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doi:10.1111/jpc.12646
INSTRUCTIVE CASE
Hyponatraemic seizure in a 6-month-old infant due to water intoxication Rakel Hansen Paediatrics, Coffs Harbour Health Campus, Coffs Harbour, New South Wales, Australia
Key words:
infant; hyponatremia; water intoxication.
A 6-month-old infant presented to a regional hospital in NSW with convulsive status epilepticus. She was managed with IV midazolam and a loading phenytoin dose, with successful termination of the seizure. Further history revealed that she had a 1-day history of green diarrhoea but had been otherwise well with no vomiting or fever. She had no medical, developmental or family history, and review of her community record showed appropriate weight gain and anthropometry, as shown in Table 1. On examination, she was drowsy but otherwise had a normal examination. She appeared well kept and weighed 8.3 kg. Investigations revealed a severe acute hyponatraemia
Key Points • Symptomatic hypo natremia due to water intoxication in infants secondary to feeding of dilute fluids is still occurring. It is likely to be due to a combination of immature neurohormonal and renal function, with reduced ability to excrete free water, and the feeding of dilute fluids. • The most common reason for a dilute fluid to be fed was due to financial concerns, which suggests infants being formula fed are most at risk, as cost is not an issue in breastfeeding. In Australia,there are a substantial proportion of infants in this category. In order to encourage breastfeeding, focus has been given to promotion and support of mainly breastfeeding for new mothers as per the ANBS. This may leave some mothers in a situation where they may have had insufficient education about the dangers of substituting or diluting formula feeds, especially for mothers who initially breastfed but then changed to formula feeding. • Simple evaluation of an infant’s diet should be taken regularly by health professionals and opportunistic education given if indicated. Correspondence: Dr Rakel Hansen, Paediatrics, Coffs Harbour Health Campus, Coffs Harbour, NSW 2450, Australia. Fax: 02 6656 5334; email: [email protected] Conflict of interest: None. Accepted for publication 2 March 2014.
with a sodium level of 120 mmol/L; a normal CT brain, normal inflammatory markers and stool specimens were ultimately negative for pathogens on microscopy and cultures. Other results are available in Table 2. The mother was questioned regarding intake of the child and admitted she was unable to afford infant formula and had been giving green cordial as replacement for ‘some’ of her feeds in the last day. She had poor understanding of the dangers of diluting or substituting formula in infants despite formula feeding since 5 weeks of age. This was consistent with the diagnosis of symptomatic hyponatraemia due to water intoxication, with perhaps some contribution from Gastrointestinal tract losses. She was managed with a 1 mL/kg bolus of 3% saline, resulting in an increase in sodium to 123 mmol, and was started on an 80% maintenance 0.9% saline infusion with normalisation of serum sodium over the next 24 h. She progressed well with no further events and was discharged after 2 days of observation, with no abnormal neurology and normal bowel motions. This case is one of the inappropriate feeding of an infant with water-based fluid, which led to symptomatic hyponatraemia due to water intoxication. No similar cases in an Australian infant have previously been reported in the literature; however, this is certainly not a new phenomenon and has been previously reported in the literature since the 1960s.1–3 Indeed, it was cited as an ‘epidemic’2 during the 1990s in the USA, attributed to poverty and poor social services. The underlying cause in cases of symptomatic water intoxication in infants is likely to be a complex interaction between immature renal and neurohormonal function, with the feeding of inappropriate fluids. As pointed out by Moritz and Ayus,4 the development of hyponatraemia requires a relative excess of free water combined with an underlying condition that impairs renal excretion of free water, such as renal hypoperfusion, reduced GFR or excess antidiuretic hormone (ADH). While the former may certainly be involved in cases of depleted volume, the latter two may be important in previously well infants given dilute fluids. Children
doi:10.1111/jpc.12646
INSTRUCTIVE CASE
Hyponatraemic seizure in a 6-month-old infant due to water intoxication Rakel Hansen Paediatrics, Coffs Harbour Health Campus, Coffs Harbour, New South Wales, Australia
Key words:
infant; hyponatremia; water intoxication.
A 6-month-old infant presented to a regional hospital in NSW with convulsive status epilepticus. She was managed with IV midazolam and a loading phenytoin dose, with successful termination of the seizure. Further history revealed that she had a 1-day history of green diarrhoea but had been otherwise well with no vomiting or fever. She had no medical, developmental or family history, and review of her community record showed appropriate weight gain and anthropometry, as shown in Table 1. On examination, she was drowsy but otherwise had a normal examination. She appeared well kept and weighed 8.3 kg. Investigations revealed a severe acute hyponatraemia
Key Points • Symptomatic hypo natremia due to water intoxication in infants secondary to feeding of dilute fluids is still occurring. It is likely to be due to a combination of immature neurohormonal and renal function, with reduced ability to excrete free water, and the feeding of dilute fluids. • The most common reason for a dilute fluid to be fed was due to financial concerns, which suggests infants being formula fed are most at risk, as cost is not an issue in breastfeeding. In Australia,there are a substantial proportion of infants in this category. In order to encourage breastfeeding, focus has been given to promotion and support of mainly breastfeeding for new mothers as per the ANBS. This may leave some mothers in a situation where they may have had insufficient education about the dangers of substituting or diluting formula feeds, especially for mothers who initially breastfed but then changed to formula feeding. • Simple evaluation of an infant’s diet should be taken regularly by health professionals and opportunistic education given if indicated. Correspondence: Dr Rakel Hansen, Paediatrics, Coffs Harbour Health Campus, Coffs Harbour, NSW 2450, Australia. Fax: 02 6656 5334; email: [email protected] Conflict of interest: None. Accepted for publication 2 March 2014.
with a sodium level of 120 mmol/L; a normal CT brain, normal inflammatory markers and stool specimens were ultimately negative for pathogens on microscopy and cultures. Other results are available in Table 2. The mother was questioned regarding intake of the child and admitted she was unable to afford infant formula and had been giving green cordial as replacement for ‘some’ of her feeds in the last day. She had poor understanding of the dangers of diluting or substituting formula in infants despite formula feeding since 5 weeks of age. This was consistent with the diagnosis of symptomatic hyponatraemia due to water intoxication, with perhaps some contribution from Gastrointestinal tract losses. She was managed with a 1 mL/kg bolus of 3% saline, resulting in an increase in sodium to 123 mmol, and was started on an 80% maintenance 0.9% saline infusion with normalisation of serum sodium over the next 24 h. She progressed well with no further events and was discharged after 2 days of observation, with no abnormal neurology and normal bowel motions. This case is one of the inappropriate feeding of an infant with water-based fluid, which led to symptomatic hyponatraemia due to water intoxication. No similar cases in an Australian infant have previously been reported in the literature; however, this is certainly not a new phenomenon and has been previously reported in the literature since the 1960s.1–3 Indeed, it was cited as an ‘epidemic’2 during the 1990s in the USA, attributed to poverty and poor social services. The underlying cause in cases of symptomatic water intoxication in infants is likely to be a complex interaction between immature renal and neurohormonal function, with the feeding of inappropriate fluids. As pointed out by Moritz and Ayus,4 the development of hyponatraemia requires a relative excess of free water combined with an underlying condition that impairs renal excretion of free water, such as renal hypoperfusion, reduced GFR or excess antidiuretic hormone (ADH). While the former may certainly be involved in cases of depleted volume, the latter two may be important in previously well infants given dilute fluids. Children
