Hyponatremia in patients with cancer, Purpose of review Hyponatremia is seen commonly in patients with cancer and is associated with increased mortality and morbidity. Understanding the proper diagnosis and therapy of cancer-associated hyponatremia is critical to ensure improved outcomes. Recent findings The most common cancers associated with hyponatremia are the various forms of lung cancer with incidences approaching 25–45%. The most common causes of hyponatremia in cancer patients are the syndrome of inappropriate antidiuretic hormone secretion [syndrome of inappropriate antidiuretic hormone (ADH)] and volume depletion. Proper diagnosis rests on clinical information supplemented by laboratory studies and is critical to ensure appropriate therapy. In recent years, the development of drugs that specifically antagonize the vasopressin type 2 receptor in the distal tubule have offered targeted and highly effective therapies for syndrome of inappropriate ADH. Summary Hyponatremia in cancer patients generally indicates advanced or severe disease but proper therapy that targets the underlying process can improve outcomes. Correspondence to Mitchell H. Rosner, MD, Division of Nephrology, Department of Medicine, University of Virginia Health System, Box 800133, Charlottesville, VA 22908, USA. Tel: +1 434 982 6999; fax: +1 434 924 5848; e-mail: mhr9r@virginia.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Recent developments in the management of acute and chronic hyponatremia Purpose of review The aim of the study is to review recent studies on the management of acute and chronic hyponatremia. Recent findings In acute symptomatic hyponatremia, bolus infusion of hypertonic saline improves hyponatremia and neurological status more quickly than continuous infusion. In chronic hyponatremia, newly identified predictors of nonresponse to fluid restriction include a high urine osmolality (>500 mOsm/kg) and high urine sodium (>133 mmol/l). Vasopressin-receptor antagonists effectively raise the serum sodium concentration in patients with euvolemic or hypervolemic hyponatremia but have a risk of overcorrection, even at low doses. Several observational studies now support the use of urea for a more gradual correction of hyponatremia without a risk of overcorrection. Recently identified risk factors for overcorrection include lower serum sodium at presentation, polydipsia, hypovolemia, and early urine output during treatment. Specific treatments with potential efficacy are the use of intravenous albumin for hyponatremia because of liver cirrhosis, and fludrocortisone for hyponatremia in tuberculous meningitis. Summary The recent data will help to further optimize and personalize the management of patients with acute and chronic hyponatremia. However, most data are still observational and retrospective. Therefore, the field is in need of prospective studies comparing interventions for chronic hyponatremia and focusing on patient-relevant outcomes. Correspondence to Goce Spasovski, University Department of Nephrology, Medical Faculty, University of Skopje, Bul. Mother Teresa 17, 1000 Skopje, N. Macedonia. Tel: +389 70 268 232; e-mail: spasovski.goce@gmail.com Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.