can present atypically with restless, confusion, urinary retention, anorexia, nausea and vomiting and even as diarrhoea.
3. Always do a digital rectal examination in patients presenting with constipation and diarrhoea.
4. Give contact laxatives in the evening and suppository in the morning to match with the massive peristalsis on waking up.
5. Avoid bulk laxatives and lactulose in patients who cannot have adequate fluid intake.
Table 1: Causes of constipation more specific to cancer patients, their management and prevention.
|
Causes |
Mechanism |
Management |
|
Drugs |
· Opioids, anticholinergics, tricyclic antidepressants, phenothiazines, anti-parkinsonism agents, iron, antacid and calcium channel blocker. |
· Cease or reduce responsible drugs · Concurrent use of laxative with opioids |
|
Dehydration |
· Poor fluid intake, excessive loss through fever, sweating, vomiting, polyuria or use of diuretic |
· Encourage fluid intake, but sometimes difficult. |
|
Reduced fibre consumption |
· Poor food intake, low fibre food |
· Normal fibre diet, fibre supplement |
|
Inactivity |
· Weakness or other causes of immobility |
· Encourage mobility |
|
confusion, depression, clouded consciousness |
· Elderly patients, medication · Reduced appreciation of rectal fullness2 |
· Minimise sedative |
|
Fear of soiling |
· History of soiling, tend to hold back the faeces.
|
· Reassurance |
|
Difficulty using bedpan |
· Physically frail, unused to using it, lack of privacy |
· Try to sit the patient up, bedside commode |
|
Difficulty using toilet |
· Admission into hospital or hospice, become confused, unfamiliar with toileting arrangement, · Toilet seat too low for weak patients or those with musculoskeletal problems |
· Clear direction to toilet facility · Easy access to toilet · Raise toilet seat |
|
Metabolic problems |
· Hypercalcaemia, hypothyroidism, hypokalaemia |
· Correct the cause if possible |
|
Neurological deficit |
· Lumbosacral spinal cord, sacral nerve roots, cauda equina or pelvic plexus by compression or infiltration or presence of cerebral tumour · General autonomic failure in small and large bowel caused either by medication or toxic substances of the cancer.3,4 (Look for associated features are rapid heart rate and gastric stasis with nausea) |
· See text
· Cisapride improves stool consistency and frequency.5 |
|
Painful anal conditions |
· Anal fissure or stenosis, perianal abscess and haemorrhoid |
· Treat accordingly |
|
Colorectal conditions |
· Obstruction of the large bowel by cancer, radiation fibrosis with or without stricture or pelvic tumour |
· Treat obstruction according to the condition and life expectancy of patient. |