Cerebral salt wasting in children. The need for recognition and treatment
C. A. Ganong and M. S. Kappy
St Joseph's Hospital and Medical Center, Department of Pediatric Education, Phoenix, Ariz 85013.
OBJECTIVES--To describe a salt-wasting syndrome in children with central
nervous system (CNS) insults and to differentiate it from the syndrome of
inappropriate secretion of antidiuretic hormone (SIADH) and diabetes
insipidus so that it may be more readily diagnosed and treated.
DESIGN--Case reports. SETTING--Community teaching hospital. PATIENTS--Two
inpatients with CNS insults (closed head trauma in one and seizure
disorder, spastic diplegia, mental retardation, and hydrocephalus in the
other). SELECTION CRITERIA--Evidence of hyponatremia accompanied by
elevated urine sodium concentration and excessive urine output.
INTERVENTIONS--Volume-for-volume urine replacement with 0.9% and/or 3%
sodium chloride. Oral salt supplementation was required for brief periods
to maintain normal plasma sodium concentration after discharge from the
hospital. MEASUREMENTS AND MAIN RESULTS--Both patients had hyponatremia,
high urine sodium concentrations, hypovolemia, and excessive urine output
while receiving maintenance fluids. They also had elevated plasma atrial
natriuretic hormone (ANH) concentrations, decreased aldosterone
concentrations, and decreased [corrected] plasma renin activity for their
degree of hyponatremia and negative fluid balance. Both patients maintained
normal serum electrolyte concentrations with appropriate treatment.
CONCLUSIONS--These patients showed true salt wasting associated with acute
or chronic CNS injury, with hormonal patterns consistent with
"inappropriate" ANH secretion and distinct from the SIADH. It is important
to distinguish cerebral salt wasting (CSW) from the two other major
disturbances of water metabolism seen following CNS injury (ie, SIADH and
diabetes insipidus), because incorrect diagnosis and treatment could
greatly increase morbidity in CSW. The etiologic roles of ANH or brain
natriuretic peptide in CSW need to be further elucidated.
