Patients

Acute diarrhoea

Most healthy people open their bowels between three times a day and three times a week. Normal stools are usually solid. The term diarrhoea is used when stools are passed more than three times a day and when the stools become loose or watery. In acute diarrhoea, symptoms come on suddenly but usually clear up within 5-10 days.

This page covers some of the key questions as a sufferer you may have.

What are the mechanisms of acute diarrhoea?

What are the causes of acute diarrhoea?

What are the symptoms that might be associated with acute diarrhoea?

When should I consult the doctor?

What will the doctor do?

How should I treat diarrhoea?

Can acute diarrhoea be avoided?

Can acute diarrhoea be prevented?

What are the mechanisms of acute diarrhoea?

  • Normal stools are solid because the small intestine and colon are highly efficient in absorbing nutrients, fluid and salts from the liquid, upper gut contents.
  • Diarrhoea occurs when these processes are impaired, for example when the lining of the gut is damaged by bacteria or viruses.
  • Diarrhoea can also occur when there is excessive secretion of fluid into the bowel that overwhelms the ability of the gut to reabsorb the secreted fluid and salts. Some laxative drugs have this effect although the most common cause relates to infection with bacteria that produce proteins (enterotoxins) that stimulate gut secretion. In some situations acute diarrhoea may occur as a result of a combination of both mechanisms.
  • Diarrhoea may result when the bowel contents move too rapidly through the gut to allow sufficient time for absorption. Anxiety and some drugs can cause diarrhoea in this way. Bowel frequency is sometimes increased in people with irritable bowel syndrome. However, there is no increase in stool volume which distinguishes it from acute diarrhoea, when stool volume is increased.

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What are the causes of acute diarrhoea?

  • The most common cause of an attack of acute diarrhoea is an intestinal infection ('gastroenteritis'). Infants and young children are particularly susceptible to intestinal infections which are most commonly caused by a rotavirus.
  • Food poisoning is another common form of acute diarrhoea, most commonly caused by the bacteria Salmonella and Campylobacter. These infections are passed on through contaminated food, such as poultry and eggs, or water; and sometimes by a person such as food handler who has the infection, but has no symptoms of that infection (a carrier).
  • People who travel a lot are also susceptible to intestinal infection, the most common cause being the bacterium, Escherichia coli. This organism releases enterotoxins in the gut, which produce intestinal secretion.
  • Acute diarrhoea can sometimes occur during or after a course of antibiotics, as a result of a variety of drugs and alcohol, and is associated with attacks of acute anxiety.
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What are the symptoms that might be associated with acute diarrhoea?

Acute intestinal infections are commonly associated with cramping central or lower abdominal pain. Some infections may cause fever, particularly infections due to Shigella and Campylobacter that get into the lining of the bowel and cause acute inflammation. When there is direct damage to the bowel, blood may be associated with the diarrhoea (dysentery).

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When should I consult the doctor?

Most episodes of acute diarrhoea get better without the need for specific medical advice. However, if diarrhoea persists for more than 14 days, is associated with blood and/or high fever, or if cramping abdominal pain becomes severe or constant then you should seek medical advice. If you are a food handler then you should consult your doctor and inform your employer.

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What will the doctor do?

  • The doctor will want to talk to you about your symptoms to try to identify a cause. The doctor will also want to examine you, including your abdomen and possibly your back passage.
  • The most important test to perform at this stage is an examination of your stool to determine whether there are any infective agents present that might be the cause of the diarrhoea and other symptoms.
  • It may also be necessary to examine the bowel by endoscopy to determine whether there is inflammation in the rectum or colon (colitis).
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How should I treat diarrhoea?

  • Before starting any treatment it is worthwhile considering that there might be an aggravating factor such as acute stress and anxiety, excess alcohol or a new recently prescribed drug.
  • Most episodes of acute diarrhoea will settle spontaneously without the need for any medical treatment. However, if the episode is severe, it is important to ensure that you take additional fluids and salts to replace those lost in the diarrhoea. For infants, young children and the elderly who are more sensitive to fluid losses, it is wise to use a pre-prepared oral rehydration solution which can be purchased over the counter of most pharmacies.
  • For most adults oral rehydration can usually be achieved simply by increasing fluid intake in the form of mineral water, fruit juices (which also contain potassium) and salty soups (sodium), together with some form of carbohydrate (rice, pasta, salty crackers) which is important for promoting fluid and salt absorption.
  • There is no need to stop eating although sufferers often prefer a lighter diet in the early phase of the illness. There need be no interruption in breast feeding for breast fed infants. Bottle-fed infants should still receive full-strength formula milk.
  • An anti-diarrhoeal drug such as loperamide is available from pharmacies without prescription. This is often helpful early in the illness to reduce bowel frequency. However, it should not be used in infants and very young children because of concerns that it may depress respiration.
  • For travellers with severe diarrhoea for whom loss of one or two days would seriously affect their activities (particularly the business traveller), the severity and duration of the illness can be dramatically reduced by taking a short course of a broad spectrum antibiotic. Even a single dose can be effective. If this might be the case, then it is worthwhile seeking medical advice about whether this might be appropriate for you before you travel.
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Can acute diarrhoea be avoided?

Because most acute diarrhoea is related to intestinal infection that is usually transmitted by contaminated food or water, then it is possible to avoid an illness by being scrupulously careful about food and fluid intake. Only drink boiled or bottled water and avoid ice cubes when the origin of the water is uncertain. Avoid raw, unpeeledfruit and salads, shellfish and all foods that might contain raw egg. The safest food is that which is hot and well cooked.

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Can acute diarrhoea be prevented?

  • For those travelling to high-risk areas (such as the Indian sub continent, South East Asia, Africa, Latin America) the chance of experiencing an attack of acute diarrhoea can be reduced by taking a broad spectrum antibiotic. However, this is not generally advised because antibiotics do have adverse effects and widespread use in this way can lead to the emergence of antibiotic resistance. There is a danger, therefore, that the treatment might be worse than the disease.
  • Vaccines for traveller's diarrhoea are under development and one moderately effective vaccine is now available in the United Kingdom (Dukoral). It is aimed at the most common cause of traveller's diarrhoea, enterotoxigenic E.coli.
  • There is some evidence that probiotics (such as lactobacilli and bifidobacteria) found in 'live yoghurts' and other preparations, may also reduce the chances of experiencing an episode of infective diarrhoea.

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