The differential diagnosis of hypernatraemia in children, with ...

The Diagnosis of Salt Poisoning Leading to Hypematraemia in Children – September 2009
not have been evaporative water loss, nor is it an endurance event. The authors
speculated that this could be due to a shift of hypotonic fluid from the extracellular
to the intracellular compartment. 143
Both studies were in adults. However, with quite young children competing in
endurance events hypernatraemia is a risk if adequate water replacement is not
taken.
Lost in the desert or at sea
The combination of inadequate water intake and increased transepidermal water
loss leads to hypernatraemia. At sea, drinking seawater will also contribute to
hypernatraemia.
4.1.2 Mineralocorticoid excess
A number of conditions with mineralocorticoid excess are encountered in paediatric
practice. These include:
• Primary hyperaldosteronism
• Deoxycorticosterone-secreting adrenal tumours
• Congenital adrenal hyperplasia due to 11-hydroxylase deficiency
Although hypernatraemia may occur with mineralocorticoid excess, it is very mild and
it is rarely, if ever, severe enough to constitute a clinical problem. In one large series (50
patients with primary hypoaldosteronism) from the MRC Blood Pressure Research Unit
in Glasgow 144 , the mean sodium concentration for the whole series was 141.8 mEq/L. For
a subgroup of 30 women the average was 143.3 and the highest recorded mean value only
147.0 mEq/L, and for another sample of men the corresponding figures were 143.6 and
145.7 mEq/L respectively.
Another review of patients with primary hypoaldosteronism by Relman 145 states “the mean
normal serum sodium concentration is approximately 140 mEq/L; 95 per cent of all normal
values are between 136 and 145 mEq/L. In primary aldosteronism the serum sodium is
usually in the range 140 to 147 mEq/L.”
In another study 146 , Conn reported on the electrolyte values in a subgroup of 18 patients
with primary hypoaldosteronism from a total population of 145 studied. Two patients had
sodium concentrations of 151 mmol/L, two others 148 mmol/L and all the rest were 147
mmol/L or below.
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