Clinical exam · General exam and vital signs
Hydration status: signs of dehydration !
- Exam technique
What to look at and feel at the bedside to tell whether a patient is short of fluid, and by how much.
Updated 2026-11-01
What it is
Hydration assessment looks for signs of volume loss: thirst, dry mucosae, sunken eyes, slow skin recoil, slow capillary refill, tachycardia, hypotension and less urine. In children, dehydration from diarrhea is still a major reason for consultation in Colombia and is graded by severity. No single sign is enough; a combination is more accurate.
Landmark anatomy
- Oral mucosa is judged on the inside of the cheeks and on the tongue.
- In infants, the anterior fontanelle lies between the frontal and parietal bones.
- Skin turgor reflects dermal elasticity, which falls with dehydration and with age.
Technique, step by step
- Ask about vomiting, diarrhea, fever, intake, thirst, how often and what colour the urine is, and diuretic use.
- Observe general state: alert, irritable, lethargic or unconscious.
- Inspect the oral mucosa and tongue, the presence of tears and whether the eyes look sunken.
- In infants, feel the anterior fontanelle with the child calm and held upright.
- Pinch the skin of the abdomen or back of the hand and see how long it takes to fall back.
- Check capillary refill, pulse, blood pressure and, if possible, orthostatic signs.
- Weigh the patient and compare with a recent weight; record urine output.
Abnormal findings
- Dehydration from acute gastroenteritis, especially in young children.
- Losses from fever, sweating or heat stroke; extensive burns.
- Polyuria from uncontrolled diabetes or diuretics.
- Poor intake in older adults and in patients with dementia or dysphagia.
- Severe signs with altered consciousness or a weak pulse: hypovolemic shock.
Common errors
- Relying on a single sign, such as a dry mouth in a mouth-breather.
- Interpreting skin turgor in an older adult, whose skin loses elasticity with age.
- Judging the fontanelle while the infant is crying or lying down.
- Not weighing the patient or recording urine output.
Test yourself
Think of the answer, then tap the question to see it.
Which signs separate severe from moderate dehydration in a child?
Absent tears, prolonged capillary refill, a fast weak pulse, hypotension, mottled skin and severely reduced consciousness.
Why is skin turgor unreliable in older adults?
Because skin loses elasticity with age and the fold returns slowly even when the person is well hydrated.
How is the anterior fontanelle correctly assessed?
With the infant calm, not crying and held upright; a sunken fontanelle suggests dehydration.
What percentage of weight loss corresponds to mild dehydration in a child?
About 3 to 5% of body weight.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Capillary refill time
- Orthostatic vital signs
- Dehydration and fluid overload
- Vital signs in children: how they change with age
Related conditions
- Dehydration (fluid volume deficit)
- Dehydration in children (acute diarrhoeal disease)
- Hypovolaemic shock
Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.
Sources: Dehydration: MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine (MedlinePlus), 2025); Dehydration in Children - Pediatrics - MSD Manual Professional Edition (Merck & Co. (MSD Manual Professional Edition), 2025).
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Representative model, for educational purposes only.