73 years female with metastatic breast cancer, on tamoxifen for 6/12. 2/7 Hx of nausea and thirst. Na+ 155, K+ 5.2, urine osm 137. Has multiple mets including sella turcica. Next most appropriate treatment:

Question

Quizplus · Accepted Answer

Fluid restrictionThe patient's presentation suggests syndrome of inappropriate antidiuretic hormone secretion (SIADH), possibly due to metastatic involvement of the sella turcica or the effect of tamoxifen. However, the high sodium level (Na+ 155) indicates hypernatremia, which is unusual for SIADH, suggesting instead that the patient may have developed diabetes insipidus (DI), likely due to the metastatic involvement of the sella turcica affecting the pituitary gland. The most appropriate initial treatment for DI, given the high sodium and the context, would be fluid restriction to manage the polyuria and prevent further dilution of serum sodium. Other options like saline, desmopressin, or demeclocycline are not appropriate given the high sodium level and the clinical context suggesting DI rather than SIADH.

73 Years Female with Metastatic Breast Cancer, on Tamoxifen for 6/12