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

The Diagnosis of Salt Poisoning Leading to Hypematraemia in Children – September 2009
in the past not to give the patient anything to drink when taking care of him. Apparently
the mother disliked changing diapers and thirsted the child. The mother stated that the
bruises occurred secondary to a fall, but their distribution did not seem consistent with the
history. The grandfather claimed the child was beaten with a rubber hose.’ One of the two
peer reviewers agreed on the balance of probability with the authors’ conclusions on cause.
The lack of details of normal tests at follow up, and the lack of a formal child protection
investigation led the second reviewer to state that they were unable to tell whether the
authors’ conclusions were correct.
The third child, a 7-year-old girl, was admitted with a history of vomiting and diarrhoea for
2 days starting 7 to 8 days before admission, then appearing to recover well. Two days prior
to admission she became anorexic and had some degree of malaise. Her father returned
home late at night and gave the girl a drink of water. The next morning she was too weak
to walk, and was taken to a doctor, from where she was admitted to hospital severely
dehydrated, extremely lethargic, nearly comatose and cyanotic. Her initial serum sodium
was 183 mEq/L. She was found to have markedly desiccated skin and mucous membranes,
a recent abrasion over the right forehead and two old resolving ecchymoses in the lumbar
area. ‘During hospitalization, a neighbour stated that the mother had exhibited bizarre
behaviour and had been depriving the child of water. Sometimes the child stood on the
front lawn and asked passersby for water. Apparently the motivation for the restriction was
the patient’s enuresis. The patient also has a peculiar craving for salt, eating the salt from
a shaker at times.’ Both peer reviewers considered that it was not possible to exclude salt
administration as an additional cause, but otherwise agreed on the balance of probability
with the authors’ diagnosis of child abuse.
It has also been suggested by others that although there was clear evidence of water
deprivation in these cases, the degree of hypernatraemia seen in the children was greater
than could be accounted for by this mechanism alone, and that they may also have been
given excess salt. 3 Urinary sodium was not measured in any of the three children. One of
the peer reviewers calculated that the degree of dehydration in each case was enough to
cause the reported degrees of hypernatraemia, assuming pure water loss.
A second publication, from France, in 1975 238 describes a 6-year-old girl who was admitted
when she attended clinic with clinical signs of dehydration and a serum sodium of 189
mEq/L. Her grandmother then reported that she was detested and beaten by her mother
who had also deprived her of water, tied her up and ensured she had no access to water; that
the child had on occasion drunk her own urine and condensation from the windows; and
that her brother had also been abused. She had previously been admitted with acute alcohol
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