Tacrolimus-Associated Posterior Reversible Encephalopathy Syndrome after Solid Organ Transplantation

[Posterior reversible encephalopathy syndrome]

Posterior reversible encephalopathy syndrome refers to a neurological disorder characterized by headache, disorders of consciousness, visual disturbances, epileptic seizures, and subcortical vasogenic edema. About two thirds of patients develop neurological symptoms, which are associated with blood pressure fluctuations. One hypothesis is that hypertensive episodes cause autoregulatory failure, and values above the upper limit of cerebral autoregulation result in a breakthrough followed by hyperperfusion and blood-brain barrier dysfunction. In another hypothesis, endothelial dysfunction triggered by numerous factors including preeclampsia, immunosuppressive agents, chemotherapeutics, sepsis, or autoimmune disorders is thought to be the key pathomechanism. Endo- or exogenic toxic agents including pharmacological substances, cytokines, or bacterial toxins are supposed to trigger endothelial activation and dysfunction resulting in the release of vasoconstrictors, pro-inflammatory mediators, and vascular leakage. Diagnosis is usually based on clinical and neuroimaging findings that frequently show a bilateral, symmetric, and parietooccipital pattern. However, the diagnosis can often only be confirmed during the course of disease after excluding important differential diagnoses. Currently, there is no specific treatment available. Lowering of arterial blood pressure and eliminating the underlying cause usually leads to an improvement of clinical and neuroradiological findings. Admission to a critical care unit is required in about 40 % of patients due to complicating conditions including status epilepticus, cerebral vasoconstriction, ischemia, or intracerebral hemorrhage. Prognosis is favorable; in the majority of patients neurological deficits and imaging findings resolve completely.

Posterior reversible encephalopathy syndrome after pediatric heart transplantation: Increased risk for children with preexisting Glenn/Fontan physiology

Identification of risk factors for PRES after organ transplant can improve early detection and avoid permanent neurological injury. High calcineurin-inhibitor levels and hypertension are recognized risk factors for PRES in adult transplant recipients. Limited data exist regarding PRES after pediatric HTx, with studies limited to case reports. We performed a retrospective review of 128 pediatric HTx recipients to identify risk factors for PRES. Seven of 128 (5.5%) recipients developed PRES at a median of 10 days (5-57) after HTx. The median age of recipients with PRES was 10.0 yr (5.7-19.0), compared to 1.4 yr (0.0-19.8) for recipients without PRES (p = 0.010). Fewer than half of recipients with PRES had elevated post-transplant calcineurin-inhibitor levels (n = 3) and/or preceding severe hypertension (n = 3). Four of seven who developed PRES (57%) had pretransplant Glenn or Fontan physiology (G/F). G/F was a significant risk factor for PRES (RR 4.99, 95% CI: 1.19-21.0, p = 0.036). Two recipients (29%), both with severe PRES, had residual neurological symptoms. In summary, PRES occurred in 5.5% of pediatric HTx recipients and presented early after HTx. All recipients with PRES were > 5 yr. Patients with pretransplant G/F were at increased risk, a risks factor not previously described.

Posterior Reversible Encephalopathy Syndrome After Transplantation: a Review

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

Posterior Reversible Encephalopathy Syndrome in a Bone Marrow Transplant Patient: A Complication of Immunosuppressive Drugs?

Posterior reversible encephalopathy is a complex but well-recognized clinical and radiological entity associated with a variety of benign and malignant conditions including hypertensive encephalopathy, eclampsia, renal failure and immunosuppressive drugs. The pathogenesis is incompletely understood, although it seems to be related to the breakthrough of auto-regulation and endothelial dysfunction. The clinical syndromes typically involve headache, altered mental status, seizures, visual disturbance and other focal neurological signs and radiographically reversible vasogenic subcortical edema without infarction. Here, we report a case of posterior reversible encephalopathy syndrome in a patient with chronic myeloid leukemia who received allogenic bone marrow transplantation (allo-BMT) and immunosuppressive drugs.

The spectrum of posterior reversible encephalopathy in systemic lupus erythematosus

Our aim was to compare our South African cohort of systemic lupus erythematosus (SLE) and posterior reversible encephalopathy syndrome (PRES) with other published series. We reviewed the records of 10 patients with SLE and PRES seen over a 10-year period and their demographic data, clinical manifestations, laboratory tests, imaging findings, and outcome were recorded. We identified 10 females who included six Indians, three mixed ethnicity, and one African Black. Three patients had PRES at the onset of SLE. The most common manifestations at presentation were seizures (100 %), hypertension (80 %), and altered mental state (50 %). On neuroimaging, nine patients had bilateral involvement, and the occipital (90 %), parietal (90 %), and frontal lobes (50 %) were most commonly involved. The risk factors for PRES were disease activity (90 %), renal disease (80 %) and hypertension (80 %). Ninety percent of the patients were on immunosuppressive therapy. Immunosuppressive therapy was increased in six patients (60 %), continued in two and reduced in two patients after the diagnosis of PRES. Seven patients recovered completely and three patients died from co-morbidities. A review of the larger case series of SLE and PRES showed that the presentation and neuroimaging findings were similar; most patients had active disease at the time of PRES and the majority of patients required intensification of immunosuppressive therapy. We have shown that the majority of patients with SLE have active disease at the time of PRES, and they require an increase in their immunosuppressive therapy.

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.

PRES in Children Undergoing Hematopoietic Stem Cell or Solid Organ Transplantation

Posterior reversible encephalopathy syndrome (PRES) is a clinical neuroradiologic entity that is becoming increasingly well known and documented in pediatrics. It is characterized by a variable association of seizures, headache, vomiting, altered mental status, visual disturbances, and seizures, as well as imaging suggesting white-gray matter edema involving the posterior regions of the central nervous system in most cases. The pathophysiology of PRES remains unclear. Although PRES has been associated with a widespread range of clinical conditions, namely infections, adverse drug events, autoimmune diseases, and many others, its onset after hematopoietic stem cell and solid organ transplantation remains the most commonly reported. Historically, PRES has proved to be generally reversible and associated with good clinical outcomes; however, severe complications, sometimes life-threatening, can also occur. Most reported cases of childhood PRES after hematopoietic stem cell or solid organ transplantation have been case reports or series across a broad spectrum of different transplant settings, and no clear consensus exists regarding how best to manage the syndrome. Thus, in this article, we provide a comprehensive review of the pathophysiological, clinical, and diagnostic aspects of PRES in children, with a specific focus on the transplant scenario. Differential diagnoses with other neurologic complications after pediatric transplantation are reviewed, and crucial issues in the management of PRES and the development of future research are ultimately addressed.

Use of stem cell transplantation to treat epilepsy: A Web of Science-based literature analysis

OBJECTIVE:

To identify global research trends in the use of stem cell transplantation to treat epilepsy.

DATA RETRIEVAL:

We performed a bibliometric analysis of studies on the use of stem cell transplantation to treat epilepsy during 2002–2011, retrieved from Web of Science, using the key words epilepsy or epileptic or epilepticus or seizure and “stem cell”.

SELECTION CRITERIA:

Inclusion criteria: (a) peer-reviewed published articles on the use of stem cell transplantation to treat epilepsy indexed in Web of Science; (b) original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items.

MAIN OUTCOME MEASURES:

(a) Annual publication output; (b) type of publication; (c) publication by research field; (d) publication by journal; (e) publication by author; (f) publication by country and institution; (g) publications by institution in China; (h) most-cited papers; and (i) papers published by Chinese authors or institutions.

RESULTS:

A total of 460 publications on the use of stem cell transplantation to treat epilepsy were retrieved from Web of Science, 2002–2011. The number of publications gradually increased over the 10-year study period. Articles and reviews constituted the major types of publications. More than half of the studies were in the field of neuroscience/neurology. The most prolific journals for this topic were Epilepsia, Bone Marrow Transplantation, and Journal of Neuroscience. Of the 460 publications, almost half came from American authors and institutions; relatively few papers were published by Chinese authors or institutions.

CONCLUSION:

Literature on stem cell transplantation for epilepsy includes many reports of basic research, but few of clinical trials or treatments. Exact effects are not yet evaluated. Epilepsy rehabilitation is a long-term, complex, and comprehensive system engineering. With advances in medical development, some effective medical, social and educational measures are needed to facilitate patient's treatment and training and accelerate the recovery of life ability, learning ability and social adaptability to the largest extent to improve patient's quality of life.

Conversion from calcineurin inhibitor-based immunosuppression to mammalian target of rapamycin inhibitors or belatacept in renal transplant recipients

The calcineurin inhibitors (CNIs) remain the standard of care for maintenance immunosuppression following renal transplantation. CNIs have demonstrated their effectiveness in reducing acute cellular rejection; however, some evidence suggests that these compounds negatively affect native renal function and are associated with allograft injury in renal transplant recipients. CNIs have also been linked with hypertension, new-onset diabetes after transplantation, tremor, and thrombotic microangiopathy, which have significant consequences for long-term allograft function and patient health overall. Thus, converting patients to a non-CNI-based regimen may improve renal function and also provide extrarenal benefits. A number of studies have been conducted that explore CNI conversion strategies in renal transplant recipients in an effort to improve long-term allograft function and survival. These include converting to alternative, non-nephrotoxic, maintenance immunosuppressants, such as the mammalian target of rapamycin inhibitors (sirolimus and everolimus) and the costimulation blocker belatacept. In this review of literature, evidence for the potential renal and extrarenal benefits of conversion to these non-CNI-based regimens is evaluated. Clinical challenges, including the adverse event profiles of non-CNI-based regimens and the selection of candidates for conversion, are also examined.

Refractory intracranial hypertension in posterior reversible encephalopathy syndrome

INTRODUCTION

Posterior reversible encephalopathy syndrome (PRES) is a largely reversible disease with long-term favorable outcome. A minority of patients, however, may develop progressive cerebral edema and ischemia resulting in severe disability or death. We report a case of severe intracranial hypertension associated with PRES that was successfully treated according to intracranial pressure (ICP)- and cerebral perfusion pressure (CPP)-driven therapy.

METHODS

Case report.

RESULTS

A 42-year-old woman underwent bilateral lung transplantation for severe bronchiectasis. Her immunosuppressive regimen consisted of azathioprine, prednisone, and tacrolimus. She acutely developed an aggressive form of PRES that rapidly resulted in severe refractory intracranial hypertension despite discontinuation of potentially causative medications and adequate supportive therapy. Accordingly, second-tier therapies, including barbiturate infusion, were instituted and immunosuppression was switched to anti-thymocyte globulin followed by mycophenolate mofetil. Within 10 h of barbiturate administration, ICP dropped to 20 mmHg. Thiopental was administered for two days and then rapidly tapered because of severe urosepsis. Six months after discharge from the intensive care unit the patient returned to near-normal life, her only complaint being short-term amnesia.

CONCLUSIONS

The decision to undertake ICP monitoring in medical conditions in which no clear recommendations exist greatly relies on physicians' judgment. This case suggests that ICP monitoring may be considered in the setting of acute PRES among selected patients, when severe intracranial hypertension is suspected, provided that a multidisciplinary team of neurocritical care specialists is readily available.

Immunosuppressant-associated neurotoxicity responding to olanzapine

Immunosuppressants, particularly tacrolimus, can induce neurotoxicity in solid organ transplantation cases. A lower clinical threshold to switch from tacrolimus to another immunosuppressant agent has been a common approach to reverse this neurotoxicity. However, immunosuppressant switch may place the graft at risk, and, in some cases, continuation of the same treatment protocol may be necessary. We report a case of immunosuppressant-associated neurotoxicity with prominent neuropsychiatric manifestation and describe psychiatric intervention with olanzapine that led to clinical improvement while continuing tacrolimus maintenance.

Rapid Resolution of Tacrolimus Intoxication–Induced AKI With a Corticosteroid and Phenytoin

Objective: To report a novel approach to the management of tacrolimus intoxication that leads to rapid normalization of serum tacrolimus concentrations. Case Summary: A 9-year-old female renal transplant recipient developed a severe tacrolimus intoxication as a result of prolonged diarrhea, which resulted in acute kidney injury, severe dehydration, and neurological symptoms. We used a combination of intravenous steroids and intravenous phenytoin to normalize the tacrolimus level from 32 to 5 ng/mL in less than 24 hours, with complete resolution of symptoms and signs. Discussion: Tacrolimus intoxication is a rare event but may result in life-threatening complications. Treatment recommendations beyond holding the drug and enzyme induction with phenytoin or phenobarbital are elusive. This approach leads to a relatively slow normalization of the tacrolimus level over 72 hours. The authors hypothesized that additional induction of the p-glycoprotein through steroids was synergistic. Conclusions: The combination of phenytoin and a corticosteroid may be an effective approach that leads to rapid normalization of severely elevated tacrolimus levels.

Immunosuppression and allograft rejection following lung transplantation: evidence to date

The enduring success of lung transplantation is built on the use of immunosuppressive drugs to stop the immune system from rejecting the newly transplanted lung allograft. Most patients receive a triple-drug maintenance immunosuppressive regimen consisting of a calcineurin inhibitor, an antiproliferative and corticosteroids. Induction therapy with either an antilymphocyte monoclonal or an interleukin-2 receptor antagonist are prescribed by many centres aiming to achieve rapid inhibition of recently activated and potentially alloreactive T lymphocytes. Despite this generic approach acute rejection episodes remain common, mandating further fine-tuning and augmentation of the immunosuppressive regimen. While there has been a trend away from cyclosporine and azathioprine towards a preference for tacrolimus and mycophenolate mofetil, this has not translated into significant protection from the development of chronic lung allograft dysfunction, the main barrier to the long-term success of lung transplantation. This article reviews the problem of lung allograft rejection and the evidence for immunosuppressive regimens used both in the short- and long-term in patients undergoing lung transplantation.

Central nervous system syndromes in solid organ transplant recipients

Solid organ transplant recipients have a high incidence of central nervous system (CNS) complications, including both focal and diffuse neurologic deficits. In the immunocompromised host, the initial clinical evaluation must focus on both life-threatening CNS infections and vascular or anatomic lesions. The clinical signs and symptoms of CNS processes are modified by the immunosuppression required to prevent graft rejection. In this population, these etiologies often coexist with drug toxicities and metabolic abnormalities that complicate the development of a specific approach to clinical management. This review assesses the multiple risk factors for CNS processes in solid organ transplant recipients and establishes a timeline to assist in the evaluation and management of these complex patients.

Alternative tacrolimus and sirolimus regimen associated with rapid resolution of posterior reversible encephalopathy syndrome after lung transplantation

BACKGROUND

Neurotoxicity is a significant complication of calcineurin inhibitor use, and posterior reversible encephalopathy syndrome has been reported. Limited data exist on the use of alternative immunosuppression regimens in the management of posterior reversible encephalopathy syndrome in transplant recipients.

METHODS

We present the immunosuppression management strategy of a girl who underwent bilateral lung transplantation for cystic fibrosis 6 months earlier, then suddenly developed a grand mal seizure due to posterior reversible encephalopathy syndrome diagnosed by magnetic resonance imaging of the brain. In an effort to reduce her tacrolimus dose, an alternative immunosuppressant regimen combining tacrolimus and sirolimus was used.

RESULTS

After the modification of her immunosuppressant regimen, there was rapid clinical improvement with no further seizures. Her brain findings had resolved on magnetic resonance imaging 2 months later. Over the next 6 months, allograft function remained stable and surveillance transbronchial biopsies found no allograft rejection on the combined sirolimus and tacrolimus therapy.

CONCLUSIONS

Tacrolimus-associated neurotoxicity resolved in a lung transplant recipient with a combined tacrolimus and sirolimus regimen. This combined therapy appears to be an effective alternative for lung transplant recipients that allow them to receive the benefits of both drugs but at lower doses, which reduces the risk for adverse effects.

An uncommon cause of acutely altered mental status in a renal transplant recipient

INTRODUCTION

Neurological complications are quite frequent in patients after solid organ transplantation presenting with focal or generalized neurologic symptoms as well as altered mental status. Posterior reversible encephalopathy syndrome is a rare cliniconeuroradiological entity characterized by headache, altered mental status, cortical blindness, seizures, and other focal neurological signs and a diagnostic magnetic resonance imaging.

CASE REPORT

We present a case of a 57-year-old woman with one episode of seizures and sudden onset of altered mental status (time and person perception) accompanied with headache at the thirtieth postoperative day after renal transplantation.

CONCLUSION

Posterior reversible encephalopathy syndrome, although an uncommon post-renal transplantation complication, should be considered in these patients, as several factors surrounding the setting of transplantation have been implicated in its development. Thus, physicians should be aware of this condition in order to establish the diagnosis and offer appropriate treatment.

Tacrolimus associated posterior reversible encephalopathy syndrome - a case series and review

Tacrolimus is an immunosuppressive drug mainly used to lower the risk of transplant rejection in individuals who are post solid organ or hematopoietic transplantation. It is a macrolide which reduces peptidyl-propyl isomerase activity and inhibits calcineurin, thus inhibiting T-lymphocyte signal transduction and interleukin-2 (IL-2) transcription. It has been associated with Posterior Reversible Encephalopathy Syndrome (PRES), a disease of sudden onset that can present as a host of different symptoms, depending on the affected area of the brain. While infectious causes of encephalopathy must always be entertained, the differential diagnosis should also include PRES in the appropriate context. We report three cases of PRES in patients with acute myeloid leukemia (AML) placed on tacrolimus after receiving a bone marrow transplant (BMT). The focus of this review is to enhance clinical recognition of PRES as it is related to an adverse effect of Tacrolimus in the setting of hematopoietic transplantation.

Neurologic complications in renal transplantation

Neurologic complications following kidney transplant are more common than in the general population with the reported incidence around 10-21%. Need for multiple drugs, decreased cellular immunity, accelerated atherosclerotic disease, and frequency of metabolic abnormalities are the most common predisposing factors for neurologic abnormalities. Neurologic side-effects of calcineurin inhibitors range from mild tremors to paraplegia or posterior reversible encephalopathy syndrome (PRES) and are generally reversible by lowering the dose or complete discontinuation of the drug when possible. Clinical presentation of central nervous system infection in transplant recipients can be different from the normal population as the anti-inflammatory effects of immunosuppressive therapy may obscure signs of meningeal inflammation and changes in the level of consciousness may be subtle. Bacterial infections remain the most common infections but unusual pathogens figure prominently in the differential diagnosis. The most frequent malignancies of the brain are lymphomas and metastatic tumors which are for the most part, de novo malignancies from immunosuppression. Decreasing immunosuppression is almost always a part of treating malignancy. The prevalence of stroke is reported to be around 8% with age>40 years, diabetic nephropathy as the underlying cause of end-stage kidney disease, and peripheral vascular disease being the strongest predictors.

Posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a recently proposed cliniconeuroradiologic entity with several well-known causes, such as hypertensive encephalopathy, eclampsia, and the use of cytotoxic and immunosuppressive drugs, as well as some causes more recently described. PRES is characterized by neuroimaging findings of reversible vasogenic subcortical edema without infarction. The pathogenesis is incompletely understood. Two opposing hypotheses are commonly cited, but the issue is controversial: (1) the current more popular theory suggests that severe hypertension exceeds the limits of autoregulation, leading to breakthrough brain edema; (2) the earlier original theory suggests that hypertension leads to cerebral autoregulatory vasoconstriction, ischemia, and subsequent brain edema. The clinical syndrome of PRES typically involves headache, encephalopathy, visual symptoms, and seizures. The clinical presentation is often nonspecific, and therefore the diagnosis of PRES has come to increasingly rely on magnetic resonance imaging (MRI) abnormalities consistent with PRES with documented recovery clinically and on repeated neuroimaging. The diagnosis has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure and/or discontinuing the offending drug.

Tacrolimus-related cerebral microbleeds after lung transplantation

Posterior reversible encephalopathy syndrome is a well-known complication of treatment by tacrolimus. We report 2 cases of lung transplant recipients treated with tacrolimus who developed cerebral microbleeds on T2∗-weighted sequences in the acute setting of posterior reversible encephalopathy syndrome. Cerebral microbleeds may be a marker of tacrolimus-induced vasculopathy that may be detected earlier by neuropsychological and magnetic resonance imaging monitoring in transplant recipients treated with tacrolimus.

Biotic acts of antibiotics

Biological functions of antibiotics are not limited to killing. The most likely function of antibiotics in natural microbial ecosystems is signaling. Does this signaling function of antibiotics also extend to the eukaryotic – in particular mammalian – cells? In this review, the host modulating properties of three classes of antibiotics (macrolides, tetracyclines, and β-lactams) will be briefly discussed. Antibiotics can be effective in treatment of a broad spectrum of diseases and pathological conditions other than those of infectious etiology and, in this capacity, may find widespread applications beyond the intended antimicrobial use. This use, however, should not compromise the primary function antibiotics are used for. The biological background for this inter-kingdom signaling is also discussed.

Review article: the management of autoimmune hepatitis beyond consensus guidelines

BACKGROUND

Consensus guidelines aid in the diagnosis and management of autoimmune hepatitis, but they are frequently based on low-quality clinical evidence, conflicting experiences and divergent opinions. Recommendations may be weak, discrepant or non-existent at critical decision points.

AIMS

To identify the decision points where guidelines are weak or non-existent and review the evidence essential in the decision process.

METHODS

Full-text articles published in English using the keyword 'autoimmune hepatitis' were identified by PubMed from 1972 to 2013. Personal experience and investigations in autoimmune hepatitis also identified important contributions.

RESULTS

Seventy per cent of the guidelines developed by the American Association for the Study of Liver Diseases and 48% of those proposed by the British Society of Gastroenterology are based on low-quality evidence, conflicting experiences or divergent opinions. The key uncertainties in diagnosis relate to the timing of liver biopsy, recognising acute severe (fulminant) disease, interpreting coincidental nonclassical histological changes, accommodating atypical or deficient features in non-White patients, differentiating drug-induced from classical disease and identifying overlap syndromes. The key uncertainties in management relate to pre-treatment testing for thiopurine methyltransferase activity, treating asymptomatic mild disease, determining treatment end points, managing suboptimal responses, incorporating nonstandard medications as front-line and salvage agents, using azathioprine in pregnancy and instituting surveillance for hepatocellular carcinoma.

CONCLUSIONS

Consensus guidelines are fraught with uncertainties in the diagnosis and management of autoimmune hepatitis. Each decision point must counterbalance the current available evidence and tailor the application of this evidence to the individual patient.

Neuroimaging findings of the post-treatment effects of radiation and chemotherapy of malignant primary glial neoplasms

Post-treatment radiation and chemotherapy of malignant primary glial neoplasms present a wide spectrum of tumor appearances and treatment-related entities. Radiologic findings of these post-treatment effects overlap, making it difficult to distinguish treatment response and failure. The purposes of this article are to illustrate and contrast the imaging appearances of recurrent tumor from necrosis and to discuss other radiologic effects of cancer treatments. It is critical for radiologists to recognize these treatment-related effects to help direct clinical management.

Toxic leukoencephalopathies

Leukoencephalopathy is a syndrome of neurologic deficits, including alteration of mental status, caused by pathologic changes in the cerebral white matter. The term, toxic leukoencephalopathy, encompasses a wide variety of exposures and clinical presentations. The diagnosis in these Frontiers in Clinical Neurotoxicology syndromes is made by careful attention to the history, clinical features, and radiologic findings. This article details three of the best-defined toxic leukoencephalopathies: delayed posthypoxic leukoencephalopathy, including delayed neurologic sequelae after carbon monoxide poisoning; heroin inhalation leukoencephalopathy; and posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome in a renal allograft recipient: A complication of immunosuppression?

Posterior reversible encephalopathy syndrome (PRES) is an uncommon post-renal transplant complication. We report a 16-year-old boy who had an acute cellular rejection immediate post-transplant and was given intravenous methylprednisolone along with an increase in tacrolimus dose. He was diagnosed to have PRES based on clinical and radiological features within 6 h of intensified immunosuppression. This is an unusual case report of successfully managing PRES with continuation of the intensified immunosuppression as warranted by the clinical situation, along with aggressive blood pressure control. After 6 weeks, magnetic resonance imaging showed complete resolution of lesions. He has good graft function and no residual neurological deficits while on small doses of three antihypertensives, 12 months after transplantation.

Lesions masquerading as acute stroke

Rapid and accurate recognition of lesions masquerading as acute stroke is important. Any incorrect or delayed diagnosis of stroke mimics will not only increase the risk of being exposed to unnecessary and possibly dangerous interventional therapies, but will also delay proper treatment. In this article, written from a neuroradiologist's perspective, we classified these lesions masquerading as acute stroke into three groups: lesions that may have "normal imaging," lesions that are "symptom mimics" but on imaging clearly not a stroke, and lesions that are "symptom and imaging mimics" with imaging findings similar to stroke. We focused the review on neuroimaging findings of the latter two groups ending with a suggestion for a diagnostic approach in the form of an algorithm.

Manic-like psychosis associated with elevated trough tacrolimus blood concentrations 17 years after kidney transplant

Several neurological side effects induced by tacrolimus are described in the scientific literature, ranging from mild neurological symptoms to delirium and psychosis. We report the case of a 46-year-old man with no prior psychiatric history who suddenly manifested manic-like psychosis associated with elevated trough tacrolimus blood concentrations 17 years after kidney transplant. The use of antipsychotics may improve the severity of symptoms; but in order to obtain a complete remission, the reduction in the dose of tacrolimus, or its replacement with alternative immunosuppressant therapies, is recommended.

Tacrolimus-induced paranoid delusions and fugue-like state

We report the case of a 43 year old male with no prior psychiatric history with apparent tacrolimus-induced psychosis. Previous reports have identified other neurotoxic adverse effects due to tacrolimus, however, to our knowledge, there are few reports that describe psychosis induced by the immunosuppressant drug. Although psychosis may be a rare adverse effect, it can have significant impact on the long-term prognosis and treatment in transplant recipients. It is imperative to quickly identify patients who develop a mental status change while on tacrolimus and to work with the appropriate transplant team in managing these patients. Treatment usually calls for prompt discontinuation of tacrolimus, substituting with another immunosuppressant, and possible use of antipsychotics.

Tacrolimus-associated posterior reversible encephalopathy syndrome in hematopoietic allogeneic stem cell transplantation

Tacrolimus-associated posterior reversible encephalopathy syndrome (PRES) is a potential complication of allogeneic stem cell transplant (SCT). Due to the paucity of information on the management of PRES in SCT patients receiving tacrolimus, more information is needed on trends associated with the incidence of PRES and to characterize its management. A retrospective review was conducted of patients receiving tacrolimus for prevention of graft versus host disease (GVHD) after allogeneic SCT who developed PRES from September 2008 to July 2011. Nineteen patients were identified. Altered mental status, seizures, and visual abnormalities were experienced by 78.9%, 52.6%, and 31.5% of the patients, respectively, at time of PRES onset. Compared with baseline, patients with PRES were likely to have an increase in mean arterial pressure (P < 0.0001) and serum creatinine. Elevated tacrolimus levels and hypomagnesemia were not observed with PRES onset. Tacrolimus was managed in three general strategy groups: not held, held then continued, and switched to another agent. Survival was defined as survival to discharge from PRES hospitalization. When tacrolimus was not held, held then continued, or switched to another agent, 40% (2 of 5), 40% (4/10), and 50% (2/4) survived to discharge, respectively. PRES was associated with high blood pressure and adequate blood pressure control should be part of its management. No management strategy pertaining to tacrolimus usage appeared more beneficial over another.

Posterior reversible encephalopathy syndrome independently associated with tacrolimus and sirolimus after multivisceral transplantation

Posterior reversible encephalopathy syndrome (PRES) is a small vessel microangiopathy of the cerebral vasculature that occurs in 0.5-5% of solid organ transplant recipients, most commonly associated with tacrolimus (Tac). Clinical manifestations include hypertension and neurologic symptoms. We report an adult multivisceral transplant recipient who experienced recurrent PRES initially associated with Tac and subsequently with sirolimus. A 49-year-old woman with short bowel syndrome underwent multivisceral transplantation due to total parenteral nutrition-related liver disease. She was initially maintained on Tac, mycophenalate mofetil (MMF) and prednisone. Three months after transplantation, she developed renal dysfunction, leading to a reduction in Tac and the addition of sirolimus. Eight months after transplantation, she developed PRES. Tac was discontinued and PRES resolved. Sirolimus was increased to maintain trough levels of 12-15 ng/mL. Fourteen months after transplant, she experienced recurrent PRES which resolved after discontinuing sirolimus. Currently 3 years posttransplant, she is maintained on cyclosporine, MMF and prednisone with no PRES recurrence. In addition to calcineurin inhibitors, sirolimus may also be associated with PRES after solid organ transplantation. Ours is the first report of sirolimus-associated PRES in the setting of multivisceral transplantation. Identifying a safe alternative immunosuppression regimen was challenging but ultimately successful.

Isolated leptomeningeal enhancement in tacrolimus-associated posterior reversible encephalopathy syndrome

We report on tacrolimus-associated posterior reversible encephalopathy syndrome with the previously unreported finding of leptomeningeal enhancement occurring separate from the site of parenchymal magnetic resonance signal abnormality. Recognition of this atypical finding as a noninfectious cause of leptomeningeal enhancement may assist those caring for patients affected by posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome: the importance of early diagnosis

A 14-year-old boy was submitted to cardiac transplant due to a dilated cardiomyopathy. On the fourth day of immunosuppression (corticosteroids, mycophenolate mofetil and tacrolimus), he developed right focal seizures and drowsiness. Blood pressure was in the normal range and laboratory findings in cerebral spinal fluid and blood were unremarkable, with drugs in non-toxic levels. The EEG showed a slow background rhythm more pronounced on the right and a seizure onset in the right occipital region. MRI revealed a diffuse hyperintense subcortical white-matter lesion on fluid attenuated inversion recovery, with lesser involvement of left temporal-occipital region. There was no enhancement with gadolinium and MRI diffusion-weighted imaging was consistent with vasogenic oedema. Tacrolimus was stopped with regression of MRI abnormalities and clinical recovery. Posterior reversible encephalopathy associated with tacrolimus is a rare but potentially serious complication of solid organ transplants. A prompt diagnosis and correct treatment is essential to avoid irreversible brain damage.

[Neurological complications in patients receiving solid organ transplants]

INTRODUCTION

Neurological complications (NC) are a significant cause of morbidity and mortality in paediatric patients receiving solid organ transplants. Our aim was to describe the experience of our hospital with NC in paediatric patients receiving heart, lung and liver transplants.

PATIENTS AND METHODS

A retrospective study was conducted on 140 paediatric patients who received a solid organ transplant during the period 2000-2011.

RESULTS

A total of 23 paediatric solid organ transplant recipients (16.4% of cases), with a median age of 6 years, had NC. The symptoms were, in order of frequency: acute symptomatic seizures (12 patients); acute encephalopathy (11 patients); neuromuscular weakness (4 children), tremor (4 children), headache (2 children), neuropathic pain (2 children), and visual disturbances (2 children). The aetiologies of NC were: the neurotoxicity of the immunosuppressive drugs (12 patients), post-hypoxic-ischaemic encephalopathy (6 patients), infections (2 cases), mechanical compression of peripheral nerve during surgery (2 cases), and a metabolic complication (1 case). The five patients who met the criteria of posterior reversible encephalopathy syndrome had a favourable outcome. Seven patients died, four of them due to hypoxic-ischaemic encephalopathy.

CONCLUSIONS

NC are common in paediatric patients receiving heart, liver, lung, and renal transplants, with acute symptomatic seizures and acute encephalopathy being the most common clinical signs. No differences were found in the NC with the different types of transplants. Neurotoxicity of the immunosuppressive drugs and hypoxic-ischaemic encephalopathy were the main causes of NC, having different management and outcomes. The prognosis was favourable in most of the patients, except for those who had moderate or severe post-hypoxic-ischaemic damage.

Drug choices in autoimmune hepatitis: part B--Nonsteroids

Nonsteroidal medications, previously unfamiliar in the management of autoimmune hepatitis, can supplement or replace conventional corticosteroid regimens, especially in problematic patients. Mycophenolate mofetil is a next-generation purine antagonist that has been useful in treating patients with azathioprine intolerance. It has been less effective in salvaging patients with steroid-refractory disease. Azathioprine is the choice as a corticosteroid-sparing agent in treatment-naive patients and in individuals with corticosteroid intolerance, incomplete response and relapse after drug withdrawal. Tacrolimus is preferred over cyclosporine for recalcitrant disease because of its established preference in organ transplantation, but replacement with cyclosporine should be considered if the disease worsens on treatment. Rapamycin has antiproliferative and proapoptotic actions that warrant further study in autoimmune hepatitis. The nonstandard, nonsteroidal medications are mainly salvage therapies with off-label indications that must be used in highly individualized and well-monitored clinical situations.

Changes in neurocognitive functioning following lung transplantation

Although neurocognitive impairment is relatively common among patients with advanced lung disease, little is known regarding changes in neurocognition following lung transplantation. We therefore administered 10 tests of neurocognitive functioning before and 6 months following lung transplantation and sought to identify predictors of change. Among the 49 study participants, native diseases included chronic obstructive pulmonary disease (n = 22), cystic fibrosis (n = 12), nonfibrotic diseases (n = 11) and other (n = 4). Although composite measures of executive function and verbal memory scores were generally within normal limits both before and after lung transplantation, verbal memory performance was slightly better posttransplant compared to baseline (p < 0.0001). Executive function scores improved in younger patients but worsened in older patients (p = 0.03). A minority subset of patients (29%) exhibited significant cognitive decline (i.e. >1 standard deviations on at least 20% of tests) from baseline to posttransplant. Patients who declined were older (p < 0.004) and tended to be less educated (p = 0.07). Lung transplantation, like cardiac revascularization procedures, appears to be associated with cognitive decline in a subset of older patients, which could impact daily functioning posttransplant.

Posterior reversible encephalopathy syndrome in liver transplant patients: clinical presentation, risk factors and initial management

Posterior reversible encephalopathy syndrome (PRES) is an uncommon but well-known complication after transplantation diagnosed by characteristic radiological features. As limited data on this complex syndrome exist we sought to better define the incidence, clinical presentation and risk factors for PRES in liver transplant (LTx) patients. We conducted a retrospective analysis of 1923 adult LTx recipients transplanted between 2000 and 2010. PRES was diagnosed radiologically in 19 patients (1%), with 84% of cases occurring within 3 months post-LTX. We compared this cohort of PRES patients to 316 other LTx recipients also requiring radiographic imaging within 3 months after LTx for neurological symptoms. Seizure was the most common clinical manifestation in the PRES group (88% vs. 16%, p< 0.001) and 31% had an intracranial hemorrhage. Those with hemorrhage on imaging were more likely to be coagulopathic. PRES patients were significantly more likely to have had alcoholic liver disease and infection/sepsis. These factors may be related to a common pathway of vascular dysregulation/damage that appears to characterize this complex syndrome. Intracranial bleeding and seizures may be the end result of these phenomena. The relationship of these associated factors to the hypothesized pathophysiology of PRES is discussed.

Catatonia as a manifestation of tacrolimus-induced neurotoxicity in organ transplant patients: a case series

Tacrolimus has been associated with severe neurotoxicity in organ transplant patients. Catatonia can be a rare manifestation of tacrolimus-induced neurotoxicity as we report two cases of catatonia in solid organ transplant patients on tacrolimus. Catatonic symptoms completely resolved in these patients after reducing the tacrolimus dosage or switching it to alternative immunosuppressants. Catatonia symptoms in organ transplant patients should alert clinicians to look for tacrolimus-induced neurotoxicity despite normal serum tacrolimus levels and neuroimaging findings.

Red cell exchange transfusion as a rescue therapy for tacrolimus toxicity in a paediatric renal transplant

Tacrolimus is a widely used macrolide immunosuppressant that has a narrow therapeutic index and potential side effects including neurotoxicity. A 20-month-old boy with kidney disease secondary to prune belly syndrome variant, managed on peritoneal dialysis, received a deceased donor transplant. Standard immunosuppression was used. There was good early graft function. Post-transplant he developed fungal peritonitis associated with a significant reduction in graft function and was treated with caspofungin and fluconazole. Despite tacrolimus dose reduction he developed a rapid rise in tacrolimus concentration to a maximum of 72 ng/ml with an otherwise unexplained reduction in consciousness. He underwent a single volume exchange transfusion with packed red cells and 4.5% albumin (ratio 2:1). This resulted in immediate reduction of his tacrolimus concentration from 61.8 ng/ml to 35.2 ng/ml. The neurological deficit rapidly resolved. The fungal peritonitis was eradicated. Renal function recovered from a nadir of eGFR <10 ml/min/1.73 m² to a baseline of 30 ml/min/1.73 m². At 30 months post-transplant the child has creatinine of 1.4 mg/dl (eGFR of 31 ml/min/1.73 m²), and is developmentally appropriate with no neurological deficit. Red cell exchange transfusion is a potentially safe and effective way of managing severe and symptomatic tacrolimus toxicity.

Achieving stable human stem cell engraftment and survival in the CNS: is the future of regenerative medicine immunodeficient?

There is potential for a variety of stem cell populations to mediate repair in the diseased or injured CNS; in some cases, this theoretical possibility has already transitioned to clinical safety testing. However, careful consideration of preclinical animal models is essential to provide an appropriate assessment of stem cell safety and efficacy, as well as the basic biological mechanisms of stem cell action. This article examines the lessons learned from early tissue, organ and hematopoietic grafting, the early assumptions of the stem cell and CNS fields with regard to immunoprivilege, and the history of success in stem cell transplantation into the CNS. Finally, we discuss strategies in the selection of animal models to maximize the predictive validity of preclinical safety and efficacy studies.