The central nervous system complications of bone marrow transplantation in children

Seizures in children undergoing stem cell transplantation

BACKGROUND

Neurological complications (NCs) are of major concern following hematological stem cell transplantation (HSCT), most of which present with seizures.

PROCEDURES

We performed a retrospective study (2002-2018) of patients undergoing HSCT in order to analyze the incidence and aetiologies related to seizures.

RESULTS

Of 155 children undergoing HSCT, 27 (17.4%) developed seizures at some point in 2 years of follow-up. The most frequent etiologies were central nervous system (CNS) infection (n = 10), drug toxicity (n = 8), and vascular disease (n = 5). A statistically significant association was found between seizure and the HSCT type (lower risk for a related identical donor, p = .010), prophylactic or therapeutic mycophenolate use (p = .043 and .046, respectively), steroid use (p = .023), selective CD45RA+ depletion (p = .002), pre-engraftment syndrome (p = .007), and chronic graft-versus-host disease (GVHD) severity (p = .030). Seizures predicted evolution to life-threatening complications and admission to intensive care (p < .001) and higher mortality (p = .023). A statistically significant association was also found between seizures and sequelae in survivors (p = .029). Children who developed seizures had a higher risk of CNS infection and vascular disease (odds ratio 37.25 [95% CI: 7.45-186.05] and 12.95 [95% CI 2.24-74.80], respectively).

CONCLUSIONS

Neurological complications highly impact survival and outcomes and need to be addressed when facing an HSCT procedure.

Neurologic Complications in Pediatric Allogeneic Stem Cell Transplantation: Analysis of Risk Factors and Outcome

Neurologic complications following stem cell transplantation are of utmost importance owing to their high morbimortality. Although many studies have been performed in the adult population, reports in children are scarce. Our objective was to determine the most common neurologic complications in a pediatric population and to analyze possible risk factors for their development. We performed an exploratory retrospective study of neurologic complications in pediatric patients who had allogeneic stem cell transplantation over the last 18 years. We identified 66 neurologic complications in 178 allogeneic stem cell transplantations. The most frequent neurologic complications were those involving the peripheral nervous system and those related to drug toxicity. Survival decreased significantly in the presence of neurologic complications. Multivariate logistic regression analysis showed that independent risk factors for developing neurologic complications were development of chronic extensive graft-vs-host disease requiring treatment, cytomegalovirus reactivation, and central nervous system radiation. Prompt diagnosis and preemptive treatment, if possible, are necessary to avoid long-term sequelae or mortality.

Imaging findings of neurologic complications in lung transplantation: Review of a 9-year cohort

Background

Lung transplantation (LT) requires complex multidisciplinary organization and constitutes a therapeutic option and a life-saving procedure. Although the number of lung recipients continues to increase, neurological complications and death rates following lung transplantation are still higher than desirable.

Purpose

This study aims to analyse the neuroimaging findings in a cohort of adult patients with LT.

Material and Methods

A retrospective cohort study of all lung transplant recipients (344 patients: 205 men and 139 women) at a single institution from January 2011 to January 2020. The collected data included demographic features, clinical data and evaluation of the imaging findings. We also recorded the date of neurological complication(s) and the underlying disease motivating lung transplantation.

Results

We found an elevated rate of neuroimaging findings in patients following LT with 32.6% of positive studies. In our cohort, the average time after LT to a neurological complication was 4.9 months post-transplant. Encephalopathy, critical illness polyneuropathy and stroke, in that order, were the most frequent neurological complications. Structural abnormalities in brain imaging were more often detected using MRI than CT for indications of encephalopathy and seizures.

Conclusions

LT recipients constitute an especially vulnerable group that needs close surveillance, mainly during the early post-transplant period.

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.

Hematopoietic Stem Cell Transplantation-Associated Neurological Complications and Their Brain MR Imaging Findings in a Pediatric Population

Simple Summary

Neurologic complications following a hematopoietic stem cell transplantation (HSCT) can be caused by various etiologies and significantly contribute to morbidity and mortality. The aim of our retrospective study was to determine the prognostic indicators for HSCT-associated neurological complications in pediatric HSCT recipients using their clinical characteristics and brain magnetic resonance imaging (MRI) lesions. The demographics, received treatments, treatment-related morbidities, laboratory findings and brain MRI findings were reviewed and compared among 51 patients who had underwent a brain MRI due to newly developed neurological symptoms or infection signs during HSCT and follow-up period. Children with neurologic complications associated with infectious causes, malignant disease or severe brain MRI abnormalities were more likely to have poor outcome.

Abstract

Purpose: To determine the prognostic indicators for hematopoietic stem cell transplantation (HSCT)-associated neurological complications, the clinical characteristics and brain magnetic resonance imaging (MRI) lesions in pediatric HSCT recipients were reviewed. Methods: This retrospective study included 51 patients who had underwent a brain MRI due to newly developed neurological symptoms or infection signs during chemotherapy or HSCT. We reviewed the demographics, received treatments, treatment-related morbidities, laboratory findings and brain MRI findings, which were compared between good and poor neurologic outcome groups. Results: Thirty-seven patients (72.5%) fully recovered from the neurologic deficits and fourteen (27.5%) persisted or aggravated. The children with an underlying malignant disease had significantly poorer neurological outcomes (p = 0.015). The neurologic complications associated with infection were more frequent in the poor outcome group (p = 0.038). In the neuroimaging findings, the extent of the white matter lesions was significantly higher in the poor outcome group, as was that of abnormal enhancement, ventriculomegaly, cortical change, deep gray matter abnormalities and cerebellar abnormalities. Conclusion: Most children with neurologic complications and neuroimaging abnormalities during HSCT had recovered. However, children with neurologic complications associated with infectious causes, malignant disease or severe brain MRI abnormalities should be more carefully monitored during HSCT.

A Review of Acute and Long-Term Neurological Complications Following Haematopoietic Stem Cell Transplant for Paediatric Acute Lymphoblastic Leukaemia

Despite advances in haematopoietic stem cell transplant (HSCT) techniques, the risk of serious side effects and complications still exists. Neurological complications, both acute and long term, are common following HSCT and contribute to significant morbidity and mortality. The aetiology of neurotoxicity includes infections and a wide variety of non-infectious causes such as drug toxicities, metabolic abnormalities, irradiation, vascular and immunologic events and the leukaemia itself. The majority of the literature on this subject is focussed on adults. The impact of the combination of neurotoxic drugs given before and during HSCT, radiotherapy and neurological complications on the developing and vulnerable paediatric and adolescent brain remains unclear. Moreover, the age-related sensitivity of the nervous system to toxic insults is still being investigated. In this article, we review current evidence regarding neurotoxicity following HSCT for acute lymphoblastic leukaemia in childhood. We focus on acute and long-term impacts. Understanding the aetiology and long-term sequelae of neurological complications in children is particularly important in the current era of immunotherapy for acute lymphoblastic leukaemia (such as chimeric antigen receptor T cells and bi-specific T-cell engager antibodies), which have well-known and common neurological side effects and may represent a future treatment modality for at least a fraction of HSCT-recipients.

Change of White Matter Integrity in Children With Hematopoietic Stem Cell Transplantation

BACKGROUND

Advances in hematopoietic stem cell transplantation have improved the survival rate of malignant diseases and congenital immunodeficiencies. It has become important to assess long-term complications in survivors. To assess neurological abnormalities in children treated by transplantation, diffusion tensor imaging was performed.

METHODS

Forty children who underwent head diffusion tensor imaging before and after their first transplantation were enrolled. Patients with brain lesions on conventional MRI were excluded. Fractional anisotropy and mean diffusivity were compared between patients and 28 control subjects using tract-based spatial statistics. The Strengths and Difficulties Questionnaire was administered as a behavioral evaluation after transplantation, and diffusion tensor images of patients with and without behavioral abnormalities were compared.

RESULTS

The age of patients and controls was 0 to 19 years and 0 to 16 years, respectively. The date of diffusion tensor imaging was 10 to 57 days before and 40 to 153 days after transplantation. Tract-based spatial statistics showed fractional anisotropy reduction in widespread white matter in patients before and after transplantation. Mean diffusivity was high before transplantation and normalized after transplantation. Analysis comparing before and after hematopoietic stem cell transplantation shows no difference in fractional anisotropy and a higher mean diffusivity before hematopoietic stem cell transplantation. In patients with behavioral abnormalities, low fractional anisotropy and high mean diffusivity remained after transplantation.

CONCLUSIONS

Longitudinal diffusion tensor imaging showed white matter abnormalities in children without conventional MRI abnormalities, which were related to behavioral problems after transplantation. Diffusion tensor imaging is useful for behavioral assessment in children undergoing transplantation.

Imaging Assessment of Complications from Transplantation from Pediatric to Adult Patients: Part 2: Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is an intravenous transfusion of pluripotent stem cells to repopulate the marrow and restore immunocompetence. However, before transplantation, the patient undergoes a conditioning regimen to eradicate the underlying disease, subsequently resulting in an immunocompromised state. Serious and some life-threatening complications involving any organ can occur. Currently, with advances in hematopoietic stem cell transplantation techniques and posttransplant management, more pediatric patients are now living longer and into their adulthood. The goal of this review article is to discuss the common neurologic, pulmonary, and abdominal complications associated with hematopoietic stem cell transplantation with emphasis on their imaging characteristics.

HIV Eradication Strategies: Implications for the Central Nervous System

PURPOSE OF REVIEW

In addition to preventive protocols and antiretroviral therapy, HIV-1 eradication has been considered as an additional strategy to help fight the AIDS epidemic. With the support of multiple funding agencies, research groups worldwide have been developing protocols to achieve either a sterilizing or a functional cure for HIV-infection.

RECENT FINDINGS

Most of the studies focus on the elimination or suppression of circulating CD4+ T cells, the best characterized HIV-1 latent reservoir. The role of the central nervous system (CNS) as a latent reservoir is still controversial. Although brain macrophages and astrocytes are susceptible to HIV-1 infection, it has not been ascertained whether the CNS carries latent HIV-1 during cART and, if so, whether the virus can be reactivated and spread to other compartments after ART interruption. Here, we examine the implications of HIV-1 eradication strategies on the CNS, regardless of whether it is a true latent reservoir and, if so, whether it is present in all patients.

Central Nervous System Complications after Allogeneic Hematopoietic Stem Cell Transplantation in Children

Central nervous system complications (CNSCs) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are common and may be a significant source of morbidity and mortality. We performed a retrospective study of 153 pediatric patients who underwent allo-HSCT to determine CNSC type, incidence, and impact on survival. A total of 34 patients (22.2%) developed CNSCs. The cumulative incidence of CNSCs at 100 days and 3 years was 18.30 and 22.73%, respectively. The most common CNSC was calcineurin inhibitor (CNI)-associated neurotoxicity (50.0%). Risk factors for CNSCs were the time from diagnosis to HSCT ≥4.8 months (p = 0.032) and the development of acute graft-versus-host disease (aGVHD) grade III-IV (p = 0.002). CNSCs after allo-HSCT negatively impacted overall survival (hazard ratio [HR] 1.97, p = 0.043) and nonrelapse mortality (HR 4.84, p < 0.001). In conclusion, CNSCs after allo-HSCT are associated with poor outcomes; patients with severe aGVHD and/or late transplantation should be given more attention.

Brain Imaging Findings and Neurologic Complications after Allogenic Hematopoietic Stem Cell Transplantation in Children

Hematopoietic stem cell transplantation (HSCT) is the only therapy for a subset of patients with malignant and nonmalignant diseases. Central nervous system (CNS) complications continue to be an important cause of morbidity and significantly contribute to mortality after HSCT. These complications include infections, cerebrovascular lesions, therapy-induced diseases, metabolic disturbances, and post-HSCT carcinogenesis. Following HSCT, three phases can be identified on the basis of the patient's immune status: 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). There is a distinct relationship between the patient's degree of immunodeficiency after HSCT and the incidence of various complications that may occur. Early diagnosis of CNS complications is crucial for successful management and a good prognosis, and computed tomography and magnetic resonance imaging play an important role in achieving these goals. The global increase in the use of HSCT requires radiologists to be familiar with CNS complications, their relationship to the patient's immune status, and their imaging appearances. This article describes the clinical background of HSCT; reviews the incidence, causes, and timeline of brain complications in children who underwent allogenic HSCT; and identifies the characteristic imaging findings of these disorders. ^©RSNA, 2018.

Central nervous system complications after allogeneic hematopoietic stem cell transplantation

Allogenic hematopoietic stem cell transplant (alloSCT) is a potentially curative modality of treatment for patients with hematological malignancies. However, CNS complications following transplant pose a risk to survival of the patients. Early recognition and management of these complications are crucial to reduce morbidity and mortality of patients following transplant. Early CNS complications associated with alloSCT are infection, cerebrovascular events, chemotherapy and radiation-induced toxicities while late complications include post-transplant lymphoproliferative disorder, CNS relapse of underlying malignancy and viral and fungal infections. Development of graft-versus-host disease can further increase the risk of CNS complications and outcomes after alloSCT. Strategies aimed to reduce the risk of CNS complications and early management may ameliorate the morbidity and mortality in transplant recipients.

Diagnostic Clues to Human Herpesvirus 6 Encephalitis and Wernicke Encephalopathy After Pediatric Hematopoietic Cell Transplantation

Human herpesvirus 6 (HHV6) encephalitis and Wernicke encephalopathy are treatable yet frequently undiagnosed causes of encephalopathy in pediatric recipients of allogeneic and autologous hematopoietic cell transplantation. Here we review representative cases of both conditions to highlight specific and relevant neurologic features that prompted effective diagnosis and treatment. Two patients with confusion accompanied by seizures, memory changes, or specific visual hallucinations and HHV6 detectable by polymerase chain reaction (PCR) in cerebrospinal fluid had improvement in viral load with ganciclovir or foscarnet treatment. Two patients had confusion, ataxia, or ocular changes and low serum thiamine levels, which resolved with parenteral thiamine. In all cases, definitive diagnosis and treatment were facilitated by a high index of suspicion and search for specific pathognomonic neurologic deficits accompanying the confusional state. It is critical to clinically differentiate these 2 conditions from other common neurologic syndromes occurring after transplant, allowing potentially improved patient outcomes by prompt diagnosis and effective treatment.

Autoimmune Encephalitis Following Bone Marrow Transplantation

BACKGROUND

Neurological complications, especially encephalopathy and seizures, are commonly seen in bone marrow transplant patients. Infections, chemotoxicity, graft versus host disease, or secondary central nervous system malignancies are the most common underlying etiologies. There is increased awareness that autoimmune encephalitis may cause neurological dysfunction in immunocompetent children. The potential role of such a mechanism in children undergoing bone marrow transplantation is unknown.

METHODS

We report a boy who developed autoimmune encephalitis with voltage-gated potassium channel-associated and thyroid autoantibodies subsequent to transplantation.

RESULTS

A 7-year-old boy presented with a change in behavior, poor attention, cognitive deficits, and abnormal movements 15 months after undergoing transplantation for idiopathic aplastic anemia. He had clinical and subclinical seizures and brain magnetic resonance imaging hyperintensities bilaterally in the uncal regions. His evaluation revealed high titers of voltage-gated potassium channel, leucine-rich glioma-inactivated 1 protein, and thyroglobulin antibodies suggestive of autoimmune limbic encephalitis. He showed significant improvement in behavior and neuropsychological testing and has remained seizure-free on levetiracetam after immunotherapy with corticosteroids and intravenous immunoglobulin.

CONCLUSION

Systemic autoimmune manifestations in bone marrow transplant patients have been well-documented, but autoimmune encephalitis after transplantation has yet to be described in children.

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 after allogeneic hematopoietic stem cell transplantation in children: analysis of prognostic factors

Neurologic complications are serious complications after hematopoietic stem cell transplantation (HSCT) and significantly contribute to morbidity and mortality. The purpose of this study was to investigate the clinical features and prognosis in pediatric patients who had neurologic complications after allogeneic HSCT. We retrospectively reviewed the medical records of children and adolescents (19 years old or younger) who underwent allogeneic HSCT at our institution from 2000 to 2012. A total of 383 patients underwent 430 allogeneic transplantations. Among them, 73 episodes of neurologic complications occurred in 70 patients. The cumulative incidence of neurologic complications at day 400 was 20.0%. Almost two thirds of the episodes (63.0%, 46 of 73) occurred within 100 days after transplantation. Calcineurin inhibitor-related neurotoxicity was observed as the most common cause of neurotoxicity (47.9%, 35 of 73) and was significantly associated with earlier onset neurologic complications, seizure, and tremor. It also showed a significant association with lower probability of headache, abnormality of cranial nerve, and neurologic sequelae. In a multivariate analysis, days to neutrophil engraftment after HSCT, extensive chronic graft-versus-host disease (GVHD) and the existence of neurologic sequelae were identified as risk factors for mortality in patients who had neurologic complications (hazard ratio [HR], 1.08; 95% confidence interval [CI], 1.02 to 1.15; P = .011; HR, 5.98; 95% CI, 1.71 to 20.90; P = .005; and HR, 4.37; 95% CI, 1.12 to 17.05; P = .034, respectively). However, there was no significant difference in the 5-year overall survival between the patients who had neurologic complications without sequelae and the patients who did not have any neurologic complications (57.3% versus 61.8%, P = .906). In conclusion, we found that the major significant risk factors for mortality in pediatric recipients with neurologic complications were the existence of neurologic sequelae and extensive chronic GVHD.