Variable incidence of cyclosporine and FK-506 neurotoxicity in hematopoeitic malignancies and marrow conditions after allogeneic bone marrow transplantation

Posterior Reversible Encephalopathy Syndrome in the Immediate Postoperative Period of Gastric Cancer

A 55-year-old female was referred to the Department of Ophthalmology with complaints of bilateral loss of vision. She had undergone subtotal gastrectomy with gastrojejunostomy and lymphadenectomy for poorly differentiated gastric adenocarcinoma in the antropyloric region the day before. On the first postoperative day, she complained of generalised weakness, drowsiness, altered sensorium, and acute, painless, bilateral loss of vision. Ocular examination revealed visual acuity as no perception of light, bilaterally, and normal pupillary light reflexes. Anterior and posterior segment examination was within normal limits. This clinical presentation of altered sensorium and cortical blindness along with characteristic radiological findings (hyperintensity on T2/fluid-attenuated inversion recovery sequence involving the bilateral parieto-occipital lobe extending in asymmetric fashion to the bilateral cerebellum, brainstem, and thalami predominantly involving the white matter with few areas of diffusion restriction on diffusion-weighted imaging sequence predominantly on the left side with gyriform pattern) confirmed the diagnosis of posterior reversible encephalopathy syndrome (PRES). In cancer patients, PRES has been reported in patients on chemotherapy regimen or two weeks after surgery for gastric cancer. Here, we want to draw attention to the fact that PRES may develop in the immediate postoperative period of gastric cancer surgery, as seen in our case.

Frequency and Risk Factors of Cyclosporine-Induced Neurotoxicity in Allogeneic Stem Cell Transplant Recipients

Background and objective

The calcineurin inhibitor cyclosporine A is routinely used for prophylaxis against graft-versus-host-disease (GvHD) in human leukocyte antigen (HLA)-matched allogeneic stem-cell transplant patients and is a major etiological factor for neuropathological symptoms that are reversible in most cases. In this study, we aimed to determine the frequency and risk factors of cyclosporine-induced neurotoxicity (CIN) in HLA-matched allogeneic stem cell transplant patients.

Methods

The study spanned the period from January 2016 to December 2019. Consecutive HLA-matched allogeneic stem-cell transplant patients of all ages were included in the study. Descriptive and risk factor analyses for the development of CIN with respect to age, sex, primary diagnosis, conditioning regimen, electrolyte abnormalities, and cyclosporine trough levels during the neurological episode were performed.

Results

A total of 106 HLA-matched patients with a median age of 6.3 years [interquartile range (IQR): 0.5-46 years], of which 37 (35%) were females, were included in the study. The mean cyclosporine trough level was 500 ±286 mg/dl. Neurological symptoms were found in 27 (26%) patients. A total of 14 (13%) patients were diagnosed with CIN. The frequency of other neurological symptoms included headache in 46 (43%), disorientation in 17 (16%), seizures in 12 (11%), visual disturbance in 11 (10%), and aphasia in seven (7%) patients. Posterior reversible encephalopathy syndrome (PRES) was found in six (6%) patients. All patients with CIN had hypertension and none had a fever. Multivariate logistic analysis showed that the presence of seizures [odds ratio (OR): 10.0, p<0.001] and the absence of fever (OR: 0.02, p<0.001) were associated with the diagnosis of CIN.

Conclusion

The prevalence of CIN is not uncommon (13%) in patients receiving cyclosporine for GvHD prophylaxis. Neurological complications, especially seizures, are common in CIN, and fever might indicate an alternative diagnosis. Prompt recognition of neurological signs and symptoms and early intervention can halt the progression of the disease.

Neurologic Complications in Patients with Cancer

Neurologic symptoms are commonly seen in patients with cancer and can be among the most challenging to diagnose and manage. It is often difficult to determine if new neurologic symptoms are secondary to direct effects of a malignant lesion, systemic complications of disease, paraneoplastic disorders, or side effects of cancer treatment itself. However, early diagnosis and treatment of each of these conditions can improve patients' quality of life and long-term functional outcomes. In this review, we describe a systematic approach to the diagnosis of new neurologic symptoms in patients with known malignancy. We have categorized the neurologic complications of cancer through a mechanistic approach, with an emphasis on ascertaining underlying pathophysiology to guide treatment choice. This review focuses on the acute neurologic complications of cancer that require hospital admission.

Clinical Presentation and Risk Factors for Poor Outcomes Among Adult Patients With Posterior Reversible Encephalopathy Syndrome: A Retrospective Cohort Study

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is an acute neurological condition with unknown global incidence, variable clinical presentation, and prognosis.

OBJECTIVES

To describe a cohort of patients with PRES with a focus on brain magnetic resonance imaging (MRI) patterns and their relationship with short-term clinical outcomes.

METHODS

Retrospective cohort study. The authors included patients if they were older than 15 years and had a PRES diagnosis on the basis of a positive brain MRI at any time during the in-hospital stay.

RESULTS

Forty-four patients were included in the present analysis. The median age was 57 years (interquartile range, 32.0-68.5) and 70.5% were women. Hypertension (59.1%), history of transplantation (27.3%), previous chemotherapy (27.3%), chronic renal failure (38.6%), and autoimmune disease (15%) were the main comorbid conditions present. The classic triad of seizures, headache, and visual impairment was present in 18.0% of the cases. Eighty-six percent of patients were admitted to the intensive care unit, with 36.0% needing invasive life support. Brain MRI showed a dominant parieto-occipital pattern in 26 patients, whereas cytotoxic edema and bleeding were present in 27.3% and 29.6%, respectively. In-hospital mortality was 11.4%. The median modified Rankin Scale at hospital discharge was 1 (0-2.5). Risk factors associated with low modified Rankin Scale scores were: headache, visual impairment, and parieto-occipital pattern. Decreased level of consciousness and mechanical ventilation requirement were associated with greater discharge disability.

CONCLUSIONS

Characteristic symptoms and signs of PRES and classic MRI patterns are associated with better clinical outcomes.

Cyclosporine A-related neurotoxicity after haploidentical hematopoietic stem cell transplantation in children with hematopathy

Background

To evaluate cyclosporine A (CSA)-related neurotoxicity after haploidentical hematopoietic stem cell transplantation (HID-HSCT) in children with hematopathy.

Methods

This retrospective case series study included children with hematopathy who underwent HID-HSCT at Fujian Medical University Union Hospital between February 2013 and January 2017.

Results

Fifty-one children (39 males) were included in the study with a median age of 8 (range, 1.1–18) years. Seven patients (13.7%) developed CSA-related neurotoxicity after a median 38 (range, − 3 to 161) days from HID-HSCT. Hypertension (5/7, 71%) was the most common prodrome. Brain magnetic resonance imaging showed posterior reversible encephalopathy syndrome in six patients and atypical abnormalities in one patient. One patient died from grade IV graft-versus-host disease (GvHD) on day + 160, and six patients were alive at the last follow-up. Four patients (71.4%) achieved complete remission, while two patients developed secondary epilepsy and exhibited persistent MRI and electroencephalogram abnormalities at the 5-year follow-up. Hypertension after CSA was more common in patients with CSA-related neurotoxicity than in those without (71% vs. 11%, P = 0.002). Five-year overall survival did not differ significantly between patients with CSA-related neurotoxicity (85.7 ± 13.2%) and those without (65.8 ± 7.2%).

Conclusions

The incidence of CSA-related neurotoxicity in children with hematopathy undergoing HID-HSCT is relatively high.

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.

Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome: Clinical and Radiological Considerations

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) are relatively uncommon neurological disorders, but their detection has been increasing mainly due to clinical awareness and spreading of magnetic resonance imaging (MRI). Because these syndromes share some common clinical and radiologic features and occasionally occur in the same patient, misdiagnosis may occur. PRES is characterized by varied neurological symptoms including headache, impaired visual acuity or visual field deficit, confusion, disorders of consciousness, seizures, and motor deficits often associated to peculiar neuroradiological pattern even if uncommon localization and ischemic or hemorrhagic lesions were described. RCVS is a group of diseases typically associated with severe headaches and reversible segmental vasoconstriction of cerebral arteries, often complicated by ischemic or hemorrhagic stroke. Pathophysiological basis of PRES and RCVS are still debated but, because they share some risk factors and clinical features, a possible common origin has been supposed. Clinical course is usually self-limiting, but prognosis may fluctuate from complete recovery to death due to complications of ischemic stroke or intracranial hemorrhage. Neuroradiological techniques such as digital angiography and MRI are helpful in the diagnostic pathway and a possible prognostic role of MRI has been suggested. This review will serve to summarize clinical, neuroradiological features and controversies underlying both syndromes that may mislead the diagnostic pathway and their possible relationship with pathophysiology, clinical course, and prognosis.

Posterior reversible encephalopathy in the intensive care unit

Posterior reversible encephalopathy syndrome (PRES) is increasingly diagnosed in the emergency department, and medical and surgical intensive care units. PRES is characterized by acute onset of neurologic symptoms in the setting of blood pressure fluctuations, eclampsia, autoimmune disease, transplantation, renal failure, or exposure to immunosuppressive or cytotoxic drugs, triggers known to admit patients to the intensive care unit (ICU). Although the exact pathophysiology remains unknown, there is growing consensus that PRES results from endothelial dysfunction. Because of the heterogeneous nature of the disorder, it is probable that different mechanisms of endothelial injury are etiologically important in different clinical situations. The presence of bilateral vasogenic edema on brain imaging, particularly in parieto-occipital regions, is of great diagnostic utility but PRES remains a clinical diagnosis. Although largely reversible, PRES can result in irreversible neurologic injury and even death. The range of clinical and radiographic manifestations of the syndrome is probably broader than previously thought, and it is imperative that clinicians become familiar with the full spectrum of the disorder, as prompt recognition and elimination of an inciting factor improve outcome. PRES may be the most frequent toxic-metabolic encephalopathy seen in the ICU.

Reversible posterior leukoencephalopathy associated with chronic graft-versus-host disease: A case report

The present study describes the clinical manifestations, magnetic resonance imaging (MRI) features and treatments of a 22-year-old male patient diagnosed with reversible posterior leukoencephalopathy syndrome (RPLS) associated with graft-versus-host disease (GVHD) 7 months after a haploid hematopoietic stem cell transplantation. The patient was admitted to hospital after falling unconscious. Head MRI demonstrated abnormal signals in the bilateral, frontal, parietal, temporal and occipital lobes, consistent with reversible posterior leukoencephalopathy syndrome (RPLS). Based on a detailed diagnosis, the response to treatment and follow-up, it was concluded that RPLS was closely associated with chronic graft-versus-host disease in the patient. The present case report is described in order to increase the awareness of RPLS.

Childhood posterior reversible encephalopathy syndrome: Magnetic resonance imaging findings with emphasis on increased leptomeningeal FLAIR signal

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiologic syndrome characterized clinically by headache, seizures, and altered sensorium and radiological changes which are usually reversible. The purpose of this study was to describe the spectrum of magnetic resonance imaging (MRI) findings in childhood PRES, to determine the common etiologies for childhood PRES, and to have an insight into the pathophysiology of PRES.

METHODS

The MRI results of 20 clinically diagnosed cases of PRES between July 2011 and June 2013 were reviewed. The final diagnosis of PRES was based on the clinical presentation and the MRI features at the time of presentation, which resolved on the follow-up imaging. The medical records of the patients were reviewed to determine the underlying medical disease.

RESULTS

Eight out of the 20 patients included in the study were on cyclosporine or tacrolimus based immunosuppressant therapy for kidney transplant. Four patients had severe hypertension at presentation. The most common MRI finding was high T2-fluid-attenuated inversion recovery (FLAIR) signal in the cortex and subcortical white matter of both cerebral hemispheres, particularly in the parietal and occipital lobes (n=16). The second most common MRI finding was increased leptomeningeal FLAIR signal (n=7). Out of seven patients with leptomeningeal signal, five demonstrated leptomeningeal enhancement as well. Four out of these seven patients had no other parenchymal findings.

CONCLUSION

Childhood PRES is commonly seen in the setting of immunosuppressant therapy for kidney transplant, severe hypertension and cancer treatment. There was high incidence of increased leptomeningeal FLAIR signal and leptomeningeal enhancement in our study. It supports the current theory of endothelial injury with increased microvascular permeability as the potential pathophysiology of PRES. Also, absence of elevated blood pressure in majority of the patients in our study supports the theory of direct endothelial injury by some agents leading to vasogenic edema.

Clinical Management of Posterior Reversible Encephalopathy Syndrome after Allogeneic Hematopoietic Stem Cell Transplantation: A Case Series and Review of the Literature

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a rare but serious complication after allogeneic hematopoietic stem cell transplantation (alloHSCT). Among others, calcineurin inhibitors (CNI) for prophylaxis of graft-versus-host disease (GvHD) may promote the development of PRES, but the pathomechanism is still controversial. Discontinuation of CNI facilitates remission of symptoms but might contribute to the unfavorable prognosis of PRES due to an elevated incidence of GvHD.

METHODS

This is a case series of 7 patients with PRES from a retrospective analysis of 146 consecutive patients who received alloHSCT for hematologic malignancies.

RESULTS

At the onset of PRES, all patients presented a systemic infection, while no influence was seen for underlying disease, conditioning regimen, donor type, or GvHD. Discontinuation of CNI and control of the blood pressure reversed neurological symptoms in 6 patients, while 1 patient died from septic multiorgan failure. After bridging with prednisolone and/or mycophenolic acid, replacement of CNI by the mammalian target of rapamycin (mTOR) inhibitor everolimus effectively prevented severe GvHD without recurrence of PRES.

CONCLUSIONS

A systemic infection/inflammation may be an important cause of PRES. Prophylaxis of GvHD by the mTOR inhibitor everolimus in case of PRES after alloHSCT demonstrated promising results but needs to be validated in larger cohorts.

Posterior Reversible Encephalopathy Syndrome in Patients With Cancer

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is characterized by neurologic symptoms with typical lesions on neuroimaging and may be associated with chemotherapy and immunosuppressive agents used in patients with cancer. We described the spectrum of PRES at a major cancer center.

METHODS

We reviewed charts of adults with PRES between 2005 and 2011 at Memorial Sloan Kettering Cancer Center for clinical information and outcome.

RESULTS

We identified 21 women (68%) and 10 men (median cohort age: 58 years). Solid tumors (n = 22, 71%) were more common than hematologic (n = 8) or primary brain malignancies (n = 1). Prior brain irradiation (16%) and central nervous system metastases (10%) were uncommon. There were 55% who received chemotherapy or targeted therapy within the month preceding PRES, including 6 patients who received bevacizumab; PRES followed allogeneic stem cell transplantation in 5 (16%). Presenting symptoms included confusion (71%), seizure (58%), and headache (48%). Maximum systolic and diastolic blood pressures were similar among patients grouped by cancer type, chemotherapy or bevacizumab use, and atypical imaging. Moreover, 37% of patients with both magnetic resonance imaging (MRI) and computed tomography (CT) had normal CT concurrent with PRES on MRI, and 84% returned to neurologic baseline at a median of 7.5 days (range: 1-167 days) from onset. Successful anticonvulsant taper was achieved in 51%. Chemotherapy rechallenge was attempted in 41% without recurrent PRES. Autopsy revealed nonspecific changes isolated to radiographically affected areas in one of two patients.

CONCLUSION

Recent chemotherapy, particularly bevacizumab, is common in cancer patients with PRES. Clinical and radiographic presentations may vary; MRI appears more sensitive than CT. Anticonvulsant taper and chemotherapy rechallenge is often possible.

IMPLICATIONS FOR PRACTICE

Posterior reversible encephalopathy syndrome is characterized by neurologic symptoms with typical lesions on neuroimaging and may be associated with chemotherapy and immunosuppressive agents used in patients with cancer. Clinical and radiographic presentations are protean, and magnetic resonance imaging is more sensitive than computed tomography. Recovery is common, and many patients can be successfully rechallenged with the apparently offending chemotherapy agent or regimen.

Neurological complications after allogeneic hematopoietic stem cell transplantation in children, a single center experience

In this study, we retrospectively examined the data of children who underwent allo-HSCT from HLA-matched family donors. We analyzed the incidence, etiological factors, clinical characteristics, possible reasons, risk factors, and follow-up of neurologic complications. BU-based conditioning regimens were used in most of the cases (n = 62). The median duration of follow-up for the 89 patients was 20 months (range 1-41 months). Eleven percent of transplanted children developed one or more neurological symptoms after HSCT with a median observation time of two months (range -6 days to 18 months). The median age of the four girls and six boys with neurological complication was 13 yr (range 5.3-17.6 yr). Cylosporine A neurotoxicity was diagnosed in five children, four of them were PRES. The rest of complications were BU and lorazepam toxicity, an intracranial hemorrhage, a sinovenous thrombosis, and a transient ischemic attack during extracorpereal photopheresis. No difference was found between groups of neurological complication according to age, gender, diagnosis, hospitalization time, neutrophil and platelet engraftment time, stem cell source, and conditioning regimen, acute and chronic GVHD or VOD. Neurological complication was the cause of death in one patient (1.1%).

Posterior reversible encephalopathy syndrome

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

High incidence of severe cyclosporine neurotoxicity in children affected by haemoglobinopaties undergoing myeloablative haematopoietic stem cell transplantation: early diagnosis and prompt intervention ameliorates neurological outcome

Background

Neurotoxicity is a recognized complication of cyclosporine A (CSA) treatment. The incidence of severe CSA-related neurological complications following hematopoietic stem cell transplantation (HSCT) is 4-11%.

Methods

We describe 6 cases of CSA related neurotoxicity out of 67 matched related HSCT performed in paediatric Middle East patients affected by haemoglobinopaties (5 beta thalassemia major, 1 sickle cell disease-SCD). Conditioning regimen consisted of iv busulphan, cyclophosphamide and graft-versus-host-disease (GvHD) prophylaxis with CSA, methylprednisolone, methotrexate and ATG.

Results

All 6 patients presented prodromes such as arterial hypertension, headache, visual disturbances and vomiting, one to two days before overt CSA neurotoxicity. CSA neurotoxicity consisted of generalized seizures, signs of endocranial hypertension and visual disturbances at a median day of onset of 11 days after HSCT (range +1 to +40). Brain magnetic resonance imaging (MRI) performed in all subjects showed reversible leukoencephalopathy predominantly in the posterior regions of the brain (PRES) in 5/6 patients. EEG performed in 5/6 patients was always abnormal. Neurotoxicity was not explainable by high CSA blood levels, as all patients had CSA in the therapeutic range with a median of 178 ng/ml (range 69-250). CSA was promptly stopped and switched to tacrolimus with disappearance of clinical and radiological findings. All patients are symptoms-free at a median follow up of 882 days (range 60-1065).

Conclusions

Our experience suggests that paediatric patients with haemoglobinopaties have a high incidence of CSA related neurological events with no correlation between serum CSA levels and neurotoxicity. Prognosis is good following CSA removal. Specific prodromes such as arterial hypertension, headache or visual disturbances occurring in the early post-transplant period should be carefully evaluated with electrophysiological and MRI-based imaging in order to intervene promptly and avoid irreversible sequels.

Hemorrhage in posterior reversible encephalopathy syndrome: imaging and clinical features

BACKGROUND AND PURPOSE

Hemorrhage is known to occur in posterior reversible encephalopathy syndrome (PRES), but the characteristics have not been analyzed in detail. The purpose of this study was to evaluate the imaging and clinical features of hemorrhage in PRES.

MATERIALS AND METHODS

Retrospective assessment of 151 patients with PRES was performed, and 23 patients were identified who had intracranial hemorrhage at toxicity. Hemorrhage types were identified and tabulated, including minute focal hemorrhages (<5 mm), sulcal subarachnoid hemorrhage, and focal hematoma. Clinical features of hemorrhage and nonhemorrhage PRES groups were evaluated, including toxicity blood pressure, coagulation profile/platelet counts, coagulation-altering medication, and clinical conditions associated with PRES. Toxicity mean arterial pressure (MAP) groups were defined as normal (<106 mm Hg), mildly hypertensive (106-116 mm Hg), or severely hypertensive (>116 mm Hg).

RESULTS

The overall incidence of hemorrhage was 15.2%, with borderline statistical significance noted between the observed clinical associations (P = .07). Hemorrhage was significantly more common (P = .02) after allogeneic bone marrow transplantation (allo-BMT) than after solid-organ transplantation. The 3 hemorrhage types were noted with equal frequency. A single hemorrhage type was found in 16 patients, with multiple types noted in 7. Patients undergoing therapeutic anticoagulation were statistically more likely to develop hemorrhage (P = .04). No difference in hemorrhage incidence was found among the 3 blood pressure subgroups (range, 14.9%-15.9%).

CONCLUSIONS

Three distinct types of hemorrhage (minute hemorrhage, sulcal subarachnoid hemorrhage, hematoma) were identified in PRES with equal frequency. The greatest hemorrhage frequency was seen after allo-BMT and in patients undergoing therapeutic anticoagulation. Hemorrhage rate was independent of the toxicity blood pressure.

Posterior reversible encephalopathy syndrome, part 1: fundamental imaging and clinical features

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique CT or MR imaging appearance. Recognized in the setting of a number of complex conditions (preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune disease and high dose chemotherapy) the imaging, clinical and laboratory features of this toxic state are becoming better elucidated. This review summarizes the basic and advanced imaging features of PRES, along with pertinent features of the clinical and laboratory presentation and available histopathology. Many common imaging/clinical/laboratory observations are present among these patients, despite the perception of widely different associated clinical conditions.

Posterior reversible encephalopathy syndrome, part 2: controversies surrounding pathophysiology of vasogenic edema

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state accompanied by a unique brain imaging pattern typically associated with a number of complex clinical conditions including: preeclampsia/eclampsia, allogeneic bone marrow transplantation, solid organ transplantation, autoimmune diseases and high dose cancer chemotherapy. The mechanism behind the developing vasogenic edema and CT or MR imaging appearance of PRES is not known. Two theories have historically been proposed: 1) Severe hypertension leads to failed auto-regulation, subsequent hyperperfusion, with endothelial injury/vasogenic edema and; 2) vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic edema. The strengths/weaknesses of these hypotheses are reviewed in a translational fashion including supporting evidence and current available imaging/clinical data related to the conditions that develop PRES. While the hypertension/hyperperfusion theory has been most popular, the conditions associated with PRES have a similar immune challenge present and develop a similar state of T-cell/endothelial cell activation that may be the basis of leukocyte trafficking and systemic/cerebral vasoconstriction. These systemic features along with current vascular and perfusion imaging features in PRES appear to render strong support for the older theory of vasoconstriction coupled with hypoperfusion as the mechanism.

Posterior reversible encephalopathy syndrome after solid organ transplantation

BACKGROUND AND PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is known to occur after solid organ transplantation (SOT), potentially associated with cyclosporine and tacrolimus. In this study, we assess the frequency and clinical and imaging characteristics of PRES after SOT.

MATERIALS AND METHODS

We identified 27 patients (13 men and 14 women; age range, 22-72 years) who developed PRES after SOT. Features noted included SOT subtype, incidence and timing of PRES, infection and rejection, mean arterial pressure (MAP), and toxicity brain edema.

RESULTS

PRES developed in 21 (0.49%) of 4222 patients who underwent transplantation within the study period (no significant difference among SOT subtypes). Transplantation was performed in 5 patients before the study period, and 1 patient underwent transplantation elsewhere. In consideration of all 27 patients, PRES typically developed in the first 2 months in patients who had SOT of the liver (9 of 10 patients) and was associated with cytomegalovirus (CMV), mild rejection, or systemic bacterial infection. PRES also typically developed after 1 year in patients who had SOT of the kidney (8 of 9 patients) and was associated with moderate rejection or bacterial infection. Toxicity MAP was significantly lower (P < .001) in liver transplants (average MAP, 104.8 +/- 16 mm Hg) compared with that in kidney transplants (average MAP, 143 +/- 20 mm Hg). Toxicity brain edema was significantly greater (P < .001) in patients who had liver transplants and developed PRES compared with patients who had undergone kidney transplants despite severe hypertension in those who had the kidney transplants.

CONCLUSION

Patients who had undergone SOTs have a similar low incidence of developing PRES. Differences between those who have had liver and kidney transplants included time after transplant, toxicity MAP, and PRES vasogenic edema noted at presentation. In patients who have undergone kidney transplants, severely elevated MAP was associated with reduced, not greater, brain edema.

Catheter angiography, MR angiography, and MR perfusion in posterior reversible encephalopathy syndrome

BACKGROUND AND PURPOSE

The cause of posterior reversible encephalopathy syndrome (PRES) is unknown. Two primary hypotheses exist: 1) hypertension exceeding auto-regulatory limits leading to forced hyper-perfusion and 2) vasoconstriction and hypo-perfusion leading to ischemia with resultant edema. The purpose of this study was to evaluate the catheter angiography (CA), MR angiography (MRA), and MR perfusion (MRP) features in PRES in order to render further insight into its mechanism of origin.

MATERIALS AND METHODS

In 47 patients with PRES, 9 CAs and 43 MRAs were evaluated for evidence of vasculopathy (vasoconstriction and vasodilation), and 15 MRP studies were evaluated for altered relative cerebral blood volume (rCBV) in PRES lesions and regions. Visualization of vessels on MRA and toxicity blood pressures were compared with the extent of hemispheric vasogenic edema.

RESULTS

Vasculopathy was present in 8 of 9 patients on CA (direct correlation to MRA in 3/6 patients). At MRA, moderate to severe vessel irregularity consistent with vasoconstriction and vasodilation was present in 30 of 43 patients and vessel pruning or irregularity in 7 patients, with follow-up MRA demonstrating reversal of vasoconstriction or vasodilation in 9 of 11 patients. Vasogenic edema was less in patients with hypertension compared with patients who were normotensive. Preserved normal length of the posterior cerebral artery (PCA) was commonly seen in patients with severe hypertension despite diffuse or focal vasoconstriction or vasodilation. In these patients, lengthier visualization of the distal PCA correlated with a lower grade of hemispheric edema (P = .002). Cortical rCBV was significantly reduced in 51 of 59 PRES lesions and regions compared with a healthy reference cortex (average 61% of reference cortex) with mild decrease in the remainder.

CONCLUSION

Vasculopathy was a common finding on CA and MRA in our patients with PRES, and MRP demonstrated reduced cortical rCBV in PRES lesions. Vasogenic edema was reduced in patients with hypertension, and superior distal PCA visualization correlated with reduced hemispheric edema in patients with PRES and severe hypertension.

Distinct imaging patterns and lesion distribution in posterior reversible encephalopathy syndrome

BACKGROUND AND PURPOSE

Although the term posterior reversible encephalopathy syndrome (PRES) was popularized because of the typical presence of vasogenic edema in the parietal and occipital lobes, other regions of the brain are also frequently affected. We evaluated lesion distribution with CT and MR in a large cohort of patients who experienced PRES to comprehensively assess the imaging patterns identified.

MATERIALS AND METHODS

The locations of the PRES lesion at toxicity were comprehensively identified and tabulated in 136 patients by CT (22 patients) and MR (114 patients) imaging including the hemispheric, basal ganglial, and infratentorial locations. Clinical associations along with presentation at toxicity including blood pressure were assessed.

RESULTS

Vasogenic edema was consistently present in the parietal or occipital regions (98%), but other locations were common including the frontal lobes (68%), inferior temporal lobes (40%), and cerebellar hemispheres (30%). Involvement of the basal ganglia (14%), brain stem (13%), and deep white matter (18%) including the splenium (10%) was not rare. Three major patterns of PRES were noted: the holohemispheric watershed (23%), superior frontal sulcal (27%), and dominant parietal-occipital (22%), with additional common partial or asymmetric expression of these primary PRES patterns (28%).

CONCLUSION

Involvement of the frontal lobe, temporal lobe, and cerebellar hemispheres is common in PRES, along with the occasional presence of lesions in the brain stem, basal ganglia, deep white matter, and splenium. Three primary PRES patterns are noted in the cerebral hemispheres, along with frequent partial or asymmetric expression of these PRES patterns. Awareness of these patterns and variations is important to recognize PRES neurotoxicity more accurately when present.