Cerebral imaging in eclampsia: magnetic resonance imaging versus computed tomography

Anesthetic management for emergency cesarean section in a patient with status epilepticus: A case report

RATIONALE

The presence of clinically significant repeated maternal epilepsies during pregnancy increases the risk of adverse maternal, fetal and neonatal outcomes. However, there are few guidelines for anesthesiologists to deal with this situation.

PATIENT CONCERNS AND DIAGNOSES

A 28-year-old primigravida was transferred to the operating room for emergency cesarean section. Based on the patient's complaints and clinical appearance, provisional diagnosis of preeclampsia at 33 weeks' gestation as well as frequent and repeated grand mal convulsions at 14 years of age were considered. The anesthetic modalities of the disease are also discussed.

INTERVENTIONS AND OUTCOMES

Because the usual antiepileptic therapy had failed, the patient with status epilepticus underwent surgery under general anesthesia. The newborn was handed to the pediatrician and the patient was transferred to the intensive care unit for further observation and discharged 4 days later. No peri-operative or anesthetic complications were observed.

LESSONS

Providing anesthesia to patients undergoing cesarean section poses major challenges for anesthesiologists. Close monitoring and proper treatment can help reduce risks for both the mother and baby.

A systematic review of posterior reversible encephalopathy syndrome in pregnant women with severe preeclampsia and eclampsia

Background

The association of posterior reversible encephalopathy syndrome (PRES) and severe preeclampsia/eclampsia has been established but the frequency is uncertain.

Objectives

To determine the frequency of PRES in severe preeclampsia or eclampsia.

Methods

We searched published articles in PubMed, Cochrane library, Embase, and CINAHL from 1990 to 2020. We included articles that reported on six or more cases of PRES with eclampsia or severe preeclampsia who underwent neuroimaging during pregnancy or up to 6 weeks postpartum.

Results

We identified 29 studies presenting data on 1519 women with eclampsia or severe preeclampsia. Among 342 women with eclampsia who had neuroimaging, 176 (51.4%) were diagnosed with PRES. Of 121 women with severe preeclampsia, 24 (19.8%) had PRES. The pooled maternal death rate was 5.3% (21/395).

Conclusion

PRES is commonly reported on neuroimaging of women with eclampsia/ severe preeclampsia. The role of neuroimaging in eclampsia and especially in women with severe preeclampsia requires re-evaluation as further management is often dictated by this finding.

Eclampsia in the 21st century

The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding within 1 to 2 weeks, but routine imaging follow-up is unnecessary unless there are findings of intracranial hemorrhage, infraction, or ongoing neurologic deficit. Eclampsia is associated with increased risk of maternal mortality and morbidity, such as placental abruption, disseminated intravascular coagulation, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, and acute renal failure. Furthermore, a history of eclamptic seizures may be related to long-term cardiovascular risk and cognitive difficulties related to memory and concentration years after the index pregnancy. Finally, limited data suggest that placental growth factor levels in women with preeclampsia are superior to clinical markers in prediction of adverse pregnancy outcomes. This data may be extrapolated to the prediction of eclampsia in future studies. This summary of available evidence provides data and expert opinion on possible pathogenesis of eclampsia, imaging findings, differential diagnosis, and stepwise approach regarding the management of eclampsia before delivery and after delivery as well as current recommendations for the prevention of eclamptic seizures in women with preeclampsia.

Posterior Reversible Encephalopathy Syndrome Following Intracranial Hypotension Due to Cerebrospinal Fluid (CSF) Leakage: A Report of Two Cases

Posterior reversible encephalopathy syndrome (PRES) in cases of intracranial hypotension is a life-threatening condition. Early suspicion, appropriate treatment, and tight control of possible contributing factors that may facilitate PRES in cerebrospinal fluid (CSF) leak patients may bring a more favorable outcome, lowering the morbidity and mortality rate.

Two cases of PRES with features of intracranial hypotension are presented.

We also discussed the possible pathogenesis of PRES in patients with intracranial hypotension. We emphasize the importance of the early diagnosis and treatment of ICH by repairing the leakage and further prompt attention to tight blood pressure control in those patients to avoid PRES development.

Specialized Diagnostic Investigations to Assess Ocular Status in Hypertensive Diseases of Pregnancy

This review describes specialized diagnostic investigations to assess ocular status in hypertensive diseases of pregnancy. Ocular assessment can aid in early detection for prompt multidisciplinary treatment, obstetric intervention and follow-up. The investigations accurately predict the possible causes of blindness in hypertensive diseases of pregnancy. The investigations include fluorescein angiography, ophthalmodynamometry, fluorophotometry, imaging modalities, OCT, ultrasonography, doppler velocimetry and blood chemistry analysis. The review includes a summary of imaging techniques and related recent developments to assess the neuro-ophthalmic aspects of the disease. The imaging modalities have been instrumental in understanding the complex neuropathophysiological mechanisms of eclamptic seizures. The importance of blood chemistry analysis in hypertensive diseases of pregnancy has been emphasized. The investigations have made a significant contribution in improving the standards of antenatal care and reducing maternal and fetal morbidity and mortality.

Prospective study of the hemodynamic behavior of ophthalmic arteries in postpartum preeclamptic women: A doppler evaluation

The aim of this study was to evaluate the hemodynamic behavior of the ophthalmic artery by means of the Doppler ultrasound, in postpartum preeclamptic women. It was an observational prospective study with 44 postpartum preeclamptic women (group 1) and 49 postpartum normal women with normal blood pressure and with no previous illnesses known (group 2). All the pregnant women had a Doppler ultrasound exam of the ophthalmic artery in the immediate puerperium, that is, 10 days for the delivery (time 1). Group 1 was then followed prospectively, 26 patients of which returned to the last test in the remote puerperium in 45 days (time 2) and 29 patients returned to the last test in the remote puerperium in 90 days (time 3). All these women had preeclampsia before the delivery. The resistance index (RI), pulsatility index (PI), peak systolic velocity (PSV), end diastolic flow velocity (EDV), second peak of systolic velocity (P2), and the peak ratio (PR) were calculated. The data obtained are expressed in average and standard deviation, by using the Lilliefors test for normality. The average of the Doppler indexes in groups 1 and 2 was compared by means of test t of the student. Group 1 was analyzed separately, comparing the three times, using the test of ANOVA for repetitive measures and Tukey post-hoc range test. In the "Results" section, the statically meaningful differences in RI, PI, P2, RPV, and EDV (p < 0.0001, p < 0.0001, p < 0.0009, p < 0.0001, p < 0.0028) were found in the immediate puerperium of group 1 in relation to group 2, indicating the persistence of hyperperfusion and orbital vasodilatation in the immediate postpartum period in patients who had complicated pregnancies previously due to preeclampsia. In the evolutionary analysis of group 1, comparing the Doppler indexes between the immediate and late puerperium, statistically relevant differences between the rates of RI, P2, and PR (p < 0,01) were observed, showing a raise of RI and reduction of P2 and PR, and also a tendency of normalization of these rates in the late puerperium. When the same indexes were compared (PI, P2, and PR) now in times 2 and 3, the remote, and late puerperium, respectively, there were no significant differences, indicating the stabilization of these indexes since the 45th day of the puerperium. Within 90 days, RI, PI, and PR are not stabilized yet in relation to the control, even though there is a tendency of these indexes to reach the control. In conclusion, there was persistence of signs of vasodilatation and hyperperfusion of the orbital territory, represented by Doppler of the ophthalmic artery in the immediate puerperium of preeclamptic women. A tendency of normalization of the orbital hemodynamic standard in the pregnant women from the period of the late puerperium was observed, but there was no complete normalization of the vascular pattern on the remote postpartum.

Seizures in pregnancy: epilepsy, eclampsia, and stroke

Seizures during pregnancy complicate <1% of all gestations; however, they are associated with increased adverse maternal and perinatal outcomes (acute and long term). The differential diagnosis of seizures in pregnancy is extensive. Determining the underlying etiology is crucial in the management of these patients. Medical providers caring for pregnant women should be educated about possible etiologies of seizures during pregnancy and the importance of prompt management of these women in a timely fashion. Evaluation and management should be performed in a stepwise fashion and may require a multidisciplinary approach with other specialties such as neurology. The objective of this review is to increase awareness and to provide a stepwise approach toward the diagnosis and management of pregnancies complicated by seizures.

Posterior reversible encephalopathy syndrome in 46 of 47 patients with eclampsia

OBJECTIVE

We sought to investigate the concurrence of posterior reversible encephalopathy syndrome (PRES) with eclampsia and to describe the obstetric, radiological, and critical care correlates.

STUDY DESIGN

This was a single-center, 2001-2010 retrospective cohort study of all patients with eclampsia who underwent neuroimaging via magnetic resonance imaging (MRI) or computerized tomography (CT) with or without contrast.

RESULTS

Forty-six of 47 of eclamptic patients (97.9%) revealed PRES on neuroimaging using 1 or more modalities: MRI without contrast, 41 (87.2%); MRI with contrast, 27 (57.4%); CT without contrast, 16 (34%); CT with contrast, 7 (14.8%); and/or magnetic resonance angiography/magnetic resonance venography, 2 (4.3%). PRES was identified within the parietal, occipital, frontal, temporal, and basal ganglia/brainstem/cerebellum areas of the brain. Eclampsia occurred antepartum in 23 patients and postpartum in 24 patients. Headache was the most common presenting symptom (87.2%) followed by altered mental status (51.1%), visual disturbances (34%), and nausea/vomiting (19.1%). Severe systolic hypertension was present in 22 patients (47%).

CONCLUSION

The common finding of PRES in patients with eclampsia suggests that PRES is a core component of the pathogenesis of eclampsia. Therapy targeted at prevention or reversal of PRES pathogenesis may prevent or facilitate recovery from eclampsia.

Relationships between edema degree and clinical and biochemical parameters in posterior reversible encephalopathy syndrome: a preliminary study

The objective of the study was to investigate the associations between the degree of edema with the clinical and biochemical parameters such as serum lactate dehydrogenase (LDH), albumin (ALB) in posterior reversible encephalopathy syndrome (PRES) patients. Forty-nine patients with typical clinical symptoms and characteristic MR imaging findings of PRES were included in this study. Lactate dehydrogenase and ALB were analyzed with the immunoluminometric assays. Fluid-attenuated inversion recovery images were used to evaluate the distribution of the extent or severity of vasogenic edema by two observers. Correlation analysis between the scores of brain edema and the blood pressures, clinical conditions and biochemical parameters was performed. No significant difference of brain edema score was found between patients with eclampsia, chronic renal failure and other clinical condition (P > 0.05). Both mean arterial pressures and LDH level were moderately correlated with the scores of brain edema distribution (Spearman's ρ test, r = 0.405 and 0.497, respectively, P < 0.01). Serum ALB level was not correlated with the scores of brain edema distribution (P > 0.05). Larger and more diffuse lesions may be predicted by higher LDH level and blood pressure. The overall severity of the systemic process might be predicted by the degree of edema expression in PRES.

Posterior Reversible Encephalopathy Syndrome in Early Postpartum Woman

There have been reports about posterior reversible encephalopathy syndrome (PRES) associated with pregnancy, especially peripartum. However, the pathophysiology of PRES is not still clear. Tonic-clonic seizure occurred during early postpartum in a woman with the tendency toward pre-eclampsia developed after vaginal delivery followed by emergency cesarean hysterectomy. Postictal findings included headache, loss of vision, and short-term memory loss and magnetic resonance imaging (MRI) findings suggesting PRES were noted. Neurologic symptoms and cerebral lesions were gradually improved with immediate supportive managements.

Circulating angiogenic and antiangiogenic factors in women with eclampsia

OBJECTIVE

The objective of the study was to determine whether eclampsia has a different circulating profile of angiogenic (placental growth factor [PlGF]) and antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 [sVEGFR-1] and soluble endoglin [sEng]) from severe preeclampsia.

STUDY DESIGN

This cross-sectional study included pregnant women in the following groups: (1) normal pregnancy (n = 40); (2) severe preeclampsia (n = 40); and (3) eclampsia (n = 20). Maternal serum PlGF, sVEGFR-1, and sEng concentrations were determined using an enzyme-linked immunosorbent assay.

RESULTS

The study results included the following: (1) the median concentration of sVEGFR-1 and sEng was higher and of PlGF was lower in severe preeclampsia or eclampsia than in normal pregnancy (P < .001 for all); and (2) the median concentrations of these 3 analytes did not differ significantly between patients with severe preeclampsia and those with eclampsia.

CONCLUSION

Eclampsia is associated with higher maternal circulating concentrations of sVEGFR-1 and sEng and lower concentrations of PlGF than normal pregnancy but with similar concentrations to severe preeclampsia. These findings suggest that eclampsia shares a common pathogenic pathway as severe preeclampsia.

Posterior Reversible Encephalopathy Syndrome in severe preeclampsia: case report and literature review

We describe a 23 year old primigravid patient with severe preeclampsia complicated by posterior reversible encephalopathy syndrome (PRES), who presented with sensory and motor deficits and amnesia in the postpartum period Cranial magnetic resonance imaging (MRI) showed abnormal areas in the white matter of bilateral parieto-occipital lobes, indicating brain edema which disappeared completely on the follow-up scan taken four weeks after delivery together with complete symptom regression. The development of PRES in preeclampsia is discussed and the importance of prompt postpartum blood pressure control is emphasized.

Cerebral magnetic resonance imaging in eclampsia: a series of 12 cases

The object of this study was to assess the ability of magnetic resonance imaging (MRI) to detect the cerebral abnormalities associated with eclampsia and therefore to establish its place in our management of the condition. This study was of particular relevance to our institution because eclampsia is common in our patient population. This was a prospective study in which 13 patients with an initial diagnosis of eclampsia received MRI brain scans. Of 12 patients with a final diagnosis of eclampsia, seven (58.3%) showed the typical MRI changes of eclampsia, namely cerebral hyperintensities representing focal areas of oedema. In five patients (41.6%) the scans were normal. The rate of abnormality detection was surprisingly low. We conclude that the reason for this was the time delay in obtaining the scans. The cerebral changes in eclampsia can be rapidly reversible. Future studies must aim to perform MRI within 48 hours of seizure activity. MRI is more sensitive than computed tomography scanning but has no practical advantages over computed tomography except where the diagnosis is in doubt.

Advances in the understanding of eclampsia

Preeclampsia, a serious hypertensive complication of pregnancy characterized by new-onset hypertension and proteinuria after midpregnancy, is a multisystem disorder that often involves the central nervous system. Neurologic signs and symptoms include hyperreflexia, headaches, visual disturbance, seizures, and cerebral hemorrhage. Eclampsia-new-onset seizures in the setting of preeclampsia-usually occurs before or within 48 hours of delivery, but can present as late as 1 month postpartum (late postpartum eclampsia). Magnesium sulfate is the drug of choice to prevent and treat eclampsia, a recommendation validated through large, randomized, and placebo-controlled trials. This review describes the pathogenesis, clinical features, and treatment of eclampsia, focusing on recent observations regarding roles of circulating antiangiogenic factors in the pathogenesis of the neurologic complications of eclampsia.

Posterior reversible encephalopathy syndrome, part 1: fundamental imaging and clinical features

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique CT or MR imaging appearance. Recognized in the setting of a number of complex conditions (preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune disease and high dose chemotherapy) the imaging, clinical and laboratory features of this toxic state are becoming better elucidated. This review summarizes the basic and advanced imaging features of PRES, along with pertinent features of the clinical and laboratory presentation and available histopathology. Many common imaging/clinical/laboratory observations are present among these patients, despite the perception of widely different associated clinical conditions.

[Eclampsia and total bilateral amaurosis in a woman subsequently diagnosed with reversible posterior leukoencephalopathy syndrome]

Eclampsia is a complication of preeclampsia and is characterized by the appearance of grand mal seizures and/or coma, in the absence of any other neurological abnormalities. Neither focal neurological deficit nor prolonged coma tends to develop following a crisis. Eclampsia should therefore lead us to consider other clinical entities that may require special treatment. We report the case of a pregnant woman who presented total bilateral loss of vision following a grand mal seizure. The patient was subsequently diagnosed with reversible posterior leukoencephalopathy syndrome, which has clinical and radiologic manifestations linked to several causes, such as hypertensive encephalopathy, eclampsia, kidney failure, and immunosuppressant therapy. The syndrome involves headache, altered states of consciousness, changes in vision (including blindness), and seizures; these symptoms generally coincide with a rapid increase in blood pressure. Diagnosis requires neuroimaging, and the typical finding is edema in the posterior zones of the brain hemispheres. The most widely accepted hypothesis concerning the pathophysiologic mechanism underlying this syndrome is failure of cerebral autoregulation with development of vasogenic edema. The prognosis is good and the alterations usually resolve completely with appropriate treatment, which is the same as for the management of eclampsia, with strict monitoring of blood pressure.

Ergometrine Administration for Postpartum Haemorrhage in an Undiagnosed Pre-Eclamptic

We report a case of a parturient who was well antenatally but presented with oliguria following delivery. The possibility of postpartum preeclampsia was obscured by simultaneous postpartum haemorrhage. Ergometrine was given and she suffered an eclamptic seizure shortly after. We discuss the diagnostic difficulties presented by simultaneous presentation of postpartum preeclampsia and haemorrhage and the likelihood that ergometrine precipitated eclampsia in a patient at risk. While ergometrine is an effective drug for the management of uterine atony, its potential role in precipitating eclampsia must be considered.

A review of the management of eclampsia: practical issues

We reviewed 90 cases of eclampsia, an obstetric emergency associated with high blood pressure and convulsions, treated in two hospitals in Durban, South Africa. We present a protocol for the management of eclampsia based on this review and extensive clinical experience on this subject, which includes hemodynamic stabilization of the mother, prevention of recurrent convulsions, prompt delivery, and intensive monitoring in the immediate post-partum period.

Pregnancy prevents hypertensive remodeling of cerebral arteries: a potential role in the development of eclampsia

We investigated how hypertension during pregnancy affected passive structural (wall:lumen, wall stress) and active (myogenic activity) responses of the cerebral circulation. Female nonpregnant (NP; n=8) Sprague Dawley rats were compared with late-pregnant (LP; day 19 to 20, n=6) rats. Some animals were treated with the NO synthase inhibitor nitro-L-arginine in their drinking water to raise blood pressure. LP rats (n=6) were treated for the last 7 days of pregnancy (last trimester) to mimic preeclampsia and compared with NP rats treated for the same duration (n=8). Active and passive responses were determined on isolated and pressurized third-order posterior cerebral arteries. Nitro-L-arginine treatment significantly raised blood pressure in both groups of animals that was associated with increased wall thickness and wall:lumen ratio in the NP hypertensive animals versus controls (P<0.05). In contrast, this response to pressure was absent in LP animals, which had similar wall measurements. In addition, arteries from NP hypertensive animals had increased myogenic tone and pressure of forced dilatation compared with NP control animals (P<0.01). Again, this response was lacking in the LP hypertensive animals that had similar tone and pressure of forced dilatation as normotensive controls. The increased tone and wall thickness decreased wall stress in the NP hypertensive animals, a response that did not occur in LP hypertensive animals. Because medial hypertrophy is considered a protective response to elevated blood pressure, these results suggest that hypertension in pregnancy may predispose the cerebral circulation to autoregulatory breakthrough and blood-brain-barrier disruption when blood pressure is elevated, as during eclampsia.

Diagnosis, prevention, and management of eclampsia

The pathogenesis of eclamptic convulsions remains unknown. Cerebral imaging suggests that cerebral abnormalities in eclampsia (mostly vasogenic edema) are similar to those found in hypertensive encephalopathy. However, cerebral imaging is not necessary for the diagnosis or management of most women with eclampsia. The onset of eclamptic convulsions can be antepartum (38-53%), intrapartum (18-36%), or postpartum (11-44%). Recent data reveal an increase in the proportion of women who develop eclampsia beyond 48 hours after delivery. Other than early detection of preeclampsia, there are no reliable tests or symptoms for predicting the development of eclampsia. In developed countries, the majority of cases reported in recent series are considered unpreventable. Magnesium sulfate is the drug of choice for reducing the rate of eclampsia developing intrapartum and immediately postpartum. There are 4 large randomized trials comparing magnesium sulfate with no treatment or placebo in patients with severe preeclampsia. The rate of eclampsia was significantly lower in those assigned to magnesium sulfate (0.6% versus 2.0%, relative risk 0.39, 95% confidence interval 0.28-0.55). Thus, the number of women needed to treat to prevent one case of eclampsia is 71. Magnesium sulfate is the drug of choice to prevent recurrent convulsions in eclampsia. The development of eclampsia is associated with increased risk of adverse outcome for both mother and fetus, particularly in the developing nations. Pregnancies complicated by eclampsia require a well-formulated management plan. Women with a history of eclampsia are at increased risk of eclampsia (1-2%) and preeclampsia (22-35%) in subsequent pregnancies. Recommendations for diagnosis, prevention, management, and counseling of these women are provided based on results of recent studies and my own clinical experience.

Magnetic resonance imaging in Posterior Reversible Encephalopathy Syndrome: report of three cases and review of literature

INTRODUCTION

Eclampsia is one of the main causes of Posterior Reversible Encephalopathy Syndrome (PRES) a recent clinico-neuroradiological entity represented by characteristic MR findings of a symmetric bilateral subcortical/cortical hyperintensity in T2-weighted images, more often in parieto-occipital lobes, accompanied by clinical neurological alterations. Neuroradiological and clinical alterations are commonly completely reversible although ischemic evolution has been described. The pathophysiology is still a matter of debate. Specific magnetic resonance (MR) techniques, such as FLAIR (fluid attenuated inversion recovery) and DWI (diffusion weighted images) sequences, have improved the ability to detect subcortical/cortical lesions and helped to clarify the underlying pathophysiological mechanism of cerebrovascular involvement, which results important for an appropriate therapeutic decision.

CASE REPORT AND DISCUSSION

We report the MR imaging findings of three patients with eclampsia and PRES as well as a careful review of literature.

Intrapartum Emergencies

Intrapartum emergencies are challenging to all perinatal nurses because of the increased risk of adverse outcomes for the mother and fetus. Perinatal emergencies, such as seizures, amniotic fluid embolus, hemorrhage, and uterine rupture, create physiological challenges and trigger intrinsic survival techniques. The pregnant uterus becomes a vital source of blood volume during hypovolemic events because it is not considered a vital organ. The pregnancy itself may become burdensome, and birth may occur as an intrinsic maternal compensatory mechanism. The resultant fetal hypoxemia may also stress the fetus into initiating labor. During extensive oxygen desaturation and decompensation, the focus should be on maternal stabilization, which will subsequently enhance fetal stabilization. Clinical assessments, critical thinking, decision making, and resource allocation must be quick and appropriate to increase the likelihood of a positive outcome for the mother, fetus, and neonate.

Neuroimaging of delayed eclampsia. Report of 3 cases and review of the literature

Computed tomography and magnetic resonance imaging findings consistent with eclampsia were recently encountered in 3 patients who developed severe headache days to weeks after uncomplicated delivery. The neurologic presentation was nonspecific, and pre-eclamptic symptoms were not present, including significant hypertension. Variable expression of pre-eclampsia occurred during the course of their observation. Conventional angiography obtained in 2 patients because of a concern for aneurysm demonstrated central and peripheral vasospasm. Magnetic resonance angiography demonstrated central vasospasm in the third patient.

Magnetic resonance imaging in preeclampsia and eclampsia complicated by visual disturbance and other neurological abnormalities

This study describes magnetic resonance imaging findings in women presenting with neurological complications associated with preeclampsia and eclampsia. One eclamptic and two preeclamptic women were studied after presenting with postpartum neurological events. In two women the brain increased in size on the initial follow-up images, following the same pattern seen in normal pregnancy. In the other woman, the brain was decreased in size at 13 days postpartum but increased in size at six weeks postpartum. This initial reduction in brain size may reflect the resolution of cerebral oedema resulting from underlying pathological processes.

Appropriate neurological evaluation and multimodality magnetic resonance imaging in eclampsia

HYPOTHESIS

Simultanagnosia is common in eclampsia and a visuospatial test may be the most appropriate method in assessing the degree and monitoring of neurological deficit.

AIM

To determine a sensitive clinical test for the degree of neurological deficit in eclampsia and in monitoring neurological change.

METHODS

Thirty women with eclampsia were evaluated by clinical neurological quantitative scales including the Canadian Neurological Scale, Glasgow Coma Scale, Mini-Mental State Examination, a validated Cookie Theft Picture Test (CTPT), magnetic resonance imaging (MRI) (T1/T2), diffusion weighted imaging (DWI) and magnetic resonance angiography (MRA).

RESULTS

The CTPT, used to measure simultanagnosia, had a sensitivity of 100% (95% CI: 84.5-100), specificity of 33.3% (95% CI: 1.8-87.5) with positive predictive value of 93.1% (95% CI: 75.8-98.8) and negative predictive value of 100% (95% CI: 5.5-100). The degree of agreement between simultanagnosia as measured by CTPT and DWI was 93.3% (Kappa=0.474; P=0.001). Standard MRI compared with DWI had a sensitivity of 77.8% (95% CI: 57.3-90.6), specificity of 100% (95% CI: 31-100), positive predictive value of 100% (95% CI: 80.8-100) and negative predictive value of 33.3% (95% CI: 9-69.1). The degree of agreement between standard MRI and DWI was 90%, this was statistically significant (Kappa=0.412: P=0.001).

CONCLUSIONS

The validated CTPT for simultanagnosia was abnormal in the majority (n=29; 96.7%) of eclamptic patients with other neurological scales normal. Standard MRI and DWI showed excellent correlation with this simple bedside clinimetric evaluation. The oedema in eclampsia is primarily of vasogenic origin.

Preeclampsia. Part 1: clinical and pathophysiologic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review begins with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). In Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder will be reviewed.

Effect of hyperventilation on cerebral blood flow velocity in preeclamptic pregnancies: is there evidence for an altered cerebral vasoreactivity?

The purpose of this study was to investigate cerebral arteriolar vasoreactivity function in preeclampsia. Preeclamptic (n = 26) and healthy pregnant (n = 22) women underwent transcranial Doppler sonography of the middle cerebral artery at rest and after 60 seconds of hyperventilation (HV). Systolic, diastolic, and mean blood flow velocities were recorded. The percentage change of the blood flow velocities after HV was calculated. Mean blood flow velocity of the middle cerebral artery was higher in preeclamptic women as compared with healthy pregnant women. No difference could be detected in percentage change of middle cerebral artery blood flow velocities after HV between the two groups. There is no evidence of a small-vessel vasoconstriction among preeclamptic patients. The role of vasoconstriction of the large cerebral arteries and vasodilation of the resistance arterioles, as well as a combination of these 2 pathomechanisms, in determining cerebral blood flow in preeclampsia and eclampsia should be investigated in further studies.

Persistence of cerebral hemodynamic changes in patients with eclampsia: A report of three cases

OBJECTIVE

This study was undertaken to compare the persistence of changes in estimated cerebral perfusion pressure and the resistance area product, an index of cerebrovascular resistance, in women with preeclampsia and women with eclampsia.

STUDY DESIGN

The maternal middle cerebral artery was evaluated by transcranial Doppler ultrasonography in 6 patients with severe preeclampsia and 3 women with eclampsia, and cerebral blood flow velocities were determined. Estimated cerebral perfusion pressure was calculated according to the following equation: Estimated cerebral perfusion pressure = Mean cerebral blood flow velocity/(Mean cerebral blood flow velocity - Diastolic cerebral blood flow velocity) x (Mean blood pressure - Diastolic blood pressure). Because the diameters of the vessels could not be measured directly, an index of resistance was calculated according to the following equation: Resistance area product = Mean blood pressure/Mean cerebral blood flow velocity. We calculated an index of cerebral blood flow according to the following equation: Index = Estimated cerebral perfusion pressure/Resistance area product. Patients were reassessed at 24 and 48 hours after delivery.

RESULTS

At the initial assessment the estimated cerebral perfusion pressure was higher in women with eclampsia than in those with severe preeclampsia. In addition, cerebrovascular resistance was significantly decreased in the eclampsia group, and it remained decreased as long as 4 days in 1 patient with eclampsia.

CONCLUSIONS

Preeclampsia is associated with increases in cerebral perfusion pressure counterbalanced by increases in cerebrovascular resistance, with no change in cerebral blood flow. In eclampsia a significant increase in cerebral perfusion pressure occurs, but a significant fall in cerebrovascular resistance also occurs and a loss of autoregulation results in cerebral overperfusion similar to that of hypertensive encephalopathy. This may persist for as long as 4 days.

Management of acute severe hypertension and encephalopathy

We still do not have an ideal drug to treat acute severe hypertension in pregnancy. Hydralazine and labetalol are the safest agents, but they are inadequate to control blood pressure in some women. Both hypertensive encephalopathy and eclampsia now appear to be forms of an acute process known as reversible posterior leukoencephalopathy syndrome.

Brain MRI in peripartum seizures: usefulness of combined T2 and diffusion weighted MR imaging

Peripartum seizure is a serious disease with significant morbidity and mortality for women and their unborn children. The underlying etiologies are varied, with eclampsia and venous stroke being the most common causes. T2 weighted MR images of the brain show hyperintense lesions in either condition. Diffusion weighted MR images (DWI) of the brain is abnormal in strokes. We report three cases of eclampsia with abnormal T2 weighted images, but normal DWI. Diffusion weighted MR images in association with T2 weighted MR images can be extremely helpful in evaluation of women with new onset peripartum seizures.

Modern management of eclampsia

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, remains an important cause of maternal mortality and morbidity. Despite being recognised since antiquity, consistent management practices are still lacking. Given that the aim of good care is to prevent seizures, it is disappointing that in the majority of cases the first eclamptic convulsion occurs after admission to hospital. This indicates that either the women who are likely to have a convulsion were not identified accurately, or the treatment given was ineffective. The answer to poor management of eclampsia lies in better education and training of all obstetricians, anaesthetists, midwives, and general practitioners in the diagnosis and treatment of severe pre-eclampsia and eclampsia. Protocols for the management of fluid balance, antihypertensive and anticonvulsant therapies should be available and reviewed regularly. The universal adoption of such guidelines in all obstetric units would substantially reduce elements of substandard care which have repeatedly been identified in the triennial reports of the confidential enquiries into maternal deaths in the UK.

Variation in cerebral perfusion pressure with different hypertensive states in pregnancy

OBJECTIVE

Our purpose was to compare the estimated maternal cerebral perfusion pressure and an index of vascular resistance, the resistance area product, in nonpregnant women with hypertensive pregnant women.

STUDY DESIGN

The maternal middle cerebral artery was evaluated by transcranial Doppler ultrasonography in 17 nonpregnant women, 17 pregnant normotensive patients, 20 pregnant patients with chronic hypertension, and 21 pregnant patients with pre-eclampsia (defined by The American College of Obstetricians and Gynecologists criteria) and cerebral blood flow velocities were determined. We calculated estimated cerebral perfusion pressure as [Estimated cerebral perfusion pressure = V mean/(V mean = V diastolic) (Mean blood pressure - Diastolic blood pressure)] modified from Aaslid et al, 1986. Because the diameter of the vessels could not be measured directly, an index of resistance, the resistance area product, was calculated. Resistance area product = Mean blood pressure/mean velocity (Evans et al, 1988). We calculated an index of cerebral blood flow (Cerebral blood flow index) = Estimated cerebral perfusion pressure/resistance area product.

RESULTS

Women who were chronically hypertensive and those with pre-eclampsia showed a significant increase in estimated cerebral perfusion pressure and resistance area product compared with nonpregnant and pregnant normotensive women. An estimate of cerebral blood flow (cerebral blood flow index) in nonpregnant women showed that pregnancy resulted in a nonsignificant 18% increase in cerebral blood flow.

CONCLUSIONS

Women with chronic hypertension and pre-eclampsia behave similarly by demonstrating significant increases in cerebral perfusion pressure (estimated cerebral perfusion pressure) and cerebrovascular resistance (resistance area product) compared with normotensive and nonpregnant women. Pregnant patients have a minimal increase in cerebral blood flow (18%).

Obstetrical anaesthesia for a parturient with preeclampsia, HELLP syndrome and acute cortical blindness

PURPOSE

To report the management of a multigravida presenting with preeclampsia, HELLP syndrome and acute cortical blindness for Caesarean section.

CLINICAL FEATURES

A 39-yr-old woman, with three past uncomplicated pregnancies presented at 33 wk with acute cortical blindness. Based on clinical and laboratory assessment, a diagnosis of preeclampsia with HELLP syndrome was made. A CT scan of her head demonstrated ischaemic lesions of her basal ganglia, extending superiorly to involve both posterior parietal and occipital regions. Infusions of magnesium sulphate and hydralazine were started and an urgent Caesarean section was performed under subarachnoid anaesthesia after insertion of an arterial line and intravenous hydration. The course of anaesthesia and surgery was uneventful and she delivered a live 1540 g female infant. By the following morning, she had recovered some vision and visual recovery was complete by 72 hr postpartum. She underwent an MRI with angiography on the first postpartum day. Ischaemic lesions were confirmed in the same sites identified on CT scan but all major cerebral vessels were patent and no significant vascular abnormality was noted. Her postoperative course was uneventful and she was discharged home seven days postpartum after being prescribed labetalol for continued hypertension.

CONCLUSION

The anaesthetic management of a parturient with acute cortical blindness and HELLP syndrome is modeled on the underlying preeclamptic condition. Invasive monitoring is not routinely indicated but is specifically indicated in some cases. Provided that it is not contraindicated because of prohibitive risk to the mother, regional anaesthesia has particular advantage in these patients. In particular, the use of spinal anaesthesia, which has been discouraged by some for this patient population, should be re-evaluated.

Eclamptic encephalopathy: imaging and pathogenetic considerations

Eclampsia is a rare condition peculiar to pregnant and puerperal women, characterized by clinical pre-eclampsia (hypertension, proteinuria, edema) and generalized seizures. Three cases of eclamptic encephalopathy are reported: CT and MRI demonstrated transient abnormalities in the cortical and subcortical regions of the posterior areas of the brain - namely, parieto-occipital lobes - associated with occasional involvement of basal ganglia and/or brainstem. Pathogenesis is still unclear. Strict similarity with the pathological findings characterizing hypertensive encephalopathy suggests that a focal impairment in cerebral autoregulation may be the cause of vasodilation and fluid extravasation leading to hydrostatic edema; selective involvement of posterior areas could be explained by their lesser degree of adrenergic innervation supporting circulatory autoregulation mechanisms.

Single photon emission and cerebral computerised tomographic scan and transcranial Doppler sonographic findings in eclampsia

OBJECTIVE

To define more clearly the neuropathophysiology of eclampsia utilising single-photon emission computed tomography (SPECT), cerebral computerised tomography (CT) and transcranial Doppler (TCD) ultrasonography.

DESIGN

A prospective study

SETTING

The obstetric unit in King Edward VIII Hospital, a large tertiary referral centre in Kwa-Zulu Natal, South Africa.

PARTICIPANTS

Sixty-five women with eclampsia.

INTERVENTIONS

Imaging and ultrasonographic investigations were performed within 48 hours postpartum. Unenhanced cerebral CT scans were performed in all the women and SPECT scans were performed on 63 women using Technetium-99m-hexamethylpropyleneamineoxime (99mTc-HMPAO) as a tracer of regional cerebral blood flow. Middle cerebral artery blood flow velocity waveforms were measured using 2 MHz pulsed Doppler ultrasound via the transtemporal approach.

MAIN OUTCOME MEASURES

Abnormalities in SPECT scan, CT scan and TCD ultrasound findings.

RESULTS

SPECT scanning revealed perfusion deficits in the watershed areas in all women, 75% of whom had concomitant deficits in the parieto-occipital areas of the brain. Hypodensities (cerebral oedema) were reported in 38 CT scans (58.5%), with parieto-occipital involvement in 97.4% of cases. Increased flow velocity measurements in the middle and posterior cerebral arteries were recorded in 36 (85.7%) women in whom TCD ultrasound was performed.

CONCLUSION

The pathophysiological mechanism of eclamptic seizures is primary cerebral vasospasm with resultant ischaemia and cerebral oedema involving mainly the watershed areas and parieto-occipital lobes of the brain. SPECT scanning has been shown to be superior to CT scanning and TCD ultrasonography in detecting neuropathophysiologic alterations in eclampsia. However, each of the three investigative tools provide its own unique information and all three are necessary research techniques to improve our understanding of the neuropathophysiological mechanism of eclamptic seizures.

Cerebrovascular disorders complicating pregnancy--beyond eclampsia

OBJECTIVE

Our purpose was to investigate the problems encountered in the diagnosis and management of cerebrovascular disorders associated with pregnancy and the puerperium.

STUDY DESIGN

Pregnancies complicated by cerebrovascular disorders were identified by retrospective chart review (1985 to 1995). Events associated with trauma, neoplasm, drug ingestion, and infection were excluded.

RESULTS

The study population comprised 24 women with a variety of cerebrovascular disorders: 14 with infarction (5 arterial, 9 venous), 6 with intracranial hemorrhage (3 anatomic malformation, 3 unknown etiology), 3 with hypertensive encephalopathy, and 1 with an unruptured aneurysm. Blood pressure reflected physical condition at presentation and did not predict diagnosis or outcome except in the 3 women with hypertensive encephalopathy. Only 4 of 14 women with infarction and 1 of 6 with intracranial hemorrhage had a diastolic blood pressure > or = 110 mm Hg. Presumption of eclampsia delayed the diagnosis in 10 women (41.7%). In addition, patient delay in seeking medical attention complicated 10 cases. After review, none of the adverse maternal outcomes were deemed preventable by earlier physician intervention. Seven maternal deaths occurred (29.2%). Neonatal outcome was related to the gestational age and the maternal condition at presentation.

CONCLUSION

Cerebrovascular disorders are an uncommon and unpredictable complication of pregnancy that are associated with substantial maternal and fetal mortality. Suspected eclampsia unresponsive to magnesium sulfate therapy warrants an immediate neuroimaging study. Interestingly, in women with intracranial hemorrhage, severe hypertension was not an associated predictive factor.

Hepatic imaging in HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count)

OBJECTIVES

Our objective was to describe the hepatic imaging findings in selected patients with HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) and to correlate these findings with the severity of concurrent clinical and laboratory abnormalities.

STUDY DESIGN

Patients with laboratory criteria for HELLP syndrome with complaints of severe right upper quadrant abdominal pain in association with either shoulder pain, neck pain, or relapsing hypotension underwent imaging of the liver. Clinical and laboratory parameters were then correlated with the hepatic imaging findings.

RESULTS

Thirty-four patients were evaluated in this study. Computed tomographic scanning of the liver was used for 33 patients. Additional imaging evaluations included magnetic resonance imaging for 4 patients and ultrasonographic evaluation of the liver for 5 patients. In 15 cases (45%) the computed tomographic results were abnormal. The most frequent abnormal hepatic imaging findings were subcapsular hematoma (n = 13) and intraparenchymal hemorrhage (n = 6). There was no statistically significant correlation between the presence of an abnormal hepatic imaging finding and the severity of liver function test abnormalities. However, the severity of thrombocytopenia did correlate with hepatic imaging findings (p = 0.04). In particular, an abnormal hepatic imaging finding was noted for 10 of 13 patients (77%) with a platelet count of < or = 20 x 10(9)/L (p = 0.012).

CONCLUSIONS

Abnormalities in liver function test results do not accurately reflect the presence of abnormal hepatic imaging findings in HELLP syndrome. Patients with HELLP syndrome having complaints of right upper quadrant pain and neck pain, shoulder pain, or relapsing hypotension should undergo imaging of the liver.

A reversible posterior leukoencephalopathy syndrome

BACKGROUND AND METHODS

In some patients who are hospitalized for acute illness, we have noted a reversible syndrome of headache, altered mental functioning, seizures, and loss of vision associated with findings indicating predominantly posterior leukoencephalopathy on imaging studies. To elucidate this syndrome, we searched the log books listing computed tomographic (CT) and magnetic resonance imaging (MRI) studies performed at the New England Medical Center in Boston and Hôpital Sainte Anne in Paris; we found 15 such patients who were evaluated from 1988 through 1994.

RESULTS

Of the 15 patients, 7 were receiving immunosuppressive therapy after transplantation or as treatment for aplastic anemia, 1 was receiving interferon for melanoma, 3 had eclampsia, and 4 had acute hypertensive encephalopathy associated with renal disease (2 with lupus nephritis, 1 with acute glomerulonephritis, and 1 with acetaminophen-induced hepatorenal failure). Altogether, 12 patients had abrupt increases in blood pressure, and 8 had some impairment of renal function. The clinical findings included headaches, vomiting, confusion, seizures, cortical blindness and other visual abnormalities, and motor signs. CT and MRI studies showed extensive bilateral white-matter abnormalities suggestive of edema in the posterior regions of the cerebral hemispheres, but the changes often involved other cerebral areas, the brain stem, or the cerebellum. The patients were treated with antihypertensive medications, and immunosuppressive therapy was withdrawn or the dose was reduced. In all 15 patients, the neurologic deficits resolved within two weeks.

CONCLUSIONS

Reversible, predominantly posterior leukoencephalopathy may develop in patients who have renal insufficiency or hypertension or who are immunosuppressed. The findings on neuroimaging are characteristic of subcortical edema without infarction.