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. 2025 Apr 21.
doi: 10.1007/s11739-025-03918-2. Online ahead of print.

Ultrasound evaluation of the optic nerve in patients with severe symptomatic hyponatremia

Giorgio Bosso #  1 , Antonio Pagano #  2 , Giovanni Porta  2 , Francesco Barbato  2 , Enrico Allegorico  2 , Roberto Allocca  2 , Gennaro Sansone  2 , Claudia Serra  2 , Valentina Minerva  2 , Paola Arbo  2 , Valeria Caterino  2 , Fabio Giuliano Numis  2
Affiliations

Ultrasound evaluation of the optic nerve in patients with severe symptomatic hyponatremia

Giorgio Bosso et al. Intern Emerg Med. .

Abstract

Severe hyponatremia can precipitate significant neurological symptoms due to osmotic imbalances that induce intracranial hypertension (ICH). This study investigates the correlation between serum sodium levels and optic nerve sheath diameter (ONSD), measured by ultrasound, in patients presenting with symptomatic severe hyponatremia in the Emergency Department. Sixty-four patients with severe hyponatremia (Na+ < 125 mmol/L) and neurological symptoms were enrolled and compared to a matched control group. Serial measurements of serum sodium and ONSD were obtained at 3, 12, and 24 h post-correction. Results demonstrated a significant inverse correlation between sodium levels and ONSD, with ONSD decreasing as sodium levels were corrected (r = -0.71). ROC analysis confirmed ONSD as a sensitive and specific indicator of elevated intracranial pressure in these patients. This study highlights ultrasound ONSD measurement as a valuable non-invasive tool for monitoring ICH in severe hyponatremia, supporting its role in emergency settings to enhance diagnostic accuracy and therapeutic monitoring. Further research is needed to validate these findings and elucidate prognostic implications.

Keywords: Hyponatremia; Optic nerve diameter; Sodium; Ultrasound.

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Conflict of interest statement

Declarations. Conflict of interest: The author(s) declare that they have no conflict of interest. Human and animal rights: The study protocol received approval from the “Campania Centro” Ethics Committee and adhered to the principles of the Declaration of Helsinki. Informed consent: Informed consent was obtained from all participants prior their inclusion in the study.

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