Mycobacterium tuberculosis-associated immune reconstitution syndrome in solid-organ transplant recipients. Transplantation. 2013;95:1173-1181. [PMID: 23435454 DOI: 10.1097/tp.0b013e31828719c8]

Tuberculosis after hematopoietic cell transplantation: retrospective study on behalf of the Infectious Diseases Working Party of the EBMT

Tuberculosis (TB) is rare following hematopoietic cell transplantation (HCT). In this multinational retrospective study, we report the frequency, characteristics, and outcome of TB following HCT performed during 2000-2019. Fifty-two patients (35 (67%) males, 15 (29%) children) from 24 centers developed TB following allogeneic (n = 47) or autologous (n = 5) HCT; with the relative frequency of 0.21% and 0.025%, respectively. Forty (77%) were bacteriologically, 12 (23%) clinically confirmed. The median time from HCT to TB was 135 (range, 16-3225) days. Eighteen (35%) patients with extrapulmonary TB (mainly involving lymph nodes and liver/spleen) were significantly younger, developed TB shorter after HCT, more often had inherited underlying disease, and received immunosuppressive therapy at TB diagnosis as compared to pulmonary TB. Five (22%) of 23 patients with drug-susceptibility testing performed, were resistant to at least one anti-TB drug. Treatment success was achieved in 38/50 (76%) of treated patients. One-year overall survival reached 75.7% and the 1-year cumulative incidence of TB-associated death was 18.1%. Concluding, TB is a rare, albeit severe complication, which can develop any time after HCT, frequently involves extrapulmonary sites, and results in high mortality rates. High proportion of drug-resistant TB warrants routine susceptibility testing.

Report of renal allograft tuberculosis a decade after transplant: challenges in diagnosis and management

Post-transplant infections constitute an important cause of morbidity and mortality in renal transplant recipients worldwide. Tuberculosis (TB) contributes significantly to this burden in endemic countries, such as India. We report a case of renal allograft TB, 10 years post-transplantation, diagnosed during a routine outpatient visit. An asymptomatic rise in serum creatinine level and a 6 month history of immunosuppressive drug non-compliance prompted evaluation of graft dysfunction. Biopsy of the renal allograft tissue suggested chronic active antibody mediated rejection with epithelioid granulomas in the interstitium. Guided by kidney biopsy, further testing with urine acid fast bacilli and urinary GeneXpert yielded positive results for TB. Treatment of TB was further complicated by the development of anti-tubercular therapy induced hepatitis and immune reconstitution inflammatory syndrome, which were managed with the reintroduction regimen and escalation of steroid dose, respectively. Our case highlights the atypical presentation and challenges in managing patients with TB in a post-renal transplant setting.

Cutaneous Tuberculosis in Heart Transplant

Tuberculosis is a disease with a significant global burden in terms of morbidity and mortality. It usually presents as a pulmonary disease but can occasionally have extrapulmonary presentations. Immunosuppressed people are at an increased risk of tuberculosis and more frequently have atypical manifestations of the disease. Cutaneous involvement is estimated to occur in only 2% of extrapulmonary presentations. We report a case of a heart transplant recipient with disseminated tuberculosis who initially presented with cutaneous manifestations in the form of multiple abscesses that were mistaken for a community-acquired bacterial infection. The diagnosis was made after positive nucleic acid amplification testing and cultures for Mycobacterium tuberculosis from the drainage of the abscesses. After initiating antituberculous treatment, the patient had 2 instances of immune reconstitution inflammatory syndrome. A combination of diminished immunosuppression due to discontinuation of mycophenolate mofetil in the setting of acute infection, rifampin drug interactions with cyclosporine, and the beginning of treatment of tuberculosis all contributed to this paradoxical worsening. The patient responded favorably to increased glucocorticoid therapy and showed no signs of treatment failure after 6 months of antituberculous therapy.

Tuberculosis treatment without rifampin in kidney/kidney-pancreas transplantation: A case series report

BACKGROUND

The best approach to tuberculosis (TB) treatment in transplanted patients is still unknown. Current guidelines are based on evidence either extrapolated from other populations or observational. Rifampin-containing regimens have strong pharmacokinetic interactions with immunosuppressive regimens, with high rates of organ dysfunction and ∼20% mortality. This report describes the results obtained using non-rifampin-containing regimens to treat confirmed TB in adult patients with kidney/kidney-pancreas transplantation.

METHODS

Retrospective data analysis from confirmed TB cases in adult kidney/kidney-pancreas transplant recipients (2006-2019), treated "de novo" with non-rifampin-containing regimens.

RESULTS

Fifty-seven patients had confirmed TB. Thirty patients were treated "de novo" with non-rifampin-containing regimens. These patients' mean age was 49.24 (±11.50) years. Induction immunosuppression was used in 22 patients. Maintenance immunosuppression was tacrolimus-mycophenolate-steroids in 13 (43%), sirolimus-mycophenolate-steroids in 6 (20%), and other immunosuppressive regimens in 11 (36%). Belatacept was used in four patients. TB localizations: pulmonary 43%; disseminated 23%; extrapulmonary 33%. Twenty-seven (90%) patients completed treatment with isoniazid, ethambutol, and levofloxacin (12 months, 23; 9 months, 3; 6 months, 1); 12 of these patients also received pyrazinamide for the first 2 months and were cured with functioning grafts. One patient (3%) lost the graft while on treatment. Two patients (7%) died while on TB treatment. Median (range) follow-up after completion of TB treatment was 32 (8-150) months. No TB relapses were observed.

CONCLUSIONS

Results with non-rifampin-containing TB treatments in this case series were better (in terms of mortality and graft dysfunction) than those previously described with rifampin-containing regimens in transplanted patients.

Mycobacterium Tuberculosis Infection after Kidney Transplantation: A Comprehensive Review

Tuberculosis (TB) in kidney transplant (KT) recipients is an important opportunistic infection with higher incidence and prevalence than in the general population and is associated with important morbidity and mortality. We performed an extensive literature review of articles published between 1 January 2000 and 15 June 2022 to provide an evidence-based review of epidemiology, pathogenesis, diagnosis, treatment and outcomes of TB in KT recipients. We included all studies which reported epidemiological and/or outcome data regarding active TB in KT, and we approached the diagnostic and treatment challenges according to the current guidelines. Prevalence of active TB in KT recipients ranges between 0.3–15.2%. KT recipients with active TB could have a rejection rate up to 55.6%, a rate of graft loss that varies from 2.2% to 66.6% and a mortality rate up to 60%. Understanding the epidemiological risk, risk factors, transmission modalities, diagnosis and treatment challenges is critical for clinicians in providing an appropriate management for KT with TB. Among diagnostic challenges, which are at the same time associated with delay in management, the following should be considered: atypical clinical presentation, association with co-infections, decreased predictive values of screening tests, diverse radiological aspects and particular diagnostic methods. Regarding treatment challenges in KT recipients with TB, drug interactions, drug toxicities and therapeutical adherence must be considered.

Anti-Cytomegalovirus Therapy: Whether and When to Initiate, Those Are the Questions

Cytomegalovirus (CMV) reactivation in patients with autoimmune bullous disease (AIBD) or severe drug eruption treated with immunosuppressive therapy was traditionally thought to be merely an epiphenomenon of the underlying immunosuppression. However, a detailed review of the clinical course of these patients revealed that CMV reactivation occurs upon rapid immune recovery, which is termed immune reconstitution inflammatory syndrome (IRIS), and that the timely initiation of anti-CMV therapy, when combined with maintenance doses of immunosuppressive agents, contributes to a rapid resolution of severe infectious complications thought to be refractory to conventional immunosuppressive therapies and unrelated to CMV reactivation. Thus, CMV reactivation resulting in fatal outcomes (CMV-IRIS) can be prevented by the timely detection of CMV DNA or antigens in the blood and by rapidly starting anti-CMV therapy while maintaining immunosuppressive therapy. Anti-CMV therapy is highly recommended for patients with CMV-IRIS or severe drug eruption who have risk factors for CMV reactivation resulting in fatal outcomes.

A Case Report of Lumbar Abscess in a Transplant Recipient: Is It Always What It Seems?

The percentage of solid organ transplant recipients who develop extrapulmonary or disseminated tuberculosis (TB) is higher than the general population. In countries where the disease is endemic, TB should always be considered a diagnostic possibility, and extrapulmonary disease should also be considered. We present the case of a kidney transplant patient who initially presented for an abscess in the left dorsolateral region and was ultimately diagnosed with pulmonary and extrapulmonary TB. With the initiation of antibacillary treatment, a drug interaction with immunosuppressants was verified, and rifampicin was maintained at a minimum dose with other antibacillary drugs at full dose, subsequently showing an improvement in the clinical picture. The adverse effects of TB treatment present great difficulty owing to the interactions of antibacillary drugs with immunosuppressants. Most patients with conventional treatment can be cured, so prompt diagnosis and treatment are important.

Tuberculosis in Pediatric Solid Organ and Hematopoietic Stem Cell Recipients

Children undergoing solid organ and hematopoietic stem cell transplantation are at high risk of morbidity and mortality from tuberculosis (TB) disease in the post-transplant period. Treatment of TB infection and disease in the post-transplant setting is complicated by immunosuppression and drug interactions. There are limited data that address the unique challenges for the management of TB in the pediatric transplant population. This review presents the current understanding of the epidemiology, clinical presentation, diagnosis, management, and prevention for pediatric transplant recipients with TB infection and disease. Further studies are needed to improve diagnosis of TB and optimize treatment outcomes for these patients.

Paradoxical Reaction In The Form Of New Pulmonary Mass During Anti-Tuberculosis Treatment: A Case Series And Literature Review

Introduction

Paradoxical reaction refers to deterioration of the original tuberculosis lesions or emergence of new infiltrative lesions during anti-tuberculosis treatment. The common manifestations of paradoxical reaction include new pleural effusion, cerebral tuberculosis and lymphadenitis. Paradoxical reaction manifested by new pulmonary mass is rare.

Patients and methods

This article summarizes and analyzes the clinical manifestations, chest CT, laboratory findings, treatments, pathological biopsy results of five patients diagnosed as paradoxical reaction in the form of new pulmonary mass. A literature review related to paradoxical reaction was conducted.

Results

Five patients diagnosed as pulmonary tuberculosis or tuberculous pleuritis received systematic anti-tuberculosis treatmensssts. New pulmonary masses were found by CT scans during the follow-ups. The patients were negative for tumor markers, examination of rheumatoid connective tissue disease and G/GM test. The original anti-tuberculosis treatments were continued. All of the masses were diminished gradually.

Conclusion

Paradoxical reaction needs to be taken into consideration when a new pulmonary mass occurs during anti-tuberculosis treatments. The diagnosis should be based on the patients’ clinical manifestations, laboratory results, imaging examinsssations and lung biopsy examinations. The original anti-tuberculosis therapy can be continued in patients without severe clinical symptoms. A close follow-up is needed.

A practical approach to tuberculosis diagnosis and treatment in liver transplant recipients in a low-prevalence area

Solid organ transplant candidates/recipients are at risk of mycobacterial infections. Although guidelines on the management of latent tuberculosis infection and active tuberculosis are available for solid organ transplant recipients, limited guidance focuses on end-stage liver disease or liver transplant recipients who require management in a referral center. Therapeutic challenges arise from direct antituberculosis drug-related hepatotoxicity, and substantial metabolic interactions between immunosuppressive and antituberculosis drugs. Another issue is the optimal timing of therapy with regards to the time of transplantation. This review focuses on the importance of tuberculosis screening with immunological tests, challenges in the diagnosis, management, and treatment of latent tuberculosis infection and active tuberculosis, as well as risk assessment for active tuberculosis in the critical peri-liver transplantation period. We detail therapeutic adjustments required for the management of antituberculosis drugs in latent tuberculosis infection and active tuberculosis, particularly when concomitantly using rifampicin and immunosuppressive drugs.

Urgent Living-Donor Liver Transplantation in a Patient With Concurrent Active Tuberculosis: A Case Report

BACKGROUND

Although active tuberculosis (TB) is considered a contraindication for liver transplantation (LT), this is the only treatment in patients with liver failure and concurrent active TB. We report a case with successful urgent living-donor LT for irreversible liver failure in the presence of active TB.

CASE PRESENTATION

A 48-year-old man, with a history of decompensated alcoholic liver cirrhosis, was presented with stupor. At admission, his consciousness had deteriorated to semi-coma, and his renal function also rapidly deteriorated to hepatorenal syndrome. A preoperative computed tomography scan of the chest revealed several small cavitary lesions in both upper lobes, and acid-fast bacillus stain from his sputum was graded 2+. Adenosine deaminase levels from ascites were elevated, suggesting TB peritonitis. A first-line anti-TB drug regimen was started immediately (rifampin, isoniazid, levofloxacin, and amikacin). An urgent living-donor LT was performed 2 days later. After LT, the regimen was changed to second-line anti-TB drugs (amikacin, levofloxacin, cycloserine, and pyridoxine). The sputum acid-fast bacillus stain tested negative on postoperative day 10. His liver function remained well preserved, even after the reversion to first-line anti-TB treatment. The patient recovered without any anti-TB medication-related complications and was discharged.

CONCLUSIONS

LT can be prudently performed as a life-saving option, particularly for patients with liver failure and concurrent active TB.

Paradoxical Reaction of Tuberculosis in a Heart Transplant Recipient During Antituberculosis Therapy: A Case Report

INTRODUCTION

Tuberculous paradoxical reactions (PRs) are excessive immune reactions occurring after antituberculosis (TB) treatment and are commonly observed in immunocompromised hosts such as patients infected with the human immunodeficiency virus.

CASE REPORT

We recently encountered a 63-year-old male heart transplant recipient who developed tuberculous PR after treatment for miliary TB. The patient had been receiving immunosuppressive therapy with cyclosporine and mycophenolate mofetil for over 15 years. The diagnosis of miliary TB was made based on the presence of intermittent fever and fatigue; thus, anti-TB treatments (isoniazid, levofloxacin, ethambutol, and pyrazinamide) were started, which led to rapid defervescence and regression of the granular shadow and pleural effusion. However, a new persistent fever and confused state developed 1 month after the anti-TB therapy was started. After excluding possible etiologies of the patient's symptom, a PR was suspected, and anti-TB drugs were continued; corticosteroids were added as anti-inflammatory agents. After that, he has shown a favorable course with long-term anti-TB chemotherapy.

CONCLUSION

A PR should always be considered when the patients' symptoms of tuberculosis re-exacerbate after an appropriate anti-TB therapy. A PR commonly occurs in patients with various immunologic conditions including heart transplant recipients.

Paradoxical immune reconstitution inflammatory syndrome associated with disseminated tuberculosis infection in an unrelated donor cord blood transplant recipient

Tuberculosis (TB) is an infrequent infection after hematopoietic cell transplant (HCT), with associated mortality up to 30%. The utility of universal screening for latent TB in HCT candidates is controversial due to the lack of sensitive screening tests. We describe a case of disseminated TB infection complicated by immune reconstitution inflammatory syndrome in an adult double unit umbilical cord blood transplant recipient who originated from the United Arab Emirates.

Tuberculosis and Transplantation

Mycobacterium tuberculosis is a major opportunistic pathogen in transplant recipients. Compared to that in the general population, the frequency of tuberculosis (TB) is 10 to 40 times higher in hematopoietic stem cell transplant (HSCT) recipients and 20 to 74 times higher in solid-organ transplant (SOT) recipients. Transplant recipients with TB are also more likely to develop disseminated disease, have longer time to definitive diagnosis, require more invasive diagnostic procedures, and experience greater anti-TB treatment-related toxicity than the general population. Specific risk factors for TB in SOT recipients include previous exposure to M. tuberculosis (positive tuberculin skin tests and/or residual TB lesions in pretransplant chest X ray) and the intensity of immunosuppression (use of antilymphocyte antibodies, type of basal immunosuppression, and intensification of immunosuppressive therapy for allograft rejection). Risk factors in HSCT recipients are allogeneic transplantation from an unrelated donor; chronic graft-versus-host disease treated with corticosteroids; unrelated or mismatched allograft; pretransplant conditioning using total body irradiation, busulfan, or cyclophosphamide; and type and stage of primary hematological disorder. Transplant recipients with evidence of prior exposure to M. tuberculosis should receive treatment appropriate for latent TB infection. Optimal management of active TB disease is particularly challenging due to significant drug interactions between the anti-TB agents and the immunosuppressive therapy. In this chapter, we address the epidemiology, clinical presentation, diagnostic considerations, and management strategies for TB in SOT and HSCT recipients.

Tuberculosis in kidney transplant recipients: A case series

Solid organ transplant recipients have an elevated risk of tuberculosis (TB) with high mortality. Data about TB in this population in the United States is sparse. We present four cases of active tuberculosis in kidney transplant recipients at our center. All patients had possible TB exposure prior to transplant and all were diagnosed with active TB within the first year of transplant. Disseminated TB was seen in half of the patients with extra-pulmonary TB being more common affecting lymph nodes, pericardium, and the kidney allograft. Delay in diagnosis from onset of symptoms ranged from fifteen days to two months. Two patients died from TB. TB is a largely preventable and curable disease. However, challenges remain in the diagnosis due to most recipients presenting with atypical symptoms. Physicians should maintain a high degree of suspicion for TB to promptly diagnose and treat post-transplant thereby minimizing complications. A review of the literature including the epidemiology, pathogenesis, clinical presentation, diagnosis and treatment options are discussed.

The demanding attention of tuberculosis in allogeneic hematopoietic stem cell transplantation recipients: High incidence compared with general population

BACKGROUND

The risk of developing tuberculosis (TB) in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is expected to be relatively high in an intermediate TB burden country. This single-center retrospective study was conducted to investigate risk factors and the incidence of TB after allogeneic HSCT.

METHODS

From January 2004 to March 2011, 845 adult patients were enrolled. Starting April 2009, patients were given isoniazid (INH) prophylaxis based on interferon-γ release assay results. The incidence of TB was analyzed before and after April 2009, and compared it with that of the general population in Korea.

RESULTS

TB was diagnosed in 21 (2.49%) of the 845 allogeneic HSCT patients. The median time to the development of TB was 386 days after transplantation (range, 49-886). Compared with the general population, the standardized incidence ratio of TB was 9.10 (95% CI; 5.59-14.79). Extensive chronic graft-versus-host disease (GVHD) was associated with the development of TB (P = 0.003). Acute GVHD, conditioning regimen with total body irradiation and conditioning intensity were not significantly related. INH prophylaxis did not reduce the incidence of TB (P = 0.548). Among 21 TB patients, one patient had INH prophylaxis.

CONCLUSION

Allogeneic HSCT recipients especially those who suffer from extensive chronic GVHD are at a high risk of developing TB. INH prophylaxis did not statistically change the incidence of TB, however, further well-designed prospective studies are needed.

Immune Reconstitution Inflammatory Syndrome Occurring in a Kidney Transplant Patient with Extrapulmonary Tuberculosis

Tuberculosis (TB) occurring in solid organ transplantation (SOT) is associated with significant morbidity and mortality usually due to delays in diagnosis, drug toxicity encountered with antimycobacterial therapy, and drug-drug interactions. TB in SOT patients may mimic other infectious and noninfectious posttransplant complications such as posttransplant lymphoproliferative disorder (PTLD) and systemic cytomegalovirus infection. Immune reconstitution inflammatory syndrome (IRIS) is a host response resulting in paradoxical worsening of an infectious disease which occurs after the employment of effective therapy and reversal of an immunosuppressed state. We describe the development of immune reconstitution inflammatory syndrome (IRIS), a unique complication occurring during the treatment of extrapulmonary tuberculosis occurring after transplant which resulted from decreasing immunosuppression in a patient who received Alemtuzumab induction therapy. Although (IRIS) has been originally described in HIV/AIDS patients receiving highly active antiretroviral therapy (HAART), solid organ transplant recipients with diagnosed or occult TB whose immune system may undergo immune reconstitution during their posttransplant course represent a new high risk group.

Paradoxical Reactions and the Immune Reconstitution Inflammatory Syndrome

In HIV-infected individuals, paradoxical reactions after the initiation of antiretroviral therapy (ART) are associated with a variety of underlying infections and have been called the immune reconstitution inflammatory syndrome (IRIS). In cases of IRIS associated with tuberculosis (TB), two distinct patterns of disease are recognized: (i) the progression of subclinical TB to clinical disease after the initiation of ART, referred to as unmasking, and (ii) the progression or appearance of new clinical and/or radiographic disease in patients with previously recognized TB after the initiation of ART, the classic or "paradoxical" TB-IRIS. IRIS can potentially occur in all granulomatous diseases, not just infectious ones. All granulomatous diseases are thought to result from interplay of inflammatory cells and mediators. One of the inflammatory cells thought to be integral to the development of the granuloma is the CD4 T lymphocyte. Therefore, HIV-infected patients with noninfectious granulomatous diseases such as sarcoidosis may also develop IRIS reactions. Here, we describe IRIS in HIV-infected patients with TB and sarcoidosis and review the basic clinical and immunological aspects of these phenomena.

Tuberculosis of the Liver, Biliary Tract, and Pancreas

Tuberculosis of the liver, biliary tract, and pancreas is discussed. In addition, tuberculosis in the setting of HIV-AIDS and liver transplantation is explored. Drug-induced liver injury secondary to antituberculosis medication and monitoring and prophylactic treatment for such injury is also considered.

Immunoregulation in Fungal Diseases

This review addresses specific regulatory mechanisms involved in the host immune response to fungal organisms. We focus on key cells and regulatory pathways involved in these responses, including a brief overview of their broader function preceding a discussion of their specific relevance to fungal disease. Important cell types discussed include dendritic cells and regulatory T cells, with a focus on specific studies relating to their effects on immune responses to fungi. We highlight the interleukin-10, programmed cell death 1, and cytotoxic T lymphocyte-associated protein 4 signaling pathways and emphasize interrelationships between these pathways and the regulatory functions of dendritic cells and regulatory T cells. Throughout our discussion, we identify selected studies best illustrating the role of these cells and pathways in response to specific fungal pathogens to provide a contextual understanding of the tightly-controlled network of regulatory mechanisms critical to determining the outcome of exposure to fungal pathogens. Lastly, we discuss two unique phenomena relating to immunoregulation, protective tolerance and immune reactivation inflammatory syndrome. These two clinically-relevant conditions provide perspective as to the range of immunoregulatory mechanisms active in response to fungi.

Immune Reconstitution Inflammatory Syndrome Secondary to Mycobacterium kansasii Infection in a Kidney Transplant Recipient

Nontuberculous mycobacteria (NTM) infection is a challenging diagnosis for clinicians in solid organ transplantation. Immune reconstitution inflammatory syndrome (IRIS) is so far unreported in this context. We report here the case of a renal transplant recipient who developed Mycobacterium kansasii-associated lymphadenitis complicated by IRIS while undergoing reduction of his immunosuppressive therapy. For IRIS, the patient required low-dose steroids and an increase in global immunosuppression, in association with NTM antibiotherapy.

Mycobacterial infections in solid organ transplant recipients

Mycobacterial infections represent a growing challenge for solid organ transplant recipients (SOT). The adverse effects of tuberculosis (TB) therapy present a major difficulty, due to the interactions with immunosuppressive drugs and direct drug toxicity. While TB may be donor-transmitted or community-acquired, it usually develops at a latent infection site in the recipient. Pre-transplant prevention efforts will improve transplant outcomes and avoid the complications associated with post-transplant diagnosis and treatment. The present review and consensus manuscript is based on the updated published information and expert recommendations. The current data about epidemiology, diagnosis, new regimens for the treatment of latent TB infection (LTBI), the experience with rifamycins for the treatment of active TB in the post-transplant period and the experience with isoniazid for LTBI in the liver transplant population, are also reviewed. We attempt to provide useful recommendations for each transplant period and problem concerning mycobacterial infections in SOT recipients.

New insights into the interaction of Mycobacterium tuberculosis and human macrophages

Mycobacterium tuberculosis is a facultative intracellular pathogen. It infects macrophages where it avoids elimination by interfering with host defense mechanisms. Until recently, it was assumed that the acidification of phagosomes is the major strategy of macrophages to eliminate M. tuberculosis. However, there is emerging evidence demonstrating that human macrophages are equipped with additional antimicrobial effector functions. Specifically, autophagy, efferocytosis and antimicrobial peptides have been identified as mechanisms to restrict mycobacterial proliferation. Here we review recent findings on effector functions of human macrophages and mechanisms of the pathogen to interfere with them.

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.