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

MRI in the Evaluation of Acute Visual Syndromes

Acute visual symptom emergencies occur commonly and present a challenge to both clinical and radiologic facets. Although most patients with visual complaints routinely require clinical evaluation with direct ophthalmologic evaluation, imaging is rarely necessary. However, there are highly morbid conditions where the prompt recognition and management of an acute visual syndrome (AVS) requires an astute physician to probe further. Suspicious symptomatology including abrupt visual loss, diplopia, ophthalmoplegia, and proptosis/exophthalmos require further investigation with advanced imaging modalities such as magnetic resonance imaging and magnetic resonance angiography. This review will discuss a variety of AVSs including orbital apex syndrome, cavernous sinus thrombosis, cavernous carotid fistula, acute hypertensive encephalopathy (posterior reversible encephalopathy syndrome), optic neuritis, pituitary apoplexy including hemorrhage into an existing adenoma, and idiopathic intracranial hypertension. A discussion of each entity will focus on the clinical presentation, management and prognosis when necessary and finally, neuroimaging with emphasis on magnetic resonance imaging. The primary purpose of this review is to provide an organized approach to the differential diagnosis and typical imaging patterns for AVSs. We have provided a template for radiologists and specialists to assist in early intervention in order to decrease morbidity and provide value-based patient care through imaging.

Posterior reversible encephalopathy syndrome in patient of severe preeclampsia with Hellp syndrome immediate postpartum

Posterior reversible encephalopathy syndrome (PRES) is a rare clinico-neuroradiologic condition, not commonly reported in the literature. PRES is an uncommon complication of severe preeclampsia/eclampsia. We report the management of one patient with postpartum preeclampsia as an association of HELLP syndrome presenting with status-epileptics. Early diagnosis along with timely supportive therapy resulted in the successful management of this challenging case. Recent understanding on the pathophysiology of this uncommon condition is discussed. We highlight the importance to obstetricians, intensive-care physicians and anesthesiologists of recognizing such cases.

Atypical Unilateral Posterior Reversible Encephalopathy Syndrome Mimicking a Middle Cerebral Artery Infarction

Posterior reversible encephalopathy syndrome (PRES) is usually a reversible clinical and radiological entity associated with typical features on brain MR or CT imaging. However, the not-so-uncommon atypical radiological presentations of the condition are also present and they may go unrecognised as they are confused with other conditions. Here, we report a very rare case of atypical, unilateral PRES in a 49-year-old uremic, post-transplant female patient who presented with seizures. Initial MRI showed high-grade occlusion of the left middle cerebral artery (MCA) and lesions suggestive of subacute infarction in the ipsilateral frontotemporoparietal lobe. Patient symptoms had resolved a day after the onset without any specific treatment but early follow-up CT findings suggested hemorrhagic transformation. Follow-up MRI performed 2 years later showed complete disappearence of the lesions and persisting MCA occlusion.

Imaging of Nontraumatic Neuroradiology Emergencies

Imaging of acute neurologic disease in the emergency department can be challenging because of the wide range of possible causes and the overlapping imaging appearance of many of these entities on nonenhanced computed tomography (CT). The key to formulating a succinct, pertinent differential diagnosis includes characterizing the pattern of abnormalities on CT and identifying key features that suggest a particular diagnosis. This article divides neurologic emergencies into 5 scenarios based on the CT findings, including subarachnoid hemorrhage, intraparenchymal hemorrhage, vasogenic edema without and with underlying mass lesion, and acute hydrocephalus. Specific common or important diagnoses in each category are discussed.

Clinical Utility of Computed Tomography and Magnetic Resonance Imaging for Diagnosis of Posterior Reversible Encephalopathy Syndrome after Stem Cell Transplantation in Children and Adolescents

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome characterized by vision changes, altered mental status, and seizures, typically caused by an acute rise in blood pressure. PRES has been reported after hematopoietic stem cell transplantation (HSCT) in association with hypertension from calcineurin inhibitors and corticosteroids. The imaging evaluation of PRES after HSCT in children and young adults has not been well described. We performed a retrospective review of all HSCT recipients presenting to the intensive care unit with new neurologic symptoms. A neuroradiologist reviewed all radiologic images and compared computed tomography (CT) versus magnetic resonance imaging (MRI) findings indicative of diagnosis of PRES. Alternative imaging diagnoses explaining the patients' symptoms were also recorded. Fifty-four transplant recipients were admitted to the intensive care unit with new neurologic symptoms. Thirty-nine percent (21 of 54) of subjects had imaging findings consistent with PRES, 24% (13 of 54) had imaging findings consistent with an alternative diagnosis, 9% (5 of 54) had a nonspecific finding, and 28% (15 of 54) had no acute imaging findings. PRES was diagnosed at a median of 49 days (interquartile range, 29 to 94) after HSCT. The presenting symptom for the majority of patients with PRES was seizures (86%), whereas 14% presented with acute encephalopathy. Ninety-five percent of subjects diagnosed with PRES (20 of 21) underwent a head CT as their initial imaging evaluation. CT scan was diagnostic of PRES in 40% (8 of 20). Subsequently, 16 patients underwent brain MRI with 12 additional patients being diagnosed with PRES on MRI. The median time elapsed between negative CT and a positive MRI examination was 20 hours (range, 3.6 hours to 9 days). CT serves as an excellent screening test for acute pathology, such as intracranial hemorrhage; however, it lacks sensitivity for the diagnosis of PRES. Patients with clinical symptoms suggestive of PRES who have a negative CT should be treated appropriately for PRES and should undergo MRI of the brain as soon as clinically stable to confirm the diagnosis.

Recurrent childhood PRES

The purpose of the study was to review the recurrent posterior reversible encephalopathy syndrome (PRES) and emphasize the possibility of repeated attacks on the basis of particular clinical situations. 32 children, diagnosed with PRES were included in our study. The recurrent cases were determined; their radiological features such as involved localizations and clinical information such as presenting symptoms, underlying diseases and clinical prognosis are retrospectively assessed. Of the 32 children (8 months to 18 years old; mean age 11), four of the patients had recurrent episodes of PRES. They had different underlying diseases. One had Chediak-Higashi syndrome, one had ALL, one had chronic renal disease on hemodialysis and one was a renal transplant recipient. Three of the children recovered with no residual neurological deficits, one of them passed away due to multiorgan failure. Three of them had high blood pressures at the time of either one or both PRES, and the renal transplant recipient had also high blood levels of Tacrolimus. Recurrent PRES is encountered most commonly because of repeated increasing blood pressures due to various underlying diseases, immune system disorders or side effects of the treatments.

Posterior reversible encephalopathy syndrome as presenting form of very early systemic sclerosis

Introduction. Posterior Reversible Encephalopathy Syndrome (PRES) is an increasingly recognized clinical and radiological entity with a wide spectrum of symptoms. Its mechanism depends on failure of the blood-brain barrier due to high systemic blood pressure (BP) and loss of integrity of vascular endothelium related with different triggers. Methods. We aim to report a case of PRES induced by arterial hypertension and very early systemic sclerosis (SSc) not previously known. Results. A 64-year-old female was admitted due to 1-week pulsating headache more prominent on frontal scalp, accompanied by phonophobia, photophobia, and facial flushing. Neurological exam revealed brisk deep tendon reflex. Brain magnetic resonance imaging (MRI) showed subcortical lesions mainly located in posterior regions. BP was monitored and episodic arterial hypertension was detected. In laboratory tests positive anti-topoisomerase I antibodies were detected. BP was controlled with angiotensin-converting-enzyme inhibitors and headache improved. In a new MRI a month later improvement of white matter lesions was observed. Capillaroscopy showed “active pattern,” considered typical of SSc. Conclusion. In SSc anti-endothelial cell antibodies impair vascular endothelium and liberation of vasoconstrictors leads to BP increasing and disruption of blood-brain barrier autoregulation mechanisms. PRES can be the first manifestation of very early SSc and this entity should be considered even in absence of skin lesions or Raynaud phenomenon.

MRI Findings in Childhood PRES: What is Different than the Adults?

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a clinical scenario with convulsion, vision abnormalities, altered mental status, and headaches in the presence of an underlying etiology, and the diagnosis can be made by support of radiological studies. In this study, we evaluated the magnetic resonance imaging (MRI) findings of PRES in children and compared our findings with that of the known features in adults, and reviewed the possible pathophysiological reasons that may cause the difference.

MATERIALS AND METHODS

A total of 29 children (13 male, 16 female, aged 1-17 years, mean age: 10 years) diagnosed as having PRES were retrospectively reviewed. Clinical records were analyzed for the clinical symptoms and the underlying etiology. MR images were evaluated for the distribution of lesions, contrast enhancement, diffusion restriction, and hemorrhage.

RESULTS

Presenting symptoms and underlying etiologies were variable. Frontal lobe (66 %) edema was almost as common as parietal and occipital involvement. Cerebellar involvement was present in almost half of the patients (48 %), which was more frequent than in the adult patients. Contrast enhancement is another finding that was found to be more common in children than in the adults (39 %). Four patients had diffusion restriction (15 %) and four patients had hemorrhage (%15), which are almost the same frequency as in the adults.

CONCLUSION

The increased incidence of cerebellar involvement may show that the posterior circulation in children is more vulnerable than the adults. The contrast enhancement in children, which is seen more commonly than in the adults, may show that the pathophysiology in children may be more commonly related to blood-brain barrier breakdown, which can support the theory of the toxic endothelial injury.

Fatal outcome of posterior "reversible" encephalopathy syndrome in metastatic colorectal carcinoma after irinotecan and fluoropyrimidine chemotherapy regimen

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, and visual disturbances. It can occur in many different clinical entities such as severe hypertension and pre-eclampsia, or due to cytotoxic or immunosuppressive therapies. The pathogenesis of PRES is unclear, with dysregulated cerebral auto-regulation and endothelial dysfunction as important mechanisms proposed. Endothelial dysfunction is important especially in cases associated with cytotoxic therapies. Herein, we describe a patient with PRES with fatal outcome, who presented 5 days after the infusion of cycle 1 of irinotecan hydrochloride, leucovorin calcium, and fluorouracil (FOLFIRI) regimen chemotherapy, without prior hypertension and other comorbidity, suggesting a link between PRES and FOLFIRI regimen. To our knowledge, this case report is the first describing PRES after FOLFIRI regimen, although others have described PRES after FOLFIRI with bevacizumab in colonic cancer patients.

Plasma levels of S100B in preeclampsia and association with possible central nervous system effects

BACKGROUND

S100B is supposed to be a peripheral biomarker of central nervous system (CNS) injury. The purpose of this study was to compare levels of S100B in women with preeclampsia with levels in healthy pregnant control subjects and furthermore to analyze levels of S100B in relation to possible CNS effects.

METHODS

A cross-sectional case–control study in antenatal care centers in Uppsala, Sweden, was performed. Fifty-three women with preeclampsia and 58 healthy pregnant women were recruited at similar gestational length; women with preeclampsia were recruited at time of diagnosis, and control subjects were recruited during their routine visit to an antenatal clinic. Plasma samples were collected, and levels of S100B were analyzed with an enzyme-linked immunosorbent assay. Information about demographic and clinical characteristics, including symptoms related to CNS affection, was collected from the medical records. The main outcome measures were plasma levels of S100B and possible CNS effects.

RESULTS

Levels of S100B were significantly higher among women with preeclampsia than among control subjects (0.12 µg/L vs. 0.07 µg/L; P < 0.001). In preeclampsia, there was a significant association between high levels of S100B and visual disturbances (P < 0.05).

CONCLUSIONS

S100B is increased among women with preeclampsia, and high levels of S100B associate with visual disturbances, which might reflect CNS affection in women with preeclampsia.

Neuroimaging correlates of acute encephalopathy

Acute encephalopathies arise as a result of various contributions from infections or toxic, metabolic, and/or structural cerebral derangements. With the variety of clinical presentations, neurologic examination, electroencephalography (EEG), and imaging may not identify specific etiologies, but in combination, they can offer guidance regarding underlying causes. Among several different neuroimaging techniques, cerebral computed tomography and brain magnetic resonance imaging are most frequently used for diagnosis, treatment monitoring, and prognostication in acute brain dysfunction. This review compiles the most common and typical features of head computed tomography and magnetic resonance imaging and presents the clinical and EEG associations in adult patients with different types of acute encephalopathy.