Point-of-care ultrasonography for detecting raised intracranial pressure through optic nerve sheath diameter in non-traumatic headache patients

Abstract

Non-traumatic headache is a common presentation in both emergency and outpatient settings, where timely identification of raised intracranial pressure (ICP) is crucial to prevent severe neurological complications. Conventional diagnostic methods such as computed tomography and lumbar puncture have important limitations, including invasiveness, delayed availability, and limited sensitivity in certain contexts. Point-of-care ultrasound measurement of the optic nerve sheath diameter (ONSD) has emerged as a rapid, non-invasive tool for detecting elevated ICP at the bedside. The technique is based on the anatomical continuity between the intracranial subarachnoid space and the optic nerve sheath, which expands in response to increased ICP. Evidence from multiple studies and meta-analyses indicates that ONSD measurements above 5.0-5.7 mm in adults strongly correlate with elevated ICP, showing pooled sensitivities and specificities approaching 90%. This modality enables immediate triage, guides urgency of neuroimaging, reduces unnecessary radiation exposure, and can be applied in outpatient and low-resource settings. Despite these advantages, ONSD assessment is subject to operator dependency, variability in threshold values, and reduced accuracy in patients with certain ocular or systemic conditions. Advances in artificial intelligence–assisted measurement, coupled with standardized training protocols, have the potential to improve reproducibility and broaden adoption. Overall, point-of-care ultrasound-based ONSD measurement represents a valuable adjunct in the early evaluation of patients with non-traumatic headache, facilitating faster diagnosis, better resource utilization, and improved patient outcomes.

Keywords: Point-of-care ultrasound; Optic nerve sheath diameter; Intracranial pressure; Headache; Non-traumatic

Core Tip: Non-traumatic headache can be the first sign of raised intracranial pressure, requiring rapid recognition to prevent neurological deterioration. Conventional diagnostics such as computed tomography and lumbar puncture have limitations. Point-of-care ultrasound measurement of optic nerve sheath diameter is a fast, non-invasive method with high sensitivity and specificity for detecting elevated intracranial pressure. Its use can expedite diagnosis, guide urgent management, and reduce unnecessary imaging, especially in outpatient and resource-limited settings. Standardized training and emerging artificial intelligence-assisted measurement promise to enhance its reliability and broaden its clinical impact.