Hyponatremia

Management of severe hyponatremia with low-dose continuous kidney replacement therapy and peripheral D5W in an infant with acute kidney injury

We report a 7-month-old female infant who presented with anuric acute kidney injury and severe hyponatremia (serum sodium 110 mEq/L). The patient was treated with low-dose continuous kidney replacement therapy (CKRT), that is, 85% of total clearance dose divided equally between normonatric (Na 140 mEq/L) replacement and dialysate fluids. The remaining 15% of the clearance was provided by peripheral infusion of dextrose 5% (D5W). The patient's sodium was maintained between 119 mEq/L and 121 mEq/L for the first 24 hours of CKRT. Over the next 2 days, the rate of D5W infusion was slowly decreased while replacement and dialysis flow rates were proportionately increased. Serum sodium was normalised by day 2 of the therapy. The patient had no neurologic sequelae associated with this therapy.

Hyponatremia and Hyporeninemic-Hypoaldosteronism in a Pediatric Intensive Care Unit Patient

Hyponatremia is one of the most commonly encountered electrolyte abnormalities encountered in the pediatric world. Defined as a serum or plasma sodium less than 135 mEq/L, the etiology of hyponatremia is one that can typically be determined by performance of a thorough history. However, occasionally the etiology of a patient's hyponatremia is more elusive and determined only after laboratory evaluation. We present a 6-year-old girl with a complex medical history including spinal muscular atrophy, tracheostomy and ventilator dependence, who was admitted to the pediatric intensive care unit for treatment and evaluation of seizures with hyponatremia that was initially thought to be due to syndrome of inappropriate anti-diuretic hormone or cerebral salt wasting. However, during her hospital course, it was determined that the hyponatremia was more indicative of a rarer and much less common cause of hyponatremia, hyporeninemic-hypoaldosteronism. The physiological factors controlling serum sodium are reviewed, the etiologies of hyponatremia are presented and the treatment of hyporeninemic-hypoaldosteronism is discussed.

Hyponatraemia in a Lao paediatric intensive care unit: Prevalence, associations and intravenous fluid use

AIM

Hyponatraemia is a common and potentially deadly complication affecting hospitalised children world-wide. Hypotonic intravenous fluids can be a significant exacerbating factor. Exclusive use of isotonic fluids, coupled with rigorous blood monitoring, has proven effective in reducing hyponatraemia in developed settings. In developing countries, where hyponatraemia is often more common and severe, different factors may contribute to its incidence and detection. We aimed to determine the prevalence and disease associations of hyponatraemia and describe the intravenous maintenance fluid prescribing practices in a Lao paediatric intensive care unit.

METHODS

We conducted a cross-sectional study of 164 children aged 1 month to 15 years admitted to intensive care at a tertiary centre in Lao People's Democratic Republic (PDR) and recorded their serum sodium and clinical data at admission and on two subsequent days.

RESULTS

Hyponatraemia was detected in 41% (67/164, confidence interval 34-48%) of children, the majority of which was mild (34%, 56/164) and present at admission (35%, 55/158). Hyponatraemia was more common in malnourished children (odds ratio (OR) 2.3, P = 0.012) and females (OR 1.9, P = 0.045). Hyponatraemia correlated with death or expected death after discharge (OR 2.2, P = 0.015); 88% received maintenance intravenous fluids, with 67% of those receiving a hypotonic solution. Electrolyte testing was only performed in 20% (9/46) of patients outside the study protocol.

CONCLUSIONS

Hyponatraemia is highly prevalent in critically ill children in Lao PDR, as is the continued use of hypotonic intravenous fluids. With financial and practical barriers to safely detecting and monitoring electrolyte disorders in this setting, this local audit can help promote testing and has already encouraged changes to fluid prescribing.

Low sodium status in cystic fibrosis-as assessed by calculating fractional Na(+) excretion-is associated with decreased growth parameters

BACKGROUND

In CF infants, normonatremic Na(+) depletion (NNaD), identified by fractional Na(+) excretion (FENa) values <0.5%, was recently linked to impaired growth. Our paper investigates the relationship between FENa and growth in CF children >2years.

METHODS

FENa values were calculated in 35 CF and 24 control children, and tested for correlations with z-scores for weight, height and BMI.

RESULTS

All CF children and controls had normal plasma Na(+) concentrations. A total of 25 of 35 (71.4%) CF patients had decreased FENa values <0.5% (group I). FENa results of 10 CF patients (group II) and 23/24 controls (group III) were normal. In Na(+)-depleted CF children, compared to normal controls, mean z-scores for weight (-0.18±0.87 vs +1.03±0.57, p<0.001), height (-0.06±0.89 vs +0.53±0.72, p=0.009) and BMI (-0.22±0.87 vs +1.00±1.06, p<0.001) were significantly reduced. Also, we found positive correlations between FENa values and z-scores for weight (r=0.521), height (r=0.292) and BMI (r=0.468), respectively.

CONCLUSION

NNaD may contribute to poor growth in CF.