Desidratação
Revisado por Dr Colin Tidy, MRCGPÚltima atualização por Dr Toni Hazell, MRCGPÚltima atualização 30 Jul 2024
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Nesta série:Náusea e vômitoMedicamento para náusea
Embora a desidratação possa ser leve e geralmente exija apenas que você beba mais líquidos, ela também pode ser muito grave e ameaçar a vida.
Em resumo
Dehydration means your body does not have enough fluid.
Symptoms can include thirst, dark urine, dizziness, and tiredness.
Causes can include not drinking enough, vomiting, or diarrhoea.
Babies, young children, and the elderly are at higher risk.
Drink plenty of fluids to treat dehydration.
Seek urgent medical help for signs of severe dehydration.
What is dehydration?
Dehydration means your body does not have enough fluid. This may be because you haven't drunk enough fluid to replace the fluids you have lost, such as when sweating or in your wee (urine). If dehydration isn't treated it can get worse and become a serious problem.
Signs and symptoms of dehydration
The symptoms include:
Feeling thirsty.
Dark yellow and strong-smelling wee (urine).
Feeling dizzy or light-headed.
Sentindo-se muito cansado.
Dry mouth, lips and eyes.
Weeing less urine and less often.
However the symptoms and signs vary depending on age and the severity of dehydration.
Signs in adults
Sede.
Dry or sticky mouth.
Not peeing very much.
Dark yellow pee.
Dry, cool skin.
Dor de cabeça.
Cãibras musculares.
Signs of severe dehydration
Not peeing, or having very dark yellow pee.
Very dry skin.
Sentir-se tonto.
Rapid heartbeat.
Respiração rápida.
Olhos fundos.
Sleepiness, lack of energy, confusion or irritability.
Desmaio.
Severe dehydration is a medical emergency and needs immediate treatment.
What are the causes of dehydration?
The causes include:
Not drinking enough fluids.
Being exposed to the sun in hot weather for long periods ('sunstroke').
Beber muito álcool.
Taking certain medicines called diuréticos that reduce the amount of fluid in your body.
Babies, young children, the elderly and people with diabetes are at increased risk of dehydration.
Do coffee and tea dehydrate you?
Coffee and tea contain caffeine, which has a slight diuretic effect (making you want to wee more). However, you would have to drink large amounts of each for this to be significant. The fluid in the tea or coffee will usually counteract this effect.
What are the treatments for dehydration?
Drinking lots of fluids
If it's difficult to drink or you keep being sick (vomiting) then keep taking small sips of fluid and gradually drink more if you can.
Rehydration sachets
These are only recommended for those who are at increased risk of dehydration - for most people, drinking normal fluids such as water is fine.
When to see a doctor for dehydration
Speak with your doctor or nurse for advice if your symptoms don't improve or you have any concerns. Call 111 (in the UK) if you can't speak to your GP or don't know what to do next.
Call 999 (in the UK) or go to Accident and Emergency (A&E) if you have any signs of severe lack of fluid in the body (dehydration), such as:
Feeling very weak and tired.
Feeling confused or disorientated.
Tontura.
Not having passed wee (urine) for eight hours.
Your pulse feeling weak and rapid.
Babies and young children with dehydration
It's quite common for young children to become lacking in fluid (dehydrated). It is often mild but can be serious if it's not dealt with quickly. Babies and young children need plenty of fluids to avoid dehydration.
Signs of dehydration in babies, infants, toddlers and young children
The signs of dehydration include:
Dry mouth and tongue
No tears when crying
Dry nappies for over 3 hours
Sunken eyes and cheeks
Sunken soft spot on the top of the skull (fontanelle) in babies
Sleepiness, lack of energy, or irritability
Treatment of dehydration in babies and young children
You should continue breastfeeding or using formula. Give smaller quantities of milk more often than usual. Don't make formula weaker by diluting it with water.
Give small children their usual diet.
Give frequent small sips of extra water.
Rehydration powder sachets are only needed if the child is at increased risk of dehydration - normal fluids are fine for most children.
Contact your doctor urgently or call an ambulance if your child displays any of the following signs or symptoms of dehydration:
Seems drowsy.
Is breathing fast.
Has a dry mouth.
Has dark-yellow wee.
Has cold and blotchy-looking hands and feet.
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Perguntas frequentes
Does dehydration cause nausea?
The article does not mention nausea as a direct symptom or sign of dehydration. The listed symptoms include thirst, dark urine, dizziness, tiredness, dry mouth/lips/eyes, and reduced urination.
How much water do I need if I'm dehydrated?
The article advises drinking lots of fluids if you are dehydrated. If it's difficult to drink or you are vomiting, you should take small sips and gradually drink more. For most people, normal fluids like water are sufficient. Rehydration sachets are recommended only for those at increased risk of dehydration.
How long does it take to recover from dehydration?
The article does not specify a timeline for recovery from dehydration. It focuses on identifying symptoms, causes, and when to seek medical attention for worsening or severe dehydration.
What causes severe dehydration?
Severe dehydration is not listed with separate causes from general dehydration. The causes mentioned include not drinking enough fluids, vomiting, diarrhoea, prolonged sun exposure in hot weather, excessive alcohol consumption, excessive sweating, fever, and certain diuretic medications.
Can you be dehydrated and not know it?
The article suggests that symptoms like feeling thirsty, dark strong-smelling urine, dizziness, tiredness, dry mouth, and reduced urination are indicators of dehydration. While some specific signs might be subtle, these listed symptoms generally help in recognising dehydration.
Leitura adicional e referências
- Diarreia e vômito em crianças menores de 5 anos; Diretriz Clínica NICE (abril de 2009; atualizada em outubro de 2022).
- Gastroenterite; NICE CKS, maio de 2024 (acesso apenas no Reino Unido)
Sobre o autorVer biografia completa

Dra. Toni Hazell, MRCGP
MBBS, BSc, MRCGP, DFSRH, Dip GU med, DRCOG, DCH (London, UK, 2000)
A Dra. Toni Hazell se formou na Escola de Medicina do Hospital St. Mary e fez seu VTS no Hospital Northwick Park.
Sobre o revisorVer biografia completa

Dr Colin Tidy, MRCGP
Médico Generalista, Autor Médico
MBBS, MRCGP, MRCP (Paediatrics), DCH
Dr Colin Tidy é um médico do NHS, baseado em Oxfordshire.
Histórico do artigo
As informações nesta página são escritas e revisadas por clínicos qualificados.
Artigo também disponível em Inglês, Alemão, Espanhol, Francês, Italiano, Português, Hindi, Hebraico, Árabe, e Sueco.
Próxima revisão prevista para: 30 Jul 2027
30 Jul 2024 | Última versão

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