Posterior reversible encephalopathy syndrome (PRES): Features on CT and MR imaging

Consciousness disturbance in patients with chronic kidney disease: Rare but potentially treatable complication. Clinical and neuroradiological review

In patients with chronic kidney disease, particularly those in end-stage kidney failure and undergoing dialysis treatment, brain complications may arise, and their potential reversibility mainly hinges on timely diagnosis and intervention. Neurological symptoms may be non-specific ranging from slight or pronounced consciousness disturbance till coma, and imaging is the main tool to guide diagnosis and may reveal the underlying pathophysiological mechanism. Kidney impairment, causing a surge in blood pressure, increases the risk of Posterior Reversible Encephalopathy Syndrome and, leads to neurochemical alterations that result in uremic encephalopathy. In end-stage kidney failure patients, Posterior Reversible Encephalopathy Syndrome predominantly occurs in atypical locations, often involving the bilateral basal ganglia, and exhibit larger volumes compared to patients without kidney dysfunction. Uremic encephalopathy may involve the basal ganglia, white matter, and cortical or subcortical regions; in the latter case, imaging features resemble the typical location of Posterior Reversible Encephalopathy Syndrome. Dialysis Disequilibrium Syndrome, Osmotic Demyelination Syndrome, and Wernicke's encephalopathy are uncommon complications associated with dialysis. Each syndrome manifests distinct imaging patterns: Dialysis Disequilibrium Syndrome shows bilateral, patchy, diffuse white matter alterations; Osmotic Demyelination Syndrome causes central pontine and less often extrapontine lesions (involving bilateral basal ganglia, thalamus, and cerebral peduncles); Wernicke's encephalopathy determines symmetrical abnormalities in the thalamus, mammillary bodies, periaqueductal gray matter, midbrain tectal plate but the nature of brain edema associated with these complications remains controversial. Besides, in rare cases, overlapping imaging features may occur, and only the accurate patient's clinical history reconstruction along with laboratory examination results can lead to a better evaluation of MRI findings and underlying causes allowing prompt therapy.

Persistent Vegetative State Following a Cardiac Arrest in a Patient With Preeclampsia and Posterior Reversible Encephalopathy Syndrome: A Case Report

We report the case of a 35-year-old female patient who presented to a tertiary referral hospital in a persistent vegetative state (PVS) following a cardiac arrest that occurred approximately one hour after an elective cesarean delivery for a postterm pregnancy complicated by preeclampsia. Magnetic resonance imaging (MRI) of the brain performed seven days after the cardiac arrest showed findings consistent with posterior reversible encephalopathy syndrome (PRES). Following transfer to our hospital, the patient was carefully evaluated, stabilized, and successfully weaned off mechanical ventilation. However, due to the lack of neurological recovery, the decision was made to transfer her to a neurorehabilitation center for further management. This case report explores the potential link between PRES and PVS.

[Posterior reversible encephalopathy syndrome in autoimmune disorders]

Posterior reversible encephalopathy syndrome (PRES) is characterized by nonspecific symptoms, including not only pronounced non-focal and various focal neurological signs but also specific neuroimaging features, including vasogenic edema affecting predominantly the posterior area. PRES usually develops in the setting of acute arterial hypertension. However, it is not uncommon for PRES to develop in non-hypertensive patients, including people with autoimmune disorders (multiple sclerosis, neuromyelitis optica spectrum disorder, etc). PRES could also be due to the toxic effects of drugs or other substances. The pathophysiological mechanisms of PRES include impaired autoregulation of cerebral blood flow due to acute arterial hypertension and toxic endotheliotropic effects of endogenous and exogenous factors.

Posterior reversible encephalopathy syndrome in children with malignancies - a single-center retrospective study

Background

Posterior reversible encephalopathy syndrome (PRES) diagnosis relies on clinical and radiological characteristics. Clinical manifestations include focal neurologic deficits, hemiparesis, seizures with symptoms of intracranial hypertension, headache, nausea, vomiting, and visual field disturbances. The majority of patients have typical changes in magnetic resonance imaging. The epidemiology and outcomes of PRES in the pediatric cancer population have not been well described. Most of the available data are from retrospective analyses.

Objective

The aim of our study was to evaluate the clinical and radiological presentation as well as the outcome of PRES in children treated for cancers in a single center.

Methods

We analyzed data from 1,053 patients diagnosed with malignancies in a single center over 15 years to determine the incidence of PRES.

Results

19/1053 (1.8%) patients developed PRES. The diagnosis was accompanied by a range of clinical symptoms including hypertension, seizures, altered mental status, and headaches. Magnetic resonance imaging was performed in all patients, and 14/19 (73.7%) exhibited typical findings consistent with PRES. Four patients (21.0%) required treatment in the Intensive Care Unit.

Conclusion

Posterior reversible encephalopathy syndrome (PRES) is a rare but significant complication in children with cancer.There is a clear need to establish clinical criteria for PRES to improve the diagnosis and treatment of patients with PRES, particularly in the pediatric oncological population.Further studies are needed to identify the risk factors for recurrent PRES, particularly in pediatric cancer patients undergoing chemotherapy or immunosuppressive treatment.

A Case of Reversible Posterior Leukoencephalopathy Syndrome (PRES) With a History of Migraine and Onset With Initial Visual Aura and Migraine-Like Headache, With a Significant Response to Lasmiditan: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a neurological disease that presents with various neurological symptoms and is often accompanied by elevated blood pressure at onset. Neuroimaging, especially magnetic resonance imaging (MRI), often shows a characteristic parieto-occipital pattern with a symmetrical distribution of changes, reflecting vasogenic edema. Hypertension and endothelial cell damage are the most common causes of PRES. An association between migraine and endothelial cell damage has been suggested, but the relationship between migraine and PRES is unknown. Reports on PRES triggered by migraines are scarce. We report a case of PRES in a 59-year-old woman with migraine without aura. At the onset, the patient experienced a first-ever visual aura and a migraine-like headache. In this case, it was also difficult to distinguish between PRES headache and headache caused by a pre-existing migraine; however, lasmiditan, an acute migraine treatment without vasoconstrictive properties, was remarkably effective for headaches.

Posterior reversible encephalopathy syndrome following uneventful clipping of an unruptured intracranial aneurysm: A case report

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is characterized mainly by occipital and parietal lobe involvement, which can be reversible within a few days. Herein, we report a rare case of PRES that developed after craniotomy for an unruptured intracranial aneurysm (UIA).

CASE SUMMARY

A 59-year-old man underwent clipping surgery for the treatment of UIA arising from the left middle cerebral artery. Clipping surgery was performed uneventfully, and he regained consciousness quickly immediately after the surgery. At the 4th hour after surgery, he developed a disorder of consciousness and aphasia. Magnetic resonance imaging revealed cortical and subcortical T2/FLAIR hyperintensities in the parietal, occipital, and frontal lobes ipsilaterally, without restricted diffusion, consistent with unilateral PRES. With conservative treatment, his symptoms and radiological findings almost completely disappeared within weeks. In our case, the important causative factor of PRES was suspected to be a sudden increase in cerebral perfusion pressure associated with temporary M1 occlusion.

CONCLUSION

Our unique case highlights that, to our knowledge, this is the second report of PRES developing after craniotomy for the treatment of UIA. Surgeons must keep PRES in mind as one of the causes of perioperative neurological abnormality following clipping of an UIA.

Posterior Reversible Encephalopathy Syndrome: Incidence and Clinical Characteristics in Children With Cancer

The etiology and outcomes of posterior reversible encephalopathy syndrome (PRES) in children with cancer are not well understood. We aim to determine the incidence of PRES, describe associated morbidity and mortality, and better understand risk factors in this patient population. A total of 473 children with a hematologic malignancy or postallogeneic hematopoietic cell transplantation between June 2015 and June 2020 were screened for PRES to determine incidence and whether age or underlying diagnosis are associated with development of PRES. We conducted a case-control study to evaluate whether comorbidities or chemotherapeutic agents are associated with PRES. Children with PRES were matched with 2 controls based on age and underlying diagnosis to identify additional risk factors. Fourteen patients developed PRES, with an incidence of 5.9/1000 people/year. Those diagnosed with PRES had commonly described PRES symptoms: hypertension, seizures, nausea/vomiting, altered mental status, and headaches. All patients received an magnetic resonance imaging, and most had findings consistent with PRES. Hematopoietic cell transplantation was associated with the development of PRES. The use of Etoposide was associated with PRES but comorbidities, steroids and calcineurin inhibitors were not. While PRES was infrequent in this population, it is associated with high morbidity and mortality, with ICU admissions and an overall hospital mortality, because of secondary causes, of 29%.

IgA nephropathy with posterior reversible encephalopathy with spinal cord involvement in a young male: A case report

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological phenomenon commonly associated with kidney diseases, especially chronic kidney disease. A consequence of endothelial dysfunction, PRES is usually associated with uncontrolled blood pressures and can rarely have atypical radiological findings involving the brain stem and spinal cord, called posterior reversible encephalopathy with spinal cord involvement (PRES-SCI). These atypical features may be confused with other etiologies causing a delay in diagnosis and management. We describe a young male patient who presented with neurological symptoms suggestive of PRES; however, the atypical radiological findings along with concomitant rapidly progressive glomerulonephritis led to a diagnostic dilemma. Repeat neuro-imaging after appropriate blood pressure control showed disappearance of the lesions confirming the diagnosis of PRES-SCI, and kidney biopsy showed advanced IgA nephropathy. Knowledge of atypical features of PRES is crucial amongst nephrologists as it is a common association with kidney disease and prompt identification and management avoid irreversible sequelae and unnecessary investigations.

Initial Normotensive Presentation of a Primigravida With Posterior Reversible Encephalopathy Syndrome: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological entity characterized by variable neurological manifestations, primarily caused by pathophysiological changes related to cerebral autoregulation that result in radiologically evident vasogenic edema. It is usually associated with hypertensive states, but it is not exclusively related to those. 

A healthy 18-year-old primigravid woman with no proteinuria or hypertension on admission presented with normotensive PRES. She had an intense diffuse headache that preceded a generalized tonic-clonic seizure. Her neurological status deteriorated, and hypertension was detected afterward. Brain imaging revealed bilateral vasogenic edema in the occipital region. Magnesium sulfate and antihypertensive medications were administered. A cesarean section was performed, and her neurological symptoms subsequently improved, leading to discharge with no complications. 

This case highlights the importance of suspecting PRES in pregnant patients even in the absence of preeclampsia.

The association of posterior reversible encephalopathy syndrome with COVID-19: A systematic review

The rise in Coronavirus disease 2019 (COVID-19) cases is revealing its unique neurological manifestations. In light of the emerging evidence, a possible association with Posterior Reversible Encephalopathy Syndrome (PRES) is being consistently reported. We conducted a systematic literature search on four databases namely Pubmed/MEDLINE, Cochrane, Google Scholar, and Science Direct. After rigorous screening as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a total of 34 articles describing 56 cases were selected as a part of this review. The mean age of the patients was 56.6 ± 15.3 years. The most common clinical presentation of PRES was altered mental status (58.9%) followed by seizures (46.4%) and visual disturbances (23.2%) while hypertension and diabetes mellitus were the most commonly reported comorbidities. 91.1% of the cases reported Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) findings suggestive of PRES in the brain. Symptomatic management was employed in most of the cases to control seizures and blood pressure, and 44 patients (78.5%) fully or partially recovered. The most likely underlying mechanism involves COVID-19 mediated cytokine storm syndrome that leads to endothelial damage and increased permeability of the cerebral vessels, thus causing the characteristic edema of PRES. High neuronal and glial cell expression of Angiotensin Converting Enzyme-2 (ACE-2) receptors also suggests the possibility of direct viral damage. Since timely diagnosis and treatment reports a good prognosis, it is vital for physicians and neurologists to be well-versed with this association.

Influenza A (H1N1)-Associated Acute Necrotizing Encephalopathy with Unusual Posterior Reversible Encephalopathy Syndrome in a Child

Other than respiratory symptoms, influenza A (H1N1) can rarely cause neurological complications in children and adults. In this article, we aimed to present H1N1-associated acute necrotizing encephalopathy (ANE) and asymmetrical involvement of posterior reversible encephalopathy syndrome (PRES) in a 30-month-old male patient with clinical and radiological imaging findings. The patient who presented to the hospital with febrile convulsion and lethargy had elevated liver enzymes and coagulopathy. The magnetic resonance (MR) examination revealed diffusion restriction in bilateral cerebellar white matter, thalami, and periventricular white matter which was consistent with ANE. Susceptibility-weighted imaging (SWI) sequence showed hemorrhage in bilateral thalami and cerebellar white matter. There was high signal on fluid-attenuated inversion recovery (FLAIR) sequences in right temporooccipital cortical, subcortical, and periventricular white matter suggestive of PRES. MR angiography showed vasculopathy which is supportive for PRES. This is the second case of H1N1-associated pediatric PRES reported in the literature.

Posterior Reversible Encephalopathy Syndrome Induced by an Acute Postinfectious Glomerulonephritis

Posterior reversible encephalopathy (PRES) is a rare but a serious disease that affects the central nervous system. PRES is responsible for various but nonspecific neurological symptoms, including confusion, coma, and seizures as well as visual disturbances. Diagnosis is made using cerebral MRI which typically shows at the early stage, bilateral symmetrical parietooccipital hyperintensities on T2 and fluid-attenuated inversion recovery (FLAIR) sequences. Case study. In this article, we base our research on a case study that includes, as a population sample, a 9-year-old boy who suffers from an acute postinfectious glomerulonephritis and arterial hypertension. Two days before diagnosis, he developed confusion with generalized tonic-clonic attacks. His blood pressure was 180/80 mmHg. A cerebral computed tomography made in emergency showed cerebral edema. It was supplemented by magnetic resonance imaging which revealed cortical and posterior cortical lesions which appear as hypointense on T1 and hyperintense on T2 and Flair. An MRI control was performed 40 days later which shows a clear improvement of the occipital lesions. PRES is a radioclinical syndrome characterized by the association of variable neurological signs which reversibility is conditioned by the early diagnosis and the correction of the contributing factors.

Neuropathophysiology of preeclampsia and eclampsia: A review of cerebral hemodynamic principles in hypertensive disorders of pregnancy

Preeclampsia and eclampsia are hypertensive disorders of pregnancy associated with abnormal placental vascular development. The systemic angiogenic imbalance, endothelial dysfunction and proinflammatory state caused by abnormal placental development results in abnormalities in renal, hepatic, pulmonary and neurologic function. Neurosensory symptoms related to pregnancy induced hypertension (PIH), the most devastating of which are intracranial hemorrhage and seizure, are among the leading causes of maternal and perinatal morbidity and mortality globally, yet risk stratification strategies and targeted therapies remain elusive. Current treatment for preeclampsia with severe features is limited to delivery, antihypertensive therapy, and magnesium sulfate seizure prophylaxis. Magnesium sulfate reduces seizure rates among severe preeclamptics, but predisposes patients to weakness, uterine atony, pulmonary edema and respiratory depression. Therefore, this drug should ideally be administered only to the subset of preeclamptics who are at increased risk for neurologic complications. While there are no objective methods validated to predict eclampsia, we hypothesize that measurement of optic nerve sheath diameters, optic disc height and middle cerebral artery transcranial doppler resistance indices may be useful in identifying subclinical cerebral edema, potentially allowing us to recognize those patients at highest risk for seizures. This summary of the current literature provides an initial framework for developing more sophisticated and noninvasive methods for identifying, monitoring and treating parturients who are at highest risk for neurologic complications from preeclampsia.

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.

Seizures after percutaneous endoscopic lumbar discectomy: A case report

RATIONALE

Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive technique for removing nucleus pulposus and achieving neural decompression via a posterolateral approach. PELD is known to have a very low rate of complications during the perioperative period. Although quite rare, seizures can occur in patients undergoing PELD.

PATIENT CONCERNS

A 58-year-old man with severe low back pain underwent the PELD procedure under general anesthesia. During the recovery phase after general anesthesia, the patient developed a tonic-clonic seizure. Two additional episodes occurred subsequently.

DIAGNOSES

Bilateral disc swelling indirectly supports the diagnosis of intracranial hypertension.

INTERVENTIONS

Midazolam and propofol were administered to control seizures. 1.0 g phenobarbital sodium was administered by intravenous injection. Ten milligrams of furosemide and 250 mL of mannitol (20%) were prescribed sequentially. Two hundred milligrams of hydrocortisone and an ice bag were used to protect the brain. Urapidil, metoprolol, and nicardipine were intermittently used to control his blood pressure. A sustained release of sodium valproate was administered and continued prophylactically for 4 weeks.

OUTCOMES

No further seizures were recorded and the patient recovered well.

LESSONS

We conclude that total volume of fluid used for irrigation was considered a possible cause of seizure. This case illustrates the fact that irrigation should be performed cautiously in PELD procedure. And anesthesiologists should be familiar with the management strategies of perioperative acute seizures.

[Posterior reversible encephalopathy syndrome as a presentation of acute intermittent porphyria]

The authors describe a clinical case of posterior reversible encephalopathy syndrome (PRES) in a 36-year-old female patient due to the first onset of not previously diagnosed acute intermittent porphyria. Only 22 clinical and radiological cases of the combination of PRES and acute porphyria were reported in the literature by 2018. This is the first report of a similar association confirmed by magnetic resonance imaging (MRI) in the Russian literature. The article describes the dynamics of the disease from unexplained abdominal pain to repeated epileptic paroxysms and subsequent formation of a detailed picture of encephalo- and polyneuropathy. The particularities of neurological presentations, the significance of epileptic paroxysms and MRI in the diagnosis of the abovementioned combined pathology are shown. Possible mechanisms causing both pathological processes are considered.

Posterior reversible encephalopathy syndrome in acute pancreatitis: a rare stroke mimic

We report a 71-year-old woman who presented with Posterior Reversible Encephalopathy Syndrome (PRES) in the setting of acute pancreatitis. On day 3 of her admission, she developed transient right-sided upper and lower limb weakness, reduced visual acuity and encephalopathy, initially regarded as an acute stroke. Brain MRI fluid-attenuated inversion recovery (FLAIR) T2 imaging performed the same day confirmed occipital and parietal hyperdensities consistent with PRES. Her blood pressure never exceeded 150/75 mm Hg throughout the course of the admission. Our case demonstrates PRES in the setting of acute pancreatitis with only a relatively moderate elevation in blood pressure. In order to prevent unnecessary intervention in the setting of presumed acute stroke, it is important to consider the potential differential diagnoses including PRES as rare masquerade of acute stroke or transient ischaemic attack.

Posterior Reversible Encephalopathy Syndrome after Allogeneic Stem Cell Transplantation in Pediatric Patients with Fanconi Anemia, a Prospective Study

Posterior reversible encephalopathy syndrome (PRES) is one of the most common neurologic complications following hematopoietic stem cell transplantation (HSCT). We aimed to evaluate the incidence, clinical, and imaging features of PRES in pediatric patients with Fanconi anemia (FA) following HSCT. This prospective study included all post-HSCT patients with underlying FA disease between 2014 and 2017. Brain computed tomography scan and magnetic resonance imaging (MRI) were performed in all individuals who developed neurologic symptoms. PRES was diagnosed based on clinic-radiological evidence. Follow-up MRI was performed in all patients with PRES within two months. Forty-one patients with FA (28 males; mean age, 8.19 ± 3.25 years) were enrolled. Out of 15 patients with acute neurologic symptoms, PRES was diagnosed in 9 individuals (21.95% of the total cohort). The occurrence of PRES was significantly higher in patients who had a donor with a 1-locus mismatch (P= .02). Donor relation, stem cell source, and graft-versus-host disease grade did not have any significant association with the development of PRES. MRI showed asymmetric vasogenic edema in 5 patients, an overt infarct in 1 patient, and foci of microhemorrhages in 3 patients, 1 of whom developed a hemorrhagic infarct. This patient died shortly, and persistent microhemorrhages were noted in the other 2 patients. Our findings demonstrate a greater risk of developing PRES after HSCT in patients with FA compared with those with other diseases (21.95% versus 1% to 10%), and in contrast to its term, it might be irreversible and has adverse effects on HSCT outcomes. The increased vascular and endothelial fragility in FA may contribute to the higher frequency of PRES in these individuals.

Pressing Issues in COVID-19: Probable Cause to Seize SARS-CoV-2 for Its Preferential Involvement of Posterior Circulation Manifesting as Severe Posterior Reversible Encephalopathy Syndrome and Posterior Strokes

Since December 2019, a novel Severe Acute Respiratory Syndrome coronavirus 2 from China has rapidly spread worldwide. Although respiratory involvement is the mainstay of coronavirus disease 2019 (COVID-19), systemic involvement has recently drawn more attention. In particular, a number of recent articles have shed light on the nervous system as one of the possible targets. At our institution, we observed 15 patients with acute brain vascular manifestations; most interesting, we had a higher prevalence of the posterior circulation acute impairment. In our series, 7 patients had acute posterior cerebral injury: 1, hemorrhagic posterior reversible encephalopathy syndrome; 5, posterior circulation ischemic stroke; and 1, parieto-occipital hemorrhagic stroke. On the basis of our evidence and previous basic science reports, we believe a common etiopathogenetic thread may connect ischemic/hemorrhagic events of the posterior circulation and posterior reversible encephalopathy syndrome in the setting of COVID-19.

Posterior Reversible Encephalopathy Syndrome After Transsphenoidal Resection of Pituitary Macroadenoma

BACKGROUND

Posterior reversible encephalopathy syndrome is manifested by a reversible neurologic deficit such as vision loss, encephalopathy, and a posterior location, typically the occipital lobes. It is commonly thought to be related to acute, severe hypertension.

CASE DESCRIPTION

A 51-year-old woman presented with visual loss for several months, and a suprasellar mass was diagnosed. She underwent transsphenoidal surgery, which was complicated by cerebrospinal fluid leak, and she developed posterior reversible encephalopathy syndrome while undergoing postoperative cerebrospinal fluid drainage via lumbar catheter. Her visual acuity progressed to blindness, but blindness was reversed by discontinuation of lumbar drainage, tight blood pressure control, and high-dose steroid drip.

CONCLUSIONS

To our knowledge, this is only the second case of posterior reversible encephalopathy syndrome following transsphenoidal surgery to be reported in the neurosurgical or ophthalmic English language literature.

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.

Cerebral microvascular and microstructural integrity is regionally altered in patients with systemic lupus erythematosus

Background

To measure regional brain microvascular and microstructural changes in childhood-onset SLE (cSLE) using diffusion-weighted imaging (DWI) at multiple b values and investigate relationships of those measures with neurocognitive function and disease activity.

Methods

In this cross-sectional, case-control study, vascular volume fraction, effective diffusion, parenchymal diffusion, and blood flow parameters were regionally compared in cSLE patients and matched healthy controls. These markers of microvascular and microstructural integrity were derived by diffusion-weighted brain MRI and intravoxel incoherent motion (IVIM) modeling. Formal neurocognitive testing was completed focused on the domains of attention, visuoconstructional ability, working memory, and psychomotor speed. Test scores and measures of disease severity were regressed against regional microvascular integrity parameters among cSLE patients.

Results

Formal cognitive testing confirmed normal cognitive ability among all cSLE patients included in the analysis (n = 11). Nevertheless, reduction in blood volume fraction coincided with increased effective diffusion and flow parameters in cSLE patients vs. controls in posterior brain regions including the cuneus and precuneus. Regional microvascular measures correlated (|r| = 0.54–0.66) with neuropsychiatric scores and disease activity among cSLE patients.

Conclusions

There is imaging evidence, using IVIM, of degraded microvascular integrity in cSLE patients with normal cognitive ability. The observed regional changes correspond with posterior vascular border zones. These outcomes appear consistent with regional gray matter volume loss previously observed in cSLE patients with overt neurocognitive deficits, supporting the notion that adverse vascular changes precede loss of cognitive ability in cSLE. Longitudinal studies are needed to confirm the findings of this initial study.

A PRESing case of visual changes and confusion

Visual disturbances are an uncommon pediatric chief complaint. Usually, after a complete ocular exam including visual acuity, most causes are benign and not life-threatening. Children with abnormal visual complaints who have underlying medical conditions, such as SLE or other autoimmune conditions, a recipient of a transplant, renal disease, and even eclampsia require closer scrutiny. We report a 10-year-old female with a history of systemic lupus erythematosus complicated by hypertension and cardiomyopathy secondary to lupus who presented to the emergency department with a history of vision loss and headache. Head computer tomography demonstrated findings of posterior reversible encephalopathy syndrome (PRES). PRES is a clinical disease associated with cranial radiological findings of heterogenous etiologies that is often reversible. Prompt recognition and treatment are important in preventing permanent damage, long term morbidity and even death.

[Posterior reversible encephalopathy syndrome: a case report]

L'encéphalopathie postérieure réversible (EPR) est une entité radio-clinique associant une atteinte réversible du système nerveux central à une imagerie encéphalique typique. Il existe une grande variabilité dans la présentation clinique de ce syndrome et des aspects en imagerie parfois atypiques. L'EPR est une complication neurologique inhabituelle survenant au cours de la grossesse ou en post-partum, en dehors de toute pathologie préexistante de la grossesse dont l'œdème vasogénique par rupture de la barrière hémato encéphalique paraît être l'acteur principal. Nous rapportons l'observation d'une patiente primipare présentant des crises convulsives généralisées tonico-cloniques associées à un pic hypertensif, survenant au cours du troisième trimestre de grossesse. L'imagerie par résonance magnétique (IRM) cérébrale était en faveur d'une encéphalopathie postérieure réversible. L'EPR doit être évoqué devant tout signe d'appel neurologique, vu l'évolution favorable sans séquelles sous un traitement précoce et rapide.

Posterior Reversible Encephalopathy Syndrome Presenting with Atypical Findings: Report of Two Cases

Background

Posterior reversible encephalopathy syndrome (PRES) is characterized by a variable association of symptoms including headache, consciousness impairment, visual disturbances, seizures, and focal neurological signs. Treating the underlying cause usually leads to partial or complete resolution of symptoms within days or weeks. Brain MRI findings include hyperintensities on T2-weighted sequences and their reversibility on follow-up exams. We describe two patients, one with an atypical clinical presentation characterized by a severe and prolonged impairment of consciousness and the other with atypical neuroimaging findings.

Case Presentation

The first patient was a 42-year-old woman, with a negative medical history, presenting with seizures, lethargy, and left hemiparesis, 60 hours after uncomplicated delivery. Brain MRI showed an atypical pattern of alterations, with patchy asymmetric distribution in all lobes. Symptoms completely resolved after twelve days. The second patient was a 59-year-old woman with a history of hypertension, presenting with severe impairment of consciousness, vision loss, and seizures. Symptoms partially resolved after three weeks.

Conclusion

PRES is characterized by reversible symptoms and radiological findings. Brain MRI usually shows widespread oedema in white matter with typical patterns. The cases we described suggest that PRES may presents with atypical symptoms and radiological manifestations, mimicking other neurological conditions.

Posterior reversible encephalopathy syndrome in HIV-positive patients: a case report and literature review

We are reporting the case of a woman who was admitted acutely to our intensive care unit without any collateral history. She was diagnosed with posterior reversible encephalopathy syndrome (PRES) as a consequence of poor adherence to anti-hypertensive, anti-diabetic and anti-retroviral medications. PRES is a rare condition, which may cause cortical blindness; contrary to its name it is not always reversible. Rapid diagnosis and aggressive management of underlying causes facilitate reversibility of PRES. We also summarise the literature on patients with HIV and PRES.

Posterior reversible encephalopathy syndrome in an HIV-infected patient on antiretroviral treatment: what is the risk factor?

Posterior reversible encephalopathy syndrome (PRES) is a rare but well-described syndrome associated with a high morbidity and a substantial mortality. We present an illustrative case of an HIV-infected but virologically suppressed patient who complained of visual impairment accompanied by severe headache and epileptic seizures. The cerebral CT scan and the follow-up cranial MRI confirmed the diagnosis of PRES. Unlike the cases of HIV-infected patients with PRES published so far, our patient suffered neither from advanced immunodeficiency nor from opportunistic infection or from any other evident predisposing factor. This case highlights that the absence of classical risk factors does not exclude the diagnosis of PRES. We discuss the hypothesis that in accordance with the new pathophysiological theory, persistent HIV-associated cerebrovascular reactivity in combination with endothelial dysfunction may represent an undetected risk factor for the development of PRES in virologically and immunologically stable patients.

Recurrent Occipital Seizures with Transient MRI Changes

Peri-ictal magnetic resonance imaging (MRI) findings following seizure activity are a recognized phenomenon that is not well understood (Cole, 2004). Transient changes are not usually expected to be present in postictal MRI studies because of their rarity. Here, we present a unique case of peri-ictal MRI findings located in the occipital lobe, present in a 34-year-old female with recurrent occipital seizures occurring twice in four years. MRI changes completely resolved after both episodes with no residual focal damage. The peri-ictal occipital changes on MRI in this patient are unique because they have been captured on more than one occasion. Peri-ictal MRI findings are a known phenomenon with unknown pathophysiology, although attempts have been made to understand these findings. Though the MRI findings and presentation appear to be stroke-like or PRES-like, seizures should be kept in the differential for better treatment outcomes.

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.

A Simplified Approach to Encephalitis and Its Mimics: Key Clinical Decision Points in the Setting of Specific Imaging Abnormalities

RATIONALE AND OBJECTIVES

Infectious encephalitis is a relatively common cause of morbidity and mortality. Treatment of infectious encephalitis with antiviral medication can be highly effective when administered promptly. Clinical mimics of encephalitis arise from a broad range of pathologic processes, including toxic, metabolic, neoplastic, autoimmune, and cardiovascular etiologies. These mimics need to be rapidly differentiated from infectious encephalitis to appropriately manage the correct etiology; however, the many overlapping signs of these various entities present a challenge to accurate diagnosis. A systematic approach that considers both the clinical manifestations and the imaging findings of infectious encephalitis and its mimics can contribute to more accurate and timely diagnosis.

MATERIALS AND METHODS

Following an institutional review board approval, a health insurance portability and accountability act (HIPAA)-compliant search of our institutional imaging database (teaching files) was conducted to generate a list of adult and pediatric patients who presented between January 1, 1995 and October 10, 2013 for imaging to evaluate possible cases of encephalitis. Pertinent medical records, including clinical notes as well as surgical and pathology reports, were reviewed and correlated with imaging findings. Clinical and imaging findings were combined to generate useful flowcharts designed to assist in distinguishing infectious encephalitis from its mimics. Key imaging features were reviewed and were placed in the context of the provided flowcharts.

RESULTS

Four flowcharts were presented based on the primary anatomic site of imaging abnormality: group 1: temporal lobe; group 2: cerebral cortex; group 3: deep gray matter; and group 4: white matter. An approach that combines features on clinical presentation was then detailed. Imaging examples were used to demonstrate similarities and key differences.

CONCLUSIONS

Early recognition of infectious encephalitis is critical, but can be quite complex due to diverse pathologies and overlapping features. Synthesis of both the clinical and imaging features of infectious encephalitis and its mimics is critical to a timely and accurate diagnosis. The use of the flowcharts presented in this article can further enable both clinicians and radiologists to more confidently differentiate encephalitis from its mimics and improve patient care.

An Unusual Complication following Ventriculoperitoneal Shunting

We present the case of a ten-year old boy diagnosed with a rare syndrome as a complication of a commonly performed Neurosurgical procedure. To our knowledge this association has not been described in the literature and we discuss the plausible aetiology.

Transient increase of fractional anisotropy in reversible vasogenic edema

Brain vasogenic edema, involving disruption of the blood-brain barrier, is a common pathological condition in several neurological diseases, with a heterogeneous prognosis. It is sometimes reversible, as in posterior reversible encephalopathy syndrome, but often irreversible and our current clinical tools are insufficient to reveal its reversibility. Here, we show that increased fractional anisotropy in magnetic resonance imaging is associated with the reversibility of vasogenic edema. Spontaneously, hypertensive rats-stroke prone demonstrated posterior reversible encephalopathy syndrome-like acute encephalopathy in response to high-dose cyclosporine A treatment; the deteriorating neurological symptoms and worsening scores in behavioral tests, which were seen in acute phase, dissappered after recovery by cessation of cyclosporine A. In the acute phase of encephalopathy, the fractional anisotropy and apparent diffusion coefficient increased in areas with IgG leakage. This increase of fractional anisotropy occurred in the absence of demyelination: fluid leakage into the myelinated space increased the axial, but not the radial, diffusivity, resulting in the increased fractional anisotropy. This increased fractional anisotropy returned to pre-encephalopathy values in the recovery phase. Our results highlight the importance of the fractional anisotropy increase as a marker for the reversibility of brain edema, which can delineate the brain areas for which recovery is possible.

Posterior reversible encephalopathy syndrome following pembrolizumab therapy for relapsed Hodgkin’s lymphoma

Posterior reversible encephalopathy syndrome (PRES) is characterized by a group of central nervous system related symptoms. Diagnosis is usually made by computed tomography or magnetic resonance imaging. Common causes can be arterial hypertension, sepsis, autoimmune disorders, and medications. We report PRES in a relapsed Hodgkin’s Lymphoma patient after a dose of pembrolizumab.

Posterior reversible encephalopathy syndrome (PRES): a rare condition after resection of posterior fossa tumors: two new cases and review of the literature

INTRODUCTION

In 1996, Hinchey and colleagues coined the term "Posterior reversible encephalopathy syndrome" (PRES) to describe a condition seen in patients with acute neurological symptoms and reversible subcortical vasogenic edema predominantly involving parieto-occipital areas demonstrated in brain MRI. The occurrence of this phenomenon after surgical resection of CNS tumors is typically linked to pediatric cases.

MATERIAL AND METHODS

Two new cases of PRES after posterior fossa surgery are reported. A thorough review of the literature is carried out with the purpose of updating and summarizing the main features regarding PRES in similar cases. Seven cases of PRES after resection of a posterior fossa tumor have been hitherto reported (4 patients were <20 years old). There is another pediatric case described after a ventriculoperitoneal shunting procedure in a patient with fourth ventricle ependymoma. Two resected tumors were ependymomas, 2 hemangiopericytomas in one patient, 1 pilocyticastrocytoma, 1 vestibular schwannoma, and 1 of the reported cases did not describe the final pathology diagnosis.

CASE REPORTS

We present 2 new cases of PRES after surgical resection of a posterior fossa tumor (medulloblastoma in case 1 and ependymoma in case 2) in pediatric patients. Case 1 developed delayed seizures and altered mental status(10 days after surgical resection) after receiving treatment with bromocriptine for cerebellar mutism. Case 2 presented with generalized seizures and altered mental status within the first 48 postoperative hours followed by right hemiparesis. Both patients fully recovered and returned to neurological baseline status. A thorough review of the literature was carried out with the purpose of updating and summarizing the main features regarding PRES in similar cases.

CONCLUSIONS

We report 2 new pediatric cases of posterior reversible encephalopathy syndrome (PRES) that developed after surgical resection of a posterior fossa tumor. Appropriate management includes supportive measures, antihypertensive agents, and antiepileptic drugs, if needed. Full recovery is the most likely outcome in line with previous articles.

Distinguishing Neuroimaging Features in Patients Presenting with Visual Hallucinations

Visual hallucinations are relatively uncommon presentations in medical and psychiatric clinics, where they are generally regarded as a marker of possible underlying "organic" brain disease. Thus, patients with visual hallucinations are often referred for imaging of the brain. This article presents a pragmatic approach for the radiologist reviewing such imaging. Because conditions that can present with visual hallucinations are legion, a familiarity with the features of the hallucinations themselves, which can serve as clues to the underlying cause, can be helpful in interpreting such cases. We consider the nature of visual hallucinations and the mechanisms underlying their formation. We then provide a framework to guide the search for their cause, first in terms of focal lesions along the visual pathway and then global conditions affecting >1 region.

Clinical outcomes and risk factors for posterior reversible encephalopathy syndrome in systemic lupus erythematosus: a multicentric case-control study

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a well-known but rare complication in patients (<1%) with systemic lupus erythematosus (SLE). However, current epidemiological data are quite scant. The aim of the present study was to describe potentially unrecognised risk factors.

PATIENTS AND METHODS

We performed a multicentre, retrospective case-control study in Mexico between 1999 and 2014. We included a total of 168 patients who accounted for 77 episodes of PRES, as follows: SLE/PRES, 43 patients with 48 episodes; SLE without PRES, 96 patients; and PRES without SLE, 29 patients. SLE diagnosis was considered when patients fulfilled ≥4 American College of Rheumatology criteria. PRES was defined by reversible neurological manifestations and MRI changes.

RESULTS

Patients with SLE/PRES were younger, presented with seizures as the most common manifestation (81%) and 18% had the typical occipital MRI finding. Hypertension (OR=16.3, 95% CI 4.03 to 65.8), renal dysfunction (OR=6.65, 95% CI 1.24 to 35.6), lymphopenia (OR=5.76, 95% CI 1.36 to 24.4), Systemic Lupus Erythematosus Activity Index ≥ 6 points (OR=1.11, 95% CI 1.01 to 1.22) and younger age (OR=0.86, 95% CI 0.81 to 0.91, p<0.001) were independent risk factors for development of PRES in SLE. Furthermore, dyslipidemia also characterised the association between PRES and SLE (OR=10.6, 95% CI 1.17 to 96.4).

CONCLUSIONS

This is the largest reported series of patients with SLE and PRES. We were able to corroborate the known risk factors for of PRES, and found two previously undescribed factors (lymphopenia and dyslipidemia), which suggests that endothelial dysfunction is a key element in PRES pathogenesis in lupus patients.

Clinical implications of the cortical hyperintensity belt sign in fluid-attenuated inversion recovery images after bypass surgery for moyamoya disease

OBJECTIVE Transient neurological symptoms are frequently observed during the early postoperative period after direct bypass surgery for moyamoya disease. Abnormal signal changes in the cerebral cortex can be seen in postoperative MR images. The purpose of this study was to reveal the radiological features of the "cortical hyperintensity belt (CHB) sign" in postoperative FLAIR images and to verify its relationship to transient neurological events (TNEs) and regional cerebral blood flow (rCBF). METHODS A total of 141 hemispheres in 107 consecutive patients with moyamoya disease who had undergone direct bypass surgery were analyzed. In all cases, FLAIR images were obtained during postoperative days (PODs) 1-3 and during the chronic period (3.2 ± 1.13 months after surgery). The CHB sign was defined as an intraparenchymal high-intensity signal within the cortex of the surgically treated hemisphere with no infarction or hemorrhage present. The territory of the middle cerebral artery was divided into anterior and posterior parts, with the extent of the CHB sign in each part scored as 0 for none; 1 for presence in less than half of the part; and 2 for presence in more than half of the part. The sum of these scores provided the CHB score (0-4). TNEs were defined as reversible neurological deficits detected both objectively and subjectively. The rCBF was measured with SPECT using N-isopropyl-p-[¹²³I]iodoamphetamine before surgery and during PODs 1-3. The rCBF increase ratio was calculated by comparing the pre- and postoperative count activity. RESULTS Cortical hyperintensity belt signs were detected in 112 cases (79.4%) and all disappeared during the chronic period. Although all bypass grafts were anastomosed to the anterior part of the middle cerebral artery territory, CHB signs were much more pronounced in the posterior part (p < 0.0001). TNEs were observed in 86 cases (61.0%). Patients with TNEs showed significantly higher CHB scores than those without (2.31 ± 0.13 vs 1.24 ± 0.16, p < 0.0001). The CHB score, on the other hand, showed no relationship with the rCBF increase ratio (p = 0.775). In addition, the rCBF increase ratio did not differ between those patients with TNEs and those without (1.15 ± 0.033 vs 1.16 ± 0.037, p = 0.978). CONCLUSIONS The findings strongly suggest that the presence of the CHB sign during PODs 1-3 can be a predictor of TNEs after bypass surgery for moyamoya disease. On the other hand, presence of this sign appears to have no direct relationship with the postoperative local hyperperfusion phenomenon. Vasogenic edema can be hypothesized as the pathophysiology of the CHB sign, because the sign was transient and never accompanied by infarction in the present series.

Does this patient have hypertensive encephalopathy?

A 63-year-old man was admitted to our hospital for further investigation and management of brain metastases. The patient was initially presented with a 4-day history of confusion. On the day of admission, the patient was confused, agitated, disorientated in place and time, and had visual disturbances. His blood pressure was repeatedly recorded high, with levels of systolic blood pressure between 170-210 mm Hg. A brain magnetic resonance imaging showed areas of high signal on T2 and fluid-attenuated inversion recovery images, located bilaterally in the white matter of the occipital regions and unilateral in the left frontal lobe, suggestive of posterior reversible encephalopathy syndrome. Aggressive treatment of hypertension resulted in complete resolution of the clinical and radiologic features of the syndrome.

Posterior Reversible Encephalopathy Syndrome in a Patient with Severe Uremia without Hypertension

A 28-year-old man was admitted to our hospital with nausea, headache and weakness of the left hand. He had severe uremia without hypertension due to recurrent/chronic pyelonephritis. Brain magnetic resonance imaging showed reversible vasogenic edema in the brainstem and bilateral frontal centrum semiovale. All of his neurological symptoms immediately improved after the introduction of hemodialysis. When a patient with uremia presents with neurological symptoms, posterior reversible encephalopathy syndrome should be considered in the differential diagnosis even if high blood pressure is not observed. Brain magnetic resonance imaging may be helpful in such a case, and an appropriate therapy could be subsequently initiated.

Posterior Reversible Encephalopathy Syndrome After Transplantation: a Review

Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disease. Recently, an increase in the number of transplantations has led to more cases being associated with PRES than what was previously reported. Calcineurin inhibitors (CNIs) are major risk factors for PRES in posttransplantation patients. The mechanisms of the development of PRES remain to be unclear. The typical clinical symptoms of PRES include seizures, acute encephalopathy syndrome, and visual symptoms. The hyperintense signal on fluid-attenuated inversion recovery image is the characteristic of the imaging appearance in these patients. In addition, other abnormal signals distributed in multiple locations are also reported in some atypical cases. Unfortunately, PRES is often not recognized or diagnosed too late due to complicated differential diagnoses, such as ischemic stroke, progressive multifocal leukoencephalopathy, and neurodegenerative diseases. Thus, this review emphasizes the importance of considering the possibility of PRES when neurological disturbances appear after solid organ transplantation or hematopoietic cell transplantation. Moreover, this review demonstrates the molecular mechanisms of PRES associated with CNIs after transplantation, which aims to help clinicians further understand PRES in the transplantation era.