Blood-Brain Barrier Disruption as a Potential Target for Therapy in Posterior Reversible Encephalopathy Syndrome: Evidence From Multimodal MRI in Rats

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.

Posterior reversible encephalopathy syndrome and autoimmunity

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome characterized by acute or subacute onset of neurological symptoms (e.g., headache, seizure, confusion, vomiting, and diminished eyesight) and impaired endothelial barrier function of the cerebral circulation that leads to bilateral subcortical vasogenic edema, while exhibiting a "reversible" feature in most cases. Clinically, various predisposing or precipitating conditions have been identified, such as hypertension, autoimmune diseases, renal dysfunction/failure, preeclampsia/eclampsia, post-transplantation conditions, and certain therapeutic agents. Among several putative mechanisms, the immune activation hypothesis prevails, as up to 50% of patients with PRES harbor abnormalities related to autoimmunity, such as concurrent systemic lupus erythematosus. In this Review, we summarize the clinical and laboratory evidence that places PRES in the context of autoimmunity.

Autoimmune encephalitis with posterior reversible encephalopathy syndrome: A case report

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a neuroimaging-based syndrome and is associated with multifocal vasogenic cerebral edema. Patients with PRES frequently demonstrate headache, seizure, encephalopathy, altered mental function, visual loss and so on. We here report a patient who showed persistent neurologic deficits after PRES and was ultimately diagnosed with autoimmune encephalitis (AE).

CASE SUMMARY

This case exhibits a rare imaging manifestation of anti-casper 2 encephalitis which was initially well-matched with PRES and associated vasogenic edema.

CONCLUSION

AE should be further considered when the etiology, clinical manifestations, and course of PRES are atypical.

Posterior reversible encephalopathy syndrome: A neuropsychiatric manifestation of systemic lupus erythematosus

Posterior Reversible Encephalopathy Syndrome (PRES) is an acute neurological syndrome clinically characterized by seizures, altered mental status, headache, and visual disturbances. It is caused by a variety of abnormalities in the endothelial function that ultimately result in vasogenic edema in the circulation of the central nervous system. This is reflected by the neuroimaging findings, that most often show reversible parieto-occipital edema. An important proportion of patients with PRES present with Systemic Lupus Erythematosus (SLE), and its complications, as their sole risk factors. This review describes the relationship between these two clinical entities and explains the pathophysiological models that have been proposed to describe the development of PRES. We explain how SLE can cause alterations in every pathway implicated in the development of PRES. Given the relatively high frequency and the distinct clinical course, PRES in the setting of SLE might be best described as a distinct neuropsychiatric syndrome associated with SLE.

Clinical and MRI Features of Posterior Reversible Encephalopathy Syndrome With Atypical Regions: A Descriptive Study With a Large Sample Size

Background: Accurate diagnosis and timely treatment for posterior reversible encephalopathy syndrome (PRES) with atypical regions are very important in clinical practice. However, until now, little has been known about the clinical and MRI manifestations of this disease. Therefore, the aim of this study is to investigate the clinical and MRI features of PRES to promote clinical management and deepen our understanding of this disease. Materials and Methods: Data from six PRES patients with atypical regions were collected from our hospital. Data from another 550 cases were obtained by searching the PubMed, EMBASE and Web of Science databases with the keywords "posterior reversible encephalopathy syndrome" "PRES" "reversible posterior leukoencephalopathy" "RPLS" "hypertensive encephalopathy" "hyperperfusion encephalopathy" or "reversible posterior cerebral edema encephalopathy." The clinical and MRI features of these 556 cases were analyzed together. Results: A total of 305 patients were female, and 248 were male, with a median age of 34 years. The information on sex and age of three patients was not available. The most common symptom was headache (282/556, 50.7%), followed by altered mental status (243/556, 43.7%), seizures (233/556, 41.9%), visual disturbances (194/556, 34.9%), nausea/vomiting (130/556, 23.4%), and focal neurological deficits (101/556, 18.2%). Hypertension (425/556, 76.4%), renal diseases (152/556, 27.3%), immunosuppressant drugs (79/556, 14.2%), and chemotherapy/chemoradiotherapy (59/556, 10.6%) were the major predisposing factors. The atypical regions of the lesions were the cerebellum (331/556, 59.5%), basal ganglia (135/556, 24.3%), periventricular/deep white matter (125/556, 22.5%), pons (124/556, 22.3%), brainstem (115/556, 20.7%), thalamus (114/556, 20.5%), midbrain (48/556, 8.6%), spinal cord (33/556, 5.9%), and medulla (29/556, 5.2%). Additionally, the following typical regions were observed: occipital (278/556, 50.0%), parietal (234/556, 42.1%), frontal (150/556, 27.0%), and temporal (124/556, 22.3%) lobes. The major treatments were antihypertensives (358/515, 69.5%), antiepileptics/sedation (126/515, 24.5%), discontinuation/switching agents (67/515, 13.0%), and steroids (54/515, 10.5%). The median time of the clinical state improved and abnormal neuroimaging resolved is 2-3 weeks after appropriate treatment. Conclusion: The common symptoms of PRES with atypical regions include headaches, altered mental status, seizures, visual disturbances, nausea or vomiting, and focal neurological deficits. The frequent predisposing factors include hypertension, renal diseases, immunosuppressant drugs and chemotherapy/chemoradiotherapy. MRI features are mainly characterized by vasogenic edema in central zones always accompanied by typical regions. Most cases can be reversed in 2-3 weeks when promptly recognized and properly treated.

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.