Snapshot A 44-year-old woman with a recent diagnosis of small cell lung cancer presents to the emergency room with her partner. She had reported some nausea and feelings of malaise yesterday. Today, she continued to feel unwell, and reported feeling lethargic and weak. She is oriented to person and place but not to time. On physical exam, she is noted to have normal skin turgor and no edema. Laboratory testing reveals hyponatremia and decreased serum osmolality. Introduction Clinical definition login to view 1 more bullet Epidemiology login to view 22 more bullets Pathogenesis login to view 4 more bullets Presentation Symptoms login to view 11 more bullets Physical exam login to view 3 more bullets Studies Serum labs login to view 4 more bullets Urine studies login to view 3 more bullets Differential Other causes of euvolemic hyponatremia login to view 7 more bullets Treatment Management approach login to view 5 more bullets Medical login to view 19 more bullets Complications Osmotic demyelination syndrome (central pontine myelinolysis) login to view 1 more bullet