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Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood-brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear., Methods: This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m 2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical., Results: The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2 cc) compared to those without renal insufficiency (110.5 ± 93.2 cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3 cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4 cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (β = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume., Conclusion: Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency., (© 2024. Fondazione Società Italiana di Neurologia.)

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., Competing Interests: Disclosures Dr Ehrmann discloses consultancies and research support from Aerogen Ltd, Fisher & Paykel Healthcare, and OpenAI for work outside the submitted article. Dr Salmon Gandonnière discloses consultancy from Sanofi, outside the scope of the submitted article. The other authors report no conflicts.

Meningeal lesions can be caused by various conditions and pose diagnostic challenges. The authors review the anatomy of the meninges in the brain and spinal cord to provide a better understanding of the localization and extension of these diseases and summarize the clinical and imaging features of various conditions that cause dural and/or leptomeningeal enhancing lesions. These conditions include infectious meningitis (bacterial, tuberculous, viral, and fungal), autoimmune diseases (vasculitis, connective tissue diseases, autoimmune meningoencephalitis, Vogt-Koyanagi-Harada disease, neuro-Behçet syndrome, Susac syndrome, and sarcoidosis), primary and secondary tumors (meningioma, diffuse leptomeningeal glioneuronal tumor, melanocytic tumors, and lymphoma), tumorlike diseases (histiocytosis and immunoglobulin G4-related diseases), medication-induced diseases (immune-related adverse effects and posterior reversible encephalopathy syndrome), and other conditions (spontaneous intracranial hypotension, amyloidosis, and moyamoya disease). Although meningeal lesions may manifest with nonspecific imaging findings, correct diagnosis is important because the treatment strategy varies among these diseases. © RSNA, 2023 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Background and aim: With an ever-increasing population of patients recovering form severe coronavirus disease 2019 (COVID-19), recognizing long-standing and delayed neurologic manifestations is crucial. Here, we present a patient developing posterior reversible encephalopathy syndrome (PRES) in the convalescence form severe coronavirus disease 2019 (COVID-19). Case presentation: A 61-year-old woman with severe (COVID-19) confirmed by nasopharyngeal real-time reverse transcription-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) required invasive mechanical ventilation 24-hours after admission. During her intensive care unit stay, she developed transient acute kidney injury and septic shock. She was extubated after 22 days. On day 25, she developed generalized tonic-clonic seizures. Magnetic resonance imaging (MRI) of the brain showed bilateral subcortical lesions on the parietal and occipital lobes and multiple micro-and macro-bleeds, consistent with PRES. At this point, RT-PCR for SARS-CoV-2 in a respiratory specimen and cerebrospinal fluid was negative. She was discharged home 35 days after admission on oral levetiracetam. Control MRI five months after discharge showed bilateral focal gliosis. On follow-up, she remains seizure-free on levetiracetam. Conclusions: PRES has been observed before as a neurological manifestation of acute COVID-19; to our knowledge, this is the first PRES case occurring in a hospitalized patient already recovered from COVID-19. A persistent proinflammatory/prothrombotic state triggered by SARS-CoV-2 infection may lead to long-standing endothelial dysfunction, resulting in delayed PRES in patients recovering from COVID-19. With a rapid and exponential increase in survivors of acute COVID-19, clinicians should be aware of delayed (post-acute) neurological damage, including PRES.

Posterior reversible encephalopathy syndrome (PRES) is an uncommon, subacute neurological disorder that presents radiologically with a pattern of bilateral parieto-occipital areas of vasogenic oedema. Conditions commonly associated with PRES include autoimmune disorders, cytotoxic drugs, metabolic abnormalities and, most frequently, hypertensive emergencies. Clinically, headache, visual disturbances, seizures and an altered level of consciousness are often reported. The outcome is favourable if the underlying cause is addressed. Posterior fossa involvement resulting in obstructive hydrocephalus is a rare presentation and may be misdiagnosed as a mass lesion or infection, leading to delayed or unnecessary treatment. We describe the clinical presentation, findings on neuroimaging and conservative management of a man with PRES resulting in severe cerebellar oedema and acute obstructive hydrocephalus. This case illustrates that awareness of atypical neuroimaging in PRES is important for the management of these patients and to avoid morbidity and mortality.

Reversible cerebral vasoconstriction syndrome (RCVS), is rare in the pediatric population and is characterized by severe headaches and other neurologic symptoms. We present a case of RCVS occurring concomitantly with posterior reversible encephalopathy syndrome in an 8-year-old African American child with sickle cell disease (HbSS). Imaging studies including computed tomography, magnetic resonance imaging and cerebral angiography of the brain showed acute hemorrhagic stroke and a beaded appearance of peripheral cerebral vessels. In this report, we focus on the typical features of RCVS and discuss the underlying risk factors that may increase the risk in patients with HbSS disease.

Serotonin syndrome (SS) is a drug-induced clinical syndrome, characterised by a triad of cognitive impairment, autonomic hyperactivity and neuromuscular abnormalities. Hypertension, one of the common autonomic manifestations in SS, may lead to lead to several life-threatening conditions. Herein, we report a case of SS who had posterior reversible encephalopathy syndrome (PRES) because of high blood pressure.A young male with a 5-month history of chronic tension-type headache and depression had been receiving amitriptyline and paroxetine. Increment of paroxetine led to the development of various new clinical features, fulfilling the Hunter criteria of SS. MRI brain revealed high-signal intensity lesions on T2 fluid-attenuated inversion recovery, and T2-weighted imaging in the posterior regions of the occipital, parietal, temporal and cerebellum lobes, suggestive of PRES. The patient responded to cyproheptadine. Autonomic hyperactivity, due to SS, is the most likely explanation of this association., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

We describe the case of a 63-year-old woman who developed a coronavirus disease 2019-associated acute encephalopathy with perivascular gadolinium enhancement., (© 2020 by American Journal of Neuroradiology.)

Background and Purpose: Children receiving chemotherapy, or immunosuppression have an increased risk for pediatric posterior reversible encephalopathy syndrome (pPRES); pPRES is scantly described in cerebral X-linked adrenoleukodystrophy (cALD) patients, for which hematopoietic stem cell transplantation improves outcomes. This study aimed to describe distinctive lesion patterns, distribution, and evolution of neuroimaging findings in PRES in a single-center pediatric cohort of cALD., Methods: We retrospectively identified all clinically acquired brain MRIs of children with cALD at a tertiary care university hospital between 1995 and 2020. We reviewed clinical features, conventional MRI, and diffusion-weighted imaging findings of patients with gray matter and white matter (WM) changes suggestive of concurrent PRES-cALD. Associations between the distinctive anatomic features, distribution, and abnormal signal intensity on MRI were examined with regard to the etiology and clinical outcome., Results: Our search revealed a series of eight pediatric cALD patients presenting with seizures, headache, or altered mental status with MRI findings suggestive of both PRES and cALD simultaneously. In each, the cortical-subcortical vasogenic edema on fluid-attenuated inversion recovery was consistent with pPRES, overlying the periventricular WM (PVWM) involvement typical of cALD. Of these 8 patients, the cortical-subcortical lesions on FLAIR were completely reversible on follow-up MRI in 7, but only partially reversible in 1., Conclusions: It is crucial to recognize that pPRES can occur in cALD, notably, the cortical edema and leptomeningeal enhancement can accelerate the diagnosis of superimposed pPRES, while the PVWM lesions of cALD remain following the resolution of pPRES., (© 2020 American Society of Neuroimaging.)

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.

Background: Reversible posterior leukoencephalopathy syndrome (RPLS) is a clinical-imaging syndrome as well as a critical maternal complication. The precise pathophysiological mechanism remains controversial, mostly due to the lack of a reliable experimental animal model. Because women with eclampsia almost always present with RPLS as a complication, we hypothesize that seizures induced by preeclampsia may lead to RPLS in rats., Methods: Pregnant Sprague-Dawley rats received pentylenetetrazol (PTZ, 40 mg/kg, intraperitoneal injection) after lipopolysaccharide (LPS, 1 µg/kg, tail vein injection) to induce eclampsia-like seizures. An anatomical view and brain water content were used to ascertain the success of the model. Moreover, blood pressure, serum biochemical indicators, serum and cerebrospinal fluid (CSF) inflammatory factors, neuroinflammation markers (Iba-1 for microglia and GFAP for astrocytes by immunofluorescence) and blood brain barrier (BBB) injury markers (VE-cadherin and ZO-1 protein by Western blotting) were measured to determine the possible mechanism., Results: The rat cerebral cortex was congested and oedematous, and water contents were significantly higher following LPS and PTZ treatments. Additionally, the BP, serum and CSF inflammatory factors and neuroinflammation markers were significantly elevated, while the expression levels of VE-cadherin and ZO-1 protein were significantly decreased by LPS and PTZ treatments., Conclusions: Excess inflammation may account for the phenotypes observed in this possible eclamptic RPLS rat model induced by LPS and PTZ, providing a better understanding of mechanism of RPLS. Specifically, excess inflammation leads to BBB dysfunction and subsequently results in fluid leakage that causes lesions and increases the entrance of inflammatory factors into the brain, thus increasing the neuronal excitability that triggers seizures., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Posterior reversible encephalopathy syndrome (PRES) is a clinically and radiologically diagnosed disorder distinguished by subcortical vasogenic cerebral edema. To date, its presentation has been described through summarized neurological categories, such as seizures, headaches, "confusion," and "altered mental function." This retrospective case series identified all cases of clinically confirmed, radiologically diagnosed PRES resulting in treatment in a large teaching hospital from 2010 to 2019. The authors conducted a search for the term "reversible encephalopathy" in the hospital clinical radiology information system, followed by an audit of scan reports and clinical records. The most common reasons for psychiatric referral were addictions, acute psychosis, depression, suicidality, and treatment refusal. Multidisciplinary staff should consider PRES as a rare, organic differential diagnosis for acute mental state changes. Physicians should be aware of elevated rates of post-PRES psychiatric symptoms and consider whether psychiatric consultation may enhance recovery.

A 25-year-old woman was admitted to our hospital due to tonic convulsion with severe headache after having experienced symptoms of nausea and vomiting for a month. Brain magnetic resonance imaging showed extensive symmetrical lesions in the cortical and subcortical areas of parieto-occipital lobes and basal ganglia, consistent with typical characteristics of posterior reversible encephalopathy syndrome (PRES). Furthermore, some residual lesions in the left side of dorsal medulla oblongata and central area of the cervical spinal cord along with the presence of serum anti-aquaporin-4 antibody yielded the diagnosis of neuromyelitis optica spectrum disorder (NMOSD). We herein discuss the mechanism by which PRES may occur together with NMOSD.

Among neurological complications associated with dengue, posterior reversible encephalopathy syndrome (PRES) has not been reported in pediatric population. We report a 10-year-old girl with severe dengue who developed PRES. The patient presented with hemorrhagic shock that required fluid resuscitation and inotropic support. She developed seizures with encephalopathy 2 days after recovering from the shock. Cerebrospinal fluid (CSF) examination was negative for dengue (no white blood cells in CSF with negative polymerase chain reaction for dengue). Her clinical features and magnetic resonance imaging (MRI) findings showed typical changes associated with posterior encephalopathy that reverted after resolution of hypertension. Repeat MRI after a month was normal. PRES should be considered as a possible differential diagnoses of dengue associated encephalopathy, especially in cases with normal CSF examination and characteristic MRI changes., (© The Author(s) [2019]. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background and Purpose: Focal signal abnormalities at the depth of the cerebellar fissures in children have recently been reported to represent a novel pattern of bottom-of-fissure dysplasia. We describe a series of patients with a similar distribution and appearance of cerebellar signal abnormality attributable to watershed injury., Materials and Methods: Twenty-three children with MR imaging findings of focal T2 prolongation in the cerebellar gray matter and immediate subjacent white matter at the depth of the fissures were included. MR imaging examinations were qualitatively analyzed for the characteristics and distribution of signal abnormality within posterior fossa structures, the presence and distribution of volume loss, the presence of abnormal contrast enhancement, and the presence and pattern of supratentorial injury., Results: T2 prolongation was observed at the depths of the cerebellar fissures bilaterally in all 23 patients, centered at the expected location of the deep cerebellar vascular borderzone. Diffusion restriction was associated with MR imaging performed during acute injury in 13/16 patients. Five of 23 patients had prior imaging, all demonstrating a normal cerebellum. The etiology of injury was hypoxic-ischemic injury in 17/23 patients, posterior reversible encephalopathy syndrome in 3/23 patients, and indeterminate in 3/23 patients. Twenty of 23 patients demonstrated an associated classic parasagittal watershed pattern of supratentorial cortical injury. Injury in the chronic phase was associated with relatively preserved gray matter volume in 8/15 patients, closely matching the published appearance of bottom-of-fissure dysplasia., Conclusions: In a series of patients with findings similar in appearance to the recently described bottom-of-fissure dysplasia, we have demonstrated a stereotyped pattern of injury attributable to cerebellar watershed injury., (© 2020 by American Journal of Neuroradiology.)

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state often characterized by altered mental state and is seen in various clinical settings. Although it is often reversible, it may result in long term sequelae. The typical and atypical neuroimaging findings seen in PRES have been previously well-described in the literature. However, the presence of other co-existing intracranial lesions along with PRES can occasionally confound the imaging findings and poses a diagnostic challenge. Herein, the authors report four cases of PRES with etiologically different co-existing intracranial lesions confounding the clinical and imaging manifestations. When presented with atypical imaging findings in PRES, the possibility of a co-existing intracranial pathology with superimposed imaging findings should be considered., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Atypical features of Posterior reversible encephalopathy syndrome (PRES) (diffusion restriction, involvement of corpus callosum & white matter tracts along posterior limbs of internal capsule) were seen in a patient after oxaliplatin administration (FOLFOX- 4 regimen). Findings were most obvious on diffusion weighted images, similar to acute methotrexate neurotoxicity, and resolved completely on follow up., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Hyponatraemia is one of the most frequent laboratory findings in hospitalised patients. We present an unusual case of hyponatraemia in a 23-year-old female secondary to acute intermittent porphyria (AIP), a rare inborn error of metabolism., Case Report: The patient presented with upper respiratory tract infection, fever, seizures and abdominal pain. An initial diagnosis of encephalitis was made. In view of the unexplained abdominal pain with other clinical findings such as posterior reversible encephalopathy syndrome by CT brain, temporary blindness as well as hyponatraemia, acute intermittent porphyria was suspected. Urine delta aminolaevulinic acid (δ-ALA) and porphobilinogen were elevated confirming the diagnosis of AIP. Genetic studies were done for this patient. The patient had a complete resolution of her symptoms with carbohydrate loading and high caloric diet., Conclusion: Although rare, AIP should be considered as a cause of hyponatraemia in a patient who presents with signs and/or symptoms that are characteristic of this disease.

Posterior reversible encephalopathy syndrome (PRES) is a reversible vasogenic brain edema in patients who present with seizure, headache, visual disturbance, and altered mental status, and a characteristic neuroimaging profile. Although PRES predominantly affects the bilateral parieto-occipital areas, involvement of the frontal and temporal lobes, basal ganglia, brainstem, and cerebellum is not uncommon. Isolated involvement of the brainstem and cerebellum sparing the parieto-occipital lobe is rarely reported. Here, we describe a 47-year-old man with end-stage renal disease on chronic hemodialysis who presented with prominent hypertension and coma after missing three dialysis sessions. On examination, there was paucity of focal neurologic signs. Diagnosis of PRES was based on brain magnetic resonance imaging findings that were consistent with vasogenic edema of the pons and cerebellum without involvement of other areas. With antihypertensive therapy and intense ultrafiltration during hemodialysis, the patient's blood pressure and consciousness returned to normal, along with complete resolution of the abnormal imaging findings. This case stresses that noncompliance with dialysis should be considered a risk factor for PRES. This case is considered relative to the available literature on three patients with brainstem variant of PRES., (© 2019 International Society for Hemodialysis.)

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological entity characterized by a typical brain edema. Its pathogenesis is still debated through hypoperfusion and hyperperfusion theories, which have many limitations. As PRES occurs almost exclusively in clinical situations with arginine vasopressin (AVP) hypersecretion, such as eclampsia and sepsis, we hypothesize that AVP plays a central pathophysiologic role. In this review, we discuss the genesis of PRES and its symptoms through this novel approach. We theorize that AVP axis stimulation precipitates PRES development through an increase in AVP secretion or AVP receptor density. Activation of vasopressin V 1 a receptors leads to cerebral vasoconstriction, causing endothelial dysfunction and cerebral ischemia. This promotes cytotoxic edema through hydromineral transglial flux dysfunction and may increase endothelial permeability, leading to subsequent vasogenic brain edema. If our hypothesis is confirmed, it opens new perspectives for better patient monitoring and therapies targeting the AVP axis in PRES.

Purpose: To explore the clinical and imaging characteristics and summarize the causes of missed diagnosis of reversible posterior leukoencephalopathy syndrome (RPLS) in eclampsia., Methods: We collected the data of a total of 45 patients with RPLS who were misdiagnosed initially (27 cases were confirmed and 18 cases were suspicious) out of 804 patients with severe eclampsia who had presented themselves to the Affiliated Hospital of Xuzhou Medical University from January 2014 to December 2016. We summarized the clinical and imaging characteristics of the patients and analyzed the possible causes of the misdiagnosis., Results: Among the 804 patients with eclampsia, 45 were misdiagnosed the first time. Their clinical manifestations included headache (20 cases), epilepsy (13 cases), blurred vision (11 cases), disturbance of consciousness (2 cases), and drowsiness (3 cases). The parietal lobe was involved in 22 cases, the occipital lobe in 15 cases, the frontal lobe in 20 cases, basal ganglia in 9 cases, and the temporal lobe in 8 cases. Low-density lesions were observed on computed tomography (CT) scans. Head magnetic resonance (MR) scans showed hypo-intense lesions on T1-weighted image (T1WI), hyper-intense lesions on the T2-weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR), iso-intense or slightly hyper-intense lesion on diffusion-weighted imaging (DWI), and slightly hyper-intense or hypo-intense lesion on apparent diffusion coefficient (ADC)., Conclusion: The incidence of reversible posterior leukoencephalopathy syndrome is extremely high. The clinical features include headache, mental disturbance, seizures, blurred vision, and other neurological symptoms. The lesion area is mainly limited to the parietal and occipital lobes; however, the frontal lobe, basal ganglia, temporal lobe, corpus callosum, and cerebellum can also be involved. The prognosis is good with timely and appropriate treatments.

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological syndrome, reversible vasogenic edema predominantly within parieto-occipital regions. However, isolated brainstem involvement in PRES has been rarely reported, little is known about its clinical manifestations, radiological features and outcomes. We reported a case with PRES with only brainstem involvement and performed a systematic review of published cases. Twenty-four cases, together with our case, were included in the analysis. Mean age was 43 years and 63% were males. Hypertension (50%), nephropathy (25%) and chemotherapy (21%) were the major risk factors. All patients except two had acute hypertension and 50% of patients had renal dysfunction at onset. The most common symptoms were altered consciousness (46%) and headache (46%), Seizure was only presented in 21% of patients. All patients except two were treated with antihypertension. Most patients recovered to their neurological baseline. Clinicians should recognize this unique variant finding in PRES. which always affects males with severe hypertension, especially combined with renal dysfunction. Antihypertensive treatment is the most widely used therapy. Outcome is usually well.

Background: Posterior Reversible Encephalopathy Syndrome (PRES) is a potentially reversible neurological disorder of acute to subacute onset characterized by headache, nausea and vomiting, visual disturbance, seizure and altered mental status. Neuroimaging findings are characteristic, which allow early diagnosis in the appropriate clinical setting and enable to institute appropriate therapy timely., Case Presentation: We report 3 adult patients with a history of hypertension presented with recurrent episode of seizure and altered mentation. While all the 3 patients were preliminarily diagnosed with Ischemic stroke, they were subsequently diagnosed with posterior reversible encephalopathy syndrome after neuroimaging revealed the typical features of the syndrome. They were started on antihypertensive and anticonvulsant drugs. On follow-up examination after 3-4 weeks, the patients showed marked clinical and neuro-imaging improvements., Conclusion: Posterior reversible encephalopathy syndrome is a rare condition. The presenting clinical symptoms are non-specific and may mimic other neurological disorders. Therefore, early recognition of classic radiographic features is vital to the diagnosis. Timely diagnosis and treatment of this syndrome is important as the treatment outcome is mostly favorable.

Stroke-prone spontaneously hypertensive rats (SHRSP) on high-salt diet are characterized by extremely high arterial pressures, and have been endorsed as a model for hypertensive small vessel disease and vascular cognitive impairment. However, rapidly developing malignant hypertension is a well-known cause of posterior reversible encephalopathy syndrome (PRES) in humans, associated with acute neurological deficits, seizures, vasogenic cerebral edema and microhemorrhages. In this study, we aimed to examine the overlap between human PRES and SHRSP on high-salt diet. In SHRSP, arterial blood pressure progressively increased after the onset of high-salt diet and seizure-like signs emerged within three to five weeks. MRI revealed progressive T2-hyperintense lesions suggestive of vasogenic edema predominantly in the cortical watershed and white matter regions. Histopathology confirmed severe blood-brain barrier disruption, white matter vacuolization and microbleeds that were more severe posteriorly. Hematological data suggested a thrombotic microangiopathy as a potential underlying mechanism. Unilateral common carotid artery occlusion protected the ipsilateral hemisphere from neuropathological abnormalities. Notably, all MRI and histopathological abnormalities were acutely reversible upon switching to regular diet and starting antihypertensive treatment. Altogether our data suggest that SHRSP on high-salt diet recapitulates the neurological, histopathological and imaging features of human PRES rather than chronic progressive small vessel disease.

Background: Posterior reversible encephalopathy syndrome (PRES) is a distinct entity with incompletely known predisposing factors. The aim of this study is to describe the incidence, risk factors, clinical course, and outcome of PRES in childhood acute lymphoblastic leukemia (ALL)., Procedure: Patients aged 1.0 to 17.9 years diagnosed with ALL from July 2008 to December 2015 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol were included. Patients with PRES were identified in the prospective NOPHO leukemia toxicity registry, and clinical data were collected from the medical records., Results: The study group included 1378 patients, of whom 52 met the criteria for PRES. The cumulative incidence of PRES at one month was 1.7% (95% CI, 1.1-2.5) and at one year 3.7% (95% CI, 2.9-4.9). Older age (hazard ratios [HR] for each one-year increase in age 1.1; 95% CI, 1.0-1.2, P = 0.001) and T-cell immunophenotype (HR, 2.9; 95% CI, 1.6-5.3, P = 0.0005) were associated with PRES. Central nervous system (CNS) involvement (odds ratios [OR] = 2.8; 95% CI, 1.2-6.5, P = 0.015) was associated with early PRES and high-risk block treatment (HR = 2.63; 95% CI, 1.1-6.4, P = 0.033) with late PRES. At follow-up of the PRES patients, seven patients had epilepsy and seven had neurocognitive difficulties., Conclusion: PRES is a neurotoxicity in the treatment of childhood ALL with both acute and long-term morbidity. Older age, T-cell leukemia, CNS involvement and high-risk block treatment are risk factors for PRES., (© 2018 Wiley Periodicals, Inc.)

Posterior reversible encephalopathy syndrome (PRES) is a cliniconeuroradiological syndrome characterised by a unique reversible pattern on imaging and total regression of clinical symptoms and signs. We describe an unusual case of PRES with isolated pontine involvement with coincidental acute ischaemic stroke in a 60-year-old man who presented with headache, unsteadiness of gait, blurred vision and elevated blood pressure. MRI scan revealed an expanded pons with diffuse T2 and Fluid attenuated Inversion Recovery (FLAIR) hyperintensities and an acute infarct in the right temporal lobe. A diagnosis of PRES was considered most likely after exclusion of other differentials and the patient was started on antihypertensive treatment as for hypertensive encephalopathy. He became asymptomatic after controlling blood pressure and the follow-up MRI scan at 3 weeks showed complete resolution of the pontine high signals which confirmed the diagnosis of PRES., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

We report here the case of a 80-year-old woman for the assessment of an acute confusional state since 2 days asssociated with diffuse and gradual headache. Brain MRI disclosed isolated hyperintense signal on fluid-attenuated inversion recovery sequence involving the medulla and the right inferior cerebellar peduncle with moderate swelling, consistent with vasogenic oedema, without abnormalities on diffusion-weighted imaging sequence. PRES diagnosis was suspected and antihypertensive therapy was introduced to achieve a blood pressure goal < 140/90 mmHg, allowing a quickly favourable clinical course. Three months later, brain MRI demonstrated a complete clearance of the abnormalities, confirming the PRES diagnosis. Atypical MRI findings are possible with involvement of basal ganglia, brainstem or cerebellum, but in these cases, oedema is most of the time accompanied by the classical parieto-occipital region involvement. Vasogenic oedema strictly unilateral or involving exclusively the brainstem or the cerebellum are very rare and should prompt suspicion for an alternative diagnosis. That constitutes a crucial diagnosis challenge in neurology.

There are multiple causes of neurotoxicity in children including medications, extrinsic toxins and insults, illicit drugs, built up of toxic metabolites due to genetic or acquired disorders, and metabolic abnormalities. The review is centered on causes of neurotoxicity affecting the pediatric brain and producing typical and easily recognized imaging manifestations. Early identification of common and less common imaging findings may point toward the correct direction, and may facilitate early diagnosis and institution of appropriate treatment to reverse or at least limit the injury to the developing brain. Two common imaging patterns of neurotoxicity in children are the posterior reversible encephalopathy syndrome and acute toxic leukoencephalopathy that are usually related to chemotherapy and immunosuppression for common pediatric malignancies. Another well-described imaging pattern of injury in children involves reversible splenial lesions with or without associated white matter abnormalities. Multiple additional extrinsic causes of neurotoxicity are presented including radiation and chemoradiation, various medications and treatment regimens, poisoning, illicit drug use or accidental exposure, and the respective characteristic neuroimaging findings are highlighted. Intrinsic neurotoxicity may occur in the setting of inborn errors of metabolism or acquired progressive organ failure leading to build up of toxic metabolites. Additional intrinsic causes of neurotoxicity include metabolic derangements and characteristic imaging findings in all instances are reviewed. The goal of the article is to enhance familiarity of neurologists and neuroradiologists with the imaging appearance of common and less common toxic insults to the pediatric brain., (© 2018 by the American Society of Neuroimaging.)

Background and Purpose: Posterior reversible encephalopathy syndrome (PRES) and acute toxic leukoencephalopathy (ATL) are both potentially reversible clinicoradiologic entities. Although their magnetic resonance imaging (MRI) findings differ, rarely both may occur simultaneously in acutely encephalopathic patients. Our aim was to determine the incidence and causes of concomitant "ATL-PRES.", Methods: Retrospective search of suspected acutely encephalopathic adults since 1998 throughout our picture archiving and communication system revealed 167 patients with PRES and 106 patients with ATL. Images of these patients were retrospectively evaluated by two neuroradiologists and a fellow to identify the cases which carry both features of PRES and ATL. Imaging findings were scored based on previously reported scoring system as mild, moderate, and severe. The clinical outcome of the patients was determined according to the modified Rankin scale., Results: Our search revealed a series of 6 patients (%2.2) in 273 patients who presented acutely with either encephalopathy or seizures, caused by various etiologies, including immunosuppression following transplantation (n = 2), hypertensive crisis (n = 2), chemotherapy (n = 1), and sepsis (n = 1). MRI demonstrated findings consistent with both PRES and ATL simultaneously on FLAIR and diffusion weighted imaging. Severity of imaging findings of concomitant "ATL-PRES" was concordant with each other (rho ≈ 1.0, P < .00001), and each patient eventually returned to clinical baseline. This finding, along with their similar etiologies, raises the possibility of an underlying common pathophysiologic thread, perhaps being endothelial toxicity., Conclusions: Concomitant "ATL-PRES" was found in 2.2% of the patients in a large cohort of ATL and PRES. Etiologies varied. Clinical symptoms and MRI findings were potentially reversible., (© 2018 by the American Society of Neuroimaging.)

Purpose: Posterior reversible encephalopathy syndrome (PRES) is associated with a range of medical conditions and medications. In this retrospective analysis, we present 19 pediatric patients with PRES who had undergone chemotherapy., Methods: We identified four female and 15 male patients diagnosed with PRES on the basis of clinical and radiologic features. Patient charts were reviewed from January 2013 to June 2016 after authorization from the institutional review board., Results: The average age of patients with PRES was 7 years. Primary diagnoses were non-Hodgkin lymphoma (n = 9), acute pre-B-cell leukemia (n = 5), relapsed pre-B-cell leukemia (n = 2), Hodgkin lymphoma (n = 2), and Ewing sarcoma (n = 1). PRES occurred during induction chemotherapy in 12 patients. Sixteen patients had hypertension when they developed PRES. Most of these patients (n = 13) were receiving corticosteroids on diagnosis of PRES. Common clinical features were hypertension, seizures, and altered mental status. With the exclusion of three patients, all others required antiepileptic therapy. Ten of these patients underwent additional magnetic resonance imaging. Ten patients are still alive., Conclusion: In patients who presented to our center with signs and symptoms of hypertension, seizures, visual loss, or altered mental status, PRES was mostly seen in those who were undergoing systemic and intrathecal chemotherapy. Approximately 40% of the patients had reversal of clinical and radiologic findings. Antiepileptic medications were discontinued after being seizure free for approximately 6 months.

Objective: The effect of blood pressure (BP) on the lesion distribution of posterior reversible encephalopathy syndrome (PRES) is controversial. The aim of this study was to identify the relationship between brain lesion distribution patterns and BP., Methods: Sixty-five patients with PRES were selected from the database. Data regarding brain MRI findings, clinical symptoms, medical conditions, and BP at the presymptomatic period (24 hr before the symptom onset) and at the symptom onset were collected. The brain lesion distribution degree was numerically calculated (lesion scoring point [LSP]) and compared with BP and medical conditions., Results: Mean onset-MAP was higher than mean pre-MAP. Pre-MAP correlated with onset-MAP. The LSP was significantly correlated with pre-MAP (p = 0.009, correlation coefficient [cc] = 0.323), whereas no significant correlation was found between LSP and onset-MAP (p = 0.159, cc = 0.177). Similarly, when patients were grouped by mean MAP values, LSP was significantly higher in the patients with high MAP at the presymptomatic period (p = 0.004), whereas no difference was found in the LSP value between patients with low MAP and high MAP at the symptom onset (p = 0.272)., Conclusion: The patient with PRES who has relatively higher BP in the presymptomatic period would be more likely to have wider lesion distribution than the patient with lower BP. BP elevation during presymptomatic period may be a heralding sign of impending PRES and a factor affecting the severity of PRES although BP was not investigated at earlier time points., (© 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.)

An uncommon side effect of cyclosporine A (CsA) use is posterior reversible encephalopathy syndrome (PRES). PRES usually develops because of disturbed capacity of posterior cerebral blood flow to autoregulate an acute rise in blood pressure. We present the case of a 10-year-old girl who was previously diagnosed in our department with focal segmental glomerulosclerosis. She was treated with CsA and developed seizures, progressive loss of consciousness, and visual disturbance on the 7th day of treatment. Brain magnetic resonance imaging showed degeneration of white matter with diffuse demyelination in the parietal and posterior occipital lobes, consistent with the diagnosis of PRES. Cases of PRES reported in children are usually secondary to immunosuppressive therapy in oncological and haematological diseases. Our case is the fifth reported case of focal segmental glomerulosclerosis in children treated with CsA and complicated by PRES. Rapid recognition of PRES and stopping neurotoxic therapy early are essential for a good prognosis.

Posterior reversible encephalopathy syndrome was described in 1996 as a clinical-neuroimaging entity characterized by parieto-occipital watershed-region edema without overt infarction. It has been linked to hypertension, eclampsia, immunosuppressive therapies, infections, and autoimmune disorders. The condition usually has an acute onset, presents with seizures, and ameliorates within days. There have been few neuropathological studies, but in some cases, tissue damage may be more permanent., (© 2017 American Association of Neuropathologists, Inc. All rights reserved.)

Posterior reversible encephalopathy syndrome (PRES) is characterized by the acute onset of neurologic symptoms (headache, altered mental status, visual changes, seizures) with accompanying vasogenic edema on brain imaging. Risk factors for PRES include infection, uremia, malignancy, autoimmune disorders, the peripartum state and hypertension. PRES is classically described as being posterior (i.e. parieto-occipital) but radiologic variants are increasingly recognized. This pictorial review demonstrates the heterogeneity of the different radiologic presentations of PRES in reference to lesion distribution, hemorrhage, diffusion restriction, contrast enhancement, and other associated findings., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Posterior reversible encephalopathy syndrome (PRES) has been described in the context of uncontrolled hypertension, eclampsia, renal disease and autoimmune conditions, or in patients treated with chemotherapy or immunosuppressive agents. In contrast, we report the occurrence of PRES in a patient with untreated metastatic transitional cell carcinoma. The case emphasizes important diagnostic challenges associated with atypical presentations without "typical" risk factors and the limitations of common diagnostic imaging modalities. It highlights the ability of nonmalignant conditions like PRES to mimic brain metastases and the importance of magnetic resonance imaging as a diagnostic tool. A high index of suspicion is warranted in atypical presentations, as prompt treatment is imperative to ensure full neurological recovery., (© 2016 John Wiley & Sons Australia, Ltd.)

Spinal cord involvement (SCI) is a rare feature of posterior reversible encephalopathy syndrome (PRES), especially in children. SCI is generally symptomatic, and may have a different outcome compared with encephalic localization of PRES. We reported about two cases of SCI in pediatric patients with PRES, after multimodal anticancer therapies, including radiotherapy, chemotherapy and targeted agents.

Background: Posterior reversible encephalopathy syndrome (PRES) is associated with variable predisposing risk factors including preeclampsia and eclampsia since it proposed. However, studies of large case series focusing on pregnancy-related PRES are still limited. We performed a large retrospective study of patients with pregnancy-related PRES admitted to our institution., Methods: This was a single-center, 2010-2015 retrospective cohort study of patients with pregnancy-related PRES who underwent neuroimaging via magnetic resonance imaging or computerized tomography from mainland China., Results: 26 of 28 women with eclampsia and 7 of 59 women with preeclampsia had confirmed PRES. A total of 36 patients were finally included as confirmed pregnancy-related PRES in this research. Acute hypertension was present in 31 patients (86%). Headache was the most common presenting symptom (81%) followed by seizures (73%), altered mental status (57%), nausea/vomiting (47%) and visual disturbance (33%). Atypical involved regions included frontal lobe (72%), temporal lobe (67%), basal ganglia (50%), cerebellum (47%), brain stem (14%) and thalamus (8%). Atypical neuroimaging features included restricted diffusion (33%), contrast enhancement (19%) and hemorrhage (19%). Comorbidities included thrombocytopenia (25%), pulmonary infection (25%), anemia (19%), fever (17%), acute renal failure (8%), HELLP syndrome (6%), DIC (6%). Most of patients recovered completely with timely diagnosis and treatment. Two patients who suffered DIC finally died., Conclusions: Patients with pregnancy-related PRES may present with atypical neuroimaging findings. Moreover, our data supported the view that nearly all imaged patients with eclampsia had clinical and radiologic findings of PRES.

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare cerebrovascular disorder affecting large- and medium-sized arteries, occurring most commonly in young women. Thunderclap headache is the usual primary symptom; seizure is uncommon. During the postpartum period, seizure is a significant concern. The main causes of postpartum seizures are posterior reversible encephalopathy syndrome and cortical venous thrombosis; RCVS-related postpartum seizure is rare. Despite its rarity, its course may be fulminant, resulting in permanent disability or death if the diagnosis is delayed and treatment is not started promptly. We report an unusual case of RCVS presenting as a subarachnoid hemorrhage in a 31-year-old woman admitted for postpartum seizure., (Copyright © 2016 Elsevier Inc. All rights reserved.)