Ultrasonographic optic nerve sheath diameter as a non-invasive marker of intracranial hypertension in pediatric patients: a pilot study

BackgroundIntracranial hypertension (IH) is a potentially life-threatening condition in pediatric patients that requires early recognition. Ultrasonographic measurement of optic nerve sheath diameter (ONSD) has emerged as a promising non-invasive surrogate for intracranial pressure (ICP), although pediatric data remain limited and diagnostic thresholds are not well established.ObjectiveTo evaluate the correlation between ONSD and directly measured ICP, and to determine an optimal ONSD cutoff for detecting intracranial hypertension in pediatric patients with closed fontanelles.MethodsThis prospective observational pilot study included pediatric patients admitted to a tertiary care center who required lumbar puncture with ICP measurement. ONSD was measured using transocular ultrasound immediately prior to lumbar puncture, at 3 mm posterior to the globe. Mean bilateral ONSD values were used when available. Correlation between ONSD and ICP was assessed using Spearman's rho. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff for detecting intracranial hypertension (defined as ICP >27 cmH₂O).ResultsThirteen patients were included, yielding 15 paired ONSD–ICP measurements. Median ONSD was 6.20 mm (IQR 5.68–6.53), and median ICP was 34 cmH₂O (IQR 26–44). A significant positive correlation was observed between ONSD and ICP (Spearman's rho = 0.65, p = 0.009). ROC analysis identified an optimal ONSD cutoff of 6.1 mm, with a sensitivity of 80% and specificity of 80% (AUC 0.88). Agreement between ONSD and ICP classification was moderate (κ = 0.57).ConclusionONSD ultrasonography appears to be a feasible and promising non-invasive method for detecting intracranial hypertension in pediatric patients with closed fontanelles. An ONSD threshold of 6.1 mm may help identify elevated ICP, although larger multicenter studies are required to validate these findings