Factors associated with fatal outcome in posterior reversible encephalopathy syndrome: a retrospective analysis of the Berlin PRES study

Experimental Models of Posterior Reversible Encephalopathy Syndrome: A Review From Pathophysiology to Therapeutic Targets

Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological entity characterized by nonspecific symptomatology (eg, headache, visual disturbances, encephalopathy, and seizures) and classically cortical and subcortical vasogenic edema predominantly affecting the parietooccipital region. PRES etiologies are usually dichotomized into toxic PRES (eg, antineoplastic drugs, illicit drugs) and clinical condition-associated PRES (eg, acute hypertension, dysimmune disorders). Although the pathophysiology of PRES remains elusive, 2 main pathogenic hypotheses have been suggested: cerebral hyperperfusion due to acute hypertension and cerebral hypoperfusion related to endothelial dysfunction. Research into the pathogenesis of PRES has emerged through the development of animal models in the last decade. The motivation for developing a suitable PRES model is 2-fold: to fill in knowledge gaps of the pathophysiological mechanisms involved, and to open new perspectives for clinical assessment of pharmacological targets to improve therapeutic management of PRES. All current models of PRES have a hypertensive background, on which other triggers (acute hypertension, inflammatory, drug toxicity) have been added to address specific facets of PRES (eg, seizures). The initial model consisted in inducing a reduced uterine perfusion pressure that mimics preeclampsia, a leading cause of PRES. More recently, a model of stroke-prone spontaneously hypertensive rats on high-salt diet, originally developed for hypertensive small vessel disease and vascular cognitive impairment, has been studied in PRES. This review aims to discuss, depending on the research objective, the benefits and limitations of current experimental approaches and thus to define the desirable characteristics for studying the pathophysiology of PRES and developing new therapies.

Demographic Disparities in the Incidence, Clinical Characteristics, and Outcome of Posterior Reversible Encephalopathy Syndrome in the United States

OBJECTIVES

To estimate age-specific, sex-specific, and race-specific incidence of posterior reversible encephalopathy syndrome (PRES) in the United States.

METHODS

We conducted a retrospective cohort study using the State Inpatient Database of Florida (2016-2019), Maryland (2016-2019), and New York (2016-2018). All new cases of PRES in adults (18 years or older) were combined with Census data to compute incidence. We evaluated the generalizability of incident estimates to the entire country using the 2016-2019 National Readmissions Database (NRD).

RESULTS

Across the study period, there were 3,716 incident hospitalizations for PRES in the selected states. The age-standardized and sex-standardized incidence of PRES was 2.7 (95% CI 2.5-2.8) cases/100,000/y. Incidence in female patients was >2 times that of male patients (3.7 vs 1.6 cases/100,000/y, p < 0.001). Incidence increased with age in both sexes (p-trend <0.001). Similar demographic distribution of first hospitalization for PRES was also noted in the entire country using the NRD. Age-standardized and sex-standardized PRES incidence in Black patients (4.2/100,000/y) was significantly greater than in Non-Hispanic White (2.7/100,000/y) and Hispanic patients (1.2/100,000/y) (p < 0.001 for pairwise comparisons).

DISCUSSION

The incidence of PRES in the United States is approximately 3/100,000/y, but incidence in female patients is >2 times that of male patients. PRES incidence is higher in Black compared with non-Hispanic White and Hispanic patients.

Septic encephalopathy in the elderly - biomarkers of potential clinical utility

Next to acute sickness behavior, septic encephalopathy is the most frequent involvement of the brain during infection. It is characterized by a cross-talk of pro-inflammatory cells across the blood-brain barrier, by microglial activation and leukocyte migration, but not by the entry of infecting organisms into the brain tissue. Septic encephalopathy is very frequent in older persons because of their limited cognitive reserve. The predominant clinical manifestation is delirium, whereas focal neurological signs and symptoms are absent. Electroencephalography is a very sensitive method to detect functional abnormalities, but these abnormalities are not specific for septic encephalopathy and of limited prognostic value. Routine cerebral imaging by computer tomography usually fails to visualize the subtle abnormalities produced by septic involvement of the brain. Magnetic resonance imaging is by far more sensitive to detect vasogenic edema, diffuse axonal injury or small ischemic lesions. Routine laboratory parameters most suitable to monitor sepsis, but not specific for septic encephalopathy, are C-reactive protein and procalcitonin. The additional measurement of interleukin (IL)-6, IL-8, IL-10 and tumor necrosis factor-α increases the accuracy to predict delirium and an unfavorable outcome. The most promising laboratory parameters to quantify neuronal and axonal injury caused by septic encephalopathy are neurofilament light chains (NfL) and S100B protein. Neuron-specific enolase (NSE) plasma concentrations are strongly influenced by hemolysis. We propose to determine NSE only in non-hemolytic plasma or serum samples for the estimation of outcome in septic encephalopathy.

Posterior Reversible Encephalopathy Syndrome in a Pediatric Patient with End-Stage Renal Disease

Posterior reversible encephalopathy syndrome (PRES) is a clinical and neuroimaging syndrome that can affect both children and adults and has variable etiology. It is clinically defined by headaches, consciousness disorders, seizures and visual disturbances. Early recognition (clinical and imaging) can lead to appropriate general measures to correct the underlying cause of PRES. In this paper, we report a case of PRES in an eight-year-old boy with bilateral renal hypoplasia and end-stage renal disease (ESRD).

Posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome in patients with COVID-19 infection: is there a link? A systematic review and case report analysis

During the SARS-CoV2 pandemic, several cases of Posterior Reversible Encephalopathy Syndrome (PRES) and of Reversible Cerebral Vasoconstriction Syndrome (RCVS) in COVID-19 patients have been reported, but the link between these syndromes and COVID-19 is unclear. We performed a systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to evaluate whether SARS-CoV2 infection or the drugs used to treat it could be deemed potential risk factors for PRES or RCVS. We performed a literature search. We found 70 articles (60 on PRES and 10 on RCVS) concerning n = 105 patients (n = 85 with PRES, n = 20 with RCVS). We analyzed the clinical characteristics of the two populations separately, then performed an inferential analysis to search for other independent risk factors. We found fewer than usual PRES-related (43.9%) and RCVS-related (45%) risk factors in patients with COVID-19. Such a low incidence of risk factors for PRES and RCVS might suggest the involvement of COVID-19 as an additional risk factor for both diseases due to its capability to cause endothelial dysfunction. We discuss the putative mechanisms of endothelial damage by SARS-CoV2 and antiviral drugs which may underlie the development of PRES and RCVS.

Clinical Features and Risk Factors of Mortality in Patients with Posterior Reversible Encephalopathy Syndrome

Objective. Although the prognosis of posterior reversible encephalopathy syndrome (PRES) is usually favourable and most patients wholly recover, the disorder can result in death in some patients. To date, the data on clinical features and risk factors for death are still lacking; therefore, we aim to investigate the clinical features and long-term prognostic risk factors of PRES in the present study. Methods. The patients with PRES were identified from the First Affiliated Hospital of Zhengzhou University from June 2011 to June 2020. Clinical characteristics, laboratory tests, magnetic resonance imaging examinations, and treatment of all patients were analyzed retrospectively. All patients were followed up by telephone. Finally, the patients were divided into the survival group and death group for prognosis analysis. Results. A total of 92 patients with PRES were included; 84.8% of whom were female, with an average age of 25.4 (5–66) years at the onset of PRES. Epilepsy was the main clinical manifestation (72.8%). The in-hospital mortality rate was 2.17%. The 3-year all-cause survival rate for PRES patients was 86%. In univariate analysis, patients with systemic lupus erythematosus ( $P=0.027$ ) and blood transfusion history within 1 month before onset ( $P=0.027$ ), need for dialysis ( $P\le 0.001$ ), nephritis ( $P=0.010$ ), stroke ( $P=0.016$ ), and heart failure ( $P=0.016$ ) were associated with death. In multivariate analysis, we found that heart failure ( $\text{OR}=0.095$ , 95% CI 0.020 to 0.441) and stroke ( $\text{OR}=0.033$ , 95% CI 0.002 to 0.467) were independent risk factors for death in PRES patients, while pregnancy was a protective factor for death in PRES patients ( $\text{OR}=7.978$ , 95% CI 1.446 to 44.006). Conclusions. Our results indicate that PRES could be considered as a sign of a very high-risk patient. We also demonstrated that heart failure and stroke were independent risk factors for death in patients with PRES; moreover, pregnancy was a protective factor.

Early Readmissions After Hospitalization for Posterior Reversible Encephalopathy Syndrome

BACKGROUND AND OBJECTIVES

To evaluate the frequency, etiologies, and risk factors for 90-day readmissions after hospitalization for posterior reversible encephalopathy syndrome (PRES).

METHODS

Data were obtained from the Nationwide Readmissions Database 2016-2018. Patients with a primary diagnosis of PRES, survival to discharge, and known discharge disposition were included. The primary outcome was nonelective readmission within 90 days of discharge. Survival analysis was performed, and independent predictors of readmission were analyzed using multivariable Cox proportional hazards regression.

RESULTS

Based on the study inclusion criteria, 6,155 eligible patients were included (mean ± SD age: 55.9 ± 17.3 years, female: 71.0%). Nonelective readmission within 90 days of discharge occurred for 1,922 (31.2%) patients. Of these, 617 readmissions were due to PRES-related or neurologic etiologies and the remaining 1,305 readmissions were due to non-neurologic conditions. In multivariable analysis, age was inversely associated with the risk of readmission (hazards ratio [HR] 0.92 for every 10 years increase in age, 95% CI 0.88-0.97). Patients with diabetes (HR 1.21, 95% CI 1.04-1.42), systemic lupus erythematosus (HR 1.42, 95% CI 1.03-1.96), acute kidney injury (HR 1.28, 95% CI 1.11-1.47), and a higher Charlson comorbidity index score (HR 1.09, 95% CI 1.06-1.13) were more likely to be readmitted. Furthermore, patients admitted at large bed size hospitals (HR 1.19, 95% CI 1.03-1.39), those with a longer length of stay (HR 1.01, 95% CI: 1.00-1.02), and those not discharged to home (HR 1.33, 95% CI: 1.14-1.55) during the index hospitalization were also at a higher risk for readmission.

DISCUSSION

Nearly one-third of patients hospitalized because of PRES are readmitted within 90 days of discharge, and approximately one-third of these readmissions are due to PRES-related or neurologic etiologies. Younger age, a higher comorbidity burden, a longer length of hospital stay, and discharge disposition other than to home are independently associated with the risk of readmission.

Posterior reversible encephalopathy in a pregnant woman without preeclampsia or eclampsia: A case report

BACKGROUND

We report a case of a pregnant woman who presented posterior reversible encephalopathy syndrome (PRES) without pre-eclampsia, eclampsia, or any other common causes of PRES.

METHODS

A 32-year-old primigravida at 25 weeks and 4 days of gestation was admitted to neurology department because of suffering intermittent headache, hearing loss, memory loss with mental and behavioral disorder, and blurred vision for 1 month. She was healthy before without hypertension, migraine, or other medical or family history. Brain magnetic resonance imaging (MRI) revealed diffuse symmetrical high-signal intensity lesions in the white matter, medulla oblongata, without enhancement. After completely multidisciplinary discussion and with the family of the patient, she accepted termination of pregnancy.

RESULTS

After the operation, the patient improved symptomatically. The follow-up MRI showed a decrease of the white matter lesion after 3 months and complete recovery at postoperative 6 months. The patient returned to work without any neurological sequelae.

CONCLUSION

It might widen the cause spectrum of PRES that pregnancy itself without pre-eclampsia, eclampsia, or any other known risk factors could cause PRES. Pregnancy with acute or subacute leukoencephalopathy should be screened related causes and risk factors carefully. Hormonal fluctuations during the pregnancy might account for pregnancy-related PRES.

Factors associated with acute symptomatic seizure occurrence among patients with posterior reversible encephalopathy syndrome

OBJECTIVES

We aimed to define the factors associated with acute symptomatic seizure occurrence in posterior reversible encephalopathy syndrome (PRES) in the Thai-Asian population.

MATERIALS AND METHODS

We conducted a retrospective cohort study enrolling patients with PRES admitted to the hospital between 2006 and 2019. In addition to seizure characteristics, baseline characteristics, clinical presentations, precipitating factors, neuroimaging characteristics, hospital complications, and hospital outcomes were compared between the seizure and non-seizure groups. Factors with p-value <0.05 in the univariate analysis were entered into the first model of multivariate logistic regression analysis to determine the factors associated with seizure occurrence if the p-value <0.05. The interaction of associated factors was also analyzed in the final multiple logistic regression analysis model.

RESULTS

Acute symptomatic seizure, which is mainly based on the clinical documentation without electroencephalography, occurred in 50.0% of 136 patients with PRES. Of these, early seizures within 14 days of PRES occurred in 98.5% which mostly developed at presentation (82.4%) with a single seizure attack (55.9%). Convulsive seizures (77.9%) were the most common seizure semiology. The seizure group was significantly younger (median [interquartile range: IQR] 36.00 years old (21.75-48.50) vs 46.50 years old (31.25-61.00), p = 0.003). In univariate analysis, the seizure group had a higher prevalence of consciousness impairment (61.76% vs 26.47%, p < 0.001), Glasgow coma scale (GCS) score of 0-13 (42.46% vs 13.23%, p < 0.001), preeclampsia (20.58% vs 4.41%, p = 0.004), autoimmune disease (17.65% vs 5.88%, p = 0.033), and frontal lesions (25.00% vs 11.76%, p = 0.046) than those in the non-seizure group. In contrast, the seizure group had a lower prevalence of headache (27.94% vs 61.76%, p < 0.001). In the final multivariate logistic regression analysis which included the interaction terms, the acute symptomatic seizure occurrence directly associated with preeclampsia (adjusted odds ratio (aOR) 6.426, 95% confidence interval (CI) 1.450-27.031, p = 0.016) and autoimmune disease (aOR 4.962, 95% CI 1.283-18.642, p = 0.025), while headache showed a reverse association (aOR 0.310, 95% CI = 0.158-0.721, p = 0.008).

CONCLUSIONS

Acute symptomatic seizure occurred in a half of patients with PRES in this cohort. Preeclampsia and autoimmune disease were directly associated with seizure occurrence, while headache showed a reverse association.

Predictors of hospital outcomes among patients with posterior reversible encephalopathy syndrome

OBJECTIVES

We aimed to identify independent predictors of the clinical outcomes of posterior reversible encephalopathy syndrome (PRES) in the Thai-Asian population.

MATERIALS AND METHODS

This retrospective cohort study recruited PRES patients admitted in the hospital between 2006 and 2019. The baseline characteristics, clinical presentations, precipitating factors, neuroimaging characteristics, hospital complications, and hospital outcomes were compared between the groups with favourable (modified Rankin scale [mRS] score, 0-2) and unfavourable (mRS score, 3-6) clinical outcomes. Factors presenting with p-values < 0.5 in univariate analysis were analysed in the multiple logistic regression model to determine independent predictors of outcome.

RESULTS

Among 136 PRES patients, 22.80% experienced unfavourable outcomes (mRS score, 3-6), and the mortality rate was 7.35%. The common presenting symptoms in the unfavourable clinical outcome group were impairment of consciousness (90.32%) and seizures (67.74%). Sepsis as a hospital complication (adjusted odds ratio [aOR], 32.95; 95% confidence interval [CI], 4.44-244.22, p = 0.001), acute kidney injury as a hospital complication (aOR, 9.94; 95% CI, 1.71-57.66; p = 0.010), and impairment of consciousness (aOR, 10.85; 95% CI, 1.72-68.53, p = 0.011) were independent predictors of unfavourable outcomes. On the other hand, headache was an independent protective factor (aOR, 0.164; 95% CI, 0.03-0.91; p = 0.039).

CONCLUSIONS

Impairment of consciousness, sepsis as a hospital complication, and acute kidney injury were independent predictors of unfavourable clinical outcomes, whereas headache showed a preventive effect.

Posterior Reversible Encephalopathy Syndrome in Guillain-Barré Syndrome: Just a Problem of Immunoglobulins? Controversy From Two Atypical Case Reports

Background

Posterior reversible encephalopathy syndrome (PRES), reversible cerebral vasoconstriction syndrome (RCVS), or the coexistence of these two entities shares similar risk factors and clinical features. For these conditions, a common origin has been supposed. Even if the majority of patients show a favorable course and a good prognosis, a small percentage of cases develop neurological complications. Up to date, only about 30 cases of PRES associated with Guillain-Barré syndrome (GBS) have been reported in the literature.

Cases

Here, we present two cases of a particularly aggressive PRES/RCVS overlap syndrome, associated with acute motor axonal neuropathy (AMAN) and acute inflammatory demyelinating polyneuropathy (AIDP) variants of GBS, respectively, presenting with similar initial clinical aspects and developing both an atypical and unfavorable outcome. On MRI examination, the first patient showed typical aspects of PRES, while, in the second case, radiological features were atypical and characterized by diffusion restriction on the apparent diffusion coefficient (ADC) map. The first patient demonstrated rapid worsening of clinical conditions until death; the second one manifested and maintained neurological deficits with a permanent disability.

Conclusions

We suggest that PRES may conceal RCVS aspects, especially in most severe cases or when associated with a dysimmune syndrome in which autoimmune system and endothelial dysfunction probably play a prominent role in the pathogenesis. Although the role of IVIg treatment in the pathogenesis of PRES has been proposed, we suggest that GBS itself should be considered an independent risk factor in developing PRES.

Clinical features and prognostic analysis of posterior reversible encephalopathy syndrome in children

BACKGROUND

We aimed to investigate the clinical features and prognosis of posterior reversible encephalopathy syndrome (PRES) in children.

METHODS

Clinical data of children with PRES diagnosed at the Children's Hospital of Chongqing Medical University from June 2015 to May 2019 were retrospectively analyzed.

RESULTS

The study enrolled 47 patients with a mean age at diagnosis of 8.79 ± 3.72 years (range, 2-15 years). PRES causes included renal disorder (29/47), hematological disease (13/47), and hypertension (5/47). PRES manifested as seizure (43/47), headache (28/47), visual impairment (18/47), dizziness (18/47), vomiting (18/47), and mental and behavioral abnormalities (17/47). Forty-six children had hypertension (46/47) at PRES onset. Magnetic resonance imaging (MRI) mainly involved the parietal and occipital lobes (42/47), 38 cases were mild (38/47), 7 were moderate (7/47), and 2 were severe (2/47). The clinical symptoms of 41 patients (41/47) were relieved within 1-2 weeks. Thirty-seven children were followed up for 7-54 months (modified Rankin Scale). Twenty-five children had favorable outcomes (25/37). Twelve children had adverse outcomes (12/37), including epilepsy, disorders of consciousness, visual impairment, and mental decline. Analysis of single factors revealed that severity on MRI, length of in-hospital stay, and mental and behavioral abnormalities were related to adverse outcomes after PRES. Analysis of multiple factors revealed that severity on MRI and length of in-hospital stay were independent risk factors for PRES.

CONCLUSION

Pediatric PRES is a clinical radiographic syndrome with multiple etiologies. Most patients have a good prognosis. Severity on MRI and length of in-hospital stay are independent risk factors.

Posterior reversible encephalopathy syndrome: characteristics, diagnostic accuracy, prognostic factors and long-term outcome in a paediatric population

Posterior reversible leukoencephalopathy syndrome (PRES) is a rare entity among children, characterised by acute neurological symptoms and radiological findings. The role of clinical symptoms and neuroimaging in predicting the prognosis of PRES have not been well-characterised. A retrospective descriptive study of children with PRES, admitted to a Paediatric Intensive Care Unit during a 10-year period, was performed to describe its characteristics, compare the accuracy of computed tomography (CT) scan and MRI on diagnosis and identify prognostic factors on paediatric population. Sixteen cases were identified. Most patients (13; 81%) presented underlying disorders, including malignancies (5; 31%), chronic kidney disease (3; 19%) and post-transplant status (3; 19%). Hypertension (15; 94%) was the most common trigger. All patients had seizures, 9 patients (56%) altered state of consciousness, 8 (50%) headache. CT scan was performed in 15 patients (94%) and MRI in 13 (81%); 1 patient underwent only MRI. MRI allows the identification of new areas of vasogenic oedema and a correct diagnosis of PRES when CT scan was inconclusive. Two patients (13%) remained with neurological sequelae and one died. In two patients (13%) cognitive disorders (specific learning disorder, intellectual disability, motor tic disorder) were diagnosed during follow-up period. Clinical presentation was not statistically associated with outcome. Also, atypical neuroimaging (haemorrhagic and unilateral lesions) were not statistically related with poor neurological or cognitive outcome. However, prospective studies with a larger cohort are needed to establish prognostic factors of PRES in the paediatric population.

Posterior Reversible Encephalopathy in Sepsis-Associated Encephalopathy: Experience from a Single Center

BACKGROUND

Sepsis-associated encephalopathy (SAE) is frequently encountered in sepsis and is often accompanied by neuroimaging findings indicating ischemia, hemorrhage, and edema. Posterior reversible encephalopathy syndrome (PRES) has been vastly underrecognized in previously reported cohorts of patients with sepsis and SAE. Our aim was to determine the prevalence and distinguishing clinical, neuroimaging, and electroencephalography features of PRES in SAE.

METHODS

In this prospective observational study, patients with radiologically identified PRES were selected from a consecutively enrolled cohort of 156 patients with SAE and assessed for neurological outcome using the extended Glasgow Outcome Scale for 12 months. Patients with SAE and PRES and other types of brain lesions were compared in terms of clinical and diagnostic workup features.

RESULTS

Fourteen of 156 patients (8.9%) were determined to be radiologically compatible with PRES, whereas 48 patients displayed other types of acute brain lesions. Patients with PRES often showed lesions in atypical regions, including frontal lobes, the corpus callosum, and the basal ganglia. Source of infection was mostly gram-negative bacteria originating from pneumonia or intraabdominal infections. Patients with PRES were not different from other patients with SAE with brain lesions in terms of features of sepsis and neurological outcome. However, patients with PRES showed increased prevalence of seizures and intraabdominal source of infection.

CONCLUSIONS

PRES is highly prevalent in SAE, often encompasses unusual brain regions, and usually presents with generalized seizures. Patients with SAE and PRES do not appear to have distinguishing clinical and diagnostic workup features. However, generalized seizures may serve as warning signs for presence of PRES in patients with SAE.

Posterior reversible encephalopathy syndrome (PRES): diagnosis and management

Posterior reversible encephalopathy syndrome (PRES) may present with diverse clinical symptoms including visual disturbance, headache, seizures and impaired consciousness. MRI shows oedema, usually involving the posterior subcortical regions. Triggering factors include hypertension, pre-eclampsia/eclampsia, renal failure, cytotoxic agents and autoimmune conditions. The mechanism underlying PRES is not certain, but endothelial dysfunction is implicated. Treatment is supportive and involves correcting the underlying cause and managing associated complications, such as seizures. Although most patients recover, PRES is not always reversible and may be associated with considerable morbidity and even mortality.

Blood transfusion-induced posterior reversible encephalopathy syndrome presenting severe brain atrophy: A report of two cases

Several cases of posterior reversible encephalopathy syndrome (PRES) after blood transfusion have been reported, but the long-term prognosis is unknown. Here, we report two cases of blood transfusion-associated PRES with severe brain atrophy at 1 year after onset. We report the case with a discussion of pathological mechanisms.

Posterior reversible encephalopathy syndrome (PRES) due to acute hypertension in children: 12 years single-center experience

The objective of the study is to evaluate the clinical and neuroradiological findings, the risk factors for recurrence and the prognosis in patients with posterior reversible encephalopathy syndrome developed secondary to acute hypertension in children. The study was conducted between 2008 and 2019 at Mersin University Faculty of Medicine. A total of 49 episodes were evaluated retrospectively in 38 patients with PRES secondary to acute hypertension. The demographic data, etiology, and clinical and neuroradiological findings were recorded. Twenty-one (55.3%) patients were female; the mean age was 11.8 years. The etiology of acute hypertension in 29 (76.3%) patients was end-stage renal disease (ESRD). The most common clinical findings were seizure (81.6%) and altered consciousness (79.6%). Status epilepticus developed in eight (16.3%) episodes. MRI lesions were atypical in 33 episodes (67.3%). In eight (21%) patients, PRES recurred. Irreversible brain damage was detected after PRES in three (7.8%) patients. C-reactive protein and erythrocyte sedimentation rate were elevated in 82.2% and 71.4% of the episodes, respectively. A statistically significant relationship was found between the recurrence, the duration of hospitalization at the PICU, SE and the occurrence of irreversible lesion (p = 0.013, p = 0.015, p = 0.001 respectively). Also, there were statistically significant relationships between recurrence and ESRD; epilepsy and recurrences; SE and irreversible brain damage (p = 0.02, p = 0.012, p = 0.025 respectively). Although PRES is usually known to have a good prognosis, the mortality and morbidity rates may increase in the long-term follow-up as in our study. In this study, the etiology, the presence of status epilepticus, PICU history, atypical MRI lesions and increased inflammatory markers were found to be important for the prognosis in PRES.

Acute posterior reversible encephalopathy syndrome (PRES) in setting of interferon-beta use: case presentation with reduction of edema in 72 h after cessation of interferon-beta therapy with sub-clinical inflammation

Background

Posterior reversible encephalopathy syndrome (PRES) represents a transient change in mental status with associated vasogenic edema of cortical and subcortical brain structures. It is often attributed to multifactorial etiology including hypertension and altered hemodynamics and disruption of vessel integrity. Patients with autoimmune disease and certain immune modulator therapies are at greater risk.

Case presentation

A 54-year-old female with past medical history of well-controlled multiple sclerosis on interferon-beta since 2013, presented with witnessed tonic colonic seizure. She also was noted to demonstrate left gaze deviation and left-sided hemiparesis. MRI fluid-attenuated inversion recovery sequence showed hyperintensity of the subcortical U fibers, concentrated in the occipital, parietal lobes and frontal lobes. Systolic blood pressure was 160 mmHg on arrival. The patient was started on seizure prophylxis and Interferon beta was discontinued. The patient’s mentation, seizures and hemiapresis significantly improved in next 72 h with tight blood pressure control, and had notble improvement on MRI imaging and inflammatory markers. Lumbar puncture CSF results were devoid of infectious and autoimmune pathology.

Conclusions

A middle-aged female with multiple sclerosis who was on chronic IFN-beta presented to the emergency room with a witnessed tonic-clonic seizure, with MRI T2 FLAIR imaging consistent with PRES. She had notable clinical improvement with decreased edema on imaging and improved inflammatory markers 72 h after cessation of IFN-beta therapy.

Clinical Presentation and Risk Factors for Poor Outcomes Among Adult Patients With Posterior Reversible Encephalopathy Syndrome: A Retrospective Cohort Study

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is an acute neurological condition with unknown global incidence, variable clinical presentation, and prognosis.

OBJECTIVES

To describe a cohort of patients with PRES with a focus on brain magnetic resonance imaging (MRI) patterns and their relationship with short-term clinical outcomes.

METHODS

Retrospective cohort study. The authors included patients if they were older than 15 years and had a PRES diagnosis on the basis of a positive brain MRI at any time during the in-hospital stay.

RESULTS

Forty-four patients were included in the present analysis. The median age was 57 years (interquartile range, 32.0-68.5) and 70.5% were women. Hypertension (59.1%), history of transplantation (27.3%), previous chemotherapy (27.3%), chronic renal failure (38.6%), and autoimmune disease (15%) were the main comorbid conditions present. The classic triad of seizures, headache, and visual impairment was present in 18.0% of the cases. Eighty-six percent of patients were admitted to the intensive care unit, with 36.0% needing invasive life support. Brain MRI showed a dominant parieto-occipital pattern in 26 patients, whereas cytotoxic edema and bleeding were present in 27.3% and 29.6%, respectively. In-hospital mortality was 11.4%. The median modified Rankin Scale at hospital discharge was 1 (0-2.5). Risk factors associated with low modified Rankin Scale scores were: headache, visual impairment, and parieto-occipital pattern. Decreased level of consciousness and mechanical ventilation requirement were associated with greater discharge disability.

CONCLUSIONS

Characteristic symptoms and signs of PRES and classic MRI patterns are associated with better clinical outcomes.

Posterior Reversible Encephalopathy Syndrome Following Blood Transfusion: A Rare Case Report with Literature Review

Background:

Posterior reversible encephalopathy syndrome (PRES) is clinicoradiological disease entity characterized by headache, seizures, altered sensorium and corticalvisual loss with characteristic MRI features of subcortical white matter hyperintensities on T2W imaging. Though hypertension is a traditional hallmark of PRES, uncommon causes without hypertension have been described. We report an unusual such case without hypertension, precipitated by red cell transfusion.

Case Presentation:

A 40 years female received six units of packed cell transfusion for severe anemia (Hemoglobin 3.0 Gm %) transfused over 8 hours. She was having menorrhagia and was operated on for a hysterectomy. She developed a headache on the second postoperative day for five days and no cause was revealed in spite of extensive workup, including MRI brain and CSF study. On the sixth day, she had recurrent seizures followed by altered sensorium in the absence of hypertension. Her repeat MRI brain findings were consistent with PRES.

Conclusion:

We reviewed 25 cases, including the present one as PRES after the blood transfusion. 24 were females, and 16 of 19 developed PRES in the course of chronic anemia lasting over 1 month. Anemia was severe in 18 of 25 cases, with haemoglobin (Hb) levels < 4.0 Gm%. In 16 of 20 cases, Hb levels increased to 5 g/dl by red cell blood transfusion until the onset of PRES. On MRI brain, 23 of 25 cases showed vasogenic edema and 3 of 25 cases showed an irreversible neurological deficit. When treating severe chronic anemia rapid correction of Hb with blood transfusion, one should consider a possibility of PRES in post-transfusion neurological symptoms in spite of normal diagnostic workup.

Posterior Reversible Encephalopathy Syndrome: Tips for Diagnosis and Treatment

Often described as a clinico-radiological entity, posterior reversible encephalopathy syndrome (PRES) is being increasingly diagnosed nowadays. However, mystery still surrounds its exact etiology. Though there are no standardized diagnostic criteria for this syndrome, there is a consistent feature associated with it: brain vasogenic edema in combination with neurotoxicity. The nonspecific nature of this condition leaves room for the diagnosis to be overlooked, leading to delays in providing appropriate treatment and unfavorable patient outcomes. PRES is associated with a variety of medical conditions including hypertension, eclampsia, autoimmune conditions, renal failure, sepsis, and an immunocompromised state, such as that secondary to the use of immunosuppressive therapy, human immunodeficiency virus (HIV), and organ transplants. Treatment by a multidisciplinary team and prompt identification and reversal of the underlying cause can lead to beneficial outcomes, as in the case we present in this report.

Cognitive Sequelae of Central-Variant Posterior Reversible Encephalopathy Syndrome (PRES)

Introduction

Although the posterior reversible encephalopathy syndrome (PRES) is often associated with headache and visual changes, central-variant PRES can be difficult to clinically diagnose in a patient with alteration of consciousness. Central-variant PRES has been previously described in the literature affecting subcortical white matter and the brainstem. Case Presentation. We describe a case presenting with hypertension (192/98) and altered level of consciousness requiring intubation. She was ultimately found to have extensive symmetric cortical and subcortical edema, with extensive involvement of bilateral thalami, consistent with central-variant PRES. Her mentation rapidly improved with blood pressure management. Confirmation of the diagnosis of central-variant PRES was made on repeat brain imaging. Our case is unique in demonstrating dramatic central white matter changes and their reversibility on repeat imaging six days later. Finally, persistent cognitive deficits at follow-up four months later are described.

Conclusion

Atypical presentations of PRES, involving alterations in levels of consciousness, can be difficult to clinically diagnose. A thorough differential diagnosis is even more important in cases of PRES with atypical imaging. Recognition of the diagnostic patterns of PRES on brain imaging, with prompt reversal of the causative factors, is crucial for the appropriate care of these patients. The long-term sequelae, which could include cognitive deficits, are poorly studied and understood.

Posterior Reversible Encephalopathy Syndrome Secondary to Varicella Encephalitis

Posterior reversible encephalopathy syndrome (PRES) is a rapidly progressive neurologic condition presenting with typical symptoms including headache, nausea, vomiting, altered mental status, and visual defects. Neuroimaging profile, particularly magnetic resonance imaging (MRI), is the most important tool for diagnosis. The most commonly reported etiological factors include hypertensive emergency and renal disease. We describe a 67-year-old lady who developed clinical and radiological characteristics of PRES secondary to Varicella encephalitis.

Detecting the Uncommon Imaging Manifestations of Posterior Reversible Encephalopathy Syndrome (PRES) in Adults: a Comprehensive Illustrated Guide for the Trainee Radiologist

Posterior reversible encephalopathy syndrome (PRES) has traditionally been described as a reversible leukoencephalopathy with a distinct pattern of posteriorly distributed vasogenic oedema involving the subcortical regions of parietal and occipital lobes. PRES commonly occurs in the setting of hypertensive emergencies, pre-eclampsia/eclampsia, impaired renal function, and immunosuppressive therapy. The various clinical presentations of PRES include encephalopathy, seizures, headache, visual, and focal neurological deficits. As knowledge of this entity grows, the range of clinical, and radiological features is seen to be much broader than originally described. The brain oedema may not always be posteriorly distributed and the syndrome may not be uniformly reversible. Of special note are some uncommon imaging features (unilateral cerebral involvement, and isolated posterior fossa involvement) and also some uncommon complications (haemorrhage, cytotoxic oedema, and vasoconstriction). These red herrings may lead to potential diagnostic challenges and pitfalls especially for trainee radiologists, who often read these scans in an emergency setting. Early and accurate diagnosis is crucial for prompt optimum management, thereby avoiding residual morbidity. This review article focusses on the atypical radiological features of PRES in adults with extensive case-based imaging examples. A brief description of the pathophysiology, clinical, and classic radiological features of PRES has also been included. A tabulated summary of potential mimics with diagnostic pearls is provided to highlight pertinent take home points and to serve as an easy guide for day-to-day clinical practice.

Chemotherapy and Immunosuppressant Therapy-Induced Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is an entity which is characterized by acute to subacute onset of neurological symptoms like altered mental status, seizures, headaches and other focal neurological deficits. It is diagnosed with the help of MRI findings which typically involve the subcortical white matter of parieto-occipital lobes. In this review, we will discuss the various etiologies and risk factors including some of the most common chemotherapeutic agents and immunosuppressant agents associated with this disorder. We will discuss the mechanism of actions and side effect profiles of a few drugs and their role in causation of PRES. This review article discusses if there is any difference in presentation and imaging findings of PRES caused by cytotoxic agents versus caused by other etiologies. It also highlights the difficulty in management of PRES caused by cytotoxic agents as the discontinuation of these drugs could be life-threatening due to graft rejections or graft versus host disease.

Patterns, risk factors and outcome predictors of posterior reversible encephalopathy syndrome in pediatric cancer patients

The purpose of this study was to assess the clinical and radiological patterns and outcome predictors of posterior reversible encephalopathy syndrome (PRES) in pediatric cancer patients. A retrospective study included patients who developed PRES during their treatment at the Children's Cancer Hospital Egypt. A total of 50 patients developed PRES. Leukemia and lymphoma were the commonest diagnoses (64%). Regarding the MRI findings, occipital affection was the most common (92%), followed by frontal and temporal lobes involvement in 32% and 22% respectively and advanced PRES was described in 8 patients. Of the whole patients, 80% had complete clinical resolution and 60% showed complete radiological resolution at 2 weeks' evaluation and 2 patients died out of PRES. Unfavorable outcome was associated with those who had motor dysfunction, status epilepticus at presentation, frontal lobe and thalamic affection and atypical PRES. PRES might present in atypical sites with poor outcome including death.

Analysis of Risk Factors Associated With Poor Outcome in Posterior Reversible Encephalopathy Syndrome After Treatment in Children: Systematic Review and Meta-Analysis

Objective: Chemotherapy and hematopoietic stem cell transplantation (HSCT) play important roles in clinical etiology, symptoms, signs, imaging findings, and biochemical parameters for inducing posterior reversible encephalopathy syndrome (PRES) in pediatric oncologic diseases. We aimed to evaluate various risk factors of pediatric oncologic diseases after conducting chemotherapy and HSCT to induce PRES for predicting the clinical prognosis frequency.

Methods: The literature was performed on PubMed, Web of Science, and Embase databases to recognize the qualified studies. The odds ratios (ORs) of related risk factors and their corresponding 95% confidence intervals (CIs) were used to compute the pooled assessments of the outcomes.

Results: Six studies were included in the meta-analysis, involving 828 records. The risk of female children has a significantly higher incidence than male children in oncologic age groups of PRES. Children over the age of 10 years old in oncologic age groups develop a significantly increased risk of PRES. Acute graft-versus-host disease (GVHD) has a significant promotion effect on the occurrence of PRES. Hypertension can promote the occurrence of PRES in children. The risk of PRES in immunodeficient children increases significantly. Children with sickle cell disease (SCD) have a significantly increased risk of PRES. The risk of PRES in children with T-cell leukemia rises considerably. The central nervous system (CNS) leukemia/involvement has a significant role in promoting the occurrence of PRES in children. The pooled OR for the factors male, ≥ 10 years old of age, acute GVHD, hypertension, immunodeficiency, SCD, T-cell leukemia, CNS leukemia/involvement was 0.66 (95% CI: 0.58, 0.76; P < 0.00001), 2.06 (95% CI: 1.23, 3.43; P < 0.006), 1.32 (95% CI: 1.14, 1.53; P < 0.0003), 8.84 (95% CI: 7.57, 10.32; P < 0.00001), 2.72 (95% CI: 1.81, 4.08; P < 0.00001), 2.87 (95% CI: 2.15, 3.83; P < 0.00001), 2.84 (95% CI: 1.65, 4.88; P < 0.0002), and 3.13 (95% CI: 1.43, 6.84; P < 0.004), respectively.

Conclusions: The result of this meta-analysis suggests that female children, age over 10 years old, acute GVHD, hypertension, immunodeficiency, SCD, T-cell leukemia, and CNS leukemia/involvement are likely to have the poor outcome in pediatric oncologic/hematologic diseases in PRES.

Posterior reversible encephalopathy syndrome (PRES): presentation, diagnosis and treatment

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder which is characterised by variable symptoms, which include visual disturbances, headache, vomiting, seizures and altered consciousness. The exact pathophysiology of PRES has not been completely explained, but hypertension and endothelial injury seem to be almost always present. Vasoconstriction resulting in vasogenic and cytotoxic edema is suspected to be responsible for the clinical symptoms as well as the neuro-radiological presentation. On imaging studies, Symmetrical white matter abnormalities suggestive of edema are seen in the computer tomography (CT) and magnetic resonance imaging (MRI) scans, commonly but not exclusively in the posterior parieto-occipital regions of the cerebral hemispheres. The management is chiefly concerned with stabilization of the patient, adequate and prompt control of blood pressure, prevention of seizures and timely caesarean section in obstetric cases with pre-eclampsia/eclampsia. In conclusion, persistently elevated blood pressures remain the chief culprit for the clinical symptoms as well as the neurological deficits. Early diagnosis by diffusion weighted MRI scans, and differentiation from other causes of altered sensorium i.e. seizures, meningitis and psychosis, is extremely important to initiate treatment and prevent further complications. Although most cases resolve successfully and carry a favorable prognosis, patients with inadequate therapeutic support or delay in treatment may not project a positive outcome.

Posterior reversible encephalopathy syndrome in an oncological normotensive patient: evidence for a pathogenic role of concomitant low magnesium serum levels and chemotherapy treatment

Background:

Posterior reversible encephalopathy (PRES) is a rare syndrome characterized by headache, confusion, seizures, visual changes and white matter edema at radiological imaging. Its pathophysiology is not clarified and different causes, including uncontrolled hypertension, eclampsia, chemotherapy and hypomagnesemia have been suggested.

Case report:

A woman affected by stage IV breast cancer with lower extremity deep vein thrombosis treated with low-molecular-weight-heparin, currently in therapy with Palbociclib/Fulvestrant (antiCDK4 and 6/estrogen receptor antagonist) but previously treated with several other chemotherapy lines (including VEGF inhibitor bevacizumab), was admitted to our Internal Medicine department because of ascites and abdominal pain. She was treated with diuretics (and paracentesis). Recently (six-month earlier) a pan-encephalic radiotherapy was done because of brain and skull metastasis. Among blood tests, low serum levels of hypomagnesemia were observed. She developed PRES that rapidly progressed to lethargy, unresponsiveness till coma without changes in blood pressure. Magnetic Resonance Imaging study showed bilateral parieto-occipital edema and a thrombosis of left transverse and sigmoid sinuses. Anti-edema therapy, intravenous supplementation of magnesium and decoagulation were started, with complete and rapid recovery (within 18 hours) of clinical and radiologic changes.

Conclusions:

PRES diagnosis was based on the rapid clinical recovery after antiedema treatment and magnesium supplementation. Low magnesium level related to both diuretic and Fulvestrant/Palbociclib therapies and recent radiotherapy can represent potential mechanisms favouring PRES development. The previous bevacizumab treatment may also be involved as a PRES predisposing factor. The concomitant occurrence of cerebral thrombosis can have precipitated the clinical situation. (www.actabiomedica.it)

<p>Posterior Reversible Encephalopathy Syndrome Due to Acute Water Intoxication in a Patient with Schizophrenia</p>

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome that presents as transient cerebral edema (vasogenic edema), usually on a background of hypertensive encephalopathy, puerperal eclampsia, or immunosuppressant drug use. We describe a case of PRES that arose in the context of a psychiatric disorder. The patient was a 26-year-old woman with schizophrenia who was hospitalized upon falling into a catatonic stupor and then suffered acute anxiety leading to impulsive polydipsia and subsequent water intoxication. She lost consciousness, and brain magnetic resonance imaging revealed a high density area, primarily affecting the cortex and subcortical white matter in areas in the occipital and parietal lobes, leading to the diagnosis. We did not treat the hyponatremia by means of aggressive sodium supplementation but rather balanced the extracellular fluid by continuous infusion of isotonic electrolyte replacement fluid. The patient’s level of consciousness improved gradually, but a total 141 days passed before hospital discharge was appropriate. The prognosis for PRES is generally favorable, but irreversible neurological damage can occur. We believe, therefore, that brain magnetic resonance imaging should be performed promptly whenever PRES is suspected and that timely, appropriate treatment is of utmost importance. If PRES is observed in a psychiatric patient, it is important to investigate whether the condition might have been caused by water intoxication and to treat the condition accordingly.

Posterior Reversible Encephalopathy Syndrome: Clinical Features and Outcome

Background: Posterior reversible encephalopathy syndrome (PRES) is an acute neurotoxic syndrome that is characterized by a spectrum neurological and radiological feature from various risk factors. Common neurological symptoms includes headache, impairment in level of consciousness, seizures, visual disturbances, and focal neurological deficits. Common triggering factors include blood pressure fluctuations, renal failure, eclampsia, exposure to immunosuppressive or cytotoxic agents and autoimmune disorders. The classic radiographic findings include bilateral subcortical vasogenic edema predominantly affecting the parieto-occipital regions but atypical features include involvement of other regions, cortical involvement, restricted diffusion, hemorrhage, contrast enhancement. This review is aimed to summarize the updated knowledge on the typical and atypical clinical and imaging features, prognostic markers and identify gaps in literature for future research.

Methods: Systematic literature review using PUBMED search from 1990 to 2019 was performed using terms PRES was performed.

Results: While clinical and radiographic reversibility is common, long-standing morbidity and mortality can occur in severe forms. In patients with malignant forms of PRES, aggressive care has markedly reduced mortality and improved functional outcomes. Although seizures were common, epilepsy is rare. Various factors that have been associated with poor outcome include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control the causative factor, elevated C reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging.

Conclusion: Large prospective studies that accurately predict factors that are associated with poor outcomes, determine the pathophysiology, and targeted therapy are required.

Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome: Clinical and Radiological Considerations

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) are relatively uncommon neurological disorders, but their detection has been increasing mainly due to clinical awareness and spreading of magnetic resonance imaging (MRI). Because these syndromes share some common clinical and radiologic features and occasionally occur in the same patient, misdiagnosis may occur. PRES is characterized by varied neurological symptoms including headache, impaired visual acuity or visual field deficit, confusion, disorders of consciousness, seizures, and motor deficits often associated to peculiar neuroradiological pattern even if uncommon localization and ischemic or hemorrhagic lesions were described. RCVS is a group of diseases typically associated with severe headaches and reversible segmental vasoconstriction of cerebral arteries, often complicated by ischemic or hemorrhagic stroke. Pathophysiological basis of PRES and RCVS are still debated but, because they share some risk factors and clinical features, a possible common origin has been supposed. Clinical course is usually self-limiting, but prognosis may fluctuate from complete recovery to death due to complications of ischemic stroke or intracranial hemorrhage. Neuroradiological techniques such as digital angiography and MRI are helpful in the diagnostic pathway and a possible prognostic role of MRI has been suggested. This review will serve to summarize clinical, neuroradiological features and controversies underlying both syndromes that may mislead the diagnostic pathway and their possible relationship with pathophysiology, clinical course, and prognosis.

Childhood Posterior Reversible Encephalopathy Syndrome: Clinicoradiological Characteristics, Managements, and Outcome

Posterior reversible encephalopathy syndrome (PRES) is a novel clinicoradiological syndrome characterized by convulsions, headache, altered mentality, and impaired vision, which are usually accompanied by hypertension. As its nomination, PRES is usually diagnosed according to the presence of typical neuroimage showing vasogenic edema predominately involving the posterior brain area. With the widespread utilization of magnetic resonance imaging (MRI), PRES is becoming more perceptible in different medical fields. Compared to adult cases, childhood PRES seems to have a broader clinical and neuroradiological spectrum. PRES can be associated with various underlying comorbidities, medication use, and therapeutic modalities in children with diverse neurological manifestations. Moreover, pediatric patients with PRES have a more significant propensity for atypical MRI findings beyond the typically posterior cerebral areas. The knowledge of typical and atypical presentations in children is essential to avoid misdiagnosing or missing PRES, which is a potentially treatable entity. Early supportive care is the mainstay of treatment, with particular attention to the treatment of hypertension with rigorous attention to all body systems. Prompt identification and symptom-directed management are imperative to achieve a reversible prognosis in childhood PRES. Future studies specially designed for the child population are required to determine potential outcome predictors, and further, to develop novel strategies of neuroprotection in childhood PRES.

Childhood Posterior Reversible Encephalopathy Syndrome: Clinicoradiological Characteristics, Managements, and Outcome

Posterior reversible encephalopathy syndrome (PRES) is a novel clinicoradiological syndrome characterized by convulsions, headache, altered mentality, and impaired vision, which are usually accompanied by hypertension. As its nomination, PRES is usually diagnosed according to the presence of typical neuroimage showing vasogenic edema predominately involving the posterior brain area. With the widespread utilization of magnetic resonance imaging (MRI), PRES is becoming more perceptible in different medical fields. Compared to adult cases, childhood PRES seems to have a broader clinical and neuroradiological spectrum. PRES can be associated with various underlying comorbidities, medication use, and therapeutic modalities in children with diverse neurological manifestations. Moreover, pediatric patients with PRES have a more significant propensity for atypical MRI findings beyond the typically posterior cerebral areas. The knowledge of typical and atypical presentations in children is essential to avoid misdiagnosing or missing PRES, which is a potentially treatable entity. Early supportive care is the mainstay of treatment, with particular attention to the treatment of hypertension with rigorous attention to all body systems. Prompt identification and symptom-directed management are imperative to achieve a reversible prognosis in childhood PRES. Future studies specially designed for the child population are required to determine potential outcome predictors, and further, to develop novel strategies of neuroprotection in childhood PRES.

Posterior reversible encephalopathy syndrome

PURPOSE OF REVIEW

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological syndrome characterized by acute cerebral endotheliopathy with consecutive disruption of the blood-brain barrier and vasogenic edema. Since its first description in 1996, PRES is increasingly recognized. However, many aspects of this syndrome with its wide spectrum of clinical and radiological features are still incompletely understood. In this review, possible pathophysiological mechanisms, approaches to diagnosis, recent study results on outcome, and future directions of research are described.

RECENT FINDINGS

Clinical manifestations of PRES include seizures, headache, visual disturbances, altered mental state, and more rarely hemiparesis or aphasia. Vasogenic edema predominantly occurs in the parieto-occipital region, but lesions affecting formerly called 'atypical' regions such as frontal lobe, cerebellum, or basal ganglia are common. If treated early and adequately, that is by removal of the underlying cause, PRES has a favorable prognosis, but neurological residual symptoms and even mortality can occur, particularly in patients with complications such as intracranial hemorrhage.

SUMMARY

In summary, validated diagnostic criteria and algorithms are warranted to standardize the diagnosis of PRES. This is essential for further research and future prospective studies that should investigate risk factors for unfavorable outcome and identify the roles of imaging features, clinical symptoms, and other biomarkers in predicting outcome.

Acute radiological pattern and outcome in posterior reversible encephalopathy syndrome patients

OBJECTIVE

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder of acute or subacute onset characterized by varied neurological symptoms including headache, impaired visual acuity or visual field deficits, confusion, disorders of consciousness, seizures, and motor neurological deficits. Even if recognition of severe forms of PRES has improved, mainly due to magnetic resonance imaging, pathogenesis is still unclear and management of these patients remains challenging. Moreover, prognosis is unpredictable varying from complete recovery to death and factors related to prognosis are still lacking. We studied early magnetic resonance imaging characteristics and their relationships with prognosis.

PATIENTS AND METHODS

We performed a retrospective analysis in patients with clinical and neuroradiological charateristics of PRES performing magnetic resonance of the brain within 2 days of symptoms onset.

RESULTS

After reviewing site database of magnetic resonance imaging and clinical records compatible with PRES, 157 patients were selected. After imaging reviewing, 25 patients with clinical and neuroradiological diagnosis of PRES were enrolled, 22 (88%) females. Mean age of enrolled patients at presentation was 44.4+18.4 years (range, 21-84 years). Patients were classified according to neuroradiological characteristics such as ischemic lesions, distribution and severity of edema, hemorrhage and contrast enhancement. In our group 23 patients (92%) showed an almost complete recovery but 2 patients (8%) died during hospitalization. Outcome was significantly related with hypointensity on ADC (p = 0.002) and CE (p < 0.001).

CONCLUSION

Early MR features may be helpful in suggesting prognosis. Moreover, neuroimaging at the early stage of PRES may give new insights in pathophysiological mechanisms underlying brain damage and neurological impairment.

Posterior reversible encephalopathy syndrome with extensive cytotoxic edema after blood transfusion: a case report and literature review

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is described as a clinical-radiological disease entity with good prognosis. In brain MRI, PRES generally presents with vasogenic edema. Although PRES is induced by various causes, a small number of PRES cases have occurred after red cell blood transfusion. It is unclear whether there are characteristic features in PRES after blood transfusion.

CASE PRESENTATION

Here, we report a case of 75-year-old Japanese woman who had acute exacerbation of subacute anemia by bleeding from gastric ulcer. After receiving a red cell blood transfusion, she showed disturbance of consciousness with extensive cytotoxic and small vasogenic edema in the occipitoparietal area on brain MRI. She was diagnosed as PRES and suffered irreversible impairments of visual acuity and fields in both eyes. We summarized and discussed clinical features of cases with PRES after blood transfusion.

CONCLUSIONS

A total of 21 cases including the present one have been reported as PRES after blood transfusion. Of the cases, 20 of 21 were female, and 15 of 17 developed PRES in the course of chronic anemia lasting over 1 month. Anemia was severe in 15 of 20 cases, with hemoglobin levels < 3.5 g/dl. In 14 of 17 cases, hemoglobin levels increased to 5 g/dl by red cell blood transfusion until the onset of PRES. On brain MRI, 2 of 21 cases showed cytotoxic edema and 3 of 21 cases showed irreversible neurological disturbance. In this patient, the occurrence of PRES in subacute anemia and the presence of extensive cytotoxic brain edema with irreversible neurological deficits were characteristic points. When treating severe anemia, even with a subacute progression, we should consider a possibility that PRES occurs after blood transfusion with extensive cytotoxic brain edema and irreversible neurological changes.

Risk factors for poor outcome in posterior reversible encephalopathy syndrome: systematic review and meta-analysis

Background

The roles of clinical etiology and symptoms, imaging findings and biochemical parameters in predicting the prognosis of posterior reversible encephalopathy syndrome (PRES) have not been well-characterized. We perform a meta-analysis of all published studies to assess the value of various risk factors in predicting the prognosis of PRES.

Methods

Searches of the PubMed, EMBASE, Cochrane Library, and Web of Science databases were performed to identify the eligible studies. The odds ratios (ORs) with their corresponding 95% confidence interval (CI) for related risk factors were used to calculate the pooled estimates of the outcomes.

Results

Six studies with 448 cases were included in the meta-analysis. Hemorrhage was associated with high risk for poor outcome in patients with PRES. Toxemia of pregnancy (pre-eclampsia/eclampsia) was associated with improved outcome in PRES patients. Cytotoxic edema was noted to be related to poor outcome, but did not show statistical significance. The pooled OR for hemorrhage, pre-eclampsia/eclampsia, cytotoxic edema was 4.93 (95% CI: 3.94-6.17; P<0.00001), 0.24 (95% CI: 0.15-0.40; P<0.00001) and 2.59 (95% CI: 0.84-7.99; P=0.10), respectively.

Conclusions

PRES patients with hemorrhage or cytotoxic edema are likely to have poor outcomes. Pre-eclampsia/eclampsia is associated with reduced risk of poor outcome in patients with PRES.

Controversy of posterior reversible encephalopathy syndrome: what have we learnt in the last 20 years?

Over two decades have passed since posterior reversible encephalopathy syndrome (PRES) was first described in 1996. It has becoming increasingly recognised because of improved and more readily available imaging modality. The exact pathophysiological mechanism is not completely understood and remains controversial at present. Precise diagnosis is essential to guide prompt, proper management. Our ability of differentiating it from other acute neurological disorders is likely to improve as we learnt more about the spectrum of this entity in the last 20 years. We emphasise the importance of recognising its diagnostic criteria and biomarker, which would be of great relevance to either outcome evaluation or study design. PRES has a favourable prognosis generally, but neurological sequelae and even fatalities can occur, especially in severe forms that might cause substantial morbidity and even mortality, particularly when the syndrome is complicated by intracranial haemorrhage or brain infarction. In this review, the pathophysiology, approach to diagnosis, some controversies as to the prognosis, as well as the future research direction of PRES are described.

Anti-Angiogenic Tyrosine Kinase Inhibitors and Reversible Posterior Leukoencephalopathy Syndrome: Could Hypomagnesaemia Be the Trigger?

Reversible posterior leukoencephalopathy syndrome (RPLS), also known frequently as posterior reversible encephalopathy syndrome (PRES), is a characteristic acute neuro-radiology syndrome with clinical presentation that typically includes acute hypertension, seizures and other neurological symptoms and signs. Many patients with RPLS have (a history of) pre-existing hypertension and in receipt of diuretics. It is being diagnosed more frequently and in association with an increasing number of morbidities and medications. Drugs most frequently implicated are immunosuppressant drugs and anticancer agents, including a number of anti-angiogenic tyrosine kinase inhibitors (TKIs). Hypomagnesaemia is a frequent finding at presentation in RPLS patients, which is known to lead to or aggravate hypertension. Pre-eclampsia, a variant of RPLS, responds effectively to intravenous magnesium. Cyclosporin, tacrolimus and some TKIs that induce RPLS are also known to give rise to both hypertension and hypomagnesaemia. This raises an interesting hypothesis that hypomagnesaemia may play a contributory role in triggering RPLS in some patients by acutely raising the blood pressure further. Additional systematic studies are required to test this hypothesis. If the hypothesis is confirmed, hypomagnesaemia offers an effective target for risk mitigation and prevention of RPLS in patients identified at risk.

Importance of correctly interpreting magnetic resonance imaging to diagnose posterior reversible encephalopathy syndrome associated with HELLP syndrome: a case report

BACKGROUND

Severe haemolysis, elevated liver enzyme levels, and low platelet count (HELLP) syndrome in pregnancy are possible underlying trigger factors for posterior reversible encephalopathy syndrome (PRES). Magnetic resonance imaging (MRI) shows diffuse signal abnormalities involving the subcortical white matter in the parieto-occipital lobes. Although the diagnosis of RPES was clearly established by the distinctive reversibility of clinical and radiological abnormalities, it is difficult to distinguish from differential diagnosis. Thus, it is important to correctly interpret MRI.

CASE PRESENTATION

We describe a case of HELLP syndrome with PRES. A 38-year-old pregnant woman was admitted to our hospital as an emergency case with a complaint of upper abdominal pain and headache at 29 weeks of pregnancy and the development of HELLP syndrome. An emergency caesarean section was immediately performed. After the operation, the patient received intravenous corticosteroids, and her blood pressure was controlled. Thereafter, she showed an altered mental status. MRI showed hypersignal intense lesions in the cortical and subcortical white matter in the occipital lobes, basal ganglia and callosal splenium in both the fluid-attenuated inversion recovery (FLAIR) sequence and apparent diffusion coefficient (ADC), but these lesions were not recognized in diffusion-weighted imaging (DWI). These images were suggestive of PRES. The patient was kept in the hospital and received the appropriate treatment, after which the patient's level of consciousness improved and all laboratory tests and imaging examinations returned normal.

CONCLUSION

The MRI findings were useful for the prompt diagnosis of PRES, characterized by hypersignals in FLAIR and ADC, but not in DWI. Additionally, there was an "atypical" MRI appearance of basal ganglial and callosal splenial involvement in this case, which may mistakenly lead clinicians to diagnose other aetiologies than typical PRES. It is considered that vasogenic oedema is the main pathology of PRES according to the MRI image findings. MRI is the gold standard for diagnosing PRES because it can provide information about cerebral involvement earlier than CT; further, it can be a useful tool in the differential diagnosis. This technique facilitated the prompt diagnosis and treatment of the said patient, ultimately resulting in a good outcome.

Imaging characteristics associated with clinical outcomes in posterior reversible encephalopathy syndrome

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a disorder of cerebrovascular autoregulation that can result in brain edema, hemorrhage, and infarction. We sought to investigate whether certain imaging characteristics in PRES are associated with clinically significant patient outcomes.

METHODS

We retrospectively reviewed all cases of PRES occurring between 2008 and 2014 at two major academic medical centers. Demographic, clinical, and radiographic data were collected. We analyzed imaging studies for vasogenic edema, hemorrhage, and diffusion restriction. We performed univariate analysis and stepwise logistic regression to assess the association between our radiologic findings of interest and clinical outcomes as defined by hospital discharge disposition and modified Rankin scale (mRS) at time of discharge.

RESULTS

We identified 99 cases of PRES in 96 patients. The median age was 55 years (IQR 30-65) and 74% were women. In 99 cases, 60% of patients had active cancer, 19% had history of bone marrow or organ transplantation, 14% had autoimmune disease, and 8% were peripartum. Imaging at clinical presentation showed extensive vasogenic edema in 39%, hemorrhage in 36%, hemorrhage with mass effect in 7%, and restricted diffusion in 16%. In our final logistic regression models, the presence of extensive vasogenic edema, hemorrhage with mass effect, or diffusion restriction was associated with worse clinical outcome as defined by both discharge disposition (OR = 4.3; 95% CI: 1.4-36.3; p = 0.047) and mRS (OR = 3.6; 95% CI: 1.2-10.7; p = 0.019).

CONCLUSIONS

Extensive vasogenic edema, hemorrhage, and restricted diffusion on initial imaging in PRES are associated with worse clinical outcomes.