Endocrine Abstracts

Introduction: pituitary duplication is a rare congenital malformation. It has been mainly reported in the pediatric and neonatal population with few reported cases in the adult population. In this case we will be discussing the presentation of an adult female patient with pituitary stalk duplication and empty Sella causing hyponatremia.

Case Presentation: A 46-year-old female presented with severe euvolemic hyponatremia. Urine analysis showed high urine osmolality and urinary sodium concentration with low serum osmolality. Chest x-ray was normal. Further history revealed the history of amenorrhea. On physical examination, the patient had underdeveloped secondary sexual characteristics. Laboratory tests showed low FSH, LH and estradiol. Prolactin was moderately elevated. Morning cortisol was low, ACTH was within lower normal range, ACTH dynamic test was suboptimal and IGF-1 was low. MRI imaging showed enlarged bony Sella with duplication of pituitary stalk.

Conclusion: Severe hyponatremia was due to secondary adrenal insufficiency with primary empty sella syndrome (PES) PES is usually asymptomatic and mostly diagnosed as an incidental radiological finding. Severe hyponatremia as the presenting manifestation of empty sella syndrome is rare. The pathogenesis of hyponatremia in patients with adrenal insufficiency is mainly attributed to an increase in ADH secretion. ADH is produced together with corticotropin-releasing hormone (CRH) by the paraventricular nuclei of the hypothalamus to activate the synthesis and release of ACTH from the pituitary gland.