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

The Diagnosis of Salt Poisoning Leading to Hypematraemia in Children – September 2009
BMRB Omnibus conducted face-to-face interviews with a nationally representative sample
of 320 adults aged 16 years or over and who are the parent or guardian of a child aged 5 or
under, across Great Britain. Their interview included the question:
“What do you think is the minimum number of level teaspoons of salt, consumed in
one day, that could kill a one year old child?”
They were given the options of ½, 2, 5, 10 or 20 teaspoons, and also could respond as
‘don’t know’ or ‘none of these’. Their answers were analysed by age, sex, social class and
geographical region.
An average 1 year old weighs approximately 10 kilograms. From section 5.2, the minimum
lethal dose of salt is thought to be between 0.75 and 3 grams of salt per kilogram. This
suggests a minimum lethal dose of between 7.5 grams to 30 grams. A level 5mls te
aspoon of salt weighs nearly 6grams. Therefore the correct answer is somewhere between 1¼
and 5 level teaspoons.
Responses obtained were as follows:
Half a teaspoon: 30%
2 teaspoons: 29%
5 teaspoons: 19%
10 teaspoons: 6%
20 teaspoons: 2%
don’t know: 12%
none of these: 2%
Therefore nearly half (48%) of the respondents gave a correct answer (2 or 5 teaspoons).
Only 8% significantly over-estimated the minimum lethal dose, with a further 12% who
responded that they did not know.
30% underestimated the minimum lethal dose (half a teaspoon equates to 0.3 grams per
kilogram). This would be an underestimate even for an unusually small 1 year old of 7
kilograms (just under 0.5g/kg).
More women than men and more social grade AB (individuals in the UK aged 16-74
employed in higher and intermediate managerial, administrative and professional occupations)
responded that they didn’t know. There were no other major differences in responses.
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