Assessing children for dehydration

Guarino, 2014

Assess the hydration status of all children with gastroenteritis so that appropriate rehydration can be given.

The best measure of dehydration in children is the percentage loss of body weight. The most recent pre-illness weight, urine output (or number of wet nappies per day), frequency of vomiting and diarrhoea (number of episodes per day and volume per episode), and thirst provide some clues about the child’s hydration status and potential for dehydration.

Note: Percentage loss of body weight is the best measure of dehydration in children.

Often the child’s recent premorbid weight is not available, and an estimation of the degree of dehydration must be based upon clinical features. Clinical features associated with different levels of dehydration in children are listed in Assessing clinical features of dehydration in children. Distinguishing between mild and moderate dehydration based upon clinical features alone is difficult. Clinical signs may not be seen in children until they have lost 3 to 5% of their body weight as fluid. The most reliable signs for predicting significant dehydration in children are prolonged central capillary refill time, reduced skin turgor and deep respirationFayomi, 2007 Caruggi, 2018 Lo Vecchio, 2016.

When determining the severity of dehydration, also consider the risk factors for dehydration or associated electrolyte abnormalities listed in Risk factors for dehydration or associated electrolyte abnormalities in children with acute gastroenteritis. Consider the need for closer monitoring or early referral in children with these risk factors. If the child is in hospital, consider the need for senior clinician support.

Table 1. Assessing clinical features of dehydration in children
Clinical feature	Degree of dehydration (percentage loss of body weight) [NB1]
Clinical feature	mild (less than 5%)	moderate (5 to 10%)	severe (11% or more)
conscious state	alert and responsive	altered responsiveness (eg lethargic, irritable)	decreased level of consciousness
skin colour	skin colour unchanged	skin colour unchanged	pale or mottled skin
extremities	warm extremities	warm extremities	cold extremities
eyes	eyes not sunken	sunken eyes	sunken eyes
mucous membranes	moist mucous membranes	dry mucous membranes	dry mucous membranes
heart rate	heart rate normal	heart rate normal	increased heart rate
breathing [NB2]	respiratory rate normal	increased respiratory rate	increased respiratory rate
peripheral pulses	peripheral pulses normal	peripheral pulses normal	weak peripheral pulses
central capillary refill time [NB2]	capillary refill normal	capillary refill normal	prolonged capillary refill (greater than 2 seconds)
skin turgor [NB2]	skin turgor normal (ie instant recoil)	decreased skin turgor	decreased skin turgor
blood pressure	blood pressure normal	blood pressure normal	decreased blood pressure
Note: NB1: When determining the severity of dehydration, consider the risk factors for dehydration or associated electrolyte abnormalities listed in Risk factors for dehydration or associated electrolyte abnormalities in children with acute gastroenteritis. Consider the need for early referral in children with these risk factors. NB2: Signs most predictive of significant dehydration (more than 5%) in children. Adapted from Children’s Health Queensland Hospital and Health Service URL. This work is licensed under a Creative Commons Attribution-Non-Commercial V4.0 International licence (CC BY-NC 4.0) (https://creativecommons.org/licenses/by-nc/4.0/deed.en).

Figure 1. Risk factors for dehydration or associated electrolyte abnormalities in children with acute gastroenteritis.

The Royal Children's Hospital Melbourne (RCH), September 2020

The risk of dehydration or associated electrolyte abnormalities may be increased in children with any of the following factors:

less than 6 kg (especially preterm infants) or younger than 3 months
chronic disease (eg chronic kidney disease, complex congenital cardiac disease)
kidney transplantation
short bowel syndrome or presence of ileostomy
immune compromise
pre-existing malnutrition
where there is concern about adherence to treatment or monitoring for dehydration at home
intractable or bilious vomiting.