Head computed tomographic scans in women with eclampsia

Preeclampsia, eclampsia, and posterior reversible encephalopathy syndrome

Preeclampsia is a disorder of pregnancy associated with gestational hypertension and end-organ dysfunction. Patients with eclampsia, by definition, have seizures as part of the clinical syndrome. However, patients with preeclampsia can also have other neurologic symptoms and deficits. Both disorders can be associated with radiographic abnormalities similar to that of posterior reversible encephalopathy syndrome, suggesting a common pathophysiology or unified clinical spectrum of disorders. This chapter reviews the pathophysiology, clinical presentation, diagnostic findings, and prognosis of patients with neurologic complications associated with preeclampsia and eclampsia.

Evaluation of the macula, retinal nerve fiber layer and choroid in preeclampsia, healthy pregnant and healthy non-pregnant women using spectral-domain optical coherence tomography

OBJECTIVE

To evaluate the macular, retinal nerve fiber layer (RNFL) and choroidal thickness alterations by using spectral-domain optical coherence tomography (SD-OCT) in preeclampsia and compare with healthy pregnant and healthy non-pregnant controls.

METHOD

The study population included healthy pregnant control group (n: 25), healthy non-pregnant control group (n: 26) and study group with preeclampsia (n: 27). Retinal thickness parameters were measured by SD-OCT.

RESULTS

There was a statistically significant difference among all of the groups for choroidal thickness (p < 0.001). Choroidal thickness in preeclamptic women was significantly thinner than healthy pregnant women. The most thick choroid layer was detected in healthy pregnant group, and also the most thin choroidal thickness was detected in healthy non-pregnant group (p < 0.001). Macular central subfield and foveal center thickness were significantly thinner in preeclamptic study and healthy pregnant groups than healthy non-pregnant group (p < 0.001). However, there was no statistically significant difference between preeclamptic study group and healthy pregnant group for both macular central subfield and foveal center thickness. Average of RNFL thickness was significantly thicker in healthy pregnant group than healthy non-pregnant group (p = 0.004).

CONCLUSIONS

This study revealed that choroidal thickness measured using SD-OCT increased in women with preeclampsia and healthy pregnant women but the increase in choroidal thickness in preeclampsia was lower than the healthy pregnant controls. This lower rise in choroidal thickness can be generally attributed to the markedly increased systemic vascular vasospasm secondary to preeclampsia.

Hypothesis: preeclampsia is a venous disease secondary to an increased intra-abdominal pressure

It is hypothesized that in some women an excessively high intra-abdominal pressure (IAP) compresses the inferior vena cava, uterine veins, portal vein, hepatic veins, splenic vein and renal veins which lead to a decreased flow in these vascular beds, producing lower extremity edema, fetal-placental ischemia, a glomerulopathy with proteinuria and hypertension, hepatic ischemia and thrombocytopenia, increased uric acid, and hemolysis/elevated liver enzymes/low platelet known as the HELLP syndrome. There can be variability in the expression of these components. Placental-fetal ischemia could lead to expression of soluble fms-like tyrosine kinase1 (sFLT) and endoglin which have been shown to cause additional diffuse endovascular damage. A further increase in IAP pushes the diaphragm cephalad, increasing intrathoracic pressure leading to upper extremity edema, decreased internal jugular venous flow, cerebral vascular engorgement, raised intracranial pressure, and if unresolved, seizures. Placental/fetal ischemia and hepatic ischemic necrosis may lead to diffuse inflammation and a septic inflammatory response syndrome (SIRS) which may become a vicious cycle, perpetuating the ischemia. It is further hypothesized that application of an externally applied negative abdominal pressure device will lower IAP and possibly reverse the pathophysiology of preeclampsia. As the abnormal placental proteins develop weeks before clinical preeclampsia, early application of external negative abdominal pressure may prevent development of the syndrome.

Acute obstructive hydrocephalus due to cysticercosis during pregnancy

BACKGROUND

Cysticercosis, due to the parasite Taenia solium, can involve any organ. When central nervous system infection occurs, signs and symptoms depend on the location of the cerebral lesions. Most patients develop seizures, focal symptoms, or headaches with nausea and vomiting.

CASE

A case of extraparenchymal (intraventricular) cysticercosis was diagnosed in a patient at term who presented with acute alteration in mental status. Ventriculostomy was performed because of acute obstructive hydrocephalus. Labor ensued and was augmented with oxytocin. Intrapartum management included magnesium sulfate seizure prophylaxis and corticosteroids. Intracranial pressures ranged between 4 and 12 cm H2O peripartum with approximately 300 mL of cerebrospinal fluid drained over the first 24 hours. Postpartum management included craniotomy with resection of a larval cyst and oral praziquantel therapy.

CONCLUSION

This case describes an uncommon presentation of neurocysticercosis that should be considered in gravidas with acute mental status changes.

Neurologic complications of pre-eclampsia

Pre-eclampsia is mainly responsible for the world's large maternal mortality rates, mostly due to acute cerebral complications. This review provides insight into the pathogenesis of the neurologic complications of hypertensive disease in pregnancy. In addition, practical relevance for clinical care is highlighted. Pertaining to pregnancy, the blood pressure level at which cerebral autoregulation operates and possible deregulation occurs is unknown, but is likely to be variable. From clinical observation, eclampsia may occur despite a mild clinical picture and before the development of hypertension or proteinuria. Furthermore, failure of cerebrovascular autoregulatory mechanisms in response to either an acute and/or relatively large blood pressure increase may be more important than the absolute blood pressure value. It may be the acuity of the blood pressure rise in the setting of endothelial dysfunction that interrupts the delicate balance between capillary and cellular perfusion pressures that leads to the neurological complications of pre-eclampsia.

Multiple brain infarcts associated with severe preeclampsia

Posterior occipital and parietal lobe infarcts shown by computed tomography (CT) scan and magnetic resonance imaging have been associated with eclampsia. Gray-white matter, infarct-like lesions of the right basal ganglia, right posterior parietal, and left posterior parieto-occipital lobes were found by CT scan in a patient at 26 weeks gestation with severe preeclampsia and neurologic deficits. A magnetic resonance image taken 3 days postpartum had similar abnormalities, despite total resolution of the patient's symptomatology. A repeat CT scan performed 6 weeks postpartum showed complete resolution of the multiple infarctions. This is a unique case report that describes these severe brain-imaging findings in a patient with severe preeclampsia and neurologic deficits.

Late postpartum eclampsia in adolescents

We present 2 cases of late postpartum eclampsia in adolescents presenting to the pediatric emergency department, neither of whom had any antepartum symptoms of preeclampsia. The purpose of this report is to discuss the importance of a high index of suspicion for preeclampsia in the postpartum adolescent who complains of headache as well as a need to recognize that seizures and more severe neurological sequelae occurring up to 3 weeks postpartum may be eclamptic in origin.

Cerebral edema on MRI in severe preeclamptic women developing eclampsia

OBJECTIVE

The aim of this study is to identify suitable applications for cerebral MR (magnetic resonance) scanning in cases of severe preeclampsia and eclampsia through comparison of clinical course and easily accessible parameters.

METHODS

From January 2001 to December 2003, cerebral MR scans were performed on 43 women with severe preeclampsia; of those 41 were enrolled in data analyses. Twenty clinical parameters, including age, body mass index, blood pressure, liver and renal function, and coagulation status, were compared for each patient. Data were analyzed using the SPSS program on a VAX main frame.

RESULTS

Among 41 severe preeclamptic women, abnormal MR images were observed in 11 cases including six with systemic seizures. Predictive accuracy of eclampsia with abnormal cerebral MR imaging was 84.9% (P=0.00001), while only 14.3% of severe preeclampsia cases had been diagnosed radiologically. Statistical analysis suggests diastolic BP and serum AST as predictive parameters for abnormal MR images with 82.9% predictive accuracy (P=0.0007).

CONCLUSIONS

Cerebral edema can be observed in preeclamptic patients developing eclampsia. Rapid delivery is indicated when diastolic BP and AST are elevated. MR scanning is useful when delivery is delayed due to fetal immaturityin cases of severe preeclampsia.

Cerebral infarction in eclampsia

OBJECTIVE

This study was undertaken to characterize the neuroimaging findings of cerebral edema associated with eclamptic seizures by use of diffusion-weighted magnetic resonance imaging (MRI).

STUDY DESIGN

During the 3-year period ending March 2002, 27 nulliparous women with eclampsia were evaluated with diffusion-weighted MRI and apparent diffusion coefficient mapping. Those with findings of restricted diffusion suggestive of cytotoxic edema underwent neuroimaging again 6 weeks post partum.

RESULTS

All but 2 of these 27 women (93%) had reversible vasogenic edema. Six were also found to have areas of cytotoxic edema consistent with cerebral infarction. Five of these 6 women had persistent imaging findings of infarction when studied post partum, however, without clinical neurologic deficits.

CONCLUSION

The spectrum of cerebral lesions in eclampsia as seen with MRI varies from initially reversible areas of vasogenic edema that may progress to cytotoxic edema and infarction in up to a fourth of women.

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.

Maternal transcranial Doppler in pre-eclampsia and eclampsia

Pre-eclampsia affects 3-7% of women and is associated with significant maternal and perinatal morbidity and mortality. Transcranial Doppler (TCD) has been used in pre-eclampsia/eclampsia to evaluate non-invasively the cerebrovascular hemodynamics in the maternal middle cerebral artery. TCD has demonstrated in pre-eclamptic women maternal cerebral vasospasm, which does not correlate with mean arterial pressure assessed simultaneously. Estimated cerebral perfusion pressure, assessed using a modified formula, has been shown to be increased in women with severe and non-severe pre-eclampsia. However, in severe pre-eclampsia, elevated cerebral perfusion pressure is counterbalanced by increases in cerebrovascular resistance and cerebral blood flow is unaffected. In eclampsia a significant fall in cerebral vascular resistance occurs which, in the presence of increases in cerebral perfusion pressure, leads to hyperperfusion. Cerebral vascular changes to date have not been sensitive enough to predict the development of pre-eclampsia or eclampsia. Longitudinal studies with the aim of predicting the onset of pre-eclampsia and to assess the effects of various drugs on the maternal cerebral circulation need to be designed.

Hemiparesis following post-partum haemorrhage and eclampsia

A primigravida at 41+ weeks gestation presented with spontaneous rupture of membranes. Labour was induced and later an emergency caesarean section was performed for failure to progress. The patient suffered a per-operative uterine tear and post-partum haemorrhage and required postoperative ventilatory support in the intensive care unit. Following tracheal extubation, she developed a left hemiparesis and grand-mal seizures. The differential diagnosis, diagnostic difficulties, investigations and clinical management of this case are all discussed. An examination of existing literature highlights some of the focal neurological abnormalities that present with eclampsia and the possible need for more sophisticated neuroradiological investigations in these cases. Finally, it is emphasized that anaesthetists and intensivists need to be aware of atypical and delayed presentations of eclampsia.

The prevention and management of eclampsia

Hypertensive disease remains second only to embolic phenomena as a leading cause of maternal mortality. This article covers the major physiologic and pathologic findings to be considered when managing pregnant women with eclampsia. Attention to detail and an increased degree of suspicion will improve fetal and maternal outcomes.

A comparison of magnesium sulfate with phenytoin for the prevention of eclampsia

BACKGROUND

Magnesium sulfate is used widely to prevent eclamptic seizures in pregnant women with hypertension, but few studies have compared the efficacy of magnesium sulfate with that of other drugs. Anticonvulsant prophylaxis with phenytoin for eclampsia has been recommended, but there are virtually no data to support its efficacy. Our objective was to compare magnesium sulfate with phenytoin in preventing seizures in hypertensive women during labor.

METHODS

We randomly assigned women with hypertension who were admitted for delivery to receive either magnesium sulfate or phenytoin. The magnesium sulfate regimen consisted of a 10-g intramuscular loading dose followed by a maintenance dose of 5 g given intramuscularly every four hours. For women with severe preeclampsia, an additional 4-g loading dose was given intravenously. The phenytoin regimen included a 1000-mg loading dose infused over a period of 1 hour, followed by a 500-mg oral dose 10 hours later. With either regimen, anticonvulsant therapy was continued for 24 hours post partum.

RESULTS

Ten of 1089 women randomly assigned to the phenytoin regimen had eclamptic convulsions, as compared with none of 1049 women randomly assigned to magnesium sulfate (P = 0.004). There were no significant differences in any risk factors for eclampsia between the two study groups. Maternal and infant outcomes were also similar in the two study groups.

CONCLUSIONS

Magnesium sulfate is superior to phenytoin for the prevention of eclampsia in hypertensive pregnant women. These results validate the long-practiced use of magnesium sulfate in the prevention of eclampsia.

Blindness associated with preeclampsia and eclampsia

OBJECTIVE

Over a 14-year period at Parkland Hospital, the clinical courses of 15 women with severe preeclampsia or eclampsia were further complicated by blindness. Our purpose is to describe their management and outcome, as well as to offer insight to the pathophysiologic characteristics of blindness complicating pregnancy-induced hypertension.

STUDY DESIGN

Prospective ascertainment of women with blindness and pregnancy-induced hypertension was done. These cases were managed according to the standardized preeclampsia-eclampsia regimen used at our hospital since 1955. Briefly, this regimen includes magnesium sulfate given intramuscularly to prevent or control seizures, hydralazine to lower dangerously elevated blood pressure, intravenous fluid restriction, and delivery.

RESULTS

There were 15 women with blindness that persisted from 4 hours to 8 days; it subsequently resolved completely in all. Of the 13 women who underwent computed tomography, 8 had low-density areas localized predominantly in the occipital lobes. Five of these 13 subsequently underwent magnetic resonance imaging and 2 showed corresponding hyperintense lesions in the occipital areas.

CONCLUSIONS

On the basis of previously published experiences with computed tomography in women with eclampsia, as well as the experiences described here, we conclude that cortical blindness associated with preeclampsia-eclampsia results from petechial hemorrhages and focal edema in the occipital cortex. These lesions are likely stimulated by disparity in cerebral regional blood flow that is characterized by vasospasm and diminished flow primarily affecting the posterior circulation.

Electroencephalogram and computerised cerebral tomography findings in eclampsia

OBJECTIVE

To define more clearly the neuropathophysiology of eclampsia.

DESIGN

A prospective study relating to computerised cerebral tomography (CAT) scan and electroencephalogram (EEG) findings in eclampsia.

SETTING

A large referral centre in a developing society.

SUBJECTS

Thirty-two women with eclampsia.

MAIN OUTCOME MEASURES

Abnormalities in EEG and CAT scan findings.

RESULTS

Approximately 45% of the women studied had CAT scan abnormalities, while 90% had EEG abnormalities. A burst suppression pattern on EEG examination was found in four women suggesting a temporary dissolution of cerebral function to the midbrain level as the cause of seizures.

CONCLUSIONS

EEGs are probably more sensitive than CAT scans in detecting the extent of the pathology in the brain in women with eclampsia.

Cerebral imaging in eclampsia: magnetic resonance imaging versus computed tomography

OBJECTIVES

Our objectives were to study the cerebral pathophysiology of eclampsia with the noninvasive technique of magnetic resonance imaging to compare the ability of magnetic resonance imaging to detect cerebral abnormalities in eclampsia with that of computed tomography.

STUDY DESIGN

Twenty-four patients with eclampsia received both magnetic resonance imaging and computed tomographic scanning.

RESULTS

Forty-six percent of the magnetic resonance imaging was abnormal and 33% of the computed tomography was abnormal. This higher incidence of abnormal magnetic resonance imaging scans was present in spite of the fact that they were obtained significantly longer after the patient's seizure activity. The most common abnormalities were cortisol, subcortical, and white matter edema.

CONCLUSION

Magnetic resonance imaging and computed tomographic scan abnormalities in eclampsia are usually similar. Cerebral imaging is not necessary in patients with uncomplicated eclampsia.

National High Blood Pressure Education Program Working Group Report on High Blood Pressure in Pregnancy

This consensus report focuses the presentation, pathophysiology, and management of the hypertensive disorders of pregnancy expanding on recommendations first presented in 1988 by the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Practicing physicians should determine whether a patient's hypertension during pregnancy falls into the classification of (1) chronic hypertension, (2) preeclampsia, (3) preeclampsia superimposed on chronic hypertension, or (4) transient hypertension. The distinction, for management considerations, is made between hypertension that is present before pregnancy (chronic and preexisting) and that occurring as part of the pregnancy-specific condition preeclampsia. When maternal blood pressure reaches diastolic levels of 100 mm Hg or greater, treatment should be instituted to avoid hypertensive vascular damage. The report includes a discussion of antihypertensive therapy specific to the chronic or acute hypertension occurring concomitantly with pregnancy. The roles of calcium supplementation and low-dose aspirin to prevent preeclampsia and chronic and transient hypertension are under investigation.