Severe hyponatremia as an atypical manifestation of pituitary macroadenoma: a case report.

Abstract

We present a case of a 45-year-old woman who presented with symptoms of lethargy, vomiting, altered sensorium, and seizure. Her initial sodium level was 107mEq/l, plasma and urinary osmolality were 250 and 455mOsm/kg, respectively, and her urine sodium level was 141mEq/day, suggestive of hyponatremia due to SIADH. MRI scan of the brain revealed approximately 14×13×11mm pituitary mass. Prolactin and cortisol levels were 41.1ng/ml and 5.65μg/dl, respectively. Hyponatremia can result from various diseases, making it hard to identify the cause. A pituitary adenoma is a rare cause of hyponatremia due to SIADH. Pituitary adenoma rarely might be the cause of SIADH presenting as severe hyponatremia. So, in case of hyponatremia due to SIADH, clinicians should keep pituitary adenoma as well in their differential diagnoses.