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

The Diagnosis of Salt Poisoning Leading to Hypematraemia in Children – September 2009
4.7 Excessive sodium administration without hypernatraemia
Clinical question
Can excessive sodium administration present without hypernatraemia?
There are two case reports of increased sodium intake in children without hypernatraemia.
The first was from Great Ormond Street Hospital in 1975. 277 A 3-month-old previously
healthy bottle-fed girl developed diarrhoea. “After 3 days the parents sought medical help
and were advised to give her clear fluid feeds prepared by adding 5 teaspoons of glucose
and 1 saltspoon of salt to 600 ml (20 fl oz) water. Having no saltspoon in the house, they
prepared each feed by adding 2 teaspoons of glucose and 5 pinches of salt to 240 ml (8 fl
oz) water.” The resulting solution contained 117 mEq/L of sodium. The baby took one litre a
day of this solution and over 3 days developed swelling of the face, abdomen and legs. Her
admission sodium was 144 mEq/L, and her blood pressure was 140/80 mm Hg. Her 24-hour
urine sodium excretion was initially 20 mEq (4.5 mEq/kg per day). The peer reviewer with
expertise in salt physiology agreed beyond reasonable doubt with the authors’ conclusions
as to the cause of the oedema and hypertension. The second peer reviewer did not feel able
to tell whether they agreed with the authors’ conclusions because of the complexity of the
biochemical data.
The second case from Columbia, USA, in 1978, 278 concerned a one-month-old boy fed Karo
syrup. He had been born at 35 weeks gestation, birth weight 2.3 kilogram. He was admitted
with excessive weight gain and oedema over 2 weeks. His admission sodium was 142
mEq/L. The baby’s fractional excretion of sodium was 1.5%. There was no mention of blood
pressure. A paediatrician had prescribed Karo syrup (concentrated sweetened corn syrup)
because of straining with bowel movements. Unfortunately, his parents had misinterpreted
the instructions and as a result the infant had received a calculated 5 mEq/kg of sodium
per day. One peer reviewer agreed beyond reasonable doubt that this was the cause of the
infant’s symptoms. The other disagreed beyond reasonable doubt, calculating that a healthy
infant should have been able to excrete the relatively small sodium load.
The first case suggests that excessive sodium intake does not invariably cause
hypernatraemia.
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