Purpose of review: Causes of hyponatremia in children include the syndrome of appropriate antidiuretic hormone secretion, the syndrome of inappropriate antidiuretic hormone secretion and cerebral salt wasting. The purpose of this review is to distinguish these possibilities, focusing on cerebral salt wasting.
Recent findings: Most cases of hyponatremia in children are due to the syndrome of appropriate antidiuretic hormone secretion. The syndrome of inappropriate antidiuretic hormone secretion can be seen with neurological injury, pain and medication use. Recent studies suggest that cerebral salt wasting is a rare cause of hyponatremia. When cerebral salt wasting is diagnosed, it is often difficult to make a direct link with the central nervous system insult.
Summary: The clinical condition, assessment of extracellular fluid space volume status, measurement of urinary electrolytes and responses to infusion of saline solutions can distinguish between syndrome of appropriate antidiuretic hormone secretion, syndrome of inappropriate antidiuretic hormone secretion and cerebral salt wasting. The word 'cerebral' in 'cerebral salt wasting syndrome' can thus be inappropriate, conveying inaccurate causation.