History and exam
Key diagnostic factors
common
presence of risk factors
History of gastroenteritis, age <3 years, history of trauma, history of burns >10% of body surface area, type 1 diabetes mellitus, and history of poor oral intake are all strongly associated risk factors.
thirst
Hyperosmolar state, as seen with relative dehydration and hypernatraemia, should be investigated.
May not be recognised in very young patients and patients with severe developmental delay.
capillary refill >3 seconds
The 3 most useful clinical findings in a child with volume depletion and dehydration were prolonged capillary refill time, decreased skin turgor, and abnormal respiratory pattern.[23]
May not be prolonged in all cases (e.g., burns, anaphylaxis, sepsis).
decreased skin turgor
Skin turgor is best assessed by pinching a small fold of skin on the abdomen adjacent to the umbilicus and observing recoil. If the skin tents and does not immediately return to its previous shape, dehydration may be suspected. However, in the setting of severe acute malnutrition, skin tenting is mostly due to loss of subcutaneous fat, and not volume depletion alone. Furthermore, in acute haemorrhagic losses, skin turgor is normal.
The 3 most useful clinical findings in a child with volume depletion and dehydration were prolonged capillary refill time, decreased skin turgor, and abnormal respiratory pattern.[23]
dry mucous membranes
Dry or tacky mucous membranes are seen with hypovolaemia; pallid mucous membranes suggest blood loss with anaemia.
abnormal mental status or activity level
Provides critical diagnostic information. Infants and small children who are inconsolable or listless, or do not seem to resist invasive or uncomfortable procedures, should be assumed to have serious/deteriorating illness.
tachycardia
Infants and young children with hypovolaemia maintain adequate cardiac output primarily through increased heart rate, due to developmentally limited capacity to augment stroke volume.
abnormal urinary output
High output in cases of excess renal losses (e.g., diabetes insipidus, diabetic ketoacidosis).
Appropriately low when volume depletion is not due to excess renal losses.
uncommon
elevated respiratory rate or deep respirations
Tachypnoea and hyperpnoea can be a compensatory response to metabolic acidosis. Classically seen in children with diabetic ketoacidosis as Kussmaul respirations. CO2 excretion can be increased in the situation of hypoperfusion leading to tissue acidosis.
The 3 most useful clinical findings in a child with volume depletion and dehydration were prolonged capillary refill time, decreased skin turgor, and abnormal respiratory pattern.[23]
Other diagnostic factors
common
vomiting
Common in gastroenteritis and may prevent oral rehydration therapy.
Other less common causes of vomiting include central nervous system disturbances (infection, migraine, tumour, bleeding, hydrocephalus), gastrointestinal causes (e.g., liver failure, infection, pyloric stenosis, volvulus, intussusception, ingestion), endocrine disorders (e.g., Addisonian crisis, DKA, metabolic disease).
diarrhoea
Defined as >3 watery stools/day. Characterises gastroenteritis.[14]
Onset, quantity, frequency, and presence of blood or mucus should be investigated.
abdominal pain
Common symptom in gastroenteritis, colitis, intra-abdominal haemorrhage, and small-bowel obstruction.
abnormal glucose test strip result
A rapid bedside blood glucose measurement should be obtained in all young children presenting with altered mental status and signs of volume depletion.
Hypoglycaemia is common in ill infants, due to higher metabolic rates and lower glycogen stores.
Patients presenting with volume depletion from new-onset diabetes are hyperglycaemic.
uncommon
low core temperature or fever
Low core temperature can indicate significant haemorrhage, sepsis (particularly in a young infant), and shock.
Peripheral skin temperature that is notably lower than central temperature is a result of increased systemic vascular resistance and indicates a state of compensated shock in hypovolaemia.
Fever is seen with infectious illness, burns, heat stress, and sepsis. It increases insensible losses, exacerbating free water loss.
abnormal BP
Children with mild or moderate hypovolaemia may have slightly high BP, due to increased systemic vascular resistance.
A low BP is a late and ominous sign in severe cases.
bruises or signs of neglect
Children presenting with hypovolaemia from internal bleeding as a result of non-accidental trauma may have evidence of prior trauma or neglect.
Importantly, these signs may be completely absent. Lack of external findings is not sufficiently reassuring to preclude further investigation.
Risk factors
strong
vomiting and/or diarrhoea
Gastroenteritis resulting in vomiting and diarrhoea is the most common aetiology of volume depletion in children worldwide. Additional risk factors for significant volume loss associated with gastroenteritis include: adverse social determinants of health; unsafe water sources and sanitation; high exposure to animals; and certain recreational activities and crowded living conditions.[6][7]
Other less common causes of vomiting include central nervous system disturbances with increased intracranial pressure or inflammation (infection, migraine, tumour, bleeding, hydrocephalus), gastrointestinal causes (e.g., liver failure, infection, pyloric stenosis, volvulus, intussusception, toxic ingestion), endocrine disorders (e.g., Addisonian crisis, diabetic ketoacidosis [DKA], metabolic disease).
age <3 years
These children have a higher proportion of total body water as extracellular fluid, have high body surface area to body mass ratios, have limited communication skills, can be difficult to examine, and depend wholly on others to provide adequate intake. It is developmentally normal for young children to put nearly everything they touch in their mouths, increasing the likelihood of infectious or toxic exposure. Poor feeding practices may be a cause of volume depletion in this age group.
Infants have an impaired ability to augment cardiac stroke volume and are less able to concentrate urine to compensate for volume depletion.
Burns and non-accidental trauma are more common in babies and toddlers than other age groups.
trauma
The larger size of spleen and liver in children relative to the skeleton leaves internal organs less protected than in an adult. Kidneys are more mobile.
Frequency of intracranial bleeds increases with blunt trauma in part due to the larger head to body size ratio in children under three, and also due to the relative fragility of the tissue of the germinal matrix and blood vessels in the developing brain.
Compared with adults, children have a lower total blood volume but similar clotting times. Thus, paediatric patients lose a significant portion of total blood volume through haemorrhage, before haemostasis can occur.
In cases of abuse, seeking treatment is usually delayed, prolonging internal bleeding.[8]
burns >10% of body surface area
Disruption of skin barrier, increased insensible losses.
type 1 diabetes mellitus
The incidence of children with newly diagnosed diabetes presenting diabetic ketoacidosis (DKA) varies widely with location and access to resources.[9] In the US, about 30% of all patients under 5 years with newly diagnosed diabetes mellitus will present in DKA.[10]
Children with known diabetes also frequently present in a ketoacidotic state due to changing growth and metabolism, reliance on others to monitor and give therapy, and significant psychosocial, socio-economic, and compliance issues (particularly in adolescents).[11]
history of poor oral intake
A child who is refusing to drink due to nausea, pain, altered mental status, or other reasons is at risk for becoming dehydrated, and consequently volume-depleted.
weak
vigorous and prolonged exercise
High ambient temperatures and humidity increase the likelihood of significant volume depletion with physical exertion.
history of diuretic use
Diuretics promote additional excretion of free water from the kidney, thus predisposing the child to potential dehydration and consequent volume depletion.
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