Sonographic Optic Nerve Sheath Diameter Following Seizure Prophylaxis in Pre‐Eclamptic Parturients With Severe Features

Abstract

Objectives Neurological manifestations, including raised intracranial pressures, are a hallmark of worsening pre‐eclampsia. Invasive methods for measuring intracranial pressure, though a gold standard, are not always a viable option. Maternal ocular sonography is a promising bedside tool, which serves as a noninvasive, cost‐effective means for measuring optic nerve sheath diameter (ONSD), a surrogate marker of raised intracranial pressures. We studied the ultrasonographically measured ONSD in severely pre‐eclamptic women, and the effect of magnesium sulfate therapy on its values. Methods Thirty severely pre‐eclamptic women at ≥28 weeks gestation were included. We recorded baseline ONSD values, serum magnesium levels, neurological symptoms, vitals, and repeated them at 4 and 12 hours following magnesium sulfate therapy, and then at 24 hours postpartum. An ONSD value >5.8 mm was suggestive of raised intracranial pressure. Primary outcome measure was to evaluate changes in ultrasonographically measured ONSD following seizure prophylaxis with magnesium sulfate. Results Women, 73.3%, had baseline ONSD >5.8 mm, with mean diameter being significantly high (6.02 ± 0.77 mm). There was a statistically nonsignificant decline in mean ONSD values at 4 and 12 hours, as well as at 24 hours postpartum. Patients with neurological symptoms declined significantly (from 70 to 10%; p value <.001) following magnesium sulfate therapy. Conclusions Majority of severely pre‐eclamptic parturients had high ONSD value suggestive of raised intracranial pressures, which persisted in the postpartum period and was unaffected by magnesium sulfate therapy. Ultrasound can thus serve as a point‐of‐care, cost‐effective, easily available bedside tool for indirectly measuring intracranial pressures in this high‐risk population.

Untitled

“…Also non-neurological conditions that can lead to cerebral edema and subsequently to increased ICP have been investigated, such as sepsis (87), acute liver failure, malignant hypertension (88), and preeclampsia or eclampsia (89)(90)(91)(92)(93). It is still unclear whether eclampsia is related to actual intracranial hypertension or to fluid status of patients (94).…”

Shear wave elastography combined with two‐dimensional ultrasonography for detecting optic nerve sheath: An effective tool for assessing preeclampsia

“…[8][9][10] Preeclampsia is associated with changes in the blood-eye barrier, choroidal thickness, and circulation, leading to varying degrees of ocular pathology. [11][12][13][14] Timely diagnosis and treatment of cerebral edema, aiming to decrease intracranial pressure (ICP), have been shown to significantly impact morbidity and mortality. 15,16 Thus, a non-invasive bedside approach to identify cerebral edema and elevated ICP is recommended in managing patients with severe preeclampsia.…”

“…Visual symptoms are reported in approximately 40% of patients with preeclampsia and can include decreased acuity, field defects, increased central corneal thickness and curvature, decreased corneal sensitivity, and decreased intraocular pressure 8–10 . Preeclampsia is associated with changes in the blood‐eye barrier, choroidal thickness, and circulation, leading to varying degrees of ocular pathology 11–14 . Timely diagnosis and treatment of cerebral edema, aiming to decrease intracranial pressure (ICP), have been shown to significantly impact morbidity and mortality 15,16 .…”