Page 74 - 15Diarrhoeaandvomiting

Assessing dehydration and shock

Admissions were predominantly from socially disadvantaged families (62% from social classes
IV and V). At the time of admission, 8.8% of children (101/1148) were clinically dehydrated,
with 1% assessed to have greater than 5% dehydration. The group of dehydrated children
(n = 101) showed a higher incidence of biochemical disturbances compared with those who
were not dehydrated (n = 1047): hypernatraemia (sodium levels > 145 mmol/l) 10.9% versus
0.6%, uraemia (urea > 7 mmol/l) 30% versus 5.3% and low bicarbonate levels (<21 mmol/l)
72% versus 55%. The difference in the incidence of biochemical abnormalities between the two
groups was statistically significant (P < 0.001) for all the three parameters. [EL = 3]
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In the second UK study, 447 children younger than 2 years and admitted to a hospital with
gastroenteritis were recruited over a 1 year period. Seventy-four percent of the children were
younger than 1 year and two-thirds of under-1-year-olds were younger than 6 months. The overall
incidence of moderate to severe dehydration (assessed clinically) was 14%. Hypernatraemia
(sodium levels ≥ 150 mmol/l) occurred in 0.8% of cases, 8% had raised urea concentration
(>6 mmol/l), and 3% had bicarbonate concentration ≤ 15 mmol/l. However, it was not specified
whether biochemical abnormalities were found only in children with moderate to severe
dehydration. [EL = 3]
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Another UK study included 215 children admitted to four paediatric units in south Wales with
gastroenteritis over a 1 year period. The age of the study population ranged from 2 weeks to
9 years and 61% of children were younger than 1 year. The primary aim of the study was to
describe the clinical characteristics, incidence of complications, and management (pre-admission
and hospital) of the patients. The authors did not specify the total number of cases with clinical
dehydration, but overall only 7% were judged to be severely dehydrated. At the time of admission,
blood testing was carried out in 35% of children (76/215) on clinical grounds. The incidence of
hypernatraemia among all the children (sodium levels > 145 mmol/l) was 0.9%, while 7.9% each
had hyponatraemia (sodium < 135 mmol/l) and raised urea concentration (>6 mmol/l). About 6%
of children had acidosis with bicarbonate levels < 15 mmol/l. [EL = 3]

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The study from Turkey aimed to investigate the relationship between blood glucose and
serum electrolytes since it was hypothesised that changes in blood glucose levels during
diarrhoea complicate the course of the illness, especially when it is associated with electrolyte
abnormalities. The study population included 119 children (age range 2 months to 15 years) with
gastroenteritis and moderate to severe dehydration (according to WHO criteria) admitted to a
tertiary children’s hospital over a 3 month period. In order to reduce age-dependant variability
of laboratory findings, the study population was further divided into two groups: younger than
2 years and more than 2 years of age. More than half of the study population had body weight/
age ratio less than the 10th percentile. Blood samples were drawn at the time of admission
in all children. Hypernatraemia (sodium levels > 150 mmol/l) was present in 7.6% of all
cases and hyponatraemia (sodium levels < 130 mmol/l) in 3.4%, while 48% of children had
bicarbonate levels < 15 mmol/l. Potassium levels < 3 mmol/l were noted in 4.2% of children.
Hyperglycaemia (blood glucose levels > 140 mg/dl) was observed in 10.9% of cases while
hypoglycaemia (threshold value not defined) was noted in only one child. The mean sodium
levels were significantly higher in the hyperglycaemic group of children compared with the rest
of children, but there was no difference between the two groups regarding serum bicarbonate
levels. Similarly, mean sodium levels were noted to be higher in children younger than 2 years
with bicarbonate levels < 15 mmol/l compared with those with higher bicarbonate levels
(>15 mmol/l). A positive correlation was found between blood glucose and serum sodium levels
in children younger than 2 years with bicarbonate levels < 15 mmol/l (r = 0.35; P < 0.05), and
this correlation became stronger when the analysis was limited to children with bicarbonate
levels < 10 mmol/l (r = 0.73; P < 0.05). No relationship was observed between blood glucose
and serum sodium levels in the older age group. However, the authors did not give detailed
information about the correlation data. [EL = 3]
A retrospective case series from the USA aimed to estimate the prevalence of hypoglycaemia
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among children with dehydration due to acute gastroenteritis who presented to an urban hospital
emergency department. For this study, dehydration was considered to be present in children
who received an IV fluid bolus. Hypoglycaemia was defined as serum glucose concentration
< 60 mg/dl (3.3 mmol/l). Medical records of 196 children (younger than 5 years) admitted
over a 1 year period were reviewed and the mean age of the study sample was 23 months

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