Triple Phase Response of Transient Hyponatremia or Secondary Adrenal Insufficiency? A Case Report

Hyponatremiais common in neurosurgical patients especially after pituitary surgery. It is the most common electrolyte abnormality encountered in general hospital admissions. Diagnosis of the underlying cause can be challenging. It has serious clinical sequelae if not diagnosed promptly, and can be fatal. Hyponatremia can result from severe hypothyroidism and secondary adrenal insufficiency. In this report, we describe a case of fluctuating sodium level in a middle aged male resembling triple phase response of transient hyponatremia. However, we suggest another diagnosis of hyponatremia due to secondary adrenal insufficiency followed by unmasking of underlying CDI by glucocorticoid replacement after resection of a large nonfunctioning pituitary macroadenoma.