Neurological complications following pediatric liver transplant

The protective effect of lncRNA NEAT1/miR-122-5p/Wnt1 axis on hippocampal damage in hepatic ischemic reperfusion young mice

Hepatic ischemic reperfusion (HIR) is a common pathophysiological process in many surgical procedures such as liver transplantation (LT) and hepatectomy. And it is also an important factor leading to perioperative distant organ damage. Children undergoing major liver surgery are more susceptible to various pathophysiological processes, including HIR, since their brains are still developing and the physiological functions are still incomplete, which can lead to brain damage and postoperative cognitive impairment, thus seriously affecting the long-term prognosis of the children. However, the present treatments of mitigating HIR-induced hippocampal damage are not proven to be effective. The important role of microRNAs (miRNAs) in the pathophysiological processes of many diseases and in the normal development of the body has been confirmed in several studies. The current study explored the role of miR-122-5p in HIR-induced hippocampal damage progression. HIR-induced hippocampal damage mouse model was induced by clamping the left and middle lobe vessels of the liver of young mice for 1 h, removing the vessel clamps and re-perfusing them for 6 h. The changes in the level of miR-122-5p in the hippocampal tissues were measured, and its influences on the activity as well as apoptotic rate of neuronal cells were investigated. Short interfering RNA modified with 2'-O-methoxy substitution targeting long-stranded non-coding RNA (lncRNA) nuclear enriched transcript 1 (NEAT1) as well as miR-122-5p antagomir were used to further clarify the role played by the corresponding molecules in hippocampal injury in young mice with HIR. The result obtained in our study was that the expression of miR-122-5p in the hippocampal tissue of young mice receiving HIR is reduced. Upregulated expression of miR-122-5p reduces the viability of neuronal cells and promotes the development of apoptosis, thereby aggravating the damage of hippocampal tissue in HIR young mice. Additionally, in the hippocampal tissue of young mice receiving HIR, lncRNA NEAT1 exerts some anti-apoptotic effects by binding to miR-122-5p, promoting the expression of Wnt1 pathway. An essential observation of this study was the binding of lncRNA NEAT1 to miR-122-5p, which upregulates Wnt1 and inhibits HIR-induced hippocampal damage in young mice.

Neurological complications in pediatric liver transplant recipients

INTRODUCTION

There is paucity of data on neurological complications (NCs) and its predisposing factors, in pediatric liver transplant (PLT) recipients.

METHODS

Records of seventy-one children who underwent LT between October 2018 and November 2019 were reviewed. Patients were categorized into group A: with NC and group B: without NC in the post-LT period. Various risk factors contributing to NC were studied.

RESULTS

In total, 15 (21.1%) had NC (group A) and 56 (78.9%) had no NC in the post-LT period. NC included cerebrovascular accident (n = 1), seizures (n = 5; 4 generalized, 1 focal), central pontine myelolysis (CPM) (n = 1), diaphragmatic palsy (n = 2), peripheral neuropathy (n = 1), extrapyramidal movements (n = 3), and encephalopathy beyond 96 h (n = 2). The median onset of NC was at 8.5 days post-LT (1-58 days). Ten (66.7%) patients in group A had grades 2-4 hepatic encephalopathy (HE) prior to LT. Eight (14.3%) patients in group B also had pre-LT neurological issues including HE in six, epilepsy and spastic diplegia in one each. On univariate analysis, pre-existing HE, high PELD/MELD score, pre-LT ventilation, pre-LT infection, higher day 1 post-operative bilirubin (all p < .05), and higher tacrolimus were found to predict post-operative NC whereas on multivariate analysis, pre-LT HE was the only predictive factor. Median follow-up was 15.5 months. Four patients died in each group (survival log-rank p = .369). All the surviving patients in group A (n = 11) fully recovered from the NC.

CONCLUSION

Pre-transplant HE was the single most significant predisposing factor for post-LT neurological complications.

2021 Clinical Update in Liver Transplantation

In 2021, the United States performed 9,236 liver transplantations, an increase of 3.7% from 2020. As the specialty of transplant anesthesiologist continues to grow, so does the body of evidence-based research to improve patient care. New technology in organ preservation offers the possibility of preserving marginal organs for transplant or improving the graft for transplantation. The sequalae of end-stage liver disease have wide-ranging consequences that affect neurologic outcomes of patients both during and after transplantation that anesthesiologists should monitor. Obesity presents several challenges for anesthesiologists. As an increasing number of patients with nonalcoholic steatohepatitis are listed for transplant, managing their multiple comorbidities can be challenging. Finally, the rebalanced hemostasis of end-stage liver disease can cause both bleeding and thrombus. Often, bleeding risks predominate as a concern, but anesthesiologists should be aware of risks of intracardiac thrombus and review therapeutic options for prevention and treatment.

Neurological impairment in children with acute liver failure following liver transplantation-A single-center experience

BACKGROUND

Although overall survival of ALF has improved, neurological restoration after recovery from ALF may not always be satisfactory. The purpose of this study was to investigate the occurrence and possible causes of NI in children with ALF following LT.

METHODS

We retrospectively examined all children younger than 16 years old with ALF who subsequently underwent LT at our center between January 2005 and December 2016. NI was assessed in December 2016 using the six-point Pediatric Cerebral Performance Category score and was defined as any increase in the score.

RESULTS

There were 62 children with median age 10 months (quartile range 5-34). The etiology of ALF was indeterminate in 47 children (75.8%). The median duration from admission to LT was 5.5 days (quartile range 4-7), and 96.8% (60/62) received living donor LT. The overall survival was 83.9% (52/62) in a median follow-up period of 4.2 years. Mild-to-moderate NI was observed in 23.1% (12/52) of the survivors. Possible causes of NI were underlying systemic disease (n = 3), perioperative brain lesion (n = 2), and unclassified (n = 7). All seven patients with unclassified NI were less than 12 months old. The unclassified NI causes were presumed to be ALF, its perioperative care, and the vulnerable infant brain.

CONCLUSIONS

NI in children with ALF following LT was not rare and should be prevented. Further investigations are required to clarify the characteristics of the patients with unclassified NI.

Neurological complications after living-donor liver transplantation in children

AIM

Liver transplantation (LT) has been used as a definitive management for children with end-stage liver disease or acute liver failure. Living-donor LT (LDLT) has been a common type of LT performed in Asian countries, including Japan, where deceased donors are rarely available. However, the neurological complications (NCs) associated with LDLT remain unknown. The purpose of this study was to clarify the characteristics of NCs in children after LDLT.

METHODS

This study is a retrospective observational study carried out at a tertiary children's hospital in Japan. We studied children who had undergone LDLT between January 2001 and January 2020.

RESULTS

We examined 602 cases of LT, of which 559 were LDLT cases (92.9%). NCs after LT were present in 21 cases (3.8%). The most common neurological symptoms were seizure (n = 17), whereas disturbance of consciousness without seizure was observed in four cases. The frequency of NCs for each of the indications was 12.2% for fulminant hepatic failure, 6.5% for metabolic liver disease, and 0.7% for cholestatic liver disease.

INTERPRETATION

We report the characteristics of NCs after LDLT in children. The frequency of NCs after LT was high in cases of fulminant hepatic failure and metabolic diseases, who might have had neurological symptoms or impaired consciousness before LT.

A case report of reversible posterior encephalopathy syndrome with intracranial hemorrhage in a child

INTRODUCTION

The objective is to analyze the clinical diagnosis and treatment of children with rescindable posterior encephalopathy syndrome (PRES) and intracranial hemorrhage (ICH) to improve the pediatrician's understanding of PRES combined with ICH in children.

PATIENT CONCERNS AND DIAGNOSIS

After liver transplantation, the patient developed symptoms of epilepsy and coma. Meanwhile, massive necrosis of acute cerebral infarction and small hemorrhage was observed in the left cerebellar hemisphere and left occipital lobe, respectively. The above symptoms were initially diagnosed as PRES.

INTERVENTIONS AND OUTCOMES

After adjusting the anti-rejection drug regimen, it was found that the child's neurological symptoms were relieved, and the limb motor function gradually recovered during follow-up. Imaging examination showed significant improvement on abnormal signals in brain.

CONCLUSION

In general, children with PRES may further develop ICH and contribute to a poor prognosis. Early diagnosis, detection of risk factors and timely adjustment of medication regimen are the keys to prevent irreversible brain damage.

Factors Associated With Neurobehavioral Complications in Pediatric Abdominal Organ Transplant Recipients Identified Using Computable Composite Definitions

OBJECTIVES

Neurologic complications occur in up to 40% of adult abdominal solid organ transplant recipients and are associated with increased mortality. Comparable pediatric data are sparse. This study describes the occurrence of neurologic and behavioral complications (neurobehavioral complications) in pediatric abdominal solid organ transplant recipients. We examine the association of these complications with length of stay, mortality, and tacrolimus levels.

DESIGN

The electronic health record was interrogated for inpatient readmissions of pediatric abdominal solid organ transplant recipients from 2009 to 2017. A computable composite definition of neurobehavioral complication, defined using structured electronic data for neurologic and/or behavioral phenotypes, was created.

SETTING

Quaternary children's hospital with an active transplant program.

PATIENTS

Pediatric abdominal solid organ transplant recipients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Computable phenotypes demonstrated a specificity 98.7% and sensitivity of 63.0% for identifying neurobehavioral complications. There were 1,542 readmissions among 318 patients, with 65 (20.4%) having at least one admission with a neurobehavioral complication (total 109 admissions). Median time from transplant to admission with neurobehavioral complication was 1.2 years (interquartile range, 0.52-2.28 yr). Compared to encounters without an identified neurobehavioral complication, encounters with a neurobehavioral complication were more likely to experience ICU admission (odds ratio, 3.9; 2.41-6.64; p < 0.001), have longer ICU length of stay (median 10.3 vs 2.2 d; p < 0.001) and hospital length of stay (8.9 vs 4.3 d; p < 0.001), and demonstrate higher maximum tacrolimus level (12.3 vs 9.8 ng/mL; p = 0.001). Patients with a neurobehavioral complication admission were more likely to die (odds ratio, 5.04; 1.49-17.09; p = 0.009). In a multivariable analysis, type of transplant, ICU admission, and tacrolimus levels were independently associated with the presence of a neurobehavioral complication.

CONCLUSIONS

Common electronic health record variables can be used to accurately identify neurobehavioral complications in the pediatric abdominal solid organ transplant population. Late neurobehavioral complications are associated with increased hospital resource utilization, mortality, and tacrolimus exposure. Additional studies are required to delineate the relationship between maximum tacrolimus level and neurobehavioral complications to guide therapeutic drug monitoring and dosing.

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.

Efficacy of Levetiracetam for Epilepsy in Pediatric Liver Transplant Recipients With Posterior Reversible Encephalopathy Syndrome

OBJECTIVES

Liver transplant is currently the most effective option for patients with end-stage liver disease. Seizures are the most common neurologic complication after liver transplant. Posterior reversible encephalopathy syndrome is a neurologic syndrome characterized by lethargy, seizures, visual disturbances, and radiologic findings of edema in the posterior regions of the cerebral hemispheres. Levetiracetam is prescribed for a broad spectrum of seizure types but does not have a specific indication for epilepsy in children after solid-organ transplant. Our aim was to investigate the efficacy and tolerability of levetiracetam in pediatric transplant recipients with posterior reversible encephalopathy syndrome and epilepsy.

MATERIALS AND METHODS

We reviewed records of patients treated for epilepsy due to posterior reversible encephalopathy syndrome after liver transplant seen at our pediatric neurology clinic between January 2010 and March 2019. Patients were assessed clinically and by neurologic examination, electroencephalography, and cerebral magnetic resonance imaging.

RESULTS

Among 134 children who had undergone liver transplant between 2010 and 2019, 10 patients (6 males, 4 females; age range,7-19 y) who were diag-nosed with posterior reversible encephalopathy syndrome and epilepsy were included in the study. All patients received levetiracetam at 20 mg/kg/day. After a mean follow-up of 28.9 months (range, 24-40 mo), 9 patients (90%) attained complete seizure freedom. One patient who had an underlying neurodegenerative disease (hemophagocytic syndrome) other than posterior reversible encephalopathy syndrome continued to have seizures under levetiracetam treatment. One patient had a mild adverse reaction (irritability) due to levetiracetam but did not require drug discontinuation.

CONCLUSIONS

In this study, 90% of patients with posterior reversible encephalopathy syndrome became seizure free with levetiracetam treatment. Our findings suggest that levetiracetam has a favorable efficacy for epilepsy due to posterior reversible encephalopathy syndrome in pediatric liver transplant recipients with tolerable adverse effects.

Is there an ethical obligation to split every donor liver? Scarce resources, medical factors, and ethical reasoning

SLT has the potential to counter the worldwide shortage of donor organs. Although the preferred recipients of SLT are usually pediatric patients, a more stringent ethical argument than the fundamental prioritization of children is to demonstrate that SLT of deceased donor organs could increase access to this potentially lifesaving resource for all patients, including children. Several empirical studies show that SLT also makes it possible to achieve similar outcomes to WLT in adults if several factors are observed. In general, it can be regarded as ethically permissible to insist on splitting a donor liver if, in an individual case, SLT is expected to have a similar outcome to that of WLT. The question is therefore no longer whether, but under what conditions SLT is able to achieve similar results to WLT. One of the main challenges of the current debate is the restricted comparability of the available data. We therefore have an ethical obligation to improve the available empirical data by implementing prospective clinical studies, SLT programs, and national registries. The introduction of 2 modes of allocation-one for patients willing to accept both SLT and WLT, and a second for patients only willing to accept WLT-would help to resolve the issue of patient autonomy in the case of mandatory splitting policy.

The Effect of Pediatric Living Donor Liver Transplantation on Neurocognitive Outcomes in Children

Background

Neurocognitive dysfunction commonly occurs after solid organ transplantation and affects 15–30% of liver transplant recipients. The aim of this study was to evaluate the neurocognitive changes pre- and post-operation and the relative factors affecting those changes.

Material/Methods

Children with biliary atresia who underwent pediatric living donor-related liver transplantation before the age of 2 years were given Bayley Scale of Infant Development-II test (BSID-II), including Mental Development Index (MDI) and Psychomotor Development Index (PDI) the week before and again half a year after transplantation to assess the effect of transplantation on neurocognition. According to the test outcome, the children were divided into a normal group and an abnormal group. The association of clinical data with neurocognitive development between the 2 groups was analyzed by logistic regression analysis.

Results

There was a certain degree of improvement in neurocognition half a year after surgery compared with preoperative. The BSID-II subscales were significantly lower than expected before and after transplantation. Preoperative blood ammonia and bilirubin levels were independent risk factors for MDI half a year after transplantation, and preoperative albumin and bilirubin levels were risk factors for PDI.

Conclusions

Liver transplantation clearly improves children’s neurocognitive function. The postoperative neurocognition is closely related to pre-operation nutritional development.

Liver transplantation during infancy: No increased rate of neurological complications

pLT is a highly standardized therapy for children with end-stage liver disease and liver-based metabolic diseases. However, NCs after transplantation occur and especially younger children are considered as more vulnerable and susceptible to NCs. Up to now, detailed data particularly for the very young age group do not exist. We therefore retrospectively studied NCs in children after pLT under age of 24 months. Forty children aged between 19 days and 22 months were evaluated according to type of NC and potential risk factors. NCs occurred in 8/40 patients (20%). All experienced new-onset seizures and in 1/6 surviving patients, seizures evolved into epilepsy. Other NCs were intracerebral abscess (1/8 patients) and subdural hemorrhage (1/8 patients). The overall 3-year mortality rate was 10% (4/40 patients). Significant risk factors for NCs and therefore seizures were HAT (P = 0.020), total surgery time (P = 0.009), retransplantation (P < 0.001), period of catecholamine therapy (P = 0.024), period of mechanical ventilation (P = 0.014), and period of sedation (P = 0.010). Our study is the first to provide detailed information on NCs after pLT in children under 24 months of age. The incidence of NCs in this particular group of very young patients was not increased compared to previously published data of children of all ages. Main NC was new-onset seizure. In the surviving infants, prognosis of seizure was excellent and the risk of developing epilepsy was low. Even more, the occurrence of NCs did not significantly affect mortality or survival in this particular age group.

Seizures after transplantation

PURPOSE

To summarize information on the history, incidence, clinical manifestation, best treatment, as well as prognosis of seizures in transplant recipients.

METHODS

In October 2017, we searched the literature on PubMed in English with the search terms: "transplantation" AND "seizure", "transplantation" AND "epilepsy", "transplantation"AND "status epilepticus", "immunosuppressant" AND "seizure", "immunosuppressant" AND "epilepsy". Publications not based on new data and original research were not included in this article.

RESULTS

Seizures including generalized seizures, focal seizures and status epilepticus are a common central nervous system complication after transplantation. The incidence of seizures varied between different kinds of transplantations. The reported incidence of seizures was 7%-27% in association with solid organ transplantations and 1.6%-15.4% with hematopoietic stem cell transplantation. Most of seizures appeared in the early post-transplantation period. Patients often had a favorable prognosis, however, in some conditions, recurrent or intractable seizures may occur.

CONCLUSIONS

The underlying pathogenesis of new-onset seizures or epilepsy in recipients of transplantation needs to be further elucidated. In addition, more information is required from prospective studies and research focusing on therapeutic strategies.

Incidence, risk factors, and outcomes related with neurological events after liver transplantation in adult and pediatric recipients

Controversy exists whether NE after LT are more frequently observed in children or adults. We aimed to compare the incidence and outcomes for NE after LT in pediatric and adult recipients. A single-center cohort study, including all LT between 2001 and 2013, was performed. Definition of NE included impaired consciousness, delirium, seizures, focal neurologic deficit, visual impairment, or slurred speech. A cohort of 443 consecutive LT recipients was included: 307 adults and 136 children. Cumulative incidence of NE was similar between adults 15% (n = 41) and children 16% (n = 20; P = .73) with a complete neurological recovery in 62% and 95% of the patients, respectively (P < .0001). Adults with NE had significantly lower survival (70% vs 76%; P = .015) with a HR of 2.36; this was similarly observed in children (45% vs 66%; HR 2.05, CI 0.66; 6.34). Independent risk factors for NE in adults were pre-LT ascites, delta sodium, and post-LT hypomagnesemia, whereas in children pre-LT encephalopathy ≥II and serum albumin were associated with NE. Although a similar incidence of NE after LT was observed, children were more likely to achieve neurological recovery. Risk factors for the development of NE are difficult to assess in both populations.

Thermodynamics in Neurodegenerative Diseases: Interplay Between Canonical WNT/Beta-Catenin Pathway-PPAR Gamma, Energy Metabolism and Circadian Rhythms

Entropy production rate is increased by several metabolic and thermodynamics abnormalities in neurodegenerative diseases (NDs). Irreversible processes are quantified by changes in the entropy production rate. This review is focused on the opposing interactions observed in NDs between the canonical WNT/beta-catenin pathway and PPAR gamma and their metabolic and thermodynamic implications. In amyotrophic lateral sclerosis and Huntington's disease, WNT/beta-catenin pathway is upregulated, whereas PPAR gamma is downregulated. In Alzheimer's disease and Parkinson's disease, WNT/beta-catenin pathway is downregulated while PPAR gamma is upregulated. The dysregulation of the canonical WNT/beta-catenin pathway is responsible for the modification of thermodynamics behaviors of metabolic enzymes. Upregulation of WNT/beta-catenin pathway leads to aerobic glycolysis, named Warburg effect, through activated enzymes, such as glucose transporter (Glut), pyruvate kinase M2 (PKM2), pyruvate dehydrogenase kinase 1(PDK1), monocarboxylate lactate transporter 1 (MCT-1), lactic dehydrogenase kinase-A (LDH-A) and inactivation of pyruvate dehydrogenase complex (PDH). Downregulation of WNT/beta-catenin pathway leads to oxidative stress and cell death through inactivation of Glut, PKM2, PDK1, MCT-1, LDH-A but activation of PDH. In addition, in NDs, PPAR gamma is dysregulated, whereas it contributes to the regulation of several key circadian genes. NDs show many dysregulation in the mediation of circadian clock genes and so of circadian rhythms. Thermodynamics rhythms operate far-from-equilibrium and partly regulate interactions between WNT/beta-catenin pathway and PPAR gamma. In NDs, metabolism, thermodynamics and circadian rhythms are tightly interrelated.

Seizures in Pediatric Patients With Liver Transplant and Efficacy of Levetiracetam

The aim of this study was to evaluate the risk factors, clinical implications, and prognosis of new-onset seizures that occurred after pediatric liver transplantation, and to assess the efficacy of levetiracetam treatment. The clinical and laboratory data of liver transplanted 28 children who had seizures after liver transplantation and specifically of 18 children who received levetiracetam were analyzed retrospectively. Sixteen patients (88.9%) remained seizure-free and in 2 (11.1%), more than 50% reduction in seizures were detected with levetiracetam treatment. In conclusion, seizures are generally the most common complication by a spectrum of seizure types, and sometimes cause symptomatic epilepsy. The most common risk factors for seizures in transplant recipients is immunosuppressant toxicity. Currently, there isn't a specific treatment involving the transplant patient population. Levetiracetam may be preferable in pediatric patients as it's reliable for liver disease and has advantages in the treatment of postoperative seizures due to its intravenous usage.

Early and late neurological complications of liver transplantation in pediatric patients

NCs occur commonly after solid organ transplantation and affect 15%-30% of liver transplant recipients. The aim of this retrospective study was to evaluate the type and incidence of neurologic events in pediatric patients following LT. Between May 2006 and June 2015, 242 patients (118 females, 124 males) requiring LT for different etiologies at the İnönü University Liver Transplantation Institute were included. The incidence, types, and risk factors of NCs that occurred following LT were evaluated retrospectively. Neurologic events occurred in 57 (23.5%) of the patients. Early NCs were encephalopathy (12.4%), seizures (11.5%), and PRES (7%). Of 57 patients, five (8.7%) experienced NCs at least 1 month after LT; these late NCs included tremor, headaches, encephalopathy, ataxia, and neuropathy. The psychiatric symptoms after LT were noted in 42 patients (17.4%). The mortality rate after LT in those with or without neurological events was not significantly different (P=.73). There was a high incidence of serious neurologic events after LT. The major neurologic manifestation in our patients was encephalopathy followed by seizures.

Medical management of children after liver transplantation

PURPOSE OF REVIEW

Successful outcomes in patient, graft survival, and quality of life depend on the prevention, early detection, and treatment of possible complications. The aim of the study was to highlight the common outcomes focusing on the unique features in children. Medical follow-up of children after liver transplantation includes monitoring of surgical complications: biliary and vascular, rejection, infections, posttransplant lymphoproliferative disease, other malignancies, recurrent disease, graft function, hypertension, diabetes, renal failure, among other conditions. The goal is to maintain normal graft function on minimal immunosuppression to avoid medication-induced side-effects.

RECENT FINDINGS

Recent findings include the importance of meticulous follow-up of Epstein-Barr virus and Cytomegalic virus viral load, leading to early diagnosis and improved prognosis, increased prevalence of renal toxicity, cognitive dysfunction, autoimmune, atopic and eosinophilic disease, oral hygiene and chronic hepatitis, and fibrosis of allografts.

SUMMARY

Caring for children after liver transplantation is extremely rewarding; however, careful attention must be paid to a variety of systems with understanding of the distinctiveness of pediatrics to assure optimal outcomes.

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.

Neurologic complications following pediatric renal transplantation

We reviewed neurologic complications after renal transplantation in children over a 20-year period. Neurologic complications were classified as early (within 3 months) and delayed (beyond 3 months). Of 115 children, 10 (8.7%) had complications. Early complications were found in 4.35% of patients: seizures in 4 (posterior reversible leukoencephalopathy syndrome due to immunosuppressant toxicity, sepsis/presumed meningitis, and indeterminate) and headaches in 1. One patient with seizures received levetiracetam for 6 months and 1 with headaches received amitriptyline prophylaxis. Late complications were noted in 4.35% of patients: seizures in 3 (posterior reversible leukoencephalopathy syndrome due to hypertension, hypertensive encephalopathy), headaches in 2, and tremors in 1. Two patients with seizures were treated with anti-epilepsy medications; 1 with migraine received cyproheptadine prophylaxis. Neurologic complications develop in children after renal transplantation. Seizures due to posterior reversible leukoencephalopathy syndrome were the commonest complication. Early detection and appropriate management of these complications is important.

Risk factors for neurological complications and their correlation with survival following pediatric liver transplantation

Despite the improved outcomes of LT, post-operative NCs remain a significant cause of morbidity and mortality. The aim of the study was to identify the incidence of and risk factors for NCs in children who underwent LT. The medical records of pediatric patients who underwent LT at Asan Medical Center Children's Hospital between January 1994 and December 2010 were retrospectively analyzed. The onset and types of NC and pretransplant variables associated with NC were evaluated. We identified 190 children (85 boys [44.7%], 105 girls [55.3%]) of mean age 4.1 ± 4.7 yr, who underwent LT. Forty-six NCs occurred in 41 (21.6%) patients after LT, the most common being seizures (n = 13, 28.3%) and encephalopathy (n = 10, 21.7%). Of the 46 NCs, 24 (52.2%) occurred within three months after LT. Multivariate analysis showed that primary liver disease, preoperative neurological problems, preoperatively higher serum creatinine concentration, and graft failure were significant risk factors for NCs. The survival rate was significantly lower for patients with NCs than for those without (p < 0.001). NCs after pediatric LTs were common and associated with a higher mortality rate in our study. Close monitoring and appropriate risk management may improve the long-term outcomes of pediatric patients who undergo LT.

Tacrolimus-related seizure after pediatric liver transplantation--a single-center experience

To identify the risk factors for new-onset seizures after pediatric LT and to assess their clinical implications and long-term prognosis. The clinical and laboratory data of 27 consecutive children who underwent LT from January 2007 to December 2010 in our center were analyzed retrospectively. Patients were divided into seizures group and a non-seizures group. Pre-operative, intra-operative, and post-operative data were collected. Seizures occurred in four children, an incidence of 14.8%. All exhibited generalized tonic-clonic seizures within the first two wk after LT. Univariate analysis showed that the risk factors associated with seizures after pediatric LT included gender, pediatric end-stage liver disease score before surgery, Child-Pugh score before surgery, serum total bilirubin after surgery, and trough TAC level. Multivariate analysis showed that trough TAC level was the only independent risk factor associated with the seizures. All children who experienced seizures survived with good graft function and remained seizure-free without anti-epileptic drugs over a mean follow-up period of 33.7 ± 14.6 months. High trough TAC level was the predominant factor that contributed to seizures in the early post-operative period after pediatric LT. High PELD and Child-Pugh scores before LT and high post-operative serum Tbil may be contributory risk factors for TAC-related seizures.

Circadian and sleep disorder in Huntington's disease

Huntington's disease is a progressive neurological disorder that starts insidiously with motor, cognitive or psychiatric disturbance, and progresses through a distressing range of symptoms to end with a devastating loss of function, both motor and executive. There is a growing awareness that, in addition to cognitive and psychiatric symptoms, there are other important non-motor symptoms in HD, including sleep and circadian abnormalities. It is not clear if sleep-wake changes are caused directly by HD gene-related pathology, or if they are simply a consequence of having a neurodegenerative disease. From a patient point of view, the answer is irrelevant, since sleep and circadian disturbances are deleterious to good daily living, even in neurologically normal people. The assumption should be that, at the very least, sleep and/or circadian disturbance in HD patients will contribute to their symptoms. At worst, they may contribute to the progressive decline in HD. Here I review the state of our understanding of sleep and circadian abnormalities in HD. I also outline a set of simple rules that can be followed to improve the chances of a good night's sleep, since preventing any 'preventable' symptoms is the a logical first step in treating disease. The long-term impact of sleep disruption in HD is unknown. There have been no large-scale systematic studies of in sleep in HD. Furthermore, there has never been a study of the efficacy of pharmaceuticals that are typically used to treat sleep deficits in HD patients. Thus treatment of sleep disturbance in HD is necessarily empirical. A better understanding of the relationship between sleep/circadian abnormalities and HD pathology is needed, if treatment of this aspect of HD is to be optimized.