[29] Dehydration Flashcards
What is dehydration?
When the body loses more fluid than it takes in
Is dehydration serious?
It can be if it is untreated
What % of an infants body weight is made up of water?
As much as 80%
What happens to the proportion of body water by 3 years?
It falls to about 65%
How is body water distributed?
Between the cells (intra-cellular) and the extracellular compartments
What can the extracellular compartment be further divided into?
- Intravascular space
- Extravascular (interstitial) space
What separates the intravascular and extravascular space?
Capillary endothelium
Depletion of what compartment can lead to dehydration?
Any
What may acute loss of fluid from the intravascular compartment be associated with?
Shock
What do the clinical signs of dehydration depend on?
The concentration of electrolytes in the intracellular and extracellular compartments
What are the major ions within the extracellular compartment?
- Sodium
- Bicarbonate
What is the major ion within the intracellular compartment?
- Potassium
What is balanced in normal body fluids?
Intake and output
What does normal fluid balance depend on?
- Fluid intake
- Urine volume
- Stool volume
- Sweating
- Insensible loss
When does dehydration occur, with regard to fluid balance?
When losses exceed input
Why do infants have a higher risk of dehydration?
- Higher SA to weight ratio than older children, leading to greater insensible water losses
- Higher basal fluid requirements
- Immature renal tubular reabsorption
- Inability to obtain fluids for themselves when thirsty
What are the causes of dehydration in children?
- Diabetes
- Vomiting and diarrhoea, e.g. gastroenteritis
- Heatstroke
- Fever
- Conditions that make it hard to swallow fluids, e.g. sore throat
What are the risk factors for dehydration?
- Infants
- Children that have passed 6 or more diarrhoeal stools in the previous 24 hours
- Children that have had vomiting 3 or more times in the previous 24 hours
- Children that have been unable to tolerate, or not offered, oral fluids
- Children with malnutrition
What infants in particular are at risk of dehydration?
- Under 6 months of age
- Low birthweight
What are the symptoms of dehydration?
- Feeling thirsty
- Dark yellow and strong-smelling urine
- Feeling dizzy or lightheaded
- Feeling tired
- Reduced urine output
- Few or no tears when crying
What needs to be determined in the history in dehydration?
- Cause of dehydration
- Severity of dehydration
What are the signs of dehydration?
- Sunken eyes
- Soft spot on head sinks inwards
- Cold and blotchy-looking hands and feet
- Dry mouth, lips, and eyes
What do you need to assess/obtain on physical examination in dehydration?
- Weight
- Severity of dehydration
- Signs of cause of dehydration
What is the importance of measuring the weight in dehydration?
Acute water loss can be estimated from the difference between actual weight and a recent weight made before dehydration occurred, and so regular weighing will allow accurate measurement of fluid replacement
How can the cause of dehydration be assessed on examination?
Should perform a thorough examination to identify the foci of infection
What should be included on thorough examination to identify the cause of dehydration?
- Ears
- Throat
- Chest
- Abdomen
What physical things etc signs should be assessed when determining the severity of dehydration?
- Mental state
- Skin turgor
- Dryness of mucous membranes
- Fontanelle
- Eye turgor
- Skin perfusion
- Pulse rate and character
What are the signs of mild dehydration?
Only physical sign may be dry mouth
What are the physical signs of moderate dehydration?
- Lethargy
- Inelastic skin
- Sunken fontanelle
- Sunken eyes
- Pulse may be fast, but of normal volume
- Slow refilling of skin when blanched
What are the signs of severe dehydration?
- Very confused, only semi-conscious
- Mottled skin
- No refilling of skin when blanched
- Fontanelle and eyes deeply sunken
- Poor eye turgor
- Thready and fast pulse