SAT-241 Pituitary Stalk Interruption Syndrome Presenting as Neonatal Hypotonia

Pituitary stalk interruption syndrome (PSIS) is a rare condition that include congenital anatomic abnormalities of the pituitary gland and hypopituitarism. There is a wide variety of clinical presentation, with the age at presentation encompassing from neonatal period to adulthood and including one or more pituitary hormone deficiencies. In recent literature there is increasing recognition of PSIS presenting in the neonatal period, mostly involving hypoglycemia. Our patient is a full-term male infant who presented in the newborn period with hypotonia and hypothermia. He also had hypoglycemia, which was initially thought to be associated to hyperinsulinism in the context of gestational diabetes. Micropenis was noted on physical exam. As part of the study for hypotonia, serial thyroid function tests were obtained revealing central hypothyroidism. A low dose ACTH stimulation test was performed which revealed adrenal insufficiency. The patient was started on cortisol and thyroid hormone replacement. Brain MRI showed an ectopic neurohypophysis located along the floor of the hypothalamus, a small anterior pituitary gland, and a partially absent infundibulum, findings consistent with pituitary stalk interruption syndrome. The patient received testosterone injections for micropenis and is being followed for development of other pituitary hormone deficiencies. PSIS is a rare congenital condition that is increasingly recognized in neonates manifesting with signs of hypopituitarism.