Posterior Reversible Encephalopathy Syndrome Associated With Preeclampsia-eclampsia

Posterior reversible encephalopathy syndrome (PRES) is a recently recognized, heterogeneous and reversible clinical and neuro-imaging syndrome. As a synonymous with typical clinical features and a unique pattern of brain vasogenic edema seen in the setting of neurotoxicity, the pathological, clinical, and neuroimaging characteristics of PRES reflect the rapid and dynamic fluctuations in blood flow and water content of the brain.The pathogenesis of PRES is unclear, and controversy still exists. It results from abnormalities in two parameters that determine transmembrane flow of intravascular fluid and proteins:capillary filtration pressure and the integrity of the blood-brain barrier (BBB). Hypertension and endothelial dysfunction may be important factors in the occurrence of PRES. Endothelial injury related to abrupt blood pressure changes or direct effects of cytokines on the endothelium, which leads to breakdown of the cerebral blood flow autoregulatory and blood-brain barrier, subsequent brain oedema. As the triggering factors of PRES, the primary role of elevated blood pressure and endothelial dysfunction, low and high perfusion status within the edema of brain tissue, are the main focuses of the debateSome researchers hypothesized:In the majority of patients with PRES, a complex underlying’systemic process’ was present. The activation of immune system and the consequence endothelial activation start a molecular cascade which finally causes the production of inflammatory cytokine and alters the normal homeostasis of BBB. In this’systemic process’, it emphasizes the crucial role of endothelial dysfunction and activation in the pathogenesis of PRES. Hypertension would be an epiphenomenon of the underlying mechanism but not the cause of PRES, at some level, may exert a protective effect limiting the developing of PRES and improving compromised cerebral perfusion. Such speculation is contradictory to the proposition that hypertension play a significant role in the autoregulation failure.Preeclampsia-eclampsia is a hypertensive, multisystem disorder of pregnancy. Endothelial cell activation and dysfunction have been proposed to be a central feature of preeclampsia-eclampsia. Vasospasm is a key component of this disorder. Hypertension is the basic diagnostic criteria. The central nervous system and kidneys are the common target organs of the multisystemic disorder. The central nervous system can be involved during the course of preeclampsia in the form of hyperreflexia; headaches; visual disturbances; mental status changes; eclampsia; and, in the most severe cases, intracranial hemorrhage. Glomeruloendotheliosis is considered to be a characteristic lesion of pre-eclampsia, proteinuria can be considered as a manifestation of damage to the fenestrated glomerular endothelium.Our understanding of PRES is derived primarily from small retrospective observational studies and case series. Study results vary considerably. This variation reflects small sample sizes, variations in definitions of patient subgroups, inadequate consideration of referral bias, differences in underlying conditions and study designs and methods.There remain many unanswered questions regarding the pathogenesis of the cerebral manifestations of preeclampsia-eclampsia. Human experimental data regarding the cerebral responses to pregnancy or preeclampsia-eclampsia are scant due to technical challenges as well as ethical problems. In addition, there is obvious difficulty in relating the histopathologic data with the hemodynamic information.As a heterogeneous clinical and neuroimaging syndrome, preeclampsia-eclampsia is the most classic clinical etiological or precipitating factor of PRES. An association between preeclampsia-eclampsia and PRES was first described by Hinchey et al in 1996. Since then, few comprehensive and systematic large sample clinical studies followed to further document and support this association. With the purpose of increasing awareness of the broadening clinical, imaging spectrum and pathogenesis of this syndrome associated with a monopathy etiological factor in a large group, we conducted a retrospective study of 48 cases of PRES associated with preeclampsia-eclampsia admitted in our department.Objective:To investigate the clinical and imaging features of PRES associated with preeclampsia-eclampsia. We assessed the main clinical features and cranial MR imaging findings in these patients and their correlation with blood pressure and laboratory data. To increase the awareness of the clinical, imaging features and pathogenesis, provide clinical evidence of reasonable effective therapy strategy, sought to explore a new method of preeclampsia-eclampsia and PRES in the future study.Methods:This was a single centric retrospective observational study conducted from December 2006 to December 2015. Clinically confirmed cases of PRES associated with preeclampsia-eclampsia from the Department of Neurology were included in the study. The following information was obtained:general demographic information; clinical and brain MRI features; laboratory data. The main clinical features and cranial MR imaging findings were assessed respectively. The correlation between cranial MR imaging findings with blood pressure and laboratory datas were analyzed.Results:1 General demographic informations Forty-eight patient were enrolled. Ages ranged from 18 to 43 years old (24±2.5 years). Thirty-six of the 48 patients were primipara. The gestational age at the onset of PRES was between 22.5 and 42.7 weeks, with the average gestational age being 34.8 weeks. There were 6 preeclampsia patients and 42 eclampsia patients, including 24 prepartum,2 intrapartum and 16 postpartum eclampsia patients (of which 10 had delayed postpartum eclampsia). Thirty-nine patients had cesarean section and 9 patients delivered vaginally. There were 7 patients with a stillbirth. None of the patients reported histories of chronic hypertension, epileptic seizures, drug abuse, smoking or drinking.2 Clinical symptoms, signs and lab dates2.1 Forty-two patients experienced seizures (87.5%). Thirty-two of the 42 patients with seizures (76%) experienced multiple attacks of epileptic seizures and 5 had persistent epilepsy. Thirty-eight patients (79%) reported headaches, including 27 patients with headaches that occurred prior to the onset of the seizure. Thirty-two patients (67%) experienced an alteration in their mental status, with 13 of these patients reporting that this alteration occurred prior to their seizure. Twenty-eight patients (54%) experienced changes in their vision,10 of which reported cortical blindness and 16 of these 28 patients indicated that these visual changes occurred before their seizure,24 patients accompanied headaches.2.2 Initial blood pressure levels prior to seizure or after admission were:1) systolic blood pressures ranging from 128-230 mmHg with an average of 169.7 mmHg, and 34 patients showing levels greater than or equal to 160 mmHg; 2) diastolic pressures ranging from 70-145 mmHg with an average of 107.1 mmHg, and 28 patients showing levels greater than or equal to 105 mmHg and 3) mean arterial pressures (MAP) ranging from 93.3-163.3 mmHg, with an average of 127.7 mmHg, and 8 patients showing levels greater than or equal to 150 mmHg.2.3 Forty-four patients showed varying levels of hypoalbuminemia with serum albumin levels ranging from 13-33.4g/L. Positive urine protein levels were present in 45 patients, with 18 showing urine protein of "+" to "++" and 24 with urine protein of "+++" to "++++"; and 13 patients were diagnosed with a combined HELLP syndrome. Two patients had lumbar punctures, with lumbar puncture pressures in these patients being 200 and 250 mmHg and the presence of a mildly elevated protein level in their cerebrospinal fluid.3 The imaging features of PRES and correlation with blood pressure and laboratory data3.1 Forty-one of the 48 patients (85%) had a parietal-occipital lobe lesion. Additional affected areas included that of the frontal lobe (36 patients,75%), temporal lobe (25 patients,52%), basal ganglia (18 patients,38%), splenium of the corpus callosum (12 patients,23%), brainstem (9 patients,19%) and cerebellar hemisphere (7 patients,15%).Involvement of the basal ganglia were present in 18 patients, out of 1 patient only with involvement of the frontal lobe, there was also varied involvement of the parietal-occipital lobe and frontal lobe. Involvement of the basal ganglia were significantly associated with serum creatinine, blood urea and the edema scale scores respectively (P< 0.05)3.2 Imaging pattern in PRES:11 (23%) of the 48 patients had lesions distributed in the typical parietal-occipital region. Three other imaging patterns for PRES presented in our study included 13 patients (27%) showing diffuse distribution in the holohemispheric watershed pattern.19 patients (40%) with a distribution in the superior frontal sulcus pattern.5 patients (10%) with a partial or asymmetric expression patterns. There was no significant difference between blood pressure with the imaging patterns (P>0.05)3.3 The edema scale scores of PRES:lscore 3 cases (6.3%)、2 score 9 cases (18.7%).3 score 14 cases (29.2%)、4 score 12 cases (25.0%)、5 score 10 cases (20.8%). The edema scale scores were correlated with the SBP、MAP、serum creatinine and blood urea respectively (Spearman’s P< 0.05)3.4 Vasogenic edema complicated with cytotoxic components was found in 15 cases (31.2%). There were significant difference in the serum creatinine, blood urea and edema scale scores respectively between patients with cytotoxic edema and those without (P<0.05)3.5 Twenty-six patients received at least 1 MRI follow-up in our study. Lesions of 19 patients were no longer present as determined within 2 weeks following their previous MRI image. Four patients continued to show abnormal white matter signals, including one patient showed a possible right parietal bleeding. One patient retained a left parietal laminar necrosis.Conclusion:1 Preeclampsia-eclampsia is a common classic clinical etiological or precipitating factor of PRES. As the primary injury in preeclampsia-eclampsia, PRES is hypothesized to as a comparable model of preeclampsia-eclampsia.2 PRES associated with preeclampsia-eclampsia displays typical clinical features. Except seizures, headache, mental status alteration and vision change are common, and can occur before the seizure. Focal neurological finding are rare.3 With the exception of the parietal-occipital lobe, PRES lesions most often occurred within the frontal lobe, temporal lobe and basal ganglia. The three most common imaging patterns for lesion distribution of PRES included the dominant parietal-occipital pattern, holohemispheric watershed pattern and superior frontal sulcal pattern. Partial or asymmetric expression patterns are also encountered. Accurate recognitions of the imaging patterns of PRES are critical for a correct diagnosis.4 Hypertension may be an important factor in the occurrence of PRES, but not the only factor. The combination of increased blood pressure and endothelial dysfunction may penetrate and interact with one another, and ultimately lead to PRES. The reasonable treatment of hypertension is important.5 Patients with post-partum eclampsia (especially late post-partum eclampsia), those with focal neurological deficits, persistent visual disturbances, and symptoms refractory to magnesium and antihypertensive treatment should undergo thorough diagnostic testing, preferably including MRI.6 PRES is dynamic pathological process and the reversibility is not the initial nature process, in which lesions may partially or completely subside after appropriate treatments. It is emphasized the importance of the prompt diagnosis and reasonable therapy.