Pituitary apoplexy (PA) is a rare endocrine emergency that occasionally presents with
sodium disturbances. Here we present a rare case with a previously healthy 41-year-old female who presented with acute onset
headache and
nausea without
visual impairment or overt pituitary dysfunction. Plasma
sodium concentrations declined abruptly during the first two days of admission to a nadir of 111 mmol/l. Urine and blood chemistry were consistent with syndrome of inappropriate
antidiuretic hormone secretion (
SIADH). Magnetic resonance imaging revealed recent
bleeding into a pituitary cystic process.
Hyponatremia was successfully corrected with fluid restriction and both visual function and anterior pituitary function remained intact. Subsequently, the patient developed
central diabetes insipidus (CDI), which responded well to
desmopressin substitution. To our knowledge, this is the first case of PA presenting predominantly with posterior pituitary dysfunction that transitioned from
SIADH to permanent CDI.