Diagnosing diarrhoea

Gaye Philpott looks at faecal incontinence.

Constipation is a common frustration for many residents and the staff who care for them in aged-care facilities. However, an even bigger frustration can be diarrhoea.

Combine diarrhoea with an inability to get to the toilet in time or faecal incontinence, and a resident can be left feeling demoralised, extremely anxious and with possibly an excoriated and very sore bottom.

In the aged-care setting, however, the possibility of faecal impaction with subsequent leakage should always be excluded before a diagnosis of diarrhoea is made. Where this occurs, ongoing management is obviously aimed at preventing constipation.

Loose bowel motions or diarrhoea occurs when the transit time of food through the bowel is faster than it should be. A range of factors can be responsible for this and they don’t always involve food. Many medications, radiation treatment, organic disease, bacterial and viral infections can trigger diarrhoea.

Determining the cause is obviously in everyone’s best interests. Sometimes there will be a simple explanation, such as a resident has begun a course of antibiotics. But it’s not always that simple. That’s when a team approach involving doctor, nurse, pharmacist and dietitian can be useful. The specific expertises of each may help reveal or at least exclude less obvious causes.

Gastrointestinal infections such as those which might be caused by food poisoning can be identified from a faecal specimen. While the infection can be short lived, it may result in temporary intolerances to substances such as lactose or, in the long-term, can result in irritable bowel syndrome. Unfortunately, symptoms for both these conditions also include diarrhoea, however then the diarrhoea is usually functional in nature and is not caused by micro-organisms or organic disease.

Functional gut symptoms such as diarrhoea, bloating and excess wind occur when certain components in food are not absorbed. A classic example is lactose malabsorption or lactose intolerance. Lactose is the sugar found in all mammal milk.

It is a disaccharide sugar meaning it consists of two saccharide units. The enzyme lactase is necessary to split the chemical bond which joins these two saccharidases.

If a person doesn’t have sufficient lactase enzymes then this split can’t occur and the lactose remains intact, increasing the concentration of particles in the distal end of the small intestine. The body then tries to correct this by drawing more water into the bowel. Compounding matters is the fact that these unabsorbed particles provide a food source for the many bacteria living in our intestines – extra gas being produced as a result. The extra fluid and gas explain bloating, wind, pain and loose motions or diarrhoea.

Another food component that some people may not absorb well and which might cause functional gut symptoms is fructose which is a sugar found dominantly in fruits and honey. Others are fructans and galactans. Vegetables of the onion family and wheat are common sources of fructans in many diets, and soy, legumes and vegetables of the cabbage family are a major source of galactans.

This is not to say that anyone with diarrhoea should exclude all milk, fruit, onions, cabbage and wheat from their diet. For a start, not all people with diarrhoea are malabsorbent of these substances.

Secondly, unlike food allergies, food intolerance and the subsequent functional gut problems they can cause, are dose-related. This means that a small amount of milk will not cause symptoms, but larger amounts will.

It is generally reported that 4-5g lactose will cause functional gut symptoms in sensitive people.

This is the amount of lactose which is present in 100ml milk and 120g yoghurt.

Unfortunately, there are no blood tests for determining whether a person is malabsorbent of milk, fructose, onions, soy or wheat. The only reputable test for determining this is a hydrogen breath test but these are not commonly available, and certainly not in smaller centres. Therefore the only reliable way to diagnose such issues is if symptoms disappear when the food items are removed from the diet but return when they are included again.

It is true that too much fibre can result in loose bowel motions and diarrhoea. However, in the aged-care setting, it is unlikely that menus provide excessive fibre. Of course some individuals experience loose motions whenever they eat certain culprits such as kiwifruit or baked beans but these are usually easy for an individual to avoid if they know they cause problems.

So while foods may cause diarrhoea, the process of identifying the culprits requires careful consideration. After all, someone just can’t stop eating. Also depending on what foods are identified as causing the problem, removing them from the diet may leave the resident short of key nutrients and make it difficult for them to get sufficient calories.

A dietitian can help solve these problems. From either discussions with the resident or the review of a written food record they will be able to estimate fibre and fat intake and spot possible culprits including the likelihood of malabsorptions or food intolerances. And if significant foods need to be avoided they can advise on how to ensure the resulting diet provides sufficient of all that is needed.

Gaye Philpott is a registered New Zealand dietitian.

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The unexplained
Not all the mechanisms by which foods trigger diarrhoea are understood. Some people experience diarrhoea when they eat curry. It could be that curry acts as a gastric irritant or stimulant much the same as kiwifruit or prunes. High fat foods and meals are known to increase the motility of the intestines resulting in the contents being moved along more quickly.

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