Acute Diarrhoea: Dehydration, When to Go In

Key takeaways

What puts someone in hospital is dehydration, not the number of trips to the toilet. The easiest sign to follow at home is urine: less of it, and darker than usual.
Unable to keep down a single sip of water, blood in the stool or black stool, drowsy and hard to rouse, hours with no urine passed: stop self-care and get to a medical facility now.
According to NIDDK, doctors usually do not recommend over-the-counter anti-diarrhoeal medicines for infants, children, or anyone who has blood in the stool or a fever.
According to CDC, antibiotics do not kill viruses. Buying antibiotics yourself for a bout of diarrhoea is usually useless, and whether they are needed at all is the doctor's decision after an examination.
A breastfed baby carries on feeding as normal. Do not make up formula weaker than usual to make it easier to digest.

Most bouts of acute diarrhoea settle on their own. What makes it dangerous is not the number of trips to the toilet but water and salts going out faster than they are being replaced. So this article does not teach counting — it teaches recognising dehydration.

Recognise dehydration, do not count trips

According to NIDDK, diarrhoea means passing loose or watery stools more often than is normal for that person — there is no single number. The measure at home is whether the person is holding on to fluid. In adults, the signs are:

Passing urine less often than usual, and the urine is darker — the earliest and easiest sign to follow.
Marked thirst, a dry mouth, a dry throat.
Tiredness, dizziness, light-headedness on standing, a fast heartbeat.
Skin on the back of the hand pinched gently and released goes back slowly.
Sunken eyes or sunken cheeks.

In young children and older people the signs are different:

Young children: a dry nappy for several hours running or very little urine, crying without tears, a dry mouth, a sunken soft spot in babies who still have one, drowsiness or unusual fretfulness, refusing the breast or refusing to drink.
Older people: according to NIDDK, a change in mental state — less alert, loss of energy, easily irritated — is a reason for a doctor to see them now. Do not put it down to age.

Two things are easily misread. Going many times while still drinking and still passing urine normally is less worrying than going a few times while unable to keep fluid down. And diarrhoea during or after a course of antibiotics should not be assumed to be something eaten — according to NIDDK, antibiotics are among the medicines that cause diarrhoea.

What to do straight away

Replacing fluid is the most important thing. According to CDC, over-the-counter oral rehydration solution helps most in mild dehydration. How to mix it, and why mixing it stronger is dangerous, is covered in a separate article on oral rehydration salts on this site.
Drink small sips, continuously — according to NHS, the more nauseated you are, the smaller the sips need to be; drinking a glass in one go usually brings on more vomiting.
According to NHS: rest at home; eat when you can, avoiding greasy and spicy dishes; a breastfed or bottle-fed baby carries on as normal, and if the baby is vomiting, feed smaller amounts more often.
Anyone who is vomiting or has diarrhoea should not cook, should not share food and should not care for others — according to CDC, wait at least two days after the symptoms have gone. And according to CDC, hand sanitiser works poorly against norovirus: hands must be washed with soap.
Write it down: the last time urine was passed, how many bouts of vomiting, whether there is blood in the stool, and what medicines are being taken including antibiotics — these are the first questions a doctor asks.

What you must not do

Do not buy antibiotics yourself. According to CDC, antibiotics do not help treat norovirus infection because they kill bacteria, not viruses. Viruses are a very common cause of diarrhoea. Whether antibiotics are needed is the doctor's decision after an examination.
Do not take anti-diarrhoeal medicine on your own when there is blood in the stool or a fever. According to NIDDK, doctors usually do not recommend the over-the-counter kind for infants, children, or anyone with blood in the stool or a fever; according to NHS, do not give it to a child under 12. The name you will see most often is loperamide.
Do not use fizzy drinks or fruit juice to replace fluid: according to NHS, they can make diarrhoea worse.
Do not make up formula weaker than usual; according to NHS, keep it at the normal strength.
Do not call for a drip at home instead of going in when any of the signs in the box below are present.

After bloody diarrhoea: the sign most easily missed

According to CDC, infection with Shiga toxin-producing E. coli can lead to haemolytic uraemic syndrome (HUS), which causes kidney failure and can be fatal. So once there has been blood in the stool, do not stop watching. According to CDC, the signs of HUS are:

Passing very little urine, or none at all.
Loss of pink colour in the cheeks and inside the lower eyelids.
Unexplained bruises or tiny red spots on the skin.
Blood in the urine.
Extreme tiredness, or being more easily irritated than usual; reduced alertness.

When you must go to hospital

GO TO EMERGENCY CARE or call 115 (the emergency number in Vietnam) NOW if: any of the HUS signs above appear after a bout of bloody diarrhoea; not a single sip of water stays down, or the vomiting is continuous; there is blood in the vomit, or vomit like coffee grounds; the stool has blood in it, is black, or has pus in it; there is drowsiness, difficulty rousing, confusion or a fit; no urine has been passed for hours; the skin is wrinkled and has lost its spring; the skin, lips or tongue turn blue, grey or mottled; there is marked difficulty breathing; the abdominal pain is severe and sudden, or fixed in one spot and rising; the headache is severe and sudden; there is a stiff neck, dislike of light, or a high fever with a stiff neck; a breastfed baby refuses the breast completely, or a young child has signs of dehydration. — BE SEEN WITHIN 24–72 HOURS if: the diarrhoea or vomiting is not easing and the fever is not coming down; there is weight loss; the diarrhoea began during or after a course of antibiotics; or the person is a young child, an older person, pregnant, or someone with heart, kidney, liver disease, diabetes or a weakened immune system — this group should not wait to see whether it eases. And if signs of dehydration persist despite oral rehydration given correctly, be seen the same day.

Plainly: the cause cannot be found at home, and fluid cannot be replaced once the oral route has stopped working. We offer a remote consultation by video call when you are not sure whether to go in; a doctor comes to the house to take the history, examine, and say clearly which cases must be admitted; a nurse gives fluids by drip as prescribed. A remote consultation is not for someone who is drowsy or having fits — with a sign from the box above, go in first and call afterwards.

This article passes on the recommendations of public health authorities — sources: CDC in the United States, NIDDK at the National Institutes of Health, and NHS in the United Kingdom — and does not replace being examined in person. Citing CDC here does not imply that CDC endorses Y Te Xanh or our services.

Need personalised advice for your loved one? Call our hotline 094 368 81 15 (24/7) — calling to ask a question or to book costs nothing. GreenCare has doctors who come to examine, nurses who carry out doctor's orders (injections, infusions, dressing changes), remote consultation by video call, and a review of the medicines you are taking; an in-depth remote consultation, or any one after the first, is a paid service. For children we take examination and acute care only — not long-term care at home, and not newborns or expectant mothers. We confirm we have staff in your area and provide transparent pricing before we begin.

Sources

CDC — About Norovirus
NHS — Diarrhoea and vomiting

Frequently asked questions

How long does acute diarrhoea last?

According to NHS, diarrhoea usually settles within about 5 to 7 days and vomiting usually settles within 1 to 2 days. But time is not what decides whether to be seen: someone still drinking and still passing urine normally can be watched at home, while someone who cannot hold fluid down needs to be seen now even if the illness only started this morning. If the diarrhoea or vomiting is not easing, or the fever is not coming down, be seen rather than wait any longer.

Should I take anti-diarrhoeal medicine so I do not have to keep going?

Ask a doctor or pharmacist first, and there are two situations where it must be avoided. According to NIDDK, doctors usually do not recommend over-the-counter anti-diarrhoeal medicine for infants, children, or anyone who has blood in the stool or a fever. Slowing the bowel down in the middle of an infection can cause serious complications, and it also hides the signs a doctor needs to see. According to NHS, do not give anti-diarrhoeal medicine to a child under 12. Replacing fluid makes a person feel far better than stopping the diarrhoea does.

Does diarrhoea need antibiotics?

In most cases no, and buying them yourself is not the way. According to CDC, antibiotics do not help treat norovirus infection because they kill bacteria and not viruses — and viruses are a very common cause. For some gut infections antibiotics do help, but which one and whether it is needed at all only an examination can tell. When there is blood in the stool in particular, antibiotics bought over the counter may even increase the risk of complications — that is the moment to be seen, not the moment to go to the pharmacy.

There is blood in the stool. What should I do?

Go to a medical facility; do not carry on watching at home and do not take anti-diarrhoeal medicine. After that, keep watching for the group of signs of haemolytic uraemic syndrome set out above, because according to CDC that is a complication which can cause kidney failure; if any of them appear, be seen at once.

My child has diarrhoea — should I make the formula weaker or change brands?

Do not make it weaker. According to NHS, keep it at the normal strength and carry on breastfeeding or bottle-feeding; if the child is vomiting, feed smaller amounts more often. Changing the type of formula or adding anything to it is a question for a doctor, not something to decide yourself. A child who refuses the breast completely, has a dry nappy for several hours, cries without tears or is unusually drowsy needs to be seen now.

When can we go back to work or school, and does the family need to eat separately?

According to NHS, stay off school and work until the vomiting and diarrhoea have been gone for at least two days. According to CDC, anyone who is ill should not cook, should not share food and should not care for others, waiting at least two days after the symptoms have gone. Use separate towels, clean the toilet and door handles, wash anything soiled with vomit or stool straight away — and wash hands with soap, because according to CDC hand sanitiser works poorly against norovirus.