FRI356 SIADH In Acromegaly And Cerebrovascular Accident

Disclosure: S. Siddiqui: None. I.A. Guatemala Funes: None. G. Simranpreet: None. T. Zahedi: None. F. Zhang: None. Introduction: Acromegaly is characterized by excess growth hormone secretion with distinctive features of acral overgrowth, soft tissue swelling, arthralgia, jaw prognostication, hyperglycemia, hyperhidrosis, and frontal bone bossing. Hypotonic hyponatremia may occur in patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH), hypothyroidism, hypocortisolism, polydipsia, medications, heart failure, liver disease, or renal dysfunction. We reported a rare case of a patient with acromegaly treated with octreotide (somatostatin analogue) who was admitted for cerebrovascular accident and developed hyponatremia due to SIADH. Case Report: Patient is an 81 year old female with typical clinical features of acromegaly who presented with expressive aphasia and left sided facial droop. MRI and CT head revealed a 26 x 14 x 29 mm densely calcified/ossified extra-axial mass in the posterior fossa, displacing the brainstem and small vessel ischemia. Patient was treated with monthly intramuscular injection of octreotide for more than 20 years before she was switched to oral octreotide formula two weeks ago. Patient had nausea, vomiting, and altered mental status. Labs showed hyponatremia with serum Na 118 mmol/L, low serum osmolality 247 mOsm/kg, high urine osmolality 437 mOsm/kg, and urine Na 104 mmol/L. Serum Na further dropped to 115 mmol/L after IV normal saline which may be related to the desalination phenomenon of SIADH. Tolvaptan and hypertonic saline were initiated followed by treatment with salt tablets and furosemide. After several days, her serum Na level slowly trending up back to normal 135 mmol/L and patient recovered with no focal neurological deficits. Discussion: Treatment for acromegaly involves multiple approaches, such as somatostatin receptor ligands, GH antagonism, surgery, radiotherapy, and dopamine receptor agonists. Life-treating endocrine disorder may result from pituitary infarction or hemorrhage in patient with acromegaly. Although gastrointestinal sodium loss may precipitate hyponatremia in our patient, her elevated urine sodium and urine osmolality were consistent with SIADH. Clinicians should be cautious of the sudden onset of hyponatremia due to SIADH in acromegaly patients and prompt treatment is warranted. Presentation: Friday, June 16, 2023