Elderly Diarrhea – Causes, Dangers, Treatment in Seniors

Diarrhea can affect any person from any age. It is one of the common ailments that we all suffer with from infancy until the senior years. Many of the causes of diarrhea across all ages are usually similar. However, there may be certain reasons why diarrhea is more likely to occur in a specific age group. Some of these age-specific causes of diarrhea should be considered for the elderly, especially when the diarrhea is recurrent or persistent and not due to any clearly identifiable disease.

Why does diarhea affect the elderly?

Chronic diarrhea is a common ailment that some seniors suffer with and the elderly may also be more prone to acute diarrhea than younger adults. However, some elderly people are more prone to the other extreme of bowel habit – constipation. When diarrhea does arise, it has to be established whether it is acute or chronic. The causes of both acute and chronic diarrhea can differ significantly and some of these causes may not be easily treated.

Acute diarrhea refers to diarrhea that arises suddenly, is intense but for a short period of time and resolves thereafter. It may require medical treatment or resolve on its own without ay treatment. Chronic diarrhea persists for long periods of time. Usually this is defined as diarrhea that persist for more than 4 weeks. However, recurrent diarrhea (diarrhea that comes and goes) may also be considered as chronic.

Most of the time acute diarrhea is due to infections and certain foods. This is not uncommon to any age group but the elderly may be prone to infectious diarrhea and dietary-related diarrhea for several reasons. Chronic diarrhea is more likely associated with certain chronic diseases of the bowel or sometimes with other organs and systems. Sometimes chronic medication may be the cause, which the elderly are more likely to use since these chronic ailments are more common in the senior years.

Causes of Diarrhea in the Elderly

It is important to understand what diarrhea is and how it can occur. Diarrhea is a symptom of various conditions. It is defined as having three or more bowel movements within a 24 hour period where the stool is typically watery.

Diarrhea is usually due to faster than normal bowel motility (movement through the bowels) which may occur for various reasons. In addition, water reabsorption may be affected thereby resulting in excessive fluid within the bowels. This prevents stool from becoming firm and solid.


Bacteria, viruses and parasites are some of the common causes of infectious diarrhea. Most of these pathogens are contracted through contaminated food or water but can also be passed through airborne particles and even through particles on inanimate objects (fomites). These microorganisms irritate and damage the bowel lining and may also disrupt the water content in the bowels.

Sometimes certain microorganisms may grow uncontrollably in the bowels like with the bacterium Clostridium difficile. This is more likely to occur after antibiotic use or some other distrbance to the normal “good” bowel bacteria. The elderly may be more prone to infections due to a weakened immune system.


A change in diet can cause gastrointestinal upset and may lead to acute diarrhea. This is usually short lived. However, with the elderly there may also be disturbances in normal digestion of food (maldigestion) and absorption of nutrients (malabsorption).

As a result the undigested food and unabsorbed nutrients affects water reabsorption and leads to diarrhea. Lactose intolerance is one such example where the body’s ability to digest milk sugars is impaired. Gallbladder problems may also affect food digestion and absorption, especialy of fats.

Read more on loss of appetite in the elderly.


Various drugs can cause diarrhea as a side effect. Apart from antibiotics which may affect the normal bowel bacteria which are necessary for bowel health, other drugs can also irritate the bowel wall, impair water reabsorption in the colon and even speed up movement through the bowels. Certain antidepressants, antacids, acid-supressing drugs and cancer medication may be responsible.

Bowel Diseases

Several bowel diseases may present with diarrhea. Inflammatory bowel disease (IBD), diverticulitis and irritable bowel syndrome (IBS) are some examples. In the elderly, conditions such as diverticulitis are more likely to occur with advancing age. This is inflammation of the abnormal pouches that form in the colon.

One of the main concerns among the elderly is colorectal cancer. This is one of the more common cancers globally and can cause changes in bowel habit like diarrhea. Surgery to the small or large intestines may also cause diarrhea, particularly if digestion and absorption are significantly affected.

Other Diseases

Some diseases that may cause diarrhea may not directly affect the bowel. Instead the activity of the bowel muscles or the nerves that control bowel movements are affected. This may be seen in conditions like diabetes where the nerves that control bowel muscles are damaged. Diseases of other organs like the pancreas (pancreatitis or pancreatic cancer) may also lead to diarrhea if the digestive enzymes secreted by the pancreas are affected.

Dangers of Elderly Diarrhea

The main complication of diarrhea is dehydration and this can be life threatening. There is a greater risk of dehydration in elderly diarrhea if seniors do not have proper care, cannot rehydrate properly or use drugs that may worsen the dehydration, like certain blood pressure medication.

The other danger with diarrhea is malnutrition. It is more likely to occur in seniors who are unable to prepare nutritious meals for themselves, with reduced appetite that is common in older peopler and seniors who tend to have poor dietary habits, like living on a tea and toast diet.

How Should Diarrhea Be Treated?

It is important to seek medical attention, especially when seniors have other pre-existing diseases, when diarrhea is severe and oral rehydration is not possible. Diarrhea is a symptom and the most effective way to treat it is to treat the underlying cause. This may required various different medication depending on the causative condition.

Bed rest, plenty of fluid intake and frequent small meals that are nutritious but bland are the most important approaches to treating and managing elderly diarrhea. Intravenous (IV) fluid administration may be necessary. Chronic medication should not be stopped without a doctor’s approval and new medication should not be started unless prescribed by a doctor.

Read more on foods to stop diarrhea.

Antidiarrheal drugs like loperamide should not be used to treat diarrhea. It can worsen certain causes of diarrhea like infections. These drugs should only be used if prescribed by a doctor.
