Diarrhoea, Gastroenteritis and Oral Rehydration

When diagnosed with acute gastroenteritis, staying hydrated with warm water or oral rehydration solutions is key, while food is less important.

The importance of rehydration

If you have been diagnosed with acute gastroenteritis, or have nausea/vomiting/diarrhoea/abdominal pains after eating something, keeping hydrated is the most important treatment. Food is not as important: remember people can survive on average 2 months without any food, but only 3 days without water!

Symptoms of dehydration

Reaching moderate to severe dehydration is potentially life-threatening, and may lead to a visit to the emergency department for intravenous fluid replacement therapy. On the other hand, as long as you are able to keep fluids down, and pass urine normally (and other causes of symptoms are excluded): even with non-stop diarrhoea, your life won’t be in danger for the typical 2-5 days this would last.

What you should drink

Warm water is the simplest and most soothing for a gastro stomach, and is the ideal beverage recommended by 3000+ years of Chinese Medicine history. Warm water is also versatile, as adding a small amount of honey will also provide some sugars and electrolytes to aid recovery.

Other fluid options include lemonade, non-alcoholic ginger beer/ale, and ginger tea. These drinks have a modest effect on reducing nausea, and adds variety to the large amount of water intake required. Sports drinks, diluted fruit juice (1 part to 4 parts water) are also ok for when there isn’t obvious signs of dehydration. These are recommended to be had at room temperature, as cold/icy drinks may cause reactive spasms of the stomach, and lead to vomiting when unwell.

Hydralyte and Gastrolyte are common brands of medical oral rehydration solution that are readily available in pharmacies and supermarkets in Australia, and is the preferred choice for oral fluid replacement in liquid or frozen (for children) forms in hospitals due to the ideal amount and concentrations of sodium and glucose for rehydration for patients without existing electrolyte or glucose imbalance.

How much to drink

Initial amount for oral rehydration is to aim for approximately 100 ml every 15 minutes. Having frequent, small amounts of fluid is easier to stomach (pun) especially when nauseous/vomiting than a large volume that stretches the stomach. If this amount is tolerated (not vomiting it back up), then should be continued till urine is passed. Work towards total daily volume of 2-3 L during the days of illness.

If vomiting is preventing adequate oral fluid intake, starting with 20-30 ml over 15 minutes, or suck on ice cube/ice pop/frozen Hydralyte to slowly get necessary fluids in. If even this is not tolerated, consult your usual doctor for effective prescription medication for nausea/vomiting in this context, such as domperidone or metoclopramide, taken 3 times a day to help restart the natural gut peristalsis, and prevent the backward movement that leads to nausea and vomiting.

Common medications

Medications that stop diarrhoea are situational, and may cause more problems. Common medications such as loperamide (Gastro-Stop, Imodium) stops the gut movement and hence reduces or stops diarrhoea, but this also means anything you put into the stomach is unable to move down the bowels, and may cause or worsens vomiting. Do not take antibiotics unless the causative organism has confirmed and is susceptible, or on your doctor’s advice once harms vs benefits have been considered.

Advice

It is important to be aware of the symptoms and signs of the stages of dehydration. If you are not able to manage the fluid intake, such as due to excessive vomiting, then it is recommended to seek medical assessment at the moderate stage, and you MUST see a GP or go to emergency department by the severe stage.

Author

Dr. Andrew Sun, FRACGP

Dr. Andrew Sun is a Specialist General Practitioner and the Clinical Lead at Sun Health Clinic, Sydney. With credentials from the University of Sydney (BMedSc), UNSW (MScTech), and the University of Queensland (MBBS), he specialises in non-invasive laser dermatology, including Aerolase Neo Elite and Emerald Laser protocols. A Fellow of the Royal Australian College of General Practitioners (FRACGP) and a Medical Officer in the Australian Army Reserve, Dr. Andrew integrates evidence-based medicine with advanced aesthetic technology to treat complex skin and body contouring cases.

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