Neuroimaging and neurologic complications after organ transplantation

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

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.

Acute Graft-Versus-Host Disease, Infections, Vascular Events and Drug Toxicities Affecting the Central Nervous System

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative therapy for patients with hematological malignancies. Acute Graft versus host diseases (GVHD) is a major immune mediated side effect of allo-HCT that can affect the central nervous system (CNS) in addition to post-allo-HCT vascular events, drug toxicity or infections. Here we summarize and discuss recent preclinical data on the CNS as a target of acute GVHD and the known mechanisms contributing to neurotoxicity with a focus on microglia and T cells. We also discuss open questions in the field and place the findings made in mouse models in a clinical context. While in mice the neurological deficits can be assessed in a controlled fashion, in patients the etiology of the CNS damage is difficult to attribute to acute GVHD versus infections, vascular events, and drug-induced toxicity. Ultimately, we discuss novel therapies for GVHD of the CNS. Our understanding of the biological mechanisms that lead to neurotoxicity after allo-HCT increased over the last decade. This review provides insights into CNS manifestations of GVHD versus other etiologies of CNS damage in mice and patients.

Tacrolimus Decreases Cognitive Function by Impairing Hippocampal Synaptic Balance: a Possible Role of Klotho

The influence of long-term tacrolimus treatment on cognitive function remains to be elucidated. Using a murine model of chronic tacrolimus neurotoxicity, we evaluated the effects of tacrolimus on cognitive function, synaptic balance, its regulating protein (Klotho), and oxidative stress in the hippocampus. Compared to vehicle-treated mice, tacrolimus-treated mice showed significantly decreased hippocampal-dependent spatial learning and memory function. Furthermore, tacrolimus caused synaptic imbalance, as demonstrated by decreased excitatory synapses and increased inhibitory synapses, and downregulated Klotho in a dose-dependent manner; the downregulation of Klotho was localized to excitatory hippocampal synapses. Moreover, tacrolimus increased oxidative stress and was associated with activation of the PI3K/AKT pathway in the hippocampus. These results indicate that tacrolimus impairs cognitive function via synaptic imbalance, and that these processes are associated with Klotho downregulation at synapses through tacrolimus-induced oxidative stress in the hippocampus.

Myelitis After Liver Transplant: A Case Report

We report a case of neurotoxicity as a side effect of a calcineurin inhibitor (tacrolimus), which is used as an immunosuppressive drug after liver transplant. Our patient had chronic hepatic failure due to Budd-Chiari syndrome and underwent a liver transplant after an appropriate deceased donor organ was obtained. After organ transplant surgery, he was kept under the effect of an immunosuppressive drug (tacrolimus) with daily control of the level of drug in his blood to avoid drug toxicity. Despite the level of drug in his blood being within the ideal range, the patient developed neurotoxicity that presented as weakness of his extremities. Appropriate diagnostic tests were done, and all proved that these signs and symptoms were related to the use of tacrolimus. Therefore, the drug was changed to cyclosporine. After a few months, the patient regained normal neurological functions of his extremities. We should take precautions to monitor neurological symptoms and signs while we administer calcineurin inhibitors.

Influence of Tacrolimus on Depressive-Like Behavior in Diabetic Rats Through Brain-Derived Neurotrophic Factor Regulation in the Hippocampus

The neurotoxicity of immunosuppressive agents and diabetes mellitus are known risk factors of neurological complications in kidney transplant recipients. The aim of the present study was to investigate the influence of tacrolimus on brain-derived neurotrophic factor (BDNF), the critical protein for maintenance of neuronal functions, in the hippocampus in a diabetic condition. A diabetic rat model was established by a single streptozotocin injection (60 mg/kg). Control and diabetic rats then received daily tacrolimus (1.5 mg/kg per day) injections for 6 weeks. BDNF expression in the hippocampus was examined in the dentate gyrus (DG) and CA3 region using immunohistochemistry. There was a significant decrease of BDNF expression in the DG and CA3 region in tacrolimus-treated and diabetic rats compared with that of the control group injected with vehicle only. However, there was no difference in BDNF expression between the two experimental groups. Tacrolimus treatment in diabetic rats further decreased the BDNF expression level in the DG and CA3 region. Interestingly, mossy fiber sprouting, demonstrated by prominent punctate immunolabeling of BDNF with synaptoporin, was observed in the diabetic group treated with tacrolimus, which localized at the stratum oriens of the CA3 region. These data suggest that tacrolimus treatment or a diabetic condition decreases BDNF expression in the hippocampus, and that tacrolimus treatment in the diabetic condition further injures the CA3 region of the hippocampus. In addition to BDNF expression, decreased locomotor activity and evident depressive behavior were observed in tacrolimus-treated diabetic rats. Moreover, there were significant decreases of the mRNA levels of γ-aminobutyric acid and serotonin receptors in the diabetic hippocampus with tacrolimus treatment. This finding suggests that tacrolimus treatment may cause further psychiatric and neurological complications for patients with diabetes, and should thus be used with caution.

Indian Antimicrobial Prescription Guidelines in Critically Ill Immunocompromised Patients

How to cite this article: Kulkarni AP, Sengar M, Chinnaswamy G, Hegde A, Rodrigues C, Soman R, Khilnani GC, Ramasubban S, Desai M, Pandit R, Khasne R, Shetty A, Gilada T, Bhosale S, Kothekar A, Dixit S, Zirpe K, Mehta Y, Pulinilkunnathil JG, Bhagat V, Khan MS, Narkhede AM, Baliga N, Ammapalli S, Bamne S, Turkar S, Bhat KV, Choudhary J, Kumar R, Divatia JV. Indian Journal of Critical Care Medicine 2019;23(Suppl 1): S64-S96.

Neurological complications of renal dialysis and transplantation

Neurological complications from renal replacement therapy contribute significantly to morbidity and mortality in patients with renal failure. Such complications can affect either the central or peripheral nervous systems. Most neurological disturbances associated with the uraemic state do not respond fully to renal replacement therapy. There are also complications specifically associated with dialysis and transplantation. A multidisciplinary approach, involving both nephrologists and neurologists, is critical for the diagnosis and effective management of these disorders.

Imaging spectrum of central nervous system complications of hematopoietic stem cell and solid organ transplantation

Neurologic complications are common after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT) and affect 30-60% of transplant recipients. The aim of this article is to provide a practical imaging approach based on the timeline and etiology of CNS abnormalities, and neurologic complications related to transplantation of specific organs. The lesions will be classified based upon the interval from HSCT procedure: pre-engraftment period <30 days, early post-engraftment period 30-100 days, late post-engraftment period >100 days, and the interval from SOT procedure: postoperative phase 1-4 weeks, early posttransplant syndromes 1-6 months, late posttransplant syndromes >6 months. Further differentiation will be based on etiology: infections, drug toxicity, metabolic derangements, cerebrovascular complications, and posttransplantation malignancies. In addition, differentiation will be based on complications specific to the type of transplantation: allogeneic and autologous hematopoietic stem cells (HSC), heart, lung, kidney, pancreas, and liver. Thus, in this article we emphasize the strategic role of neuroradiology in the diagnosis and response to treatment by utilizing a methodical approach in the work up of patients with neurologic complications after transplantation.

Clinical Characteristics of Transplant-associated Encephalopathy in Children

We aimed to analyze characteristics of encephalopathy after both hematopoietic stem cell and solid organ pediatric transplantation. We retrospectively reviewed medical records of 662 pediatric transplant recipients (201 with liver transplantation [LT], 55 with heart transplantation [HT], and 67 with kidney transplantation [KT], 339 with allogeneic hematopoietic stem cell transplantation [HSCT]) who received their graft organs at Asan Medical Center between January 2000 and July 2014. Of the 662 patients, 50 (7.6%) experienced encephalopathy after transplantation. The incidence of encephalopathy was significantly different according to the type of organ transplant: LT, 16/201 (8.0%), HT, 13/55 (23.6%), KT, 5/67 (7.5%), and HSCT, 16/339 (4.7%) (P < 0.001). Drug-induced encephalopathy (n = 14) was the most common encephalopathy for all transplant types, but particularly after HSCT. Hypertensive encephalopathy was the most common after KT and HT, whereas metabolic encephalopathy was the most common after LT. The median time to encephalopathy onset also differed according to the transplant type: 5 days after KT (range 0-491 days), 10 days after HT (1-296 days), 49.5 days after HSCT (9-1,405 days), and 39 days after LT (1-1,092 days) (P = 0.018). The mortality rate among patients with encephalopathy was 42.0% (n = 21/50). Only 5 patients died of neurologic complications. Transplant-associated encephalopathy presented different characteristics according to the type of transplant. Specialized diagnostic approach for neurologic complications specific to the type of transplant may improve survival and quality of life in children after transplantation.

The immunologic considerations in human head transplantation

The idea of head transplantation appears at first as unrealistic, unethical, and futile. Here we discuss immunological considerations in human head transplantation. In a separate accompanying article we discuss surgical, ethical, and psychosocial issues concerned in body-to-head transplantation (BHT) [1]. The success of such an unusual allograft, where the donor and the recipient can reject each other, depends on prevention of complex immunologic reactions, especially rejection of the head by the body (graft-vs-host) or probably less likely, the possibility of the head rejecting the total body allograft (host-vs-graft). The technical and immunologic difficulties are enormous, especially since rapid nerve and cord connections and regeneration have not yet been possible to achieve. In this article we begin by briefly reviewing neuro-immunologic issues that may favor BHT such as the blood brain barrier (BBB) and point out its shortcomings. And we touch on the cellular and humoral elements in the brain proper that differ in some respects from those in other organs and in the periphery. Based on recent successes in vascular composite allografts (VCAs), we will elaborate on potential specific advantages and difficulties in BHT of various available immunosuppressive medications already utilized in VCAs. The risk/benefit ratio of these drugs will be emphasized in relation to direct brain toxicity such as seizure disorders, interference, or promotion of nerve regeneration, and potentiation of cerebral viral infections. The final portion of this article will focus on pre-transplant immunologic manipulation of the deceased donor body along with pretreatment of the recipient.

Neurologic emergencies in HIV-negative immunosuppressed patients

HIV-negative immunosuppressed patients comprise a heterogeneous group including transplant patients, patients undergoing treatment with immunosuppressors, uremic patients, alcoholics, undernourished patients, diabetics, patients on dialysis, elderly patients, and those diagnosed with severe or neoplastic processes. Epileptic seizures, focal neurologic signs, and meningoencephalitis are neurologic syndromes that require urgent action. In most of these situations, neuroimaging tests are necessary, but the findings can be different from those observed in immunocompetent patients in function of the inflammatory response. Infectious disease is the first diagnostic suspicion, and the identification of an opportunistic pathogen should be oriented in function of the type and degree of immunosuppression. Other neurologic emergencies include ischemic stroke, cerebral hemorrhage, neoplastic processes, and pharmacological neurotoxicity. This article reviews the role of neuroimaging in HIV-negative immunodepressed patients with a neurologic complication that requires urgent management.

Gangliocytoma Presenting With Tacrolimus Neurotoxicity in a Renal Transplant Recipient: Case Report

Tacrolimus is a widely used macrolide immunosuppressant in transplant surgery, with mild and major neurologic side effects. A 21-year-old woman had undergone preemptive transplantation of a kidney from her mother. On the 1st postoperative day, the patient had headache, nausea, vomiting, and agitation. Magnetic resonance imaging (MRI) of the brain showed hyperintensity and a lesion in the right mesial temporal lobe. After we switched from tacrolimus to cyclosporine, the symptoms regressed. Persistence of the lesion, confirmed by repeated MRI, required that the patient be operated on. Pathologic examination showed the gangliocytoma, a rare brain tumor. Our case shows that preexisting brain lesions may cause tacrolimus-induced neurotoxicity in the early postoperative period.

The neurology of solid organ transplantation

Transplantation is the rescue treatment for end-stage organ failure with more than 110,000 solid organs transplantations performed worldwide annually. Recent advances in transplantation procedures and posttransplantation management have improved long-term survival and quality of life of transplant recipients, shifting the focus from acute perioperative critical care needs toward long-term chronic medical problems. Neurologic complications affect up to 30-60 % of solid organ transplant recipients. Common etiologies include opportunistic infections and toxicities of antirejection medications, and wide spectrum of toxic and metabolic disturbances. Most complications are common to all allograft types, but some are relatively specific for individual allograft types (e.g., central pontine myelinolysis in liver transplant recipients). Close collaboration between neurologists and other transplant team members is essential for effective management. Early recognition of complications and accurate diagnosis leading to timely treatment is essential to reduce the morbidity and improve the overall transplant outcome.

American society of Nephrology Quiz and Questionnaire 2014: transplantation

The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the Annual Kidney Week Meeting of the American Society of Nephrology. Once again, the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases representing each of these categories along with single best answer questions were prepared and submitted by the panel of experts. Before the meeting, program directors of United States nephrology training programs and nephrology fellows answered the questions through an internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. They compared their answers in real time using audience response devices with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the audience responses and the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the session and reproduces its educational value for the readers of CJASN. Enjoy the clinical cases and expert discussions.

Infektionen

In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.

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.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Neurologic aspects of heart transplantation

Cardiac transplantation remains the best treatment option for patients with end-stage, NYHA class IV heart failure who have failed conventional therapy. However, transplant rates have remained static largely due to limited organ donor supplies. Therefore, appropriate allocation of this precious resource is critical to maximize benefit, both at a patient level and at a societal level. Neurologic diseases, such as cerebrovascular disease and peripheral neuropathy, are prevalent in this patient population, as the major risk factors for heart disease place patients at risk for neurologic disease as well. Examples include hypertension, smoking, hypercholesterolemia, obesity, and diabetes. Pretransplant neurologic evaluation is very important to identify conditions that may limit survival after cardiac transplantation. In general, systemic diseases exacerbated by immunosuppression, conditions limiting ability to rehabilitate, and dementias are considered contraindications. Post-transplant neurologic complications are divided into central versus peripheral, and early versus late. The most common early complication is ischemic stroke. Other serious complications include hemorrhagic stroke, encephalopathy, and critical illness neuropathy. Over the long term, post-transplant immunosuppressive regimens are considered "a double edged sword." Although immunosuppressive medications are critical to preventing rejection and allograft dysfunction, they do have significant risk of morbidity and mortality associated with them, including neurologic side-effects. These include: (1) drug toxicities, such as lowering of seizure thresholds; (2) encephalopathy, such as posterior reversible encephalopathy syndrome (PRES); (3) infections; (4) malignancies, such as post-transplant lymphoproliferative disorder (PTLD). Many of the same considerations discussed in adult heart transplant recipients apply to pediatric heart transplant recipients as well. In children, seizures are the most common neurologic complication, although other neurologic complication rates are comparable.

Neurologic complications after liver transplantation

Neurologic complications are relatively common after solid organ transplantation and affect 15%-30% of liver transplant recipients. Etiology is often related to immunosuppressant neurotoxicity and opportunistic infections. Most common complications include seizures and encephalopathy, and occurrence of central pontine myelinolysis is relatively specific for liver transplant recipients. Delayed allograft function may precipitate hepatic encephalopathy and neurotoxicity of calcineurin inhibitors typically manifests with tremor, headaches and encephalopathy. Reduction of neurotoxic immunosuppressants or conversion to an alternative medication usually result in clinical improvement. Standard preventive and diagnostic protocols have helped to reduce the prevalence of opportunistic central nervous system (CNS) infections, but viral and fungal CNS infections still affect 1% of liver transplant recipients, and the morbidity and mortality in the affected patients remain fairly high. Critical illness myopathy may also affect up to 7% of liver transplant recipients. Liver insufficiency is also associated with various neurologic disorders which may improve or resolve after successful liver transplantation. Accurate diagnosis and timely intervention are essential to improve outcomes, while advances in clinical management and extended post-transplant survival are increasingly shifting the focus to chronic post-transplant complications which are often encountered in a community hospital and an outpatient setting.

[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.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.

Analytic Review: Neurological Complications of Transplantation

Recipients of solid organ or hematopoietic cell transplants are at risk of life-threatening neurological disorders including encephalopathy, seizures, infections and tumors of the central nervous system, stroke, central pontine myelinolysis, and neuromuscular disorders—often requiring admission to, or occurring in, the intensive care unit (ICU). Many of these complications are linked directly or indirectly to immunosuppressive therapy. However, neurological disorders may also result from graft versus host disease, or be an expression of the underlying disease which prompted transplantation, as well as injury induced during radiation, chemotherapy, surgery, and ICU stay. In rare cases, neuroinfectious pathogens may be transmitted with the transplanted tissue or organ. Diagnosis may be a challenge because clinical symptoms and findings on neuroimaging lack specificity, and a biological specimen or tissue diagnosis is often needed for definitive diagnosis. Management is centered on preventing further neurological injury, etiology-targeted therapy, and balancing the benefits and toxicities of specific immunosuppressive agents.

Neurologic manifestations of transplant complications

Neurologic complications affect posttransplant recovery of more than 20% of transplant recipients. Etiology is usually related to surgical procedure of transplantation, primary disorders causing failure of transplanted organ, opportunistic infections, and neurotoxicity of immunosuppressive medications. Risk of opportunistic infections and immunosuppressant neurotoxicity is greatest within the first six months, but it persists along with long-term maintenance immunosuppression required to prevent graft rejection. Neurotoxicity may require alteration of immunosuppressive regimen, and prompt therapy of opportunistic infections improves outcomes.

Reversible posterior leukoencephalopathy syndrome (RPLS) in a heart transplant recipient treated by substitution of cyclosporine A with tacrolimus

Reversible posterior leukoencephalopathy syndrome (RPLS) is one of the important adverse events following organ transplantation, associated with calcineurin inhibitors (CNIs). We describe a case of 54-year-old woman, who was diagnosed with RPLS within weeks after transplantation. Considering the risk of causing fatal rejection by discontinuation of CNIs, the immunosuppressive regimen of the patient was switched from a cyclosporine A-based regimen to a tacrolimus-based regimen. The patient recovered rapidly from RPLS following the switch to tacrolimus. This case demonstrated that not only discontinuation but also a substitution of CNIs would be a valid treatment option for RPLS in transplant recipients.