Ocular ultrasonography for diagnosing increased intracranial pressure in patients with severe preeclampsia

Background Ultrasound measurements of optic nerve sheath diameter (ONSD) and optic disc height (ODH) measured outside pregnancy correlate with intracranial hypertension. Data on the usefulness of ocular ultrasonography in preeclampsia are limited. Objective To determine whether ONSD and ODH are greater in patients with features of severe preeclampsia compared to healthy controls. Methods Consecutively admitted patients with severe preeclampsia (according to the ACOG Task Force on Hypertension in Pregnancy) and healthy term control pregnant women were included in this prospective observational study. Optic nerve sheath diameter measured 3 mm behind the globe and ODH were assessed using ocular ultrasonography. Patients with severe preeclampsia were compared to controls before delivery, and at one and four days post-delivery. Results We included 30 patients with severe preeclampsia and 30 controls. Optic nerve sheath diameter was significantly higher in patients with severe preeclampsia compared to controls before delivery, and one day and four days post-delivery (P <0.001). Optic disc height was significantly greater in patients with severe preeclampsia compared to controls before delivery (P <0.001), and one day (P <0.001) but not four days, post-delivery (P=0.66). Before delivery, 43% of patients with severe preeclampsia had an ONSD >5.8 mm and 77% an ODH ≥1 mm: compatible with intracranial hypertension. None of the control patients had an ONSD of >5.8 mm or an optic disc height of ≥1 mm before or after delivery. Conclusions Severe preeclampsia was associated with a significantly higher ONSD and increased ODH, which could be ultrasonographic evidence of papilledema.