Investigation of association of ONSD with hyponatremia in symptomatic patients.

89 patients who were diagnosed to have hyponatremia (Na + <135 mmol/L) were prospectively analyzed and compared with 72 patients who have normal serum sodium levels presented to ED at the same time interval. Subjects' demographic properties including age and sex were recorded, as were admission symptoms, serum Na + level, and pre-treatment and post-treatment optic nerve sheath diameter (ONSD).

The mean age of the study population was 62.3 ± 17.6 years, and the control group 55.1 ± 20.0 years (p < 0.05). There was a significant difference between the patient group's pre-treatment and post-treatment OSNDs compared to the controls (p < 0.05). There was a significant negative correlation between the admission sodium level and ONSD in the patient group (p < 0.05). In the pre-treatment period, patients with symptoms had a significantly greater mean ONSD than those without symptoms (0.546 ± 0.068 mm vs 0.448 ± 0.081 mm; p < 0.05). The area under the curve was 0.870; the cut-off level calculated for hyponatremia was 0.49 mm, which had a sensitivity of 81% and a specificity of 81.9%.

Ultrasonic imaging of ONSD measurement in the emergency department appears to reflect changes consistent with ICP changes in hyponatremia and change in serum sodium.