Posterior reversible encephalopathy syndrome after solid organ transplantation

Clinical features and outcomes of posterior reversible encephalopathy syndrome after heart transplantation: a case series

Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disease that may be associated with hypertension, autoregulatory failure, and the use of calcineurin inhibitors following heart transplantation (HT). In this article, we present a case series of PRES, discussing its potential causes and management strategies. Among the 126 HT recipients at our hospital, four were diagnosed with PRES. Three of these patients developed PRES within 7 days after HT. Prior to the onset of PRES, all patients experienced sustained hypertension, and strict blood pressure (BP) control was maintained. Three of the four patients recovered without PRES recurrence, while one patient died of sepsis after an episode of altered consciousness. Hypertension was observed in all patients prior to the onset of PRES, and the majority experienced symptom improvement with BP control. While most cases of PRES were reversible with conservative treatment, including the administration of antiepileptics, one irreversible case resulted in in-hospital mortality. Thus, PRES can have serious outcomes and is not invariably benign.

Posterior Reversible Encephalopathy Syndrome With Hemorrhagic Transformation in the Postoperative Period of a Kidney Transplant

Patients with end-stage renal disease (ESRD) who undergo kidney transplantation are at an increased risk of developing surgical and/or medical complications. Posterior reversible encephalopathy syndrome (PRES) is a rare complication that occurs in 0.34% of kidney transplant patients. It is characterized by a combination of neurological manifestations, risk factors, and characteristic radiological findings in neuroimaging studies. The development of PRES has been associated with various medical conditions and factors, including hypertension, the use of cytotoxic and immunosuppressive drugs, acute or chronic kidney disease, pre-eclampsia/eclampsia, autoimmune diseases, and solid organ and bone marrow transplantation. This report presents the case of a 19-year-old woman diagnosed with ESRD on hemodialysis due to lupus nephritis who experienced an episode of PRES with intraparenchymal hemorrhage during the postoperative period of kidney transplantation. The case emphasizes the importance of closely monitoring these patients during this period to enable early diagnosis and timely treatment of complications, ensuring a favorable prognosis.

Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Kidney transplantation is the first-choice treatment for end-stage renal disease (ESRD). Kidney transplant recipients (KTRs) are at higher risk of experiencing a life-threatening event requiring intensive care unit (ICU) admission, mainly in the late post-transplant period (more than 6 months after transplantation). Urosepsis and bloodstream infections account for almost half of ICU admissions in this population; in addition, potential side effects related to immunosuppressive treatment should be accounted for cytotoxic and ischemic changes induced by calcineurin inhibitor (CNI), sirolimus/CNI-induced thrombotic microangiopathy and posterior reversible encephalopathy syndrome. Throughout the ICU stay, Acute Kidney Injury (AKI) incidence is common and ranges from 10% to 80%, and up to 40% will require renal replacement therapy. In-hospital mortality can reach 30% and correlates with acute illness severity and admission diagnosis. Graft survival is subordinated to baseline estimated glomerular filtration rate (eGFR), clinical presentation, disease severity and potential drug nephrotoxicity. The present review aims to define the impact of AKI events on short- and long-term outcomes in KTRs, focusing on the epidemiologic data regarding AKI incidence in this subpopulation; the pathophysiological mechanisms underlying AKI development and potential AKI biomarkers in kidney transplantation, graft and patients' outcomes; the current diagnostic work up and management of AKI; and the modulation of immunosuppression in ICU-admitted KTRs.

Drugs associated with posterior reversible encephalopathy syndrome, a worldwide signal detection study

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) can occur in a variety of clinical conditions, such as severe hypertension, pregnancy, inflammatory diseases, hematopoietic stem cells or solid organ transplantation. Apart increased blood pressure levels and altered renal function, several drugs have been reported as potential triggering factor. These descriptions are nevertheless limited to case reports or small case series. Systematic analysis of drugs associated with PRES using global pharmacovigilance database is lacking and can be useful.

METHODS

We performed a disproportionality analysis using VigiBase, the World Health Organization pharmacovigilance database, using the information component (IC). The IC compares observed and expected values to find associations between drugs and PRES using disproportionate Bayesian reporting. An IC_0.25 (lower end of the IC 95% credibility interval) > 0 is considered statistically significant.

RESULTS

Here we present an analysis of 3278 cases of PRES reported in VigiBase. These results identified 73 molecules statistically associated with PRES using full database as background with an IC_0.25 > 0. Only 34% (N = 25/73) of them had this information written in the summary of product characteristics. The main drug classes involved were antineoplastic and immunomodulating agents and the drugs with the greatest number of cases were tacrolimus, cyclosporin, bevacizumab, methotrexate, and vincristine. An overall mortality of 8.1% (N = 267/3278) was identified in cases of drug-associated PRES.

CONCLUSION

These results will help clinicians identify potential suspected drugs associated with PRES and decide which drug to discontinue and eventually lead to a re-evaluation of drug labels for some molecules.

Posterior reversible encephalopathy syndrome after lung transplantation: Risk factors and management

INTRODUCTION

Posterior reversible encephalopathy syndrome is a rare neurologic complication that can occur under immunosuppressive therapy with CNI after organ transplantation.

METHODS

We retrospectively reviewed medical records of 545 patients who underwent lung transplantation between 2012 and 2019. Within this group, we identified 30 patients with neurological symptoms typical of PRES and compared the characteristics of patients who were diagnosed with PRES (n = 11) to those who were not (n = 19).

RESULTS

The incidence of PRES after lung transplantation was 2%. Notably, 73% of the patients with PRES were female and the mean age was 39.2. Seizure (82% vs. 21%, p = .002) was the most common neurological presentation. The risk of developing PRES was significantly associated with age (OR = .92, p < .0001) and having cystic fibrosis (CF) (OP = 10.1, p < .0001). Creatinine level (1.9 vs. 1.1 mg/dl, p = .047) and tacrolimus trough level (19.4 vs. 16.5 ng/ml, p = .048) within 1 week prior to neurological symptoms were significantly higher in patients with PRES.

CONCLUSION

Renal insufficiency and high tacrolimus levels are associated with PRES. A change of immunosuppressive drug should be done after confirmed PRES diagnosis or immediately in case of severe neurological dysfunction to improve neurological outcomes and minimize the risk of early allograft rejection.

Acute obstructive hydrocephalus in posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is an uncommon, subacute neurological disorder that presents radiologically with a pattern of bilateral parieto-occipital areas of vasogenic oedema. Conditions commonly associated with PRES include autoimmune disorders, cytotoxic drugs, metabolic abnormalities and, most frequently, hypertensive emergencies. Clinically, headache, visual disturbances, seizures and an altered level of consciousness are often reported. The outcome is favourable if the underlying cause is addressed. Posterior fossa involvement resulting in obstructive hydrocephalus is a rare presentation and may be misdiagnosed as a mass lesion or infection, leading to delayed or unnecessary treatment. We describe the clinical presentation, findings on neuroimaging and conservative management of a man with PRES resulting in severe cerebellar oedema and acute obstructive hydrocephalus. This case illustrates that awareness of atypical neuroimaging in PRES is important for the management of these patients and to avoid morbidity and mortality.

Neuropsychiatric Symptoms after Liver Transplantation in a 65-Year-Old Male Patient

The development of immunosuppressants has been key for the advancement of solid organ transplant surgery. Specifically, cyclosporine, tacrolimus, or everolimus have significantly increased the survival rate of patients by reducing the risk of a rejection of the transplanted organ and limiting graft-versus-host disease. We report the case of a 65-year-old man who, after undergoing a liver transplantation and receiving an immunosuppressive treatment with cyclosporine and everolimus, presented severe obsessive, psychotic, and behavioral symptoms over the past three years, and describe the pharmacological and non-pharmacological interventions implemented against these symptoms. In this case, the immunosuppressants used have been cyclosporine and, preferably, everolimus. On the other hand, potential adverse reactions to the treatment have been observed, including neuropsychiatric symptoms such as tremor, anxiety, dysthymia, psychosis, and behavioral disorders, which make it necessary to use corrective psychoactive drugs such as benzodiazepines, antidepressants, and antipsychotics, combined with non-pharmacological interventions. A transversal approach, from the medical and psychosocial disciplines, facilitates success in managing neuropsychiatric symptoms after soft organ transplants.

Model-informed Estimation of Acutely Decreased Tacrolimus Clearance and Subsequent Dose Individualization in a Pediatric Renal Transplant Patient with Posterior Reversible Encephalopathy Syndrome

BACKGROUND

Considerable inter-patient and inter-occasion variability has been reported in tacrolimus pharmacokinetics (PK) in the pediatric renal transplant population. The present study investigated tacrolimus PK in a 2-year-old post-renal transplant patient and a known CYP3A5 expresser who developed posterior reversible encephalopathy syndrome (PRES) and had significantly elevated tacrolimus blood concentrations during tacrolimus treatment. A model-informed PK assessment was performed to assist with precision dosing. Tacrolimus clearance was evaluated both before and after the development of PRES on post-transplant day (PTD) 26.

METHODS

A retrospective chart review was conducted to gather dosing data and tacrolimus concentrations, as part of a clinical pharmacology consultation service. Individual PK parameters were estimated by Bayesian estimation using a published pediatric PK model. Oral clearance (CL/F) was estimated for three distinct time periods-before CNS symptoms (PTD 25), during the PRES event (PTD 27-30), and after oral tacrolimus was re-started (PTD 93).

RESULTS

Bayesian estimation showed an estimated CL/F of 15.0 L/h in the days preceding the PRES event, compared to a population mean of 16.3 L/h (95% confidence interval 14.9-17.7 L/h) for CYP3A5 expressers of the same age and weight. Samples collected on PTD 27-30 yielded an estimated CL/F of 3.6 L/h, a reduction of 76%, coinciding with clinical confirmation of PRES and therapy discontinuation. On PTD 93, an additional assessment showed a stable CL/F value of 14.5 L/h one month after re-initiating tacrolimus and was used to recommend a continued maintenance dose.

CONCLUSION

This is the first report to demonstrate acutely decreased tacrolimus clearance in PRES, likely caused by the downregulation of metabolizing enzymes in response to inflammatory cytokines. The results suggest the ability of model-informed Bayesian estimation to characterize an acute decline in oral tacrolimus clearance after the development of PRES, and the role that PK estimation may play in supporting dose selection and individualization.

A Case of Pediatric Posterior Reversible Encephalopathy Syndrome (PRES) Secondary to Post-streptococcal Glomerulonephritis: A Literature Review and Assessment of Treatment Modalities

Posterior reversible encephalopathy syndrome (PRES) is a disorder that most commonly affects adults, and is characterized by neurologic symptoms such as encephalopathy, seizures, headaches, and visual disturbances. It usually occurs in the context of other systemic disturbances that result in hypertensive crises, such as renal failure, cytotoxic drugs, and autoimmune conditions. In children, it rarely manifests following chemotherapy induction or hematopoietic stem cell transplantation. No cases have been reported in the English literature connecting renal dysfunction and hypertensive emergency secondary to post-streptococcal glomerulonephritis (PSGN) with PRES. We present a case of an eight-year-old boy, who developed a constellation of symptoms suggestive of PSGN and later developed PRES. PRES is often confirmed upon suspicion through brain MRI showing subcortical edema of various brain regions including occipital, temporal, or parietal cortices. Our patient demonstrated subcortical edema of the bilateral occipital lobes and right cerebellar hemisphere, with positive antistreptolysin O (ASO) titers demonstrating PSGN as the likely etiology for his hypertensive emergency. Management included antihypertensive and anticonvulsant treatment, which allowed the resolution of the offending hypertensive emergency that resulted in PRES. Our case adds to the growing body of literature on PRES and describes a new etiology of pediatric PRES secondary to PSGN.

Posterior reversible encephalopathy syndrome associated with use of Atezolizumab for the treatment of relapsed triple negative breast cancer

Posterior reversible encephalopathy syndrome (PRES) is a complex neurological disorder with multiple clinical manifestations including headaches, seizures, and altered mental status. It is associated with many conditions including malignancy and medications including chemotherapy and immunotherapy. We report the case of a 56-year old female with a history of advanced triple negative breast cancer treated with atezolizumab (a PD-L1 inhibitor), paclitaxel and ipatasertib (investigational AKT inhibitor), who developed hypertension, confusion, and imaging findings consistent with PRES.

Late presentation of posterior reversible encephalopathy syndrome following liver transplantation in the setting of tacrolimus and cannabis use

A 45-year-old female presented to hospital with confusion and visual disturbances. She had undergone a liver transplant 3 years prior for cirrhosis secondary to primary biliary cholangitis. Computed tomography and magnetic resonance imaging of the brain showed features consistent with posterior reversible encephalopathy syndrome. Her medications included tacrolimus, sirolimus, and prednisone. She reported smoking 4 grams of cannabis per day. Following cessation of tacrolimus, the patient's encephalopathy and visual disturbances resolved. To our knowledge, this case represents the longest time elapsed from liver transplantation to the development of tacrolimus-associated posterior reversible encephalopathy syndrome in the literature. This case highlights the potential danger of cannabis use in transplant recipients who are on immunosuppressants such as tacrolimus. Clinicians should have a high index of suspicion for posterior reversible encephalopathy syndrome in post-transplant patients presenting with altered mental status, even years after liver transplantation, and be familiar with potential interactions between cannabis and immunosuppressants.

Posterior reversible encephalopathy syndrome (PRES): diagnosis and management

Posterior reversible encephalopathy syndrome (PRES) may present with diverse clinical symptoms including visual disturbance, headache, seizures and impaired consciousness. MRI shows oedema, usually involving the posterior subcortical regions. Triggering factors include hypertension, pre-eclampsia/eclampsia, renal failure, cytotoxic agents and autoimmune conditions. The mechanism underlying PRES is not certain, but endothelial dysfunction is implicated. Treatment is supportive and involves correcting the underlying cause and managing associated complications, such as seizures. Although most patients recover, PRES is not always reversible and may be associated with considerable morbidity and even mortality.

Posterior Reversible Encephalopathy Syndrome: A Narrative Review for Emergency Clinicians

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic disorder characterized by seizures, headache, altered mental status, and visual disturbances, and is often associated with acute hypertension.

OBJECTIVE

This narrative review provides a focused description of the presentation, diagnostic evaluation, and management of PRES.

DISCUSSION

PRES is associated with a variety of factors, including acute rise in blood pressure, renal disease, preeclampsia/eclampsia, and immunosuppressive therapy. The pathophysiology is theorized to involve dysfunction of cerebral autoregulation leading to vascular leak or endothelial dysfunction resulting in vasogenic edema. In the emergency department (ED), clinical findings suggestive of PRES should prompt diagnostic testing focused on confirming the diagnosis and excluding other conditions that may present similarly. Laboratory studies are primarily useful for excluding alternative diagnoses. Computed tomography (CT) and, in particular, magnetic resonance imaging (MRI) are the recommended neuroimaging modalities for diagnosis. CT and MRI may demonstrate cerebral vasogenic edema, most often in the distribution of the posterior circulation. Treatment involves management of seizures, control of blood pressure if elevated, and treatment of any underlying trigger.

CONCLUSION

PRES is a neurological disorder that is typically reversible if recognized on presentation and promptly and appropriately managed. This narrative review characterizes this condition for emergency clinicians.

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.

Neuroimaging findings of posterior reversible encephalopathy syndrome (PRES) following haematopoietic stem cell transplantation in paediatric recipients

BACKGROUND

Haematopoietic stem cell transplantation (HSCT) is used worldwide in various malignant and nonmalignant childhood diseases, including haematologic, genetic, autoimmune and metabolic disorders, and is the only curative treatment for many of these illnesses. The survival rates of many childhood diseases have been increased due to HSCT treatment. However, associated complications are still important for management. Central nervous system (CNS) complications in paediatric HSCT recipients can be associated with high morbidity and significantly contribute to mortality. Posterior reversible encephalopathy syndrome (PRES) is one of the most common CNS complications in patients with neurological symptoms following HSCT. Magnetic resonance imaging (MRI) is the modality of choice and shows typical bilateral vasogenic oedema at the posterior parts of the cerebral hemispheres; however, various atypical imaging manifestations can also occur. In this study, we retrospectively examined CNS complications in our paediatric HSCT recipients with a focus on the typical and atypical neuroimaging manifestations of PRES following HSCT.

METHODS

We retrospectively reviewed the medical records of 300 consecutive paediatric HSCT recipients from January 2014 to November 2018. A total of 130 paediatric HSCT recipients who experienced neurological signs and symptoms and were evaluated with neuroimaging studies following HSCT were enrolled in the study. The timing of CNS complications was defined according to immune status, including the pre-engraftment period (< 30 days after HSCT), the early postengraftment period (30-100 days after HSCT), and the late postengraftment period (> 100 days after HSCT), which were defined as phases 1, 2 and 3, respectively.

RESULTS

Overall, 130 paediatric HSCT recipients experienced neurological signs and symptoms and therefore underwent neuroimaging examinations. Among these 130 patients, CNS complications were present in 23 patients (17.6%, 23/130), including 13 (56.5%) females and 10 (43.5%) males with a median age of 8.0 years (range, 8 months to 18.0 years). Among these 23 patients, 14 cases of PRES (60.9%), 5 (21.7%) cases of leukoencephalopathy, 3 cases of acute subdural haemorrhage (ASDH) (13%) and 1 (4.3%) case of fungal CNS infection were identified by neuroimaging. On MRI, typical parietooccipital vasogenic oedema was present in 78.5% of the PRES cases (11/14). The following atypical neuroimaging manifestations were observed: isolated involvement of the bilateral frontal lobes in 1 case, isolated cerebellar vermis involvement in 1 case, and isolated basal ganglia involvement in 1 case. Restricted diffusion associated with cytotoxic damage was demonstrated in 2 of 14 cases, one of which also showed subacute cytotoxic injury with ADC pseudonormalization.

CONCLUSION

Paediatric HSCT recipients presenting with CNS signs and symptoms should be evaluated by neuroimaging studies for timely diagnosis and early management. PRES is the most common CNS complication and may present with atypical MRI manifestations, which should not dissuade a PRES diagnosis in appropriate clinical settings.

Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome as Syndromes of Cerebrovascular Dysregulation

PURPOSE OF REVIEW

This article describes the causes, clinical and imaging features, management, and prognosis of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS), in which the underlying pathophysiology is related to reversible dysregulation of the cerebral vasculature.

RECENT FINDINGS

PRES and RCVS are descriptive terms, each bringing together conditions with similar clinical-imaging manifestations. Headache, visual symptoms, seizures, and confusion occur in both syndromes. RCVS is usually heralded by recurrent thunderclap headaches, whereas encephalopathy and seizures are typical in PRES. In PRES, brain imaging shows reversible vasogenic edema that is typically symmetric and located in subcortical regions (mostly posterior predominant). In RCVS, brain imaging is often normal; cerebral angiography shows segmental vasoconstriction-vasodilatation affecting the circle of Willis arteries and their branches. Aside from shared clinical features, significant imaging overlap exists. Both PRES and RCVS can be complicated by ischemic and hemorrhagic brain lesions; angiographic abnormalities frequently occur in PRES and vasogenic edematous lesions in RCVS. Common triggers (eg, eclampsia, vasoconstrictive and chemotherapeutic agents) have been identified. Abnormal cerebrovascular tone and endothelial dysfunction may explain both syndromes. Management of these syndromes includes the removal of identified triggers, symptomatic treatment of headache or seizures, and moderate blood pressure control. Both syndromes are self-limited, with clinical recovery occurring within days to weeks. Long-term deficits and mortality are uncommon.

SUMMARY

PRES and RCVS have been well characterized and acknowledged to have significant overlap. Advances in our understanding of pathophysiology and risk factors for poor outcome are expected to optimize the management of these not uncommon syndromes.

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.

Unusual Presentation of a Posterior Reversible Encephalopathy Syndrome With Brainstem Involvement and Subarachnoid Haemorrhage

Posterior reversible encephalopathy syndrome is an increasingly recognized disorder characterized by a headache, visual disturbances, and seizures. It is a reversible neurotoxic state, with multiple risk factors in which endothelial injury and compromised brain perfusion are the common characteristics. Diagnosis is usually made by cerebral magnetic resonance imaging that typically shows early-stage bilateral symmetrical parieto-occipital hyperintensities on T2 and fluid-attenuated inversion recovery (FLAIR) sequences. However, other locations have been described where the disease may appear less frequently. We describe the case of a 62-year-old man, with a medical history of hypertension, who presented with anisocoria with mydriatic non-reactive pupil and ptosis of the left eye. CT head showed a slightly hypodense brainstem, in relation to vasogenic edema. This was confirmed with magnetic resonance imaging. The angiography did not identify cerebral artery aneurysms. The symptoms and radiological findings were almost completely reversible after improving the patient's blood pressure. This case highlights a rare single presentation of posterior reversible encephalopathy syndrome associated with subarachnoid hemorrhage. A high index of suspicion, careful examination, and exploration with imaging techniques were essential to reach this diagnosis.

Rapid clinical recovery of posterior reversible encephalopathy syndrome in two cases of IgA nephropathy disease and nephrotic syndrome type 9 post-renal transplant

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological syndrome often associated with immunosuppressant drug use, renal disease, and eclampsia and characterized by parieto-occipital vasogenic edema that usually resolves within days. Globally and in the settings of renal transplant, literature concerning PRES is very scattered. In this report, we provide two cases, one diagnosed with IgA nephropathy and another with nephrotic syndrome type 9 that developed episodes of tonic-clonic seizure immediately after renal transplant in case 1 and four days post-transplant in case 2. The two patients had a history of hypertension, renal disease, corticosteroid and immunosuppressant drug use. Neuro-imaging showed typical vasogenic edema involving the parieto-occipital areas. Therefore, the clinical-radiological presentation confirmed the diagnosis of PRES in both cases. Also, rapid neurologic recovery was witnessed upon administration of anti-epileptic and anti-hypertensive medications. Non-discontinuation of immunosuppressants, steroids, early symptomatic management, and blood pressure control are favorable factors that might explain the rapid recovery of these two patients.

Thrombotic Microangiopathy, Antibody-Mediated Rejection, and Posterior Reversible Leukoencephalopathy Syndrome in a Liver Transplant Recipient: Interplay Between COVID-19 and Its Treatment Modalities

The present COVID-19 pandemic is a cause for concern among solid-organ transplant recipients, who are generally at high risk for infection and for whom infection with COVID-19 carries additional risks for complications and mortality that are higher than the COVID-19-associated risks for the general population. We report the case of a liver transplant recipient who presented with COVID-19 and multiple complications. A 39-year-old woman with a liver transplant was diagnosed with COVID-19 within the first week after transplant surgery. Mycophenolate was withheld, and interferon β was administered for management of COVID-19. She developed thrombotic thrombocytopenic purpura, acute antibody-mediated rejection, and posterior reversible leukoencephalopathy syndrome during hospitalization. All of these complications may be related to COVID-19 or its management modalities. We considered 3 possible causes for thrombotic thrombocytopenic purpura in this patient: the COVID-19 infection itself, immunosuppression treatment with cyclosporine, and treatment with interferon β. Immunosuppression reduction and interferon treatment may result in antibody-mediated rejection. COVID-19, thrombotic thrombocytopenic purpura, and cyclosporine may play a combined role in the development of posterior reversible leukoencephalopathy syndrome. In conclusion, thrombotic thrombocytopenic purpura, antibody-mediated rejection, and posterior reversible leukoencephalopathy syndrome may represent a continuum of 3 thrombotic microangiopathy conditions fostered by interplay between the COVID-19 infection and the treatment modalities for COVID-19 management in this patient.

The association between systemic autoimmune disorders and epilepsy and its clinical implications

Systemic autoimmune disorders occur more frequently in patients with epilepsy than in the general population, suggesting shared disease mechanisms. The risk of epilepsy is elevated across the spectrum of systemic autoimmune disorders but is highest in systemic lupus erythematosus and type 1 diabetes mellitus. Vascular and metabolic factors are the most important mediators between systemic autoimmune disorders and epilepsy. Systemic immune dysfunction can also affect neuronal excitability, not only through innate immune activation and blood-brain barrier dysfunction in most epilepsies but also adaptive immunity in autoimmune encephalitis. The presence of systemic autoimmune disorders in subjects with acute seizures warrants evaluation for infectious, vascular, toxic and metabolic causes of acute symptomatic seizures, but clinical signs of autoimmune encephalitis should not be missed. Immunosuppressive medications may have antiseizure properties and trigger certain drug interactions with antiseizure treatments. A better understanding of mechanisms underlying the co-existence of epilepsy and systemic autoimmune disorders is needed to guide new antiseizure and anti-epileptogenic treatments. This review aims to summarize the epidemiological evidence for systemic autoimmune disorders as comorbidities of epilepsy, explore potential immune and non-immune mechanisms, and provide practical implications on diagnostic and therapeutic approach to epilepsy in those with comorbid systemic autoimmune disorders.

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Posterior reversible encephalopathy syndrome after induced hypertension therapy for delayed cerebral ischemia after subarachnoid hemorrhage: A case-control study

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is associated with arterial hypertension. Our aim was to investigate whether induced hypertension (IH) as therapy for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) is associated with PRES and to identify risk factors for PRES.

MATERIAL AND METHODS

We retrospectively searched our database for patients with SAH and IH in our institution between 2009 and 2018 and identified additional cases of PRES after SAH with IH from the literature. We then analyzed demographic findings and clinical features of these patients.

RESULTS

172 patients with acute SAH received IH. PRES was diagnosed in 3/172 (1.7%) patients. Our literature search revealed 17 additional cases. The pooled PRES group (n = 20) was non-significantly older than the non-PRES group (n = 169) (median, 62.5 years vs. 52 years, p = 0.06). No significant differences were found between both groups with regard to sex (p = 0.73), Hunt & Hess-Score (p = 0.9), aneurysm treatment (p = 0.13), and time from diagnosis of SAH to the start of IH (p = 0.14).

CONCLUSIONS

PRES after IH in SAH patients occurred in 1.7% of our patients. Our results imply that it is important to be aware of a possible development of a PRES in older SAH patients with IH, irrespective of sex, initial clinical status, and treatment modality.

Neurologic Toxicities Associated with Tumor Necrosis Factor Inhibitors and Calcineurin Inhibitors

The calcineurin inhibitors cyclosporine and tacrolimus are used for their immunosuppressive effects. Neurotoxic side effects include tremor, paresthesia, and headache. Rarer neurotoxicities include seizure, posterior reversible encephalopathy syndrome, and encephalopathy. Tacrolimus tends to be more neurotoxic than cyclosporine. Management of toxicities associated with calcineurin inhibitors includes dose reduction, switching between calcineurin inhibitors, or switching to a calcineurin-free regimen. Tumor necrosis factor (TNF) inhibitors are used in autoimmune diseases. Management of demyelinating conditions among patients treated with anti-TNF should follow standard of care and withdrawal of the anti-TNF. This drug class should be avoided in patients with a history of demyelinating conditions.

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

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

Posterior reversible encephalopathy syndrome and heart failure tacrolimus-induced after liver transplantation: A case report

BACKGROUND

Patients undergoing liver transplantation can develop posterior reversible encephalopathy syndrome (PRES) and acute heart failure (HF) in the post-operative period. But PRES with HF caused by tacrolimus has rarely been described.

CASE SUMMAR

A 40-year-old female patient who had a normal preoperative cardiac and neural evaluation developed PRES with acute heart failure tacrolimus-induced after liver transplantation. The challenges associated with both diagnosis and management in the setting of a newly implanted graft are discussed.

CONCLUSION

Tacrolimus can induce neurotoxicity and then cardiac toxicity. Magnetic resonance imaging, echocardiography, and increased brain natriuretic peptide may be predictive of post-operative PRES with acute heart failure. Further investigations are necessary to verify this finding.

Cerebellar Parieto-occipital Posterior Reversible Encephalopathy Syndrome and Cerebral Metamorphopsia Associated with Asymptomatic Atrial Septum Vegetation and Renal Disease: Case Report

Patient: Female, 25-year-old

Final Diagnosis: Posterior reversible encephalopathy syndrome

Symptoms: Visual disturbances

Medication: —

Clinical Procedure: —

Specialty: Neurology

Posteriores reversibles enzephalopathisches Syndrom und Hyperammonämie: zwei Entitäten für Hirnödem und Status epilepticus bei einer Patientin nach Lungentransplantation

Fünf Wochen nach primär erfolgreicher Lungentransplantation entwickelt eine 58-jährige Patientin rasch progrediente neurologische Symptome mit Vigilanzverlust. Als Ursachen können einerseits ein posteriores reversibles enzephalopathisches Syndrom (PRES) unter Therapie mit Tacrolimus, andererseits eine schwere Hyperammonämie durch Sepsis mit Ureaplasma urealyticum identifiziert werden. Infektionen mit Ureaplasmen, die Ammoniak als Stoffwechselprodukt produzieren, werden durch spezifische „polymerase chain reaction“(PCR, Polymerase Kettenreaktion)-Verfahren zunehmend bei Immunsupprimierten identifiziert und sollten grundsätzlich als Ursache für unklare neurologische Symptome in Betracht gezogen werden.

Etiologies, Cerebral Vasomotion, and Endothelial Dysfunction in the Pathophysiology of Posterior Reversible Encephalopathy Syndrome in Pediatric Patients

The posterior reversible encephalopathy syndrome was characterized by Hinchey and colleagues in the 1990s. The condition frequently afflicts patients suffering from hematologic and solid organ malignancy and individuals undergoing transplantation. Cases are more frequently described in the adult population compared with children. In the pediatric population, malignancy, transplantation, renal disease, and hypertension represent the most common etiologies. Theories on pathogenesis have centered upon cerebrovascular dysautoregulation with increases in blood–brain barrier permeability. This generates vasogenic edema of the cerebral parenchyma and consequent neurologic deficits. The parietal and occipital lobes are affected with greatest prevalence, though frontal and temporal lobe involvement is frequent, and that of the contents of the infratentorial posterior cranial fossa are occasionally described. The clinical presentation involves a characteristic constellation of neurologic signs and symptoms, most typically inclusive of headache, visual-field disturbances, abnormalities of visual acuity, and seizures. Supportive care, withdrawal of the offending agent, antihypertensive therapy, and prophylactic anticonvulsants affect convalescence in majority of cases. The principal challenge lies in identifying the responsible agent precipitating the condition in patients with malignancy and those having undergone transplantation and thus deciding which medication among a multidrug treatment regimen to withhold, the duration of drug cessation required to effect clinical resolution, and the safety of resuming treatment with the compound. We accordingly reviewed and evaluated the literature discussing the posterior reversible encephalopathy syndrome in children.

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.

Posterior reversible encephalopathy syndrome (PRES): Is DWI a prognosis factor?

INTRODUCTION

Posterior reversible encephalopathy syndrome is a clinicoradiologic entity with typical MR imaging showing a white matter vasogenic edema predominantly affecting the occipital and parietal lobes of the brain. The aim of this article is evaluated the importance of DWI as a prognosis factor in patients with PRES.

MATERIALS AND METHODS

We reviewed data from 70 patients with PRES (35 with restricted DWI and 35 with no DWI abnormalities), that were admitted to Hospital São Lucas-PUCRS. These two groups were evaluated in age, sex, previous diseases and past medical history, use of medications, the neurologic manifestations, the highest blood pressure during the neurologic presentation and the highest creatinine during the period of observation.

RESULTS

Evaluating 70 patients with PRES with a mean age of 25.4 years old (range from 2 to 74 years old; 55 female and 15 male) we identified 35 cases were brain MRI presents with restricted DWI. Restricted DWI was associated with higher mortality in 90 days (14.2% vs 0.0%; p: 0.027).

CONCLUSIONS

Few articles present new data that will help clinicians in therapeutic decisions or that modify the knowledge of this syndrome. We suggested that restricted DWI is associated with a worst prognosis in PRES.

Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome: Distinct Clinical Entities with Overlapping Pathophysiology

The clinical and radiologic manifestations of posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome are reviewed. The relationship between these entities is discussed. A hypothesis of a common underlying pathophysiology is proposed and substantiated based on the current medical literature.

Neurologic Complications of Transplantation

Neurologic disturbances including encephalopathy, seizures, and focal deficits complicate the course 10-30% of patients undergoing organ or stem cell transplantation. While much or this morbidity is multifactorial and often associated with extra-cerebral dysfunction (e.g., graft dysfunction, metabolic derangements), immunosuppressive drugs also contribute significantly. This can either be through direct toxicity (e.g., posterior reversible encephalopathy syndrome from calcineurin inhibitors such as tacrolimus in the acute postoperative period) or by facilitating opportunistic infections in the months after transplantation. Other neurologic syndromes such as akinetic mutism and osmotic demyelination may also occur. While much of this neurologic dysfunction may be reversible if related to metabolic factors or drug toxicity (and the etiology is recognized and reversed), cases of multifocal cerebral infarction, hemorrhage, or infection may have poor outcomes. As transplant patients survive longer, delayed infections (such as progressive multifocal leukoencephalopathy) and post-transplant malignancies are increasingly reported.

Posterior reversible encephalopathy syndrome in pediatric patients: pathophysiology, diagnosis, and management

Posterior reversible encephalopathy syndrome (PRES) is well-described in adults, but has been reported with relative rarity in children, usually occurring in the context of chemotherapy for acute leukemia. Pathogenesis involves perturbed cerebral autoregulation leading to vasogenic edema predominantly affecting the parieto-occipital white matter, though involvement of the frontal and temporal lobes, as well as posterior fossa, is also described. We review the literature on the pathophysiology, diagnosis, and management of PRES in pediatric patients.

Posterior Reversible Encephalopathy Syndrome in a Five-Year-Old Child: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a neuroradiologic syndrome. The etiology of PRES is still unclear. Some factors were described. We present a case of a pediatric patient with liver transplant who developed PRES following blood transfusion while receiving tacrolimus therapy. A 5½-year-old boy who underwent living donor liver transplantation, and PRES developed on the sixth day post transplant under tacrolimus treatment after 6 hours of red blood transfusion. PRES is a rare condition; it should be kept in mind about patients who have received organ transplants and develop sudden neurologic symptoms.

Recent Topics on The Mechanisms of Immunosuppressive Therapy-Related Neurotoxicities

Although transplantation procedures have been developed for patients with end-stage hepatic insufficiency or other diseases, allograft rejection still threatens patient health and lifespan. Over the last few decades, the emergence of immunosuppressive agents such as calcineurin inhibitors (CNIs) and mammalian target of rapamycin (mTOR) inhibitors have strikingly increased graft survival. Unfortunately, immunosuppressive agent-related neurotoxicity commonly occurs in clinical practice, with the majority of neurotoxicity cases caused by CNIs. The possible mechanisms through which CNIs cause neurotoxicity include increasing the permeability or injury of the blood–brain barrier, alterations of mitochondrial function, and alterations in the electrophysiological state. Other immunosuppressants can also induce neuropsychiatric complications. For example, mTOR inhibitors induce seizures, mycophenolate mofetil induces depression and headaches, methotrexate affects the central nervous system, the mouse monoclonal immunoglobulin G2 antibody (used against the cluster of differentiation 3) also induces headaches, and patients using corticosteroids usually experience cognitive alteration. Therapeutic drug monitoring, individual therapy based on pharmacogenetics, and early recognition of symptoms help reduce neurotoxic events considerably. Once neurotoxicity occurs, a reduction in the drug dosage, switching to other immunosuppressants, combination therapy with drugs used to treat the neuropsychiatric manifestation, or blood purification therapy have proven to be effective against neurotoxicity. In this review, we summarize recent topics on the mechanisms of immunosuppressive drug-related neurotoxicity. In addition, information about the neuroprotective effects of several immunosuppressants is also discussed.

Neurologic complications of kidney transplantation

Renal transplant is the most common organ transplant in the United States, and the frequency of kidney transplants continues to rise as transplant offers improved survival and quality of life compared to dialysis. However, complications are not uncommon and patients frequently encounter issues requiring hospitalization, especially in the first year postoperatively. Complications that arise are typically related to surgical complications, immunosuppressive medications, or infection due to immunosuppression. Neurological complications are fairly common post-operatively, and are associated with increased morbidity and mortality in this population. This review discusses the most common etiologies of neurological complications after kidney transplant, including infection, malignancy, medication related, acute neuropathy, and other neurological pathology.

Arginine Vasopressin and Posterior Reversible Encephalopathy Syndrome Pathophysiology: the Missing Link?

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological entity characterized by a typical brain edema. Its pathogenesis is still debated through hypoperfusion and hyperperfusion theories, which have many limitations. As PRES occurs almost exclusively in clinical situations with arginine vasopressin (AVP) hypersecretion, such as eclampsia and sepsis, we hypothesize that AVP plays a central pathophysiologic role. In this review, we discuss the genesis of PRES and its symptoms through this novel approach. We theorize that AVP axis stimulation precipitates PRES development through an increase in AVP secretion or AVP receptor density. Activation of vasopressin V_1a receptors leads to cerebral vasoconstriction, causing endothelial dysfunction and cerebral ischemia. This promotes cytotoxic edema through hydromineral transglial flux dysfunction and may increase endothelial permeability, leading to subsequent vasogenic brain edema. If our hypothesis is confirmed, it opens new perspectives for better patient monitoring and therapies targeting the AVP axis in PRES.

Overdose of Tacrolimus as the Trigger Causing Progression of Posterior Reversible Encephalopathy Syndrome and Subsequent Hepatic Infarction After Liver Transplant: A Case Report

Posterior reversible encephalopathy syndrome is a neurotoxic state accompanied by unique brain imaging patterns and neurologic abnormalities, typically associated with several complex clinical conditions such as preeclampsia/eclampsia, solid-organ transplant procedures, autoimmune diseases, and immunosuppressive agents. The detailed mechanism of posterior reversible encephalopathy syndrome is not known, and the current therapy is only supportive care. Here, we present a 33-year-old parturient woman with preeclampsia complicated with hemolysis, elevated liver enzymes, and low platelet syndrome, fulminant hepatitis B, acute fatty liver, and posterior reversible encephalopathy syndrome. The patient developed gross hepatic infarction soon after liver transplant. After several possible causes were excluded, we found that progression of underlying posterior reversible encephalopathy syndrome-induced endothelial damage by overdose of tacrolimus may have been the major cause for deteriorating hypoperfusion of the transplanted liver and fatal graft failure. In liver transplant recipients, severe posttransplant hypoperfusion of the grafted liver may result in loss of the liver allograft and even mortality. Poor control of underlying posterior reversible encephalopathy syndrome-associated endothelial damage because of tacrolimus overdose may lead to severe hypoperfusion of grafted hepatic vessels and subsequent hepatic infarction. This report highlights tacrolimus as a potential trigger of posterior reversible encephalopathy syndrome and may inform clinical decisions regarding tacrolimus administration in liver transplant recipients with preexisting or newly developed posterior reversible encephalopathy syndrome.

Posterior Reversible Encephalopathy Syndrome as a Complication of Induced Hypertension in Subarachnoid Hemorrhage: A Case-Control Study

BACKGROUND

Induced hypertension (IH) remains the mainstay of medical management for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). However, raising blood pressure above normal levels may be associated with systemic and neurological complications, of which posterior reversible encephalopathy syndrome (PRES) has been increasingly recognized.

OBJECTIVE

To ascertain the frequency and predisposing factors for PRES during IH therapy.

METHODS

We identified 68 patients treated with IH from 345 SAH patients over a 3-yr period. PRES was diagnosed based on clinical suspicion, confirmed by imaging. We extracted additional data on IH, including baseline and highest target mean arterial pressure (MAP), comparing PRES to IH-treated controls.

RESULTS

Five patients were diagnosed with PRES at median 6.6 d (range 1-8 d) from vasopressor initiation. All presented with lethargy, 3 had new focal deficits, and 1 had a seizure. Although baseline MAP (prior to DCI) did not differ between cases and controls, both MAP immediately prior to IH (112 vs 90) and highest MAP targeted were greater (140 vs 120 mm Hg, both P < .01). Magnitude of MAP elevation was greater (54 vs 34 above baseline, P = .004) while degree of IH was not (37 vs 38 above pre-IH MAP). All 4 surviving PRES patients had complete resolution with IH discontinuation.

CONCLUSION

PRES was diagnosed in 7% of SAH patients undergoing IH therapy, most often when MAP was raised well above baseline to levels that exceed traditional autoregulatory thresholds. High suspicion for this reversible disorder appears warranted in the face of unexplained neurological deterioration during aggressive IH.