Gastroenteritis or food poisoning is a frequent cause of diarrhoea. It is due to the ingestion of food or water contaminated by bacteria or viruses, causing inflammation of the stomach and/or intestines.
improperly cooked and mishandled, or left unrefrigerated for long period before consumption. Warm temperature stimulates bacteria to grow and multiply in the food. Contaminated water also serves a vehicle for outbreaks of food poisoning.
The symptoms of food poisoning are profuse vomiting, diarrhoea and crampy abdominal pain within eight to 24 hours after consumption of the contaminated foods. Fever may or may not be present.
Diarrhoea can range from a very mild, self-limiting disease of one to a few loose stools and only minimal symptoms. At the other end of the spectrum, 'dysentery'-like syndrome can be seen with soft, watery stools that may contain blood, mucus and pus.
Medical advice should be sought under the following circumstances:
If diarrhoea persists for more than one week despite adequate self-medication with hydration and anti-diarrhoeal agents.
If you have just returned from an area endemic with cholera (especially if your diarrhoea is profuse and watery).
If you fail to keep your body hydrated with oral rehydration solutions due to severe vomiting. This means your doctor may need to give you intravenous fluids for a few days. The very young and old persons are particularly at risk.
If your stool shows blood and pus.
If you have high running fever.
The causes for food poisoning can be bacterial or viral agents.
Common bacterial agents are Salmonella species, Shigella species, Escherichae coli, Bacillus cerues, Campylobacter species and staphylococcal aureus.
Some bacteria cause the symptoms of gastroenteritis by releasing toxins. These toxins are heat resistant and can not be destroyed by reheating ( such as frying). Other bacterial toxins cause symptoms by directly invading and causing damage to the gut wall.
Viral gastroenteritis is estimated to be responsible for 25% to 40% of hospital admissions for diarrhoeal illness. Viruses are easily transmitted through water and contaminated and improperly cooked seafood such as clams, oysters. Hepatitis A can present as food poisoning during the early stages of the disease.
Diarrhoea can usually be treated effectively by self-medication.
Hydration and fluid replacement
The mainstay of therapy is adequate hydration. Illness is usually self-limiting and does not require any specific medical therapy. The overwhelming majority of adults have mild diarrhoea that will not lead to dehydration provided adequate fluids are taken.
Hydration can be achieved by drinking boiled barley or rice water with a sprinkle of salt. This formulation helps to increase water absorption across the gut wall. An easier way is to consume commercially available oral rehydration salts in tablets or sachets form (Rehidrat, Dioralyte). These tablets can be drunk after reconstitution in boiled water (Please read the manufacturer's instructions for methods of dilution).
Dietary considerations
Most people will find it more comfortable to rest the bowel for a few days by avoiding high-fibre, high-fat foods. Frequent feedings of fruit drinks, tea, de-fizzed carbonated beverages and soft easily digested foods (eg. soups, crackers) are encouraged.
Antibiotics
Routine use of antibiotics is not recommended as illness is self-limiting. Antibiotics are indicated for those persons with high fever and prolonged diarrhoea. Antibiotics are used in diarrhoea due to invasive bacterial agents (e.g., shigella, salmonella) as antibiotics are believed to reduce environmental contamination.
Anti-diarrhoeal medications
Anti-diarrhoeal agents (such Lomotil) work by decreasing bowel contraction and may be used to decrease the frequency of diarrhoea, liquidity of stool and abdominal cramps. It should not be used if there is a high fever and blood is present in the stool indicating severe large bowel inflammation. This drug should also be discontinued and medical advice should be sought if diarrhoea worsens after a few days of therapy.
Lactose avoidance
Avoidance of milk and milk products is recommended for the first few weeks to avoid worsening of the diarrhoea from lactase deficiency. Gastroenteritis can reduce the concentration of the enzyme lactase and thus the ability of the small bowel to digest lactose present in milk.
Illness is usually self-limiting and lasts for 3 to 4 days. If diarrhoea is prolonged for more than one week, you are advised to visit your doctor for assessment and to obtain a course of antibiotics.
Most people recover from an attack of gastroenteritis without any complications. In a minority of patients who fail to keep up with the loss of water in their stool, their body may become too dry and this can result in kidney failure.
If the symptoms are severe or prolonged, your doctor may order stool specimens for culture, blood tests to check for white counts and degree of dehydration.
Prevention lies in the adherence to standard food-handling techniques, with particular attention paid to avoiding the multiplication of the organism within food (i.e. proper heating and the prompt refrigeration after cooking of food items). This basic principle of food handling applies just as much to you as it does to your favorite hawker stalls.
High-risk areas for traveller's diarrhoea include developing regions where endemic diarrhoea rates are highest. This includes Latin America, Africa, the Middle East and parts of Asia. Developed nations such as the United States, Europe and Australia pose the lowest risk.
Travellers from low-risk, industrialised countries face a higher risk when visiting high-risk areas. The illness appears to be associated with more frequent reliance on public rather than private eating establishments and alterations in diet.
Illness is usually self-limiting and lasts for three to four days if left untreated. Mortality from the illness is almost nonexistent but morbidity can be considerable, confining travelers to bed in up to 30% of cases or altering 40% of itineraries.
Escherichae coli (E. coli) is a common cause of traveller's diarrhoea, accounting for up to 70% of cases. Acquisition of these pathogenic agents is through ingestion of contaminated food or water.
Raw vegetables, raw meat or seafood and other moist foods maintained at room temperature are high-risk items. Tap water and ice are also considered to be unsafe. In general, food should be chosen if it is served piping hot. The risk for the development of travelers's diarrhoea increases when eating at restaurants, particularly when eating food purchased from street vendors. Safe food items include boiled or bottled water and beverages, canned products and fruits that can be peeled.
Studies have shown that prophylactic antibiotics are effective in reducing the frequency of traveler's diarrhoea, but this is generally not recommended due to side effects inherent with antibiotics consumption, especially with prolonged use.
Oral fluid is the mainstay of therapy.
If symptoms are moderately severe (stool frequency of up to 5x per day), anti-diarrhoeal agents such as loperamide (Lomotil) at 4mg three times per day are recommended.
Medical opinion and antibiotics are recommended if the frequency of diarrhoea is more than 6 times per day especially if there is associated fever or blood in the stools.
Cholera is caused by the bacterium Vibrio cholerae and is endemic in southern Asia, Africa and Latin America, where overcrowding and poor water and waste sanitation contribute to its spread. Faecally contaminated water and seafood are the major vehicles of transmission for cholera.
Illness is caused by the bacterial toxin that induces the small bowel mucosa from an 'active absorber' of water to a 'secretor' of water. Illness varies from mild gastroenteritis to severe profuse watery diarrhoea.
Faecal material has been described as of 'rice water' consistency. Up to one litre of water per hour can be lost in the diarrhoea. Diagnosis is made by isolation of the organism from the stool. The main line of treatment is rehydration through oral or intravenous routes. Antibiotic is generally given as it shortens the duration of illness.
Diarrhoea may occur during or after a course of antibiotics; there is usually no obvious pathogen. Symptoms usually resolve after the completion of antibiotics. The course is benign and does not require any therapy.
However, the severe end of antibiotic-associated diarrhoea is a condition called pseudomembranous colitis. This is so called because there is inflammation of the large bowel with a layer of mucus overlying the surface. There is suppression of the usual 'resident' bacteria which keeps the large bowel in healthy condition by the antibiotics with subsequent overgrowth of 'harmful' bacteria (Clostridium difficle).
This bacteria secretes a toxin which causes inflammation to the large bowel. A symptom indicating this condition is diarrhoea associated with the passage of blood and mucus. If you have an onset of diarrhoea after a recent course of antibiotics and the stool is bloody, you should visit your doctor to get the appropriate therapy.
World Health Organization. (n.d.). Diarrhoeal disease. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease
Nemours KidsHealth. (n.d.). Diarrhea. KidsHealth. https://kidshealth.org/en/parents/diarrhea.html
Patient.info. (n.d.). Diarrhoea. Patient.info. https://patient.info/digestive-health/diarrhoea
Subscribe to our mailing list to get the updates to your email inbox...
