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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.
