Hyponatremia is common in cancer patients and has a negative impact on outcomes and survival. Both the diagnosis and treatment of hyponatremia are challenging. Easy-to-use, practical guidelines are needed. The aim of this article is to discuss practical issues related to the diagnostic workup and management of hyponatremia, with particular attention to complex patients, such as those affected by neoplastic diseases. Admittedly, these patients may present several comorbidities, which may cause sodium alterations. In addition, multidrug therapy may precipitate serum sodium fall. An algorithm for the diagnosis and treatment of hyponatremia was also developed, based on the discussion of the results of a questionnaire completed by the authors and of the published recommendations/guidelines on hyponatremia. The goal was to produce an algorithm that was as simple as possible but still comprehensive, without compromising information completeness. Many explanatory notes were added with the aim of guiding clinicians throughout the management of complex patients with hyponatremia, such as those with cancer. The resulting algorithm and supporting literature are presented.
Keywords: Antidiuretic hormone; Arginine vasopressin; Hyponatremia; SIADH; Tolvaptan; Water excretion.