Urea Therapy for Hyponatremia in Subarachnoid Hemorrhage

Summary

Hyponatremia is defined as a plasma sodium concentration below 135 mmol / L. This is a common occurrence (20-50%) during subarachnoid hemorrhage (SAH). Its appearance is often associated with vasospasm. It is associated with an increase in morbidity and mortality linked to induced neurological disorders. Hyponatremia is caused by two etiologies: the syndrome of inappropriate secretion of anti-diuretic hormone (SIADH), and the cerebral salt wasting syndrome, CSWS. Theoretically, these two entities are differentiated by the patient's volemia; in practice, this parameter is difficult to measure. In addition, the correction of hyponatremia is diametrically opposed according to its mechanism: water restriction in the case of SIADH, sodium intake in the event of CSWS. Urea is offered as a second-line treatment in the event of treatment failure to correct hyponatremia. However, the efficacy of this treatment is based on small, observational, retrospective studies. Moreover, the mechanism of action of urea remains poorly understood: it could be a hyperosmolar effect or passive renal reabsorption of sodium.

Timeline

Start

2020-12-03

Primary completion

2024-12-03

Completion

2025-08-01

Publications

• Background Hall A, O'Kane R. The Extracranial Consequences of Subarachnoid Hemorrhage. World Neurosurg. 2018 Jan;109:381-392. doi: 10.1016/j.wneu.2017.10.016. Epub 2017 Oct 16.
• Background Mapa B, Taylor BE, Appelboom G, Bruce EM, Claassen J, Connolly ES Jr. Impact of Hyponatremia on Morbidity, Mortality, and Complications After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review. World Neurosurg. 2016 Jan;85:305-14. doi: 10.1016/j.wneu.2015.08.054. Epub 2015 Sep 7.
• Background Hannon MJ, Behan LA, O'Brien MM, Tormey W, Ball SG, Javadpour M, Sherlock M, Thompson CJ. Hyponatremia following mild/moderate subarachnoid hemorrhage is due to SIAD and glucocorticoid deficiency and not cerebral salt wasting. J Clin Endocrinol Metab. 2014 Jan;99(1):291-8. doi: 10.1210/jc.2013-3032. Epub 2013 Dec 20.
• Background Nakajima H, Okada H, Hirose K, Murakami T, Shiotsu Y, Kadono M, Inoue M, Hasegawa G. Cerebral Salt-wasting Syndrome and Inappropriate Antidiuretic Hormone Syndrome after Subarachnoid Hemorrhaging. Intern Med. 2017;56(6):677-680. doi: 10.2169/internalmedicine.56.6843. Epub 2017 Mar 17.
• Background Hoorn EJ, Zietse R. Diagnosis and Treatment of Hyponatremia: Compilation of the Guidelines. J Am Soc Nephrol. 2017 May;28(5):1340-1349. doi: 10.1681/ASN.2016101139. Epub 2017 Feb 7.

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