Gastroenteritis in children and adults: causes, symptoms and treatment

Discover how to recognise the signs of gastroenteritis and why it’s best to manage and treat symptoms as early as possible.

Viral gastroenteritis (stomach flu) affects both children and adults, causing symptoms like nausea, vomiting, diarrhoea, and stomach cramps. Understanding the causes, such as drinking contaminated water, and viral infections, is key to preventing and treating this condition. Dr Marelize Vlok, a GP at Mediclinic Louis Leipoldt Emergency Centre, explains its causes, symptoms, and management.

Can you have stomach flu without nausea or vomiting?

Gastroenteritis (GE) is often confused with the flu. This is due to shared symptoms like nausea, vomiting, diarrhoea, and stomach cramps, but it primarily targets the gut rather than the respiratory system. Dr Vlok says it’s important to recognise the range of symptoms associated with GE, which can include fever, headaches, and fatigue, alongside gastrointestinal distress.

Gastroenteritis encompasses a spectrum of symptoms beyond just nausea and vomiting, she emphasises. "GE isn't confined to just one set of symptoms. These are hallmark signs, but patients can also experience diarrhoea, fever, headaches, and fatigue."

Is gastroenteritis different for children and adults?

Children usually experience severe diarrhoea and vomiting but may struggle to express their discomfort clearly. Always look out for increased fussiness, Dr Vlok advises. Dehydration can escalate quickly in children, so watch for signs like reduced urination, dry mouth, and lethargy; these are signs that your child needs urgent medical attention.

In contrast, adults may have a wider range of symptoms, including gastrointestinal issues, fever, and body aches. Although they tend to tolerate dehydration better than children, underlying health conditions, or some medications may worsen symptoms. Alongside gastrointestinal problems, adults might experience fatigue, headache, and malaise (a general feeling of illness).

Does drinking contaminated water lead to acute gastroenteritis?

Contaminated water serves as a potential breeding ground for GE-causing pathogens, warns Dr Vlok. "Consuming water contaminated with viruses like norovirus or bacteria such as Escherichia coli (E. coli) can trigger acute gastroenteritis." Access to clean drinking water is critical in preventing infections, particularly in areas susceptible to waterborne illnesses, she says.

Hand hygiene and sanitation practices also help to curb transmission, especially in crowded environments. In such cases, infection arises from person-to-person contact, such as touching contaminated hands, surfaces, and items, or ingesting contaminated water or food.

Be aware that you can also develop gastroenteritis from accidentally swallowing contaminated water from a pool, hot tub, river, the sea, or any body of water containing infectious micro-organisms.

What are the mild to serious viral gastroenteritis symptoms?

Symptoms of gastroenteritis usually surface within days of exposure to the virus, says Dr Vlok. "The most common indicators range from gastrointestinal disturbances like diarrhoea and vomiting to systemic symptoms such as fever, headache, and muscle aches. The onset of symptoms is closely linked to the cause of the gastroenteritis. In very severe cases due to some bacteria, symptoms can present after a few hours. In other cases, the symptoms can develop over a day or two.”

Recognising these symptoms early helps doctors reduce the risk of complications. "If vomiting persists for more than two days in adults, for more than 24 hours in children over two years old, or 12 hours in children under one year old, dehydration becomes a concern," she warns.

Viral gastroenteritis: your treatment options

Gastroenteritis usually resolves on its own without the need for major medical intervention, but supportive measures can help with the symptoms and prevent dehydration – Dr Vlok recommends oral rehydration solutions for replacing lost fluids. In severe cases, intravenous fluids are administered. Symptomatic relief with antiemetics (antinausea medicines) and probiotics also helps to manage symptoms, promoting quicker recovery and reducing the likelihood of complications.