AGING
October 1, 1999

Constipation in the Elderly

Ariba Khan, M.B.B.S., and John E. Morley, M.D.
Dr. Khan received her medical degree from University of Punjab and is currently a visiting scientist in the Division of Geriatric Medicine at Saint Louis University Health Sciences Center.


Constipation is a very common complaint among older persons. It is defined as defecation less than three times a week or straining on defecation at least a quarter of the time. Though many consider defecation every day as a sign of good health, this is not necessarily the case. Constipation can be classified into two types: functional and rectosigmoid outlet delay.

The prevalence of constipation is not known. However, in the U.S., a distinct geographic distribution exists that may suggest three global environmental factors: rural living, colder temperature and low socio-economic status.

Risk factors include:
  • Older age
  • African-American
  • Female
  • Poor socio-economic status
  • Less exercise
  • Less education
  • Low calorie intake.

Diet and Constipation
It is not entirely clear how diet and constipation are related. Decreased caloric intake and/or dehydration may be the cause of constipation in some patients. Lack of dietary fiber may be related to constipation.5,7 Foods high in fiber, such as 100% bran cereals, beans, peas, raspberries and broccoli, can help but, in addition to eating these foods, the person needs to be physically active and drinking adequate amounts of fluid.

Laxative Abuse
A large number of people use laxatives to self-medicate constipation. This is not a good idea, especially if they are used regularly. Chronic laxative use can injure the nerves and muscles of the colon. As a result, a chronic abuser may develop a serious condition, megacolon, where the colon becomes as flabby as an overblown balloon and is unable to push along the waste matter, thus worsening the constipation.

A large number of people use laxatives to self-medicate constipation. This is not a good idea... Chronic laxative use can injure the nerves and muscles of the colon.

Causes
Constipation is a symptom of many diseases. If you are concerned about constipation, it helps to keep a diary of bowel habits, recording stool frequency, consistency and straining. Colon cancer may cause any kind of change of bowel habits in the elderly and should always be considered a possibility. Decreased food intake can also cause constipation, as can an underactive thryoid (hypothyroidism), an overactive parathyroid (hyperparathyroidism), depression, dehydration, scleroderma (a connective tissue disease), Parkinsonism, stroke and diabetes, all of which are potentially treatable causes. Constipation may occur in an acutely hospitalized patient due to bed rest and altered dietary routines. Pain, fever, urinary or fecal incontinence, diarrhea and/or delirium may appear in persons with prolonged constipation (fecal impaction). Impaired, bed-bound patients with neurological complications may develop a twisting of the gut called volvulus. Volvulus can produce intestinal obstruction, a serious condition, causing sudden abdominal distention, cramping and vomiting and requiring immediate medical treatment.

Drugs Causing Constipation

Taking certain medicines may cause constipation:

Antacids
  • Aluminum hydroxide
  • Calcium Carbonate

Anticholinergics
Antidiarrheals
Antiparkinson's
Antidepressants
  • Tricyclics
  • Lithium
Antihypertensives/Antiarrhythmics
  • Calcium channel blockers especially verapamil
Metals
  • Bismuth
  • Iron
  • Heavy metals
Opioids
Laxatives (used chronically)
NSAIDs
Sympathomimetics
  • Pseudoephedrine

Treatment
A simple, common sense examination will usually help the doctor determine the cause of the constipation.8 Based on the results, there are several possible treatment options.

The Acute Case
An elderly patient, having a bout of constipation, should be admitted to a nursing home or hospital and given a nonstimulant laxative, such as sorbitol (if this doesn't work, irritant laxatives may need to be used), water, Fleets enemas or polyethylene glycol to clear the bowels. If they do not respond to this, increased fluid intake, either by instilling fluids into the stomach (1-2 liters) or alternatively using a high tap water enema, can be useful.

Chronic Situations
As mentioned earlier, daily bowel movements and purging are not necessary for health. People should be encouraged to train themselves to have regular bowel movements, especially after breakfast when they can take advantage of the body's natural urge (gastrocolic reflex), and counseled never to resist or postpone acting on the urge to defecate. Regular exercise, a diet including prune juice and good hydration are also important. Occasionally, biofeedback techniques are helpful if constipation is not responsive to traditional methods. Generally, modifying your diet, increasing fluid intake and exercising, is all that is needed.

If life style modifications fail, then pharmacological therapy, usually with laxatives, should be started. There are four main types of laxatives:

Bulk-forming
  • Bran
  • Psyllium preparations
  • Methylcellulose
  • Calcium polycarbophil
Surfactant laxatives
  • Docusates
  • Poloxamers
  • Castor oil
Stimulant
  • Diphenylmethane derivates
  • Bisacodyl
  • Phenophthalein
  • Anthraquinone derivates
  • Senna
  • Cascara
  • Aloe
  • Rheum (Rhubarb)
Osmotic
  • Sodium phosphate
  • Magnesium sulfate
  • Milk of magnesia
  • Magnesium citrate
  • Sorbitol
  • Mannitol
  • Glycerine
  • Lactulose

Our treatment of choice is sorbitol (30-50 cc) at night. Lactulose will have similar effects. It is important to remember that this regimen can eventually lead to diarrhea, which is cured by stopping the sorbitol! Stimulant laxatives should be used only intermittently but never long term. Sorbitol and psyllium are safe laxatives to use.10 As compared to docusate sodium, phyllium is considered superior. All laxatives may result in fluid depletion and too much potassium in the blood (hyperkalemia). Thus always drink plenty of fluid if you take a laxative.

Bulk forming laxatives work by two methods. They attract water and thus increase stool mass and soften consistency. They should not be used if the patient has a mechanical obstruction of the colon.

Mineral oil impairs absorption of fat-soluble vitamins. Patients with impaired gag and swallowing reflexes may aspirate mineral oils and develop lipoid pneumonia. Docusate produces mild side effects (cramping, rashes, nausea) and does not seem to be more useful than fluids.

Lactulose is not digested in the small intestine and can cause electrolyte changes in the colon. Senna, aloe and cascara are processed by the liver and can cause a serious protein losing condition.

Phenolphthalein is a fat-soluble stimulant and can lead to dermatitis, photosensitivity and should never be used.

Castor oil inhibits glucose and sodium absorption and is not recommended.

Bisacodyl is not absorbed and can cause diarrhea.

Summary
Constipation is a frequent problem, especially in older persons. Treatable causes should first be excluded. Treatment with fluids and, where appropriate, bulk forming laxatives (bran) and osmotic laxatives (sorbitol) are recommended. This approach will solve the problem in the majority of patients. Stimulant laxatives should be avoided.
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