We present an infant who underwent endoscopic third ventriculostomy due to
symptomatic hydrocephalus secondary to aqueductal stenosis. This is the fir
st reported case of inappropriate secretion of antidiuretic hormone complic
ated by hyponatriemia and seizures following endoscopic surgery. The possib
ility of such a neuroendoscopic complication should alert neurosurgeons and
close observation of serum electrolytes is highly recommended in the acute
postoperative period, particularly in infants.