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

The Diagnosis of Salt Poisoning Leading to Hypematraemia in Children – September 2009
old or less, one of whom (case 3), “a neglected one-month-old”, had intradural and
subarachnoid haemorrhages with an initial serum sodium of 180 mEq/l. 243 One peer
reviewer could not tell the cause of the hypernatraemia from the publication. The
other peer reviewer agreed on the balance of probability with the authors’ conclusion
that this was secondary to hypernatraemic dehydration.
The same year the authors used clinical observation 244 and experimental studies 245
to add weight to the evidence that hypernatraemia may be a cause of subdural
haemorrhage. The clinical paper included 7 cases of hypernatraemia with a subdural
effusion, one of which was bloody and one xanthochromic. A major limitation of
the clinical study is that most of the subdurals were chronic, and very little detail
is given of all but one of the cases. Subdural tap may in itself cause bleeding, and
in the one case where 5mls of grossly bloody fluid was obtained on subdural tap
subsequent exploration showed no membrane or large haematoma.
The one case described in detail was of a 5-week-old infant with evidence of a
chronic subdural hygroma, and acute presentation with salt poisoning, thought by
the authors to be accidental. The mother made up the infant’s formula while in the
home of the child’s grandmother, and “it was subsequently learned that sugar and salt
were kept in identical canisters and that salt had inadvertently been substituted for
sugar. The patient took between 360 and 600 ml of this mixture…” The timing of the
poisoning and the chronicity of the subdural fluid collection excludes hypernatraemia
as the cause. Both peer reviewers agreed, one on the balance of probability and the
other beyond reasonable doubt, with the authors’ conclusion in this case that this was
due to an error making up the feed with salt instead of sugar.
These studies were also conducted before the widespread recognition of nonaccidental
injury in children, first highlighted in 1962 by the landmark article
outlining the features of ‘Battered-Child Syndrome’. 246 As stated by Kempe,
“subdural haemorrhage with or without a skull fracture in our experience is an
extremely frequent finding even in the absence of fracture of the long bones” and
it was recommended that ‘Battered-Child Syndrome’ should be considered in any
child with a subdural haemorrhage.
Therefore the lack of available neuroimaging techniques, coupled with the lack of
appreciation of child abuse in the late 1950’s makes it very difficult to interpret
Finberg’s findings.
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