Constipation in ALS
Although we joke about constipation, it is a miserable experience and should never be taken lightly in the ALS patient. Loss of appetite from frequent constipation leads to weight loss, weakness, and dehydration. Constipation can progress to blockage in the intestines and nausea, vomiting, and abdominal distension. (Vomiting is very dangerous for a person who cannot turn over when lying on his back because it causes choking.) One early sign of blockage is often overlooked. Repeated small loose or liquid stools may be ignored or thought to be sufficient when they are actually the result of a large amount of hard stool blocking the bowel with only liquid stool being able to pass around it. The blockage can become so severe as to require hospitalization and possibly even surgery to correct.
What is constipation?
That may sound like a foolish question, but many people think of constipation as having infrequent, dry, hard bowel movements. It is actually defined simply as having stools that are hard to pass. Many people have only a couple of bowel movements a week, but if they do so without straining, they are not constipated.
Normally food is liquefied in the stomach by digestive juices and moves through the small intestine in liquid form. Nutrients are absorbed in the small intestine. Waves of muscle contraction called peristalsis move the remainder along into the large intestine. In the large intestine, water is reabsorbed from the left over waste product, leaving just fecal material (stool) which is moved along and passed out of the body in a bowel movement.
Anything that changes the speed with which foods move through the large intestine interferes with the re-absorption of water and causes problems. Rapid passage causes diarrhea, slowed passage allows too much water to be reabsorbed, leaving hard, dry stool that doesn't move easily through the bowel. Common causes in ALS patients include:
- Many medications affect bowel function. Prescription pain medications are especially constipating.
- Certain foods, a poor diet or changes in diet.
- Constipation is very common in anyone with poor mobility because lack of activity and exercise slow bowel motility.
- Long delays in getting to the bathroom further complicate the problem by keeping the stool in the large intestine longer where it becomes drier and harder.
- There is some evidence that ALS can affect the autonomic nervous system as well as skeletal muscle and slow the entire digestive process.
- In ALS swallowing problems make getting a good diet and sufficient fluids and fiber difficult and the problem gets worse.
- Breathing problems make it difficult to take a deep breath and bear down, something we don't even realize is important in having a bowel movement until we cannot do it.
Because so many things contribute to constipation in the ALS patient, the solution may change over time.
How to Prevent or Treat Constipation
DietThe first -- and best -- way to approach constipation is by improving your diet.
- Drink lots of fluids.
- Eat lots of high fiber foods. (Check with your doctor if you have other digestive or bowel problems or are on a special diet.) There are many high fiber cereals available and granola bars are convenient and easy to handle when feeding yourself begins to be difficult. Raw fruits and vegetables are also easy to eat sources of fiber if swallowing is not a problem.
- If you are using tube feeding, fiber is added to most tube feedings formulas. Check the label to see if your brand has added fiber.
- When diet alone isn't quite enough, try the old remedy of prunes or prune juice for occasional constipation. It really does work!
- Fiber laxatives supply the fiber necessary to add bulk which holds water and makes it easier to move the stool through the bowels.
- Today's over-processed foods are low in fiber to begin with and when swallowing problems begin there is usually even less fiber in the diet.
- Fiber laxatives are very slow acting and are taken daily to prevent constipation rather than for relief of existing constipation.
- Generally the first laxative recommended for frequent constipation, fiber laxatives are also ideal for long-term use because the fiber is not absorbed.
- Two well-known brands are Metamucil and Citrucel. Available without a prescription, some use natural fiber (agar, psyllium, kelp and plant gum.) Others are synthetic cellulose (methylcellulose). Natural and synthetic bulk-forming laxatives act similarly.
- Fiber laxatives are available as a powder (which is mixed with water or juice and generally needs to be swallowed fairly quickly before it thickens to a goo, though newer brands without that problem are available.), a tablet, or a wafer.
- It is possible to be allergic or sensitive to flavorings or other additives. Some brands may also contain enough sugar as to cause problems for diabetics.
- For the ALS patient there are two concerns with this type of laxative;
- It is essential that fluid intake be very good. 8 ounces of fluid must be taken immediately with each dose and more throughout the day is needed for safe, effective use. Taking fiber laxatives without enough fluid can cause intestinal blockage.
- They are not to be used when swallowing problems begin. Failure to drink enough water to wash down the fiber might allow it to begin to swell in the esophagus and this requires immediate medical attention. Fiber laxatives can safely be given through a feeding tube, but the fiber needs to be promptly followed by flushing the tube with water to prevent clogging.
- Stool Softeners
- Stool softeners, also called emollient laxatives, also keep the water content of the stool higher which keeps it softer and allow it to move more easily through the bowels. Stool softeners are often ideal for ALS patients. Not only do they help keep the stool soft when fiber and fluid intake is difficult, but they also are very helpful when breathing problems make it difficult to bear down and push. They do not cause frequent bowel movements, cramping or urgency but greatly reduce the amount of straining needed to have a bowel movement. Stool softeners are taken daily as a preventive measure rather than to force a bowel movement on a certain day.
- Stool softeners are available in pill or liquid form. Colace is the most commonly prescribed stool softener, but there are many non-prescription brands of the active ingredient, docusate, available, such as Surfak. Liquid docusate is also available without a prescription but the pharmacist will probably have to special order it for you as it is seldom stocked by drug stores. (Note: liquid docusate needs to be diluted in juice for drinking or it burns all the way down!!!!)
Hyperosmotic laxatives draw water into the bowel from surrounding body tissues, softening the stool. There are three types of hyperosmolar laxatives.
- The saline type is the most well-known -- and disliked! Saline laxatives are harsh, fast acting, and total in effect. They are primarily used to completely clear the bowel in preparation for surgery or bowel exams.
- The polymer type is a large molecule that causes water to be retained in the stool to soften it and increase the number of bowel movements. It is not used long term.
- Of the three types of hyperosmotic laxatives only one, lactulose, is useful for preventing constipation. Its action is so much less rapid and harsh than the saline that it is often used for long-term treatment of chronic constipation. Because it has sugar-like properties it may not be suitable for diabetics. Lactulose is available only by prescription.
- Lubricant Laxatives
Lubricants use mineral oil to coat the stool for easier passage. Mineral oil should not be taken by patients with even the slightest swallowing problem. Aspiration of oil into the lungs causes chemical pneumonia.
- Stimulant Laxatives
- The majority of non-prescription laxatives are stimulants and contain senna, castor oil, cascara, aloe, bisacodyl, or combinations. These laxatives are often marketed as being safe, "natural" remedies because the active ingredients come from plants. That makes them natural but, like many other plants, they are basically poisonous. That is why the body finds them irritating and reacts so quickly to get rid of them.
- Stimulant Laxatives increase the muscle contractions (peristalsis) of the bowel which moves the stool along. Most are intended to be fairly gentle and result in a bowel movement within 6 to 12 hours, but even these can cause cramping. If constipation is already making you uncomfortable, stimulant suppositories will provide relief within an hour but are likely to cause cramping.
- Stimulant laxatives are not for continuous or long term use! Even in ALS, they should be reserved for occasional use until other methods fail. Frequent use of stimulant laxatives can actually aggravate constipation because the bowels become dependent on them for the stimulation for even normal peristalsis. These laxatives work by irritating intestinal nerve endings, which in turn stimulates muscle contractions that move the irritant through the gut and out of the body. After a while, the nerve endings no longer respond to this amount of stimulation and larger doses are needed. For long term ALS patients, after years of frequent use, the nerves of the colon slowly disappear, the colon muscles wither, and the colon becomes dilated and unresponsive to laxatives.