Macroprolactinoma Presenting With Hyponatremia; A Rare Case Report

Abstract Background: Hyponatremia is a common electrolyte abnormality, investigating the etiology can be challenging to clinician, especially when cause has rarely been associated with hyponatremia. Macroprolactinoma reported as of We are reporting case macroprolactinoma presenting Care Report: A 67 year old female previously healthy female, presented fall due syncopal episode. Patient lightheadedness for week prior presentation. On physical examination, patient had bilateral periorbital ecchymoses, and swelling nose. Remaining exam was unremarkable. Lab work showed hyponatremia high urine osmolality sodium, consistent syndrome inappropriate antidiuretic hormone (SIADH). CT head Intrasellar soft tissue mass represents pituitary macroadenoma. Pituitary hormonal workup prolactin: 2,808 ng/mL, rest profile normal, including pituitary-adrenal axis evaluation. MRI confirmed large macroadenoma measuring 1.7 x 2.9 2.5 cm, which displaces compresses optic chiasm invades right cavernous sinus. She treated fluid restriction salt tablets improvement sodium level normal. Cabergoline 0.25 mg twice started prolactin 156 ng/mL over 9 months period. Discussion: hyponatremia, it usually secondary hypopituitarism (low ACTH or low TSH). However, there few cases SIADH related in presence normal function. Although exact mechanism exaggerated production arginine vasopressin (AVP) not fully understood, likely theory thought mechanical pressure on axonal terminal AVP neurons by tumor. Conclusion: linked nonfunctioning adenoma. Only two found literature producing adenoma, our being third case.