Contemporary clinical management of the cerebral complications of preeclampsia

Optic nerve sheath diameter measurements using ultrasonography to diagnose raised intracranial pressure in preeclampsia: an observational study

Objective

To estimate the incidence of raised intracranial pressure (ICP) as evident by enlarged optic nerve sheath diameter (ONSD) by ocular ultrasound among patients with preeclampsia and its relationship to severity of disease.

Material and Methods

Sixty pregnant mothers with preeclampsia were compared to 30 normotensive, uncomplicated pregnant controls. For ONSD measurement, a 7-MHZ linear probe was used and three values from each optic nerve were taken and the mean of six values of both eyes was recorded. All study subjects were followed until seven days after delivery.

Results

Two cut off values (5.8 mm and 4.6 mm) were used to compare ONSD in severe and non-severe preeclampsia with that of healthy pregnant individuals. The incidence of raised ICP among severe preeclampsia above 5.8 mm and 4.6 mm cut-off were 43.3% and 90%, respectively, before delivery. ONSD was significantly elevated among preeclampsia subjects at both cut-off values at pre-delivery (p=0.004 for ONSD >5.8 mm and p<0.001 for ONSD >4.6 mm) compared to controls. There a significant association between presence of neurological manifestations and enlarged ONSD (p<0.001 for ONSD >5.8 mm and p=0.04 for ONSD >4.6 mm) before delivery.

Conclusion

Severe preeclampsia with neurological features was associated with increased ONSD, reflecting raised ICP. Further studies are needed to compare ONSD values with invasive ICP monitoring for better understanding of this relationship.

Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

Preeclampsia and other hypertensive disorders of pregnancy are major contributors to maternal morbidity and mortality worldwide. This group of disorders includes chronic hypertension, gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension, and eclampsia. The body undergoes important physiological changes during pregnancy to allow for normal placental and fetal development. Several mechanisms have been proposed that may lead to preeclampsia, including abnormal placentation and placental hypoxia, impaired angiogenesis, excessive pro-inflammatory response, immune system imbalance, abnormalities of cellular senescence, alterations in regulation and activity of angiotensin II, and oxidative stress, ultimately resulting in upregulation of multiple mediators of endothelial cell dysfunction leading to maternal disease. The clinical implications of preeclampsia are significant as there are important short-term and long-term health consequences for those affected. Preeclampsia leads to increased risk of preterm delivery and increased morbidity and mortality of both the developing fetus and mother. Preeclampsia also commonly leads to acute kidney injury, and women who experience preeclampsia or another hypertensive disorder of pregnancy are at increased lifetime risk of chronic kidney disease and cardiovascular disease. An understanding of normal pregnancy physiology and the pathophysiology of preeclampsia is essential to develop novel treatment approaches and manage patients with preeclampsia and hypertensive disorders of pregnancy. © 2023 American Physiological Society. Compr Physiol 13:4231-4267, 2023.

Nanoparticle-Mediated Simultaneous Downregulation of Placental Nrf2 and sFlt1 Improves Maternal and Fetal Outcomes in a Preeclampsia Mouse Model

Preeclampsia has impacted 3-5% pregnancies among the world and its complications lead to both maternal and fetal morbidity and mortality. However, management of preeclampsia is limited. Nanoparticles targeting chondroitin sulfate A (CSA) can deliver drugs to placenta. Inactivation of soluble fms-like tyrosine kinase (sFlt-1) and nuclear factor-erythroid 2-like 2 (Nrf2) has been proved to alleviate preeclampsia and improve maternal and fetal outcomes. Carboxyl-polyethylene glycol-poly (d,l-lactide) (COOH-PEG5K-PLA8K), cationic lipid DOTAP, and siNrf2 and sisFlt-1 were used to construct the nanoparticles and conjugating peptides targeting CSA was fabricated to it. The expression levels of proteins and RNAs were estimated by qRT-PCR and Western blot assays. ELISA assays were performed to evaluate levels of circulating sFlt-1. The nanoparticles containing siNrf2 and sisFlt-1 are targeted to the placenta trophoblasts and downregulated the expression levels of Nrf2 and sFlt-1 as well as their downstream genes in the placental cells of model mice. Treatment of nanoparticles induced the expression of angiogenic factors in placenta. Knocking down Nrf2 and sFlt-1 synchronously alleviated the preeclampsia and increased the maternal and fetal outcomes in preeclampsia model mice. Nanoparticle-mediated simultaneous downregulation of placental Nrf2 and sFlt1 improved maternal and fetal outcomes in a preeclampsia mouse model.

Placental extracellular vesicles and pre-eclampsia

Pre-eclampsia is a hypertensive disease of pregnancy characterized by new-onset hypertension, with either proteinuria and/or organ dysfunction. Pre-eclampsia is a leading cause of maternal morbidity and mortality; however, the underlying cellular and molecular mechanisms are not well understood. There is consensus that the underlying mechanism(s) resulting in pre-eclampsia is centered around abnormal placentation, inadequate spiral-artery remodeling, and deficiency in trophoblast invasion, resulting in impaired maternal blood flow to the placenta and a release of signals and/or inflammatory mediators into maternal circulation triggering the systemic manifestations of pre-eclampsia. ER stress, resulting in impaired autophagy and placental release of aggregated proteins, may also confer systemic stress to maternal organs in pre-eclampsia. Extracellular vesicles (EVs), lipid-bilayer enclosed structures containing macromolecules including proteins, miRNA, and other important nucleotides, have been suggested to play an important role in this maternal-fetal communication. Circulating EVs are present in greater quantity in the plasma of pre-eclampsia subjects compared to normal pregnancy, and the placental derived EVs have been shown to have altered protein and RNA cargo. In this review, we will focus on EVs and their role in pre-eclampsia, specifically their role in immune responses, inflammation, altered angiogenesis, and endothelial dysfunction.

Placental Syncytiotrophoblast-Derived Extracellular Vesicles Carry Active NEP (Neprilysin) and Are Increased in Preeclampsia

NEP (neprilysin) is a widely expressed membrane-bound metalloprotease, which binds and cleaves a variety of peptides including vasodilators, natriuretics, and diuretics. Higher levels of NEP result in hypertension-a cardinal feature of the placental disease preeclampsia. Syncytiotrophoblast-derived extracellular vesicles (EVs), comprising microvesicles and exosomes, are released into the peripheral circulation in pregnancy and are postulated as a key mechanism coupling placental dysfunction and maternal phenotype in preeclampsia. We aimed to determine whether higher levels of active NEP are found in syncytiotrophoblast-derived EVs in preeclampsia compared with normal pregnancy. Using immunostaining and Western blotting, we first demonstrated that NEP levels are greater not only in preeclampsia placental tissue but also in syncytiotrophoblast-derived microvesicles and exosomes isolated from preeclampsia placentas ( P<0.05, n=5). We confirmed placental origin using antibody-coated magnetic beads to isolate NEP-bound vesicles, finding that they stain for placental alkaline phosphatase. NEP on syncytiotrophoblast-derived EVs is active and inhibited by thiorphan ( P<0.01, n=3; specific inhibitor). Syncytiotrophoblast-derived microvesicles, isolated from peripheral plasma, demonstrated higher NEP expression in preeclampsia using flow cytometry ( P<0.05, n=8). We isolated plasma exosomes using size-exclusion chromatography and showed greater NEP activity in preeclampsia ( P<0.05, n=8). These findings show that the placenta releases active NEP into the maternal circulation on syncytiotrophoblast-derived EVs, at significantly greater levels in preeclampsia. NEP has pathological roles in hypertension, heart failure, and amyloid deposition, all of which are features of preeclampsia. Circulating syncytiotrophoblast-derived EV-bound NEP thus may contribute to the pathogenesis of this disease.

Optic nerve sonography and ophthalmic artery Doppler velocimetry in healthy pregnant women: an Australian cohort study

PURPOSE

Maternal ocular sonography offers a window into cerebrovascular and intracranial pressure changes in pregnancy. This study aimed to determine the Doppler velocimetric variables of the ophthalmic artery, and the mean diameter of the optic nerve sheath (ONSD), in an Australian cohort of healthy pregnant women.

METHODS

A prospective observational cohort study of healthy women with uncomplicated singleton pregnancies in the third trimester was undertaken in a tertiary maternity service. A single prenatal ultrasonographic examination was performed on all participants, with a postnatal examination performed on a subgroup with uncomplicated deliveries.

RESULTS

Fifty women were examined at a mean gestation of 35 weeks. The mean ± SD Doppler variables in the ophthalmic artery were peak systolic velocity (PSV) 41.89 ± 13.13 cm/s, second peak velocity 20.63 ± 8.97 cm/s, end diastolic velocity 9.29 ± 5.13 cm/s, pulsatility index 1.97 ± 0.53, resistive index 0.78 ± 0.07, peak ratio (second peak velocity/PSV) 0.49 ± 0.12, while the mean ONSD was 4.34 ± 0.4 mm. None of these variables had a demonstrable relationship with gestation or mean arterial pressure (MAP), nor did the sheath diameter have a relationship with any of the Doppler variables.

CONCLUSIONS

The ocular sonographic variables observed in this population are similar to those reported in other cohorts. No clear relationship could be identified in this cohort between ophthalmic artery Doppler variables and the ONSD, and between each of these variables and gestation or MAP.

Preeclampsia: Acute Complications and Management Priorities

Acute complications of preeclampsia contribute substantially to maternal and fetal morbidity and mortality. The considerable variation in onset, clinical presentation, and severity of this hypertensive disease that is unique to pregnancy creates challenges in identifying risk factors for clinical deterioration. Delivery of the fetus remains the only definitive treatment for preeclampsia. Surveillance of signs and symptoms and laboratory parameters consistent with progression in severity requires an appreciation of the dynamic and progressive nature of the disease. This article provides a comprehensive overview of the pathophysiology of preeclampsia, setting the foundation for discussion of management priorities for acute complications that pose the greatest risks to maternal health.

Spontaneous haemorrhagic stroke complicating severe pre-eclampsia in pregnancy: a case report in a resource-limited setting in Cameroon

BACKGROUND

Spontaneous intracerebral haemorrhage is a rare complication of preeclampsia during pregnancy associated with a high morbidity and mortality. Compared with the non-pregnant women stroke rates are relatively rare during pregnancy.

CASE PRESENTATION

We report the case of a 32-year-old female Cameroonian gravida 4 para 3 who presented at 34 weeks of gestation with sudden onset of right sided hemiplegia associated with headache, blurred vision and a blood pressure of 182/126. Cerebral CT scan confirmed a left parietal spontaneous haemorrhage. Emergency caesarean delivery was done and the recovery uneventful.

CONCLUSION

This case highlights the importance of good neurological examination in pregnant women presenting with neurological symptoms as well as the place of multidisciplinary management in severe life threatening conditions.

Magnesium in obstetric anesthesia and intensive care

Magnesium, one of the essential elements in the human body, has numerous favorable effects that offer a variety of possibilities for its use in obstetric anesthesia and intensive care. Administered as a single intravenous bolus dose or a bolus followed by continuous infusion during surgery, magnesium attenuates stress response to endotracheal intubation, and reduces intraoperative anesthetic and postoperative analgesic requirements, while at the same time preserving favorable hemodynamics. Applied as part of an intrathecal or epidural anesthetic mixture, magnesium prolongs the duration of anesthesia and diminishes total postoperative analgesic consumption with no adverse maternal or neonatal effects. In obstetric intensive care, magnesium represents a first-choice medication in the treatment and prevention of eclamptic seizures. If used in recommended doses with close monitoring, magnesium is a safe and effective medication.

Atypical eclampsia and postpartum status epilepticus

Preeclampsia is an entity that may present from 20th week of gestation up to 48 hours postpartum and is associated with hypertension and proteinuria. Eclampsia is emergence of convulsions pre-eclampsia in pregnant women with signs and symptoms. Recent studies showed that in some women, preeclampsia and even eclampsia may occur without hypertension or proteinuria. Here, we present a case of 26 years old women who had an uneventful pregnancy until 30 weeks' of gestation. She had only proteinuria in laboratory tests and was diagnosed as status epilepticus in early postpartum period. Preeclampsia and eclampsia is related with serious fetal and maternal morbidity and mortality and may present with atypical course. The awareness of atypical cases of preeclampsia enhances early diagnosis and management which are critical to avoid feto-maternal complications.