Serial MR Spectroscopy in Relapsing Reversible Posterior Leukoencephalopathy Syndrome

Pediatric Posterior Reversible Encephalopathy Syndrome: A Review With Emphasis on Neuroimaging Characteristics

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder characterized by the sudden onset of seizures, headaches, and visual disturbances. Its exact cause is unknown, but several triggers and associated conditions are identified, including high blood pressure, kidney dysfunction, and various medications. Magnetic resonance imaging (MRI) plays a crucial role in diagnosis due to its high sensitivity and specificity for detecting characteristic features. Pediatric PRES exhibit age-dependent differences in triggers, radiological findings, and clinical course. The lesions typically involve the posterior cortical and subcortical white matter, but atypical locations and features are also observed. While generally reversible with appropriate treatment, PRES carries a risk of permanent neurological damage. Despite increasing cases, the current literature on pediatric PRES remains limited. This review highlights the need for further research to understand the mechanisms, delineate distinct clinical and radiological features, and develop precise diagnostic and management strategies for pediatric patients.

Posterior Reversible Encephalopathy Syndrome (PRES): Pathophysiology and Neuro-Imaging

Posterior reversible encephalopathy syndrome (PRES) represents a unique clinical entity with non-specific clinical symptoms and unique neuroradiological findings. This syndrome may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury. In this article, we will review the clinical, typical, and atypical radiological features of PRES, as well as the most common theories behind the pathophysiology of PRES. Additionally, we will discuss some of the treatment strategies for PRES related to the underlying disease state.

Advanced Imaging Techniques in Diagnosis of Posterior Reversible Encephalopathy Syndrome (PRES)

Diagnosis of Posterior Reversible Encephalopathy Syndrome (PRES) in some circumstances can be challenging and structural imaging may not be sufficient to distinguish it from other differential diagnostic considerations. Advanced imaging techniques, such as MR spectroscopy or positron emission tomography (PET) can provide additional information to determine the diagnosis. Other techniques, such as susceptibility weighted imaging (SWI) improves detection of hemorrhage which has prognostic role. CT or MR Perfusion as well as Single-Photon Emission Computed Tomography (SPECT) are more useful to understand the underlying vasculopathic changes in PRES and may answer some of the unresolved controversies in pathophysiology of this complex disease. In this review we summarized the findings of previous studies using these advanced methods and their utilities in diagnosis or prognosis of PRES.

Fishing in muddy waters- co-existing dual intracranial pathology in PRES: A case series and review of literature

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.

Posterior reversible encephalopathy syndrome and association with systemic lupus erythematosus

Introduction

Posterior reversible encephalopathy syndrome (PRES) is a neurological complex disorder with many clinical associations and causative factors. It is important to recognize this condition because early diagnosis and treatment usually result in its complete resolution, radiological imaging becoming the key for the correct diagnosis.

Methods

We retrospectively reviewed charts and magnetic resonance imaging findings in the University of Campinas from January 2005 to July 2015, selecting three cases of patients with systemic lupus erythematosus syndrome who developed PRES, for whom risk factors, characteristics, magnetic resonance imaging findings and neurological resolution were analyzed. We also conducted a review of the English-language literature.

Results

The three cases had neurological symptoms like acute onset of headache, altered mental status, cortical blindness and seizures. Brain magnetic resonance imaging demonstrated posterior cortical and white matter alterations involving posterior brain territories, which were more conspicuous on T2-weighted and fluid-attenuated inversion recovery . Spectroscopy, diffusion-weighted imaging and susceptibility-weighted imaging were also important for neuroradiological evaluation. Immunosuppressive drugs were taken in all cases. Partial clinical and radiological recovery was observed in two cases, and complete resolution was observed in the third patient.

Literature review

We found 52 cases of PRES in systemic lupus erythematosus patients. Almost all patients were women 94%, ranging from 8 to 62 years old. Posterior brain territory involvements were found in 98% of patients. Hemorrhagic complications involved 26% of patients, becoming a risk factor for clinical sequels. The total percentage of patients with no complete resolution of radiological findings on follow-up images was 27.5%.

Discussion

In patients with autoimmune disorders, endothelial dysfunction may occur secondary to autoimmunity and the use of cytotoxic drugs, supposedly facilitating the occurrence of more severe PRES. The hypothesis that patients with autoimmune diseases have a propensity to develop non-reversible lesions has been raised.

Atypical presentation of posterior reversible encephalopathy syndrome: Clinical and radiological characteristics in eclamptic patients

Posterior reversible encephalopathy syndrome (PRES) is an obstetric emergency frequently occurring in a pregnant or puerperal woman, manifested with an acute headache, consciousness impairment, seizures, and visual deficits and is associated with white matter changes predominantly affecting the posterior parietal and occipital lobes of the brain. Apart from the above-described typical location of the changes, the most common atypical location involves the brain stem and basal ganglia. Since magnetic resonance imaging (MRI) is more sensitive and specific imaging technique compared to computerized tomography, establishing the diagnosis and follow-up in patients with PRES is based mainly on MRI findings. It is particularly important not to exclude PRES as a possible diagnosis when we have the appropriate clinical presentation accompanied by the atypical radiological findings, since this clinical-radiological syndrome can often be manifested with an atypical MRI image.

Good outcome after posterior reversible encephalopathy syndrome (PRES) despite elevated cerebral lactate: a case report

Posterior reversible encephalopathy syndrome (PRES) may cause irreversible brain damage. The diagnosis is confirmed by magnetic resonance imaging (MRI), where vasogenic edema may be seen especially in the posterior parts of the brain. MR spectroscopy (MRS) may be included to help predict the outcome by measuring selected metabolites for instance lactate. Usually lactate is immeasurable in brain tissue, but elevates in cases of hypoxia, and it has been associated with poor outcome. We report a case of a patient with eclampsia and PRES, who had elevated lactate initially, but complete remission clinically and on MRI.

Delayed leukoencephalopathy after acute carbon monoxide intoxication

Delayed leukoencephalopathy is an uncommon complication of hypoxic-ischemic events of different etiologies, including carbon monoxide intoxication. We present a case of a 40-year-old male patient who was admitted with rapidly progressive neurocognitive and behavioral deficits. There was a history of accidental carbon monoxide intoxication one month before, presenting with loss of consciousness and short hospitalization, followed by a complete clinical recovery. The imaging studies in the delayed phase depicted confluent, symmetric supra-tentorial white matter lesions in keeping with diffuse demyelinization. Restricted diffusion and metabolite abnormalities in magnetic resonance proton spectroscopy were also seen. The diagnosis of CO-mediated delayed post-hypoxic leukoencephalopathy was assumed after exclusion of other mimickers. Hyperbaric oxygen therapy was tentatively performed and the patient had a favorable clinical and radiological evolution.

Posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is characterized by headache, altered mental status, visual disturbances, and seizures. Radiological features typically include edema of the posterior cerebral regions, especially of the parietooccipital lobes. Atypical imaging features, such as involvement of anterior cerebral regions, deep white matter, and the brain stem are also frequently seen. Vasoconstriction is common in vascular imaging. Different conditions have been associated with PRES, but toxemia of pregnancy, solid organ or bone marrow transplantation, immunosuppressive treatment, cancer chemotherapy, autoimmune diseases, and hypertension are most commonly described. The pathophysiology of PRES is unclear and different hypotheses are being discussed. Posterior reversible encephalopathy syndrome is best managed by monitoring and treatment in the setting of a neurointensive care unit. The prognosis is usually benign with complete reversal of clinical symptoms within several days, when adequate treatment is immediately initiated. Treatment of severe hypertension, seizures, and withdrawal of causative agents represent the hallmarks of specific therapy in PRES. Delay in diagnosis and treatment may lead to permanent neurological sequelae. Therefore, awareness of PRES is of crucial importance for the intensivist.