Daily Optic Nerve Sheath Diameter Monitoring for Early Detection of Cerebral Edema in Preeclampsia and Eclampsia

Abstract

Cerebral edema is a severe neurological complication of preeclampsia and eclampsia, and continues to be a major contributor to maternal morbidity and mortality worldwide. Conventional methods for monitoring intracranial pressure (ICP) are invasive and unsuitable for obstetric patients, creating a need for a safe, non-invasive tool for early detection. In this prospective observational study, we evaluated the clinical utility of daily optic nerve sheath diameter (ONSD) monitoring using bedside ultrasonography in 50 women admitted to a tertiary ICU within 24 hours of symptom onset. Patients who developed eclampsia (n = 20) exhibited significantly higher mean ONSD values (5.66 ± 0.20 mm) compared with those with preeclampsia (4.61 ± 0.18 mm; p < 0.001). Notably, elevated ONSD consistently preceded overt neurological deterioration by 24–48 hours, showed a strong correlation with symptom severity (r = 0.76, p < 0.001), and was associated with longer ICU stays (7.8 ± 1.2 vs. 3.7 ± 0.8 days; p < 0.01). ROC curve analysis identified an optimal cutoff of 5.27 mm with 100% sensitivity and 100% specificity for detecting neuroimaging-confirmed cerebral edema. These findings indicate that daily ONSD measurement is a practical, reliable, and low-cost method for early identification of cerebral edema in hypertensive pregnancy disorders. By integrating ONSD into maternal ICU protocols, as summarized in our proposed monitoring algorithm, clinicians can anticipate neurological deterioration and implement timely interventions, particularly in settings where access to neuroimaging is limited. Beyond its immediate clinical value, this study underscores the potential role of ONSD monitoring in global maternal health strategies and highlights the need for multicenter trials to establish obstetric-specific cutoff values and validate its incorporation into international guidelines.