Diarrhoea, vomiting and dehydration

Gastroenteritis is among the most common illnesses in early childhood, and the main risk is dehydration rather than the infection itself.

What it usually is

Most cases are viral, with rotavirus historically the leading cause in young children and norovirus common in all ages.

Rotavirus vaccination, included in the routine schedule in many countries, has substantially reduced severe cases and hospital admissions.

Typical course: vomiting for one to two days, diarrhoea for five to seven days, sometimes with fever and abdominal pain, resolving without treatment.

Diarrhoea occasionally persists for up to a fortnight.

Recognising dehydration

The clinical priority.

Early signs: fewer wet nappies, dark concentrated urine, thirst, dry mouth, and a child who is less active than usual.

More significant: sunken eyes, sunken fontanelle in a baby, no tears when crying, drowsiness or irritability, cold hands and feet, rapid breathing, and reduced skin elasticity.

Severe dehydration is an emergency, presenting with marked drowsiness, pale or mottled skin, very rapid breathing and reduced urine output.

Infants dehydrate considerably faster than older children, which is why the threshold for seeking help is lower.

Managing it at home

Fluid, mostly.

Continue breastfeeding, more frequently and in smaller amounts.

Continue formula, unless advised otherwise, and do not dilute it.

Offer oral rehydration solution, which is formulated with the correct balance of salt and sugar for absorption, in small frequent amounts — a few millilitres every few minutes works better than large volumes that are immediately vomited.

A syringe or spoon helps in a child who will not drink.

Continue food once eating is tolerated, since prolonged starvation is not recommended and normal diet aids recovery.

And do not give fruit juice, fizzy drinks or sports drinks, which have the wrong osmolality and can worsen diarrhoea.

What not to use

Anti-diarrhoeal medications such as loperamide are not recommended in young children and can cause serious adverse effects.

Anti-emetics are used selectively in medical settings and are not for home use in this age group without advice.

Antibiotics do not help viral gastroenteritis and are reserved for specific bacterial infections.

Homemade salt and sugar solutions risk incorrect concentrations, and commercial sachets are inexpensive.

Probiotics have some evidence for modestly reducing duration and are not part of standard guidance in all countries.

When to seek help

Signs that change the picture.

Any signs of dehydration listed above.

A baby under six months, or a child with an underlying condition.

Vomiting everything and unable to keep any fluid down.

Green or bile-stained vomit, which suggests obstruction and is an emergency.

Blood in stool or vomit.

Severe or persistent abdominal pain, or a swollen tender abdomen.

Fever with an unwell child, or a fever in a baby under three months.

Drowsiness, floppiness or a child who is difficult to rouse.

Diarrhoea lasting more than about a week, or vomiting beyond a couple of days.

Recent foreign travel.

And red jelly-like stool with intermittent severe pain and drawing up the legs, which suggests intussusception and requires immediate assessment.

Preventing spread

Practical measures that work.

Handwashing with soap and water, which is more effective than alcohol gel against norovirus.

Cleaning surfaces and bathrooms with an appropriate disinfectant.

Washing soiled clothing and bedding separately at a high temperature.

Not sharing towels.

Keeping the child away from nursery or school until forty-eight hours after the last episode, which is the standard exclusion period.

And avoiding swimming pools for a period, commonly two weeks after diarrhoea has stopped in certain infections.

Afterwards

A few points.

Temporary lactose intolerance can follow gastroenteritis in some children, causing continued loose stools, and resolves over weeks.

Appetite frequently takes days to return.

Weight loss during the illness is regained.

And persistent diarrhoea beyond a fortnight, blood, poor weight gain or recurrent episodes warrant further assessment rather than being attributed to a lingering bug.

General information only, not medical advice. Seek urgent care for signs of dehydration, green vomit, blood in stool, or a drowsy or unwell child.