Hyponatremia is a relatively common disorder occurring in up to 6% of hospitalized patients and can occur through any mechanism that produces a relative excess of body water to body sodium. Although most hyponatremia patients are asymptomatic, severe symptomatic hyponatremia is a medical emergency that may lead to cerebral edema, tentorial herniation and death. More aggressive therapy is indicated in these patients. However, in some patients, the treatment itself may result in central nervous system demyelination that may be associated with permanent neurologic sequelae. The therapeutic strategy that should guide optimal treatment of hyponatremia requires attention to the following four factors: the patient’s volume status, the presence or absence of symptoms, duration of hypo-osmolality, and the presence or absence of risk factors for the development of neurologic complication. An initial categorization according to the clinical ECF volume status of the patient will allow a determination of the appropriate initial therapy in the majority of cases. The importance of duration of hyponatremia and the presence or absence of symptoms relates to how well the brain has adapted to the hyponatremia. The severity of hyponatremia is also an important consideration because osmotic demyelination is rarely seen in patients with the initial serum sodium greater than 120 mEq/l. Clinical surveys have identified subgroups of patients at greatest risk for developing neurologic complication of hyponatremia. Optimal therapy of these patients must consider balancing the risks of hyponatremia against the risks of correction for each patient individually. Although individual variability in response to treatment is considerable, consensus guidelines for treating hyponatremic patients allow a rational and safe therapeutic approach to minimize the neurologic complications.

Anderson RJ: Hospital associated hyponatremia. Kidney Int 1986;29:1237–1240.
Burton DR: Hypoosmolar state-hyponatremia; in Burton DR (eds): Clinical Physiology of Acid-Base and Electrolyte Disorders. Boston, McGraw-Hill, 2001, pp 696–745.
Verbalis JG: Hyponatremia and hypoosmolar disorders; in Arthur G (eds): Primer on Kidney Diseases. New York, Academic Press, 2001, pp 57–63.
Halterman R, Berl T: Treatment of dysnatremic disorder in therapy in nephrology and hypertension; in Brady H, Wilcox C (eds): Therapy in Nephrology and Hypertension. Philadelphia, Saunders,1999.
Ayus JC, Wheeler JM, Arieff AI: Postoperative hyponatremic encephalopathy in menstruant women. Ann Intern Med 1992;117:891–897.
Karp BI, Laureno R: Pontine and extrapontine myelinolysis: A neurologic disorder following rapid correction of hyponatrenmia. Medicine 1993;72:359–373.
Sterns RH: Severe symptomatic hyponatremia: Treatment and outcome. A study of 64 cases. Ann Intern Med 1987;107:656–664.
Sterns RH, Cappucio JD, Silver SM, Cohen EP: Neurologic sequelae after treatment of severe hyponatremia: A multicenter perspective. J Am Soc Nephrol 1994;4:1522–1530.
Arieff AI, Llach F, Massry SG: Neurological manifestations and morbidity of hyponatremia: Correlation with brain water and electrolytes. Medicine 1976;55:121–129.
Verbalis JG: Hyponatremia: Epidemiology, pathophysiology and therapy. Curr Opin Nephrol Hypertens 1993;2:636–652.
Ayus JC, Arieff AI: Chronic hyponatremic encephalopathy in postmenopausal women: Association of therapies with morbidity and mortality. JAMA 1995;281:2299–2304.
Verbalis JG, Martinez AZ: Neurological and neuropathological sequelae of correction of chronic hyponatremia. Kidney Int 1991;39:1274–1282.
AAP Provisional Committee on Quality Improvement, Subcommittee on Acute Gastroenteritis: Practice parameter: The management of acute gastroenteritis in young children. Pediatrics 1996;97:424.
Finberg L, Kravath R, Hellerstein S, Saenger P: Water and Electrolyte in Pediatrics. Philadelphia, Saunders, 1993.
Furth S, Oski FA: Hyponatremia and water intoxication in infants: An American epidemic. Am J Dis Child 1993;147:932.
Keating JP, Schears GH, Dodge PR: Oral water intoxication in infants: An American epidemic. Am J Dis Child 1991;5:985,.
Berl T: Treating hyponatremia: Damned if we do and damned if we don’t. Kidney Int 1990;37:1006–1008.
Verbalis JG: Adaptation to acute and chronic hyponatremia: Implications for symptomatology, diagnosis, and therapy. Semin Nephrol 1998;18:3–19.
Lauriat S, Berl T: The hyponatremic patient: Practical focus on therapy. J Am Soc Nephrol 1997;8:1599–1607.
Laureno R, Karp BI: Myelinolysis after correction of hyponatremia. Ann Intern Med 1997;126:57.
Meyers A : Fluid and electrolyte therapy for children. Curr Opin Pediatr 1994;6:303.
Adrogue HJ, Madias NE: Hyponatremia. N Engl J Med 2000;342:1493–1499.
Forrest JN, Cox M, Hong C, Morrison G, Bia M, Singer I: Superiority of demeclocycline over lithium in the treatment of chronic syndrome of inappropriate secretion of antidiuretic hormone. N Engl J Med 1978;298:173–177.
Decaux G, Brimiolle S, Genette F, Mockel J: Treatment of the syndrome of inappropriate secretion of antidiuretic hormone by urea. Am J Med 1981;283:1081–1083.
Serradeil-Le Gal C, Lacour C, Valette G, et al: Characterization of SR 121463A, a highly potent and selective V2 receptor antagonist. J Clin Invest 1996;98:2729.
Bichet DG, Madore F, Cusson J, Arthus MF, Lonergan M, Nelson CB, Bakker-Arkema RG: Pharmacotherapy for hyponatremia in SIADH: Effects of a new orally administered dual V1a/V2 vasopressin antagonist YM087 (abstract). J Am Soc Neprol 1999;10:119A.
Inoue T, Ohinshi A, Matsuo A, et al: Aquaretic effect of a potent, orally active, nonpeptide V2 antagonist in cirrhosis. Hepatology 1996;23:265.
Saito T, Ishikawa S, Abe K, et al: Acute aquaresis by the nonpeptide argine vasopressin(AVP) antagonist OPC-31260 improves hyponatremia in patients with syndrome of inappropriate secretion of antidiuretic hormone (SIADH). J Clin Endocrinol Metab 1997;82:1054–1057.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.