Central-variant posterior reversible encephalopathy syndrome: brainstem or basal ganglia involvement lacking cortical or subcortical cerebral edema. AJR Am J Roentgenol. 2013;201:631-638. [PMID: 23971457 DOI: 10.2214/ajr.12.9677]

Association between renal insufficiency and lesion characteristics of posterior reversible encephalopathy syndrome

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/1.73m2 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.

Multisystem Imaging Manifestations of Kidney Failure

Kidney failure (KF) refers to a progressive decline in glomerular filtration rate to below 15 ml/min per 1.73 m2, necessitating renal replacement therapy with dialysis or renal transplant. The hemodynamic and metabolic alterations in KF combined with a proinflammatory and coagulopathic state leads to complex multisystemic complications. The imaging hallmark of systemic manifestations of KF is bone resorption caused by secondary hyperparathyroidism. Other musculoskeletal complications include brown tumor, osteosclerosis, calcinosis, soft-tissue calcification, and amyloid arthropathy. Cardiovascular complications and infections are the leading causes of death in KF. Cardiovascular complications include accelerated atherosclerosis, cardiomyopathy, pericarditis, myocardial calcinosis, and venous thromboembolism. Neurologic complications such as encephalopathy, osmotic demyelination, cerebrovascular disease, and opportunistic infections are also frequently encountered. Pulmonary complications include edema and calcifications. Radiography and CT are used in assessing musculoskeletal and thoracic complications, while MRI plays a key role in assessing neurologic and cardiovascular complications. CT iodinated contrast material is generally avoided in patients with KF except in situations where the benefit of contrast-enhanced CT outweighs the risks and in patients already undergoing maintenance dialysis. At MRI, group II gadolinium-based contrast material can be safely administered in patients with KF. The authors discuss the extrarenal systemic manifestations of KF, the choice of imaging modality in their assessment, and imaging findings of complications. ©RSNA, 2024 Supplemental material is available for this article.

Imaging of Reversible Cerebral Vasoconstriction Syndrome and Posterior Reversible Encephalopathy Syndrome

PRES and RCVS are increasingly recognized due to the wider use of brain MRI and increasing clinical awareness. Imaging plays a crucial role in confirming the diagnosis and guiding clinical management for PRES and RCVS. Imaging also has a pivotal role in determining the temporal progression of these entities, detecting complications, and predicting prognosis. In this review, we aim to describe PRES and RCVS, discuss their possible pathophysiological mechanisms, and discuss imaging methods that are useful in the diagnosis, management, and follow-up of patients.

Optic pathway involvement in the posterior reversible encephalopathy syndrome: A case report and review of the literature

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition characterized by reversible vasogenic edema of the white matter and acute neurological symptoms. PRES typically affects the parieto-occipital regions but rarely affects the optic pathway. Herein, we describe a case of central-variant PRES in a 57-year-old man with abnormal signal intensities in the optic pathway on magnetic resonance imaging (MRI). The patient underwent hemodialysis, initiated diuretics and antihypertensive medications, and the abnormal signal intensities of the brainstem and optic pathway on MRI improved. Although rare, PRES can affect the optic pathway, thus suggesting the possibility of fragility of the optic pathway itself to hyperperfusion.

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.

Dramatic Amelioration in Serial Magnetic Resonance Imaging in an "Isolated Brainstem" Reversible Encephalopathy Syndrome Case

Posterior reversible encephalopathy syndrome (PRES) is characterized by transient vasogenic edema predominantly in supratentorial areas within the posterior circulation regions. Although PRES with only brainstem involvement is quite rare, accurate diagnosis is important because prompt antihypertensive therapy contributes to a favorable outcome. Herein, we report a case with isolated brainstem PRES showing dramatical improvement in an apparent diffusion coefficient (ADC) value of the lesion in magnetic resonance imaging (MRI) after clinical remission. The present case suggests the association between favorable clinical course and complete amelioration on MRI.

Atypical posterior reversible encephalopathy syndrome associated with Sjögren'‍s syndrome: a case report

Sjögren'‍s syndrome (SJS) is a common autoimmune disease. Generally, posterior reversible encephalopathy syndrome (PRES) is often concomitant with autoimmune disease; however, PRES rarely complicates SJS. Thus, the detailed clinical course of cases with SJS and PRES remains unknown. We present the case of a 71-year-old female patient with primary SJS, whose magnetic resonance (MR) images showed bilateral vasogenic edema in the basal ganglia, brainstem, and cerebellum. Cerebrospinal fluid (CSF) examination revealed increased IgG index and higher interleukin-6 and anti-SSA-autoantibody levels. Management of her blood pressure combined with corticosteroid therapy improved her neurological symptoms, including abnormal CSF and MR imaging findings.

Pathogenesis of acute encephalopathy in acute hepatic porphyria

Acute encephalopathy (AE) can be a manifestation of an acute porphyric attack. Clinical data were studied in 32 patients during AE with or without polyneuropathy (PNP) together with 12 subjects with PNP but no AE, and 17 with dysautonomia solely. Brain neuroimaging was done in 20 attacks during AE, and PEPT2 polymorphisms were studied in 56 subjects, 24 with AE. AE manifested as a triad of seizures, confusion and/or blurred vision. Symptoms lasting 1-5 days manifested 3-19 days from the onset of an attack. 55% of these patients had acute PNP independent of AE. Posterior reversible encephalopathy syndrome (PRES) was detected in 42% of the attacks. These patients were severely affected and hyponatremic (88%). Reversible segmental vasoconstriction was rare. There was no statistical difference in hypertension or urinary excretion of porphyrin precursors among the patients with or without AE. In 94% of the attacks with AE, liver transaminases were elevated significantly (1.5 to fivefold, P = 0.034) compared to a normal level in 87% of the attacks with dysautonomia, or in 25% of patients with PNP solely. PEPT2*2/2 haplotype was less common among patients with AE than without (8.3% vs. 25.8%, P = 0.159) and in patients with PNP than without (9.5% vs. 22.9%, P = 0.207), suggesting a minor role, if any, in acute neurotoxicity. In contrast, PEPT2*2/2 haplotype was commoner among patients with chronic kidney disease (P = 0.192). Acute endothelial dysfunction in porphyric encephalopathy could be explained by a combination of abrupt hypertension, SIADH, and acute metabolic and inflammatory factors of hepatic origin.

Central Variant Posterior Reversible Encephalopathy Syndrome in a Pregnant Woman With Eclampsia: A Case Report

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico-radiological diagnosis characterized by acute or subacute neurological symptoms. A 27-year-old woman at 35 weeks of pregnancy, who presented with generalized tonic-clonic seizures had persistently low Glasgow Coma Scale (GCS) score after delivery of the baby. Magnetic Resonance Imaging (MRI) of the brain showed T-2 Fluid Attenuated Inversion Recovery (FLAIR) hyperintensities in the brainstem, bilateral medial cerebellar hemispheres, bilateral medial temporal lobes, bilateral thalami, lentiform and caudate nuclei, and bilateral fronto-parieto-occipital lobes. There was diffusion restriction in bilateral caudate nuclei, left thalamus and right frontal lobe, and microhemorrhages in the left thalamus. These findings were suggestive of central variant PRES. She improved with strict blood pressure control and anti-edema measures. A repeat MRI brain on day 10 showed significant improvement, and she had no residual neurological deficits. The central variant of PRES is a rare entity that has to be considered in a patient presenting with neurological deficits in the setting of uncontrolled blood pressure, eclampsia, immunomodulatory medication use, or renal failure. While most patients with PRES fully recover with timely therapy targeted at reversing the primary cause, some may have residual neurological deficits or rarely, die.

Role of MRI and CT in the Evaluation of Headache in Pregnancy and the Postpartum Period

Approximately 35% of acute headaches in pregnant women are secondary to an underlying condition. Headaches are also common in the postpartum period where they occur in 30% to 40% of patients. The majority of secondary headaches are due to hypertensive disorders: preeclampsia-eclampsia, posterior reversible encephalopathy syndrome, and acute arterial hypertension. Other causes include reversible cerebral vasoconstriction syndrome and pituitary apoplexy, as well as life-threatening conditions such as cerebral venous thrombosis. In this article, we review general recommendations for imaging the pregnant patients and discuss the imaging findings of common causes of headaches in pregnancy and the postpartum period.

Cerebral perfusion in posterior reversible encephalopathy syndrome measured with arterial spin labeling MRI

BACKGROUND AND PURPOSE

The pathophysiologic basis of posterior reversible encephalopathy syndrome (PRES) remains controversial. Hypertension (HTN)-induced autoregulatory failure with subsequent hyperperfusion is the leading hypothesis, whereas alternative theories suggest vasoconstriction-induced hypoperfusion as the underlying mechanism. Studies using contrast-based CT and MR perfusion imaging have yielded contradictory results supporting both ideas. This work represents one of the first applications of arterial spin labeling (ASL) to evaluate cerebral blood flow (CBF) changes in PRES.

MATERIALS AND METHODS

After obtaining Institutional Review Board approval, MRI reports at our institution from 07/2015 to 09/2020 were retrospectively searched and reviewed for mention of "PRES" and "posterior reversible encephalopathy syndrome." Of the resulting 103 MRIs (performed on GE 1.5 Tesla or 3 Tesla scanners), 20 MRIs in 18 patients who met the inclusion criteria of clinical and imaging diagnosis of PRES and had diagnostic-quality pseudocontinuous ASL scans were included. Patients with a more likely alternative diagnosis, technically non-diagnostic ASL, or other intracranial abnormalities limiting assessment of underlying PRES features were excluded. Perfusion in FLAIR-affected brain regions was qualitatively assessed using ASL and characterized as hyperperfusion, normal, or hypoperfusion. Additional quantitative analysis was performed by measuring average gray matter CBF in abnormal versus normal brain regions.

RESULTS

HTN was the most common PRES etiology (65%). ASL showed hyperperfusion in 13 cases and normal perfusion in 7 cases. A hypoperfusion pattern was not identified. Quantitative analysis of gray matter CBF among patients with visually apparent hyperperfusion showed statistically higher perfusion in affected versus normal appearing brain regions (median CBF 100.4 ml/100 g-min vs. 61.0 ml/ 100 g-min, p < 0.001).

CONCLUSION

Elevated ASL CBF was seen in the majority (65%) of patients with PRES, favoring the autoregulatory failure hypothesis as a predominant mechanism. Our data support ASL as a practical way to assess and noninvasively monitor cerebral perfusion in PRES that could potentially alter management strategies.

Posterior reversible encephalopathy syndrome with a special focus on seizures

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder characterized by headache, seizures, confusion and visual disturbances, as well as potentially reversible neuroimaging findings in most patients after proper treatment. Seizures is one of the most common clinical presentations of PRES. This review summarizes the potential pathophysiology and clinical features of PRES, as well as a multimodal approach to imaging and also briefly discusses the phenomenon of seizures in paediatric population.

Postpartum Reversible Cerebral Vasoconstriction Syndrome Presenting with Radiological Plethora

Reversible cerebral vasoconstriction syndrome (RCVS) is a clinicoradiological syndrome characterized by segmental vasoconstriction of cerebral arteries with resolution in most patients within 1 to 3 months. It has been known to be a benign uniphasic reversible illness but cases of fulminant RCVS with mortality have also been reported. The symptoms can be varied with presentations like transient ischemic attack (TIA), ischemic stroke (IS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and posterior reversible encephalopathy syndrome (PRES). We report a postpartum female with RCVS with radiological features of ICH, SAH, atypical PRES, and atypical clinical presentation as well. RCVS can be frequently missed unless there is a high index of suspicion. Hence clinicians should be aware of the typical and the atypical presentation of RCVS along with the radiological findings with the potential complications. Early suspicion and detection in the emergency help in recovery and reducing morbidity.

Fatal Thrombotic Microangiopathy and Posterior Reversible Encephalopathy Syndrome in a Patient with Anti-melanoma Differentiation-associated Gene 5 Antibody-positive Dermatomyositis

A 56-year-old woman presented with dermatomyositis positive for anti-melanoma differentiation-associated gene 5 antibody. No interstitial lung disease was detected. Despite treatment with methylprednisolone pulse therapy and cyclosporine, dysphagia developed. Furthermore, the presence of thrombocytopenia, elevated lactate dehydrogenase levels, and an undetectable haptoglobin level suggested the possibility of thrombotic microangiopathy (TMA). Disturbed consciousness developed shortly after TMA onset, and brain magnetic resonance imaging revealed hyperintensity lesions in the bilateral basal ganglia, thalami, and brainstem. The patient was diagnosed with atypical posterior leukoencephalopathy syndrome before dying of heart failure later that day. In conclusion, early TMA recognition and prompt intensive treatment are critical in such cases.

Evaluation of neuroimaging findings in thalamic lesions: what can we think?

The diseases that affect the thalamus are heterogeneous in their etiologies, including infectious, inflammatory, vascular, toxic-metabolic, and neoplastic causes. It is often difficult to make the clinical differentiation between different entities. Within this context, computed tomography and magnetic resonance imaging have come to be of fundamental importance for defining the etiology and planning the treatment. In this pictorial essay, we will illustrate the main causes of diseases affecting the thalamus, discussing the possible differential diagnoses, as well as the most relevant imaging aspects.

Efficacy of renin-angiotensin-aldosterone system blockades for acute phase hypertensive emergencies in patient complicating severe acute kidney injury

Renin-angiotensin-aldosterone system (RAAS) is primarily involved with pathological mechanism of developing hypertensive emergencies. However, none of clinical practice guidelines mention RAAS blockers for the treatment of hypertensive emergencies. A 44 year-old woman presented with severe hypertension, brain stem posterior reversible encephalopathy syndrome and severe acute kidney injury (AKI). We started anti-hypertensive therapy with continuous intravenous nitroglycerin and oral calcium channel blocker (CCB) and spironolactone. Since severe AKI persisted despite this therapy, we administered losartan potassium, which resulted in improvement in her blood pressure and creatinine. Clinical course of our patient suggests that timely initiation of ARB and spironolactone for hypertensive emergencies could be beneficial in terms of blood pressure control and for protection of target organs from this condition.

Systemic Lupus Erythematosus Induced Central Variant of Posterior Reversible Encephalopathy Syndrome: A Rare Association

Involvement of the posterior cerebral structures is well established in patients with posterior reversible encephalopathy syndrome (PRES). In striking contrast to this, a subset of patients may have an atypical presentation characterized by the involvement of central structures. This is usually seen in the backdrop of systemic lupus erythematosus (SLE), a rare but known cause of PRES. Timely diagnosis with judicious use of radiological modalities and therapeutic intervention is key for successful recovery; however, the prognosis of PRES in patients with SLE is not very promising. We are describing an extremely rare case of a patient diagnosed with a central variant of PRES with previously undiagnosed SLE.

Optic pathways and brainstem involvement in posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a neurological syndrome manifesting with acute focal signs, and concomitant neuroimaging findings of vasogenic oedema. It affects the parieto-occipital regions in a vast majority of cases, although atypical variants have been described comprising the brainstem, basal ganglia or spinal cord. We report the case of a 41-year-old woman, admitted for persistent headache and inferior altitudinal field defect in the right eye. She presented with severe, non-medicated, hypertension. Brain MRI showed findings compatible with atypical PRES, involving the brainstem and optic pathways. With antihypertensive therapy the headache remitted, although visual field remained and was interpreted in the context of a vascular aetiology-non-arteritic anterior ischaemic optic neuropathy. MRI was repeated 3 weeks later and showed almost complete reversal of the previous changes.

Posterior reversible encephalopathy syndrome coexists with acute cerebral infarction: challenges of blood pressure management

Hypertension is the most common cause of posterior reversible encephalopathy syndrome (PRES) and acute cerebral infarction. Due to the lack of randomized controlled clinical trials (RCTs), early antihypertensive methods are diverse, even contradictory. So far, there is no consensus on the method of blood pressure (BP) management when the 2 diseases coexist. Generally, antihypertensive therapy should be initiated quickly in the acute phase of PRES, as most patients have elevated BP. However, various factors must be considered before the administration of early antihypertensive therapy in acute cerebral infarction. The coexistence of PRES and acute cerebral infarction is uncommon clinically, and more complicated subsequent BP management. This article reports a case of PRES coexisting with acute lacunar cerebral infarction, which was caused by hypertension. We have analyzed and summarized the antihypertensive principles in PRES and different phases of acute cerebral ischemic injury. We assert that when PRES and acute cerebral infarction coexist, the antihypertensive treatment should be individualized, and careful consideration should be given to the various influencing factors.

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.

Tentorial Dural Arteriovenous Fistulas as a Cause of Thalamic Edema: 2 Cases of an Important Differential Diagnosis to Consider

The differential diagnosis for bilateral thalamic edema is extensive and includes vascular, neoplastic, metabolic, and infectious causes. Of the vascular causes of thalamic edema, arterial and venous infarctions are well-documented, but dural arteriovenous fistulas (dAVFs) are a relatively uncommon and widely underrecognized cause of thalamic edema. Dural AVFs are notoriously difficult to diagnose clinically, especially in the absence of hemorrhage, and cross-sectional imaging findings can be subtle. This can result in a delayed diagnosis, and occasionally, an invasive biopsy for further clarification of a purely vascular disease. In this review, we detail our experience with the imaging diagnosis of dAVF as a cause of thalamic edema and present a short differential of other vascular causes.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

Potentially Reversible and Recognizable Acute Encephalopathic Syndromes: Disease Categorization and MRI Appearances

"Encephalopathy" is a vague term that encompasses varying definitions, often with a nonspecific clinical presentation and numerous possible pathophysiologic causes. Hence, MR imaging plays a crucial role in the early diagnosis and treatment by identifying imaging patterns when there is limited clinical history in such patients with acute encephalopathy. The aim of this review was to aid in remembrance of etiologies of potentially reversible acute encephalopathic syndromes on MR imaging. The differential includes vascular (reversible cerebral vasoconstriction syndrome, transient global amnesia, disseminated intravascular coagulation, and thrombotic microangiopathy), infection (meningitis, encephalitis), toxic (posterior reversible encephalopathy syndrome, acute toxic leukoencephalopathy; carbon monoxide, alcohol-related, medication- and illicit drug-related toxic encephalopathies), autoimmune, metabolic (osmotic demyelination syndrome, uremic, acute hepatic encephalopathy), idiopathic/inflammatory (stroke-like migraine attacks after radiation therapy syndrome), neoplasm-related encephalopathy, and seizure-related encephalopathy.

Posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome associated spinal subdural hematoma: A case report

RATIONALE

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) are separate clinical entities with distinct pathophysiological features. But in some special conditions PRES and RCVS can occur simultaneously.

PATIENT CONCERNS

We report the unique case of a 40-year-old female presented with crescendo headache, blurred vision, and recurrent generalized tonic-clonic seizure. She had a minor neck injury 1 week before but attracted no more attention. Neurological tests on admission yielded a Glasgow Coma Scale score of 13. No obvious focal neurological deficit apart from positive signs of meningeal irritation was presented.

DIAGNOSES

Xanthochromia and hemorrhagic cerebrospinal fluid with pleocytosis was found on lumbar puncture. Cranial computed tomography was negative but magnetic resonance imaging demonstrated bilateral areas of vasogenic edema in the parieto-occipital lobes and cerebellum consistent with PRES. An incidental subacute spinal subdural hematoma extending from the level of C6 to T1 was depicted by spinal magnetic resonance imaging, presumably as a complication of negligible neck trauma. Spinal digital subtraction angiography showed no evidence of spinal aneurysm, arteriovenous malformation, or dural arteriovenous fistula. Cerebral digital subtraction angiography showed segmental narrowing and dilatation of vessels, a potential feature of RCVS, involving the circle of Willis and their branches.

INTERVENTIONS

The patient was treated with nimodipine for vasodilation and other symptomatic therapies. The spinal subdural hematoma was not warranted for surgical intervention and managed with simple analgesics.

OUTCOMES

The patient experienced a dramatic improvement in neurological symptoms and was discharged without sequelae. Follow-up imaging showed complete resolution of all radiological changes.

LESSONS

Clinician should be aware of spinal subdural hematoma as the potential trigger in development of PRES and RCVS. We speculate that endothelial dysfunction and vascular tone dysregulation may be implicated to play the major pathophysiologic role.

Posterior reversible encephalopathy syndrome, a clinically diverse and challenging disorder

The characterizing features of Posterior reversible encephalopathy syndrome (PRES) are broad and diverse, making early recognition and diagnosis challenging tasks. To illustrate the heterogeneous nature of PRES, we present three cases and discuss their clinical and radiological presentation.

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.

Neurotoxicity including posterior reversible encephalopathy syndrome after initiation of calcineurin inhibitors in transplanted methylmalonic acidemia patients: Two case reports and review of the literature

Introduction

New neurological symptoms in methylmalonic acidemia (MMA) patients after liver and/or kidney transplantation (LKT) are often described as metabolic stroke‐like‐events. Since calcineurin inhibitors (CNIs) are a well‐known cause of new neurological symptoms in non‐MMA transplanted patients, we investigated the incidence of CNI‐induced neurotoxicity including posterior reversible encephalopathy syndrome (PRES) in post‐transplanted MMA patients.

Methods

We report the two MMA patients treated with LKT in our center. Additionally, we performed a systematic review of case reports/series of post‐transplanted MMA patients and determined if CNI‐induced neurotoxicity/PRES was a likely cause of new neurological symptoms. Definite CNI‐induced neurotoxicity was defined as new neurological symptoms during CNI treatment with symptom improvement after CNI dose reduction/discontinuation. PRES was defined as CNI‐induced neurotoxicity with signs of vasogenic edema on brain magnetic resonance imaging (MRI)‐scan post‐transplantation.

Results

Our two MMA patients both developed CNI‐induced neurotoxicity, one had PRES. In literature, 230 transplanted MMA patients were identified. Neurological follow‐up was reported in 54 of them, of which 24 were excluded from analysis since no anti‐rejection medication was reported. Thirty patients, all using CNI, were included. Sixteen patients (53%) had no new neurological symptoms post‐transplantation and five patients (17%) had definite CNI neurotoxicity of whom two had PRES. Including our cases this results in a pooled incidence of 22% (7/32) definite CNI neurotoxicity and 9% PRES (3/32) in post‐transplanted MMA patients on CNI.

Conclusion

In MMA post‐transplanted patients with new neurological symptoms CNI‐induced neurotoxicity/PRES should be considered. Early recognition of CNI‐induced neurotoxicity is essential to initiate dose reduction/discontinuation of CNI to minimize persistent neurologic damage and improve outcome.

Concise one sentence take home message

In all post‐transplanted MMA patients with new neurological symptoms CNI‐induced neurotoxicity/PRES should be considered, and directly reducing the dose/discontinuation of CNI is essential.

Tumour-like presentation of atypical posterior reversible encephalopathy syndrome with prominent brainstem involvement

Typical posterior reversible encephalopathy syndrome (PRES) is a clinical-neuroradiological entity characterised by bilateral white matter oedema, which is usually symmetrical and totally reversible in 2-3 weeks. A 46-year-old man presented with a persistent headache and visual blurring in the right eye. On admission, the clinical examination revealed minimal unsteadiness of gait and elevated blood pressure. A brain MRI showed a hyperintense signal on T2-weighted sequences in the whole brainstem, extended to the spinal cord (C2-C6), the left insula and the right cerebellum. When his blood pressure was controlled, his symptoms gradually improved. The follow-up MRI scan at 3 weeks revealed a dramatic regression of the hyperintense lesions on T2-weighted sequences. The differential diagnosis of PRES is very wide, especially in the case of conspicuous brainstem involvement. Treatable causes of white matter oedema should be always kept in mind to avoid misdiagnosis and prevent complications, such as intracranial haemorrhage.

Imaging of Atypical and Complicated Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a condition clinically characterized by headache, altered mental status, seizures, and visual loss and may be associated with systemic hypertension, preeclampsia/eclampsia, chemotherapy, immunosuppressive therapies in the setting of organ transplantation, and uremic encephalopathy. While brain imaging in patients with PRES typically reveals symmetric vasogenic edema within the parietal and occipital lobes, PRES may present with atypical imaging findings such as central brainstem and deep gray involvement without subcortical edema, and even spinal cord involvement. Additionally, PRES may be complicated in some cases by the presence of cytotoxic edema and hemorrhage. This review will serve to summarize the pathophysiologic theories and controversies underlying PRES, imaging features encountered in atypical and complicated PRES, and the implications these findings may have on patient prognosis.

Posterior Reversible Encephalopathy Syndrome Secondary to Hypertensive Encephalopathy Brought on by a MAO Inhibitor: A Case Report

An elderly woman was admitted to the Family Medicine inpatient service for altered mental status after being brought to the emergency room by a concerned neighbor, who had come across the patient speaking incoherently. Initial evaluation was notable for elevated blood pressures, but extensive lab testing and head computed tomographic imaging were within normal limits. However, subsequent magnetic resonance imaging showed white matter changes consistent with posterior reversible encephalopathy syndrome (PRES), a neurologic syndrome characterized by headache, altered mental status, loss of vision, and seizures as well as radiographic findings of posterior cerebral white matter edema. Multiple etiologies of PRES have been described and include hypertensive encephalopathy, immunosuppressant medications, and eclampsia. This case describes an episode of PRES secondary to hypertensive encephalopathy brought about by an inappropriate dose of a monoamine oxidase (MAO) inhibitor. The patient had significant improvement in symptoms with removal of the offending agent and control of her blood pressure. While PRES generally has a good prognosis, prompt recognition, and management are important in preventing significant disease morbidity and mortality.

Posterior reversible encephalopathy syndrome with isolated infratentorial involvement: A case report

Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological entity of acute neurological symptoms associated with characteristic MRI finding. Vasogenic edema in the white matter of parieto-occipital regions is the classical MRI findings. Spinal cord involvement in PRES is extremely rare and frequently underrecognized condition. Recently, a variant-type PRES with isolated involvement of infratentorial structures is getting more attention. Herein, we present a case of hypertensive emergency and associated radiological features of PRES with isolated involvement of the brain stem, cerebellum, and spinal cord.

Atypical MRI presentation of posterior reversible encephalopathy syndrome with predominant brainstem involvement

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.

Atypical posterior reversible encephalopathy syndrome in a noncompliant hemodialysis patient: Case report and literature review

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.

Isolated pan-pontine posterior reversible encephalopathy syndrome in a patient with uncontrolled hypertension

Recognition of central variant PRES is key to avoiding detrimental treatment. The pons may be the most vulnerable area in central PRES, and delayed presentation may result in greater damage. CSF reporting may lead to eventual recognition of a common profile, and possible aid in future diagnosis.

Atypical Variant of Posterior Reversible Encephalopathy Syndrome in the Setting of Renovascular Hypertension: Case Report and Review of Literature

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiologic syndrome resulting in subcortical vasogenic edema appreciated on T2/fluid-attenuated inversion recovery (FLAIR) sequence of magnetic resonance imaging (MRI). PRES classically involves bilateral parieto-occipital lobes and is usually reversible. Atypical variant of PRES includes the involvement of brainstem, basal ganglia, thalami, or periventricular white matter. We report an unusual case of PRES with isolated brainstem involvement with periventricular white matter changes in a patient with renovascular hypertension from unilateral renal artery stenosis. To our knowledge, this is the first case of secondary hypertension from renal artery stenosis resulting in the atypical variant of PRES.

Posterior Reversible Encephalopathy Syndrome With Isolated Involving Infratentorial Structures

Typical neuroimaging findings of posterior reversible encephalopathy syndrome include symmetrical white matter edema in subcortical white matter of bilateral occipital and parietal lobes, although variations do occur and more and more attention is being focused upon disease of infratentorial-isolated involved posterior reversible encephalopathy syndrome. In this article, we described 1 case of posterior reversible encephalopathy syndrome with isolated infratentorial brain involvement and reviewed the literature to identify an additional 36 cases in the PubMed database. We used various search terms, such as "brainstem/cerebella/spinal posterior reversible encephalopathy syndrome," "brainstem/cerebella/spinal reversible posterior leukoencephalopathy syndrome," "brainstem/cerebella/spinal hypertensive encephalopathy," "infratentorial posterior reversible encephalopathy syndrome," and "posterior reversible encephalopathy syndrome variant." Then, we systematically analyzed the clinical and imaging characteristics of the 37 cases and found that posterior reversible encephalopathy syndrome with isolated involving infratentorial structures predominantly affect male patients compared with typical posterior reversible encephalopathy syndrome. The presence of extremely high blood pressure at onset is essential to the development of infratentorial-isolated involved posterior reversible encephalopathy syndrome. A relatively high rate of hydrocephalus and spinal cord involvement can be a distinctive feature of this kind of variant. Symptoms and outcomes are basically similar to typical posterior reversible encephalopathy syndrome.