Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) and Subsequent Central Diabetes Insipidus: A Rare Presentation of Pituitary Apoplexy

Abstract

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.

Relapsing Syndrome of Inappropriate Antidiuretic Hormone Production Responding to Tolvaptan Treatment in a Patient With a Micronodular Formation of the Posterior Pituitary Gland

“…Cases of SIADH due to a macroadenoma of the pituitary and cure after surgery have been described [3][4][5]. In addition, a case of SIADH after pituitary apoplexy is also reported [6]. In the absence of histopathologic or laboratory evidence of hormone production, mechanical stimulus leading to ADH production is suspected in these cases.…”