Central nervous system cryptococcosis in solid organ transplant recipients: clinical relevance of abnormal neuroimaging findings

Meningeal cryptococcosis in a pancreas transplant recipient requiring grafectomy: A case report

BACKGROUND

Through continuous improvement in transplantation medicine, a wider range of solid organ transplant (SOT) recipients is considered suitable for complex procedures. Despite advances in modern transplantation practice, transpiring invasive fungal infections pose a substantial threat for SOT recipients. To our knowledge, cryptococcal infection confined amidst sole pancreas SOT recipients has not been described to date. Enforcement of a multidisciplinary transplant team approach in the management of pancreas SOT recipients presenting with complex cryptococcal complications is fundamental in improving patient outcomes.

CASE SUMMARY

We present the case of a female pancreas transplant recipient, with confirmed meningeal cryptococcosis, referred to our institution for further evaluation and treatment from the Regional Center for Infectious Diseases. On admission, the patient was weaned from the protocolized immunosuppression therapy for two consecutive weeks, in addition to tapering systemic corticosteroid remedial treatment. Our novel multidisciplinary transplant team approach embodied exhaustive discussions of possible complex and diverse multiple organ system physiologic and pathologic challenges associated with distinct management strategies in pancreas transplant recipients. Owing to the potentially devastating impact of invasive cryptococcosis in terms of morbidity and mortality, a definitive surgical intervention of pancreas transplant grafectomy was reinforced, as a pathway towards secure access to early meaningful expertise care. The patient was discharged to the Regional Center for Infectious Diseases 2 mo after the admittance further advancing to a clinical improvement.

CONCLUSION

The precision transplantation approach by tailoring complex medical interventions to individual needs proved indispensable in improving our patient's outcomes.

Association between neuroimaging and clinical outcomes in individuals with central nervous system cryptococcosis

BACKGROUND

The radiological manifestations of central nervous system (CNS) cryptococcosis are diverse and often subtle. There is heterogeneity on how different neuroimaging patterns impact prognosis. This study aims to assess the association between the neuroimaging and clinical outcomes of CNS cryptococcosis.

METHODS

All patients with CNS cryptococcosis between July 2017 and April 2023 who underwent brain magnetic resonance imaging (MRI) were included. The primary outcome was mortality during hospitalisation. Secondary outcomes were readmission, ventricular shunting, duration of hospitalisation and time to the first negative cerebrospinal fluid culture. We compared the outcomes for each of the five main radiological findings on the brain MRI scan.

RESULTS

We included 46 proven CNS cryptococcosis cases. The two main comorbidity groups were HIV infection (20, 43%) and solid organ transplantation (10, 22%), respectively. Thirty-nine patients exhibited at least one radiological abnormality (85%), with the most common being meningeal enhancement (34, 74%). The mortality rates occurred at 11% (5/46) during hospitalisation. We found no significant disparities in mortality related to distinct radiological patterns. The presence of pseudocysts was significantly associated with the need for readmission (p = .027). The ventricular shunting was significantly associated with the presence of pseudocysts (p = .005) and hydrocephalus (p = .044).

CONCLUSION

In this study, there is no association between brain MRI findings and mortality. Larger studies are needed to evaluate this important issue.

Cryptococcosis in kidney transplant recipients: Current understanding and practices

Cryptococcosis is the third most commonly occurring invasive fungal disease in solid organ transplant recipients (SOT). It is caused by encapsulated yeast, Cryptococcus species, predominantly Cryptococcus neoformans and Cryptococcus gattii. Though kidney transplant recipients are at the lowest risk of cryptococcosis when compared to other solid organ transplant recipients such as lung, liver or heart, still this opportunistic infection causes significant morbidity and mortality in this subset of patients. Mortality rates with cryptococcosis range from 10%-25%, while it can be as high as 50% in SOT recipients with central nervous system involvement. The main aim of diagnosis is to find out if there is any involvement of the central nervous system in disseminated disease or whether there is only localized pulmonary involvement as it has implications for both prognostication and treatment. Detection of cryptococcal antigen (CrAg) in cerebrospinal fluid or plasma is a highly recommended test as it is more sensitive and specific than India ink and fungal cultures. The CrAg lateral flow assay is the single point of care test that can rapidly detect cryptococcal polysaccharide capsule. Treatment of cryptococcosis is challenging in kidney transplant recipients. Apart from the reduction or optimization of immunosuppression, lipid formulations of amphotericin B are preferred as induction antifungal agents. Consolidation and maintenance are done with fluconazole; carefully monitoring its interactions with calcineurin inhibitors. This review further discusses in depth the evolving developments in the epidemiology, pathogenesis, diagnostic assays, and management approach of cryptococcosis in kidney transplant recipients.

Non-meningeal, non-pulmonary cryptococcosis with limited posterior uveitis in a kidney organ transplant recipient with antibody-mediated rejection: a case report

BACKGROUND

Cryptococcosis is one of the most frequent fungal eye infections in patients with immunosuppression. Currently, treatment approaches for non-meningeal, non-pulmonary cryptococcosis are based on those used for cryptococcal meningitis or pneumonia.

CASE PRESENTATION

We present a rare case of non-meningeal, non-pulmonary cryptococcosis with clinical manifestations limited to one eye of a cadaveric kidney transplant recipient with chronic-active antibody-mediated rejection. Typical manifestations, diagnosis, and treatments, including antifungal therapies, adjunctive therapies, and immunosuppression reduction, are discussed. After timely diagnosis and treatment, her visual acuity recovered to baseline without recurrence or sequelae of cryptococcosis.

CONCLUSIONS

Clinicians should be aware of rare presentations of fungal infections, especially when a kidney transplant recipient with rejection has been treated with intensive immunosuppressants. Early diagnosis with individualized therapies may have a favorable prognosis.

Neuroimaging of Cryptococcal Meningitis in Patients without Human Immunodeficiency Virus: Data from a Multi-Center Cohort Study

BACKGROUND

A clearer understanding is needed about the use of brain MRI in non-HIV patients with cryptococcal meningitis.

METHODS

Cerebral CT and MRI were studied in 62 patients in a multicenter study of cryptococcal meningitis in non-HIV patients. CT was performed in 51 and MRI in 44. MRI results are reported for the images read at NIH for 29 of the 44 patients. CT reports obtained from the original REDCap database were added to calculate the incidence of normal findings.

RESULTS

CTs were read as normal in 24 of 51 (47%), MRIs were normal in 10% (three of 29). The most characteristic lesions of cryptococcal meningitis on MRI were small basal ganglia lesions representing dilated perivascular spaces in 24% and basal ganglia lesions with restricted diffusion (infarcts) in 38%. In the 18 patients who received contrast, contrast-enhancing lesions, likely representing masses of cryptococci and inflammatory cells, were found in the basal ganglia in 22% and elsewhere in the brain in 22%. Meningeal enhancement was seen in 56%, ependymal enhancement in 24%, and choroid plexus enhancement in 11%. Hydrocephalus was found in five (18%), though increased intacranial pressure was not detected. Suboptimal imaging (n = 6), lack of contrast administration (n = 11) and lack of follow-up, however, markedly limited the accurate assessment of abnormalities in multiple cases.

CONCLUSION

MRI characteristics of non-HIV cryptococcal meningitis include hydrocephalus, meningeal and ependymal enhancement and basal ganglia lesions. Optimal imaging is, however, necessary to maximize the diagnostic and prognostic usefulness of MRI.

Cryptococcal Meningitis in Kidney Transplant Recipients: A Two-Decade Cohort Study in France

Cryptococcosis is the third most common cause of invasive fungal infection in solid organ transplant recipients and cryptococcal meningitis (CM) its main clinical presentation. CM outcomes, as well as its clinical features and radiological characteristics, have not yet been considered on a large scale in the context of kidney transplantation (KT). We performed a nationwide retrospective study of adult patients diagnosed with cryptococcosis after KT between 2002 and 2020 across 30 clinical centers in France. We sought to describe overall and graft survival based on whether KT patients with cryptococcosis developed CM or not. Clinical indicators of CNS involvement and brain radiological characteristics were assessed. Eighty-eight cases of cryptococcosis were diagnosed during the study period, with 61 (69.3%) cases of CM. Mortality was high (32.8%) at 12 months (M12) but not significantly different whether or not patients presented with CM. Baseline hyponatremia and at least one neurological symptom were independently associated with CM (p < 0.001). Positive serum cryptococcal antigen at diagnosis was also significantly associated with CM (p < 0.001). On magnetic resonance imaging (MRI), three patterns of brain injury were identified: parenchymal, meningeal, and vascular lesions. Although CM does not affect graft function directly, it entails a grim prognosis.

Consensus guidelines for the diagnosis and management of cryptococcosis and rare yeast infections in the haematology/oncology setting, 2021

Cryptococcosis caused by the Cryptococcus neoformans-Cryptococcus gattii complex is an important opportunistic infection in people with immunodeficiency, including in the haematology/oncology setting. This may manifest clinically as cryptococcal meningitis or pulmonary cryptococcosis, or be detected incidentally by cryptococcal antigenemia, a positive sputum culture or radiological imaging. Non-Candida, non-Cryptococcus spp. rare yeast fungaemia are increasingly common in this population. These consensus guidelines aim to provide clinicians working in the Australian and New Zealand haematology/oncology setting with clear guiding principles and practical recommendations for the management of cryptococcosis, while also highlighting important and emerging rare yeast infections and their recommended management.

Unexpected postmortem diagnoses in cases of clinically diagnosed amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease that is clinically and pathologically characterized by impairment of the upper and lower motor neurons. The clinical diagnosis of ALS is not always straightforward because of the lack of specific biomarkers and clinical heterogeneity. This review presents the clinical and pathological findings of four autopsied cases that had been diagnosed with ALS before death. These cases had demonstrated definite and progressive motor neuron signs and symptoms, whereas postmortem assessment revealed miscellaneous disorders, including fungal infection, paraneoplastic syndrome, and amyloidosis. Importantly, nonmotor neuron signs and symptoms, including seizures, extra-pyramidal signs, ocular movement disorders, sensory disturbance, and dysautonomia, had also been documented during the disease course of the cases in the present study. The ALS-unlike symptoms were indicative of the "true" diagnosis in each case when those symptoms were isolated from motor neuron signs/symptoms.

CryptoCEST: A promising tool for spatially resolved identification of fungal brain lesions and their differentiation from brain tumors with MRI

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The fungal disaccharide trehalose generates a concentration-dependent CEST MRI contrast.

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CEST MRI can detect endogenous trehalose in Cryptococcus neoformans and C. gattii cells.

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This enables spatially resolved identification of fungal lesions in the mouse brain.

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The CryptoCEST contrast can differentiate cryptococcal brain lesions from gliomas.

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CryptoCEST holds potential for non-invasive differential diagnosis of cryptococcomas.

Infectious brain lesions caused by the pathogenic fungi Cryptococcus neoformans and C. gattii, also referred to as cryptococcomas, could be diagnosed incorrectly as cystic brain tumors if only based on conventional magnetic resonance (MR) images. Previous MR spectroscopy (MRS) studies showed high local concentrations of the fungal disaccharide trehalose in cryptococcomas. The aim of this study was to detect and localize fungal brain lesions caused by Cryptococcus species based on Chemical Exchange Saturation Transfer (CEST) MR imaging of endogenous trehalose, and hereby to distinguish cryptococcomas from gliomas. In phantoms, trehalose and cryptococcal cells generated a concentration-dependent CEST contrast in the 0.2 – 2 ppm chemical shift range, similar to glucose, but approximately twice as strong. In vivo single voxel MRS of a murine cryptococcoma model confirmed the presence of trehalose in cryptococcomas, but mainly for lesions that were large enough compared to the size of the MRS voxel. With CEST MRI, combining the more specific CEST signal at 0.7 ppm with the higher signal-to-noise ratio signal at 4 ppm in the CryptoCEST contrast enabled localization and distinction of cryptococcomas from the normal brain and from gliomas, even for lesions smaller than 1 mm³. Thanks to the high endogenous concentration of the fungal biomarker trehalose in cryptococcal cells, the CryptoCEST contrast allowed identification of cryptococcomas with high spatial resolution and differentiation from gliomas in mice. Furthermore, the CryptoCEST contrast was tested to follow up antifungal treatment of cryptococcomas. Translation of this non-invasive method to the clinic holds potential for improving the differential diagnosis and follow-up of cryptococcal infections in the brain.

Trehalose as quantitative biomarker for in vivo diagnosis and treatment follow-up in cryptococcomas

Brain lesions caused by Cryptococcus neoformans or C. gattii (cryptococcomas) are typically difficult to diagnose correctly and treat effectively, but rapid differential diagnosis and treatment initiation are crucial for good outcomes. In previous studies, cultured cryptococcal isolates and ex vivo lesion material contained high concentrations of the virulence factor and fungal metabolite trehalose. Here, we studied the in vivo metabolic profile of cryptococcomas in the brain using magnetic resonance spectroscopy (MRS) and assessed the relationship between trehalose concentration, fungal burden, and treatment response in order to validate its suitability as marker for early and noninvasive diagnosis and its potential to monitor treatment in vivo. We investigated the metabolites present in early and late stage cryptococcomas using in vivo ¹H MRS in a murine model and evaluated changes in trehalose concentrations induced by disease progression and antifungal treatment. Animal data were compared to ¹H and ¹³C MR spectra of Cryptococcus cultures and in vivo data from 2 patients with cryptococcomas in the brain. In vivo MRS allowed the noninvasive detection of high concentrations of trehalose in cryptococcomas and showed a comparable metabolic profile of cryptococcomas in the murine model and human cases. Trehalose concentrations correlated strongly with the fungal burden. Treatment studies in cultures and animal models showed that trehalose concentrations decrease following exposure to effective antifungal therapy. Although further cases need to be studied for clinical validation, this translational study indicates that the noninvasive MRS-based detection of trehalose is a promising marker for diagnosis and therapeutic follow-up of cryptococcomas.

Cryptococcus neoformans infection in Human Immunodeficiency Virus (HIV)-infected and HIV-uninfected patients at an inner-city tertiary care hospital in the Bronx

Cryptococcus neoformans causes life-threatening meningoencephalitis. Human immunodeficiency virus (HIV) infection is the most significant predisposing condition, but persons with other immunodeficiency states as well as phenotypically normal persons develop cryptococcosis. We retrospectively reviewed medical records of all patients with a diagnosis of cryptococcosis between 2005 and 2017 at our inner-city medical center in the Bronx, an epicenter of AIDS in New York City, and analyzed demographic data, clinical manifestations, laboratory findings, treatment, and mortality for these patients. In sum, 63% of the cases over this 12-year period occurred in HIV-infected patients. And 61% of the HIV-infected patients were non-adherent with antiretroviral therapy, 10% were newly diagnosed with AIDS, and 4% had unmasking cryptococcus-associated immune reconstitution inflammatory syndrome. The majority were Hispanic or black in ethnicity/race. HIV-uninfected patients (47/126) were older (P < .0001), and the majority had an immunocompromising condition. They were less likely to have a headache (P = .0004) or fever (P = .03), had prolonged time to diagnosis (P = .04), higher cerebrospinal fluid (CSF) glucose levels (P = .001), less CSF culture positivity (P = .03), and a higher 30-day mortality (P = .03). Cases in HIV-uninfected patients were often unsuspected during their initial evaluation, leading to a delay in infectious diseases consultation, which was associated with mortality (P = .03). Our study indicates that HIV infection remains the most important predisposing factor for cryptococcosis despite availability of antiretroviral therapy and highlights potential missed opportunities for earlier diagnosis and differences in clinical and prognostic factors between HIV-infected and HIV-uninfected patients.

Impaired consciousness and decreased glucose concentration of CSF as prognostic factors in immunocompetent patients with cryptococcal meningitis

Background

Cryptococcal meningitis (CM) is the most common fungal infection of the central nervous system and has high morbidity and mortality. Almost studies about prognostic factors have largely focused on the immunocompromised population rather than immunocompetent patients. So that we sought to conduct a retrospective study to determine prognostic factors which predict the outcomes in immunocompetent patients with CM.

Methods

We retrospectively collected and analyzed the demographic and clinical data of 76 apparently immunocompetent patients with cryptococcal meningitis from January 2003 to June 2019 in China. The clinical outcome was graded by the Glasgow outcome scale (GOS) at discharge, and patients were divided into good (score of 5) and unfavorable (score of 1–4) outcome groups, potential prognostic factors were analyzed.

Results

Non-parametric test confirmed that unfavorable outcome was associated with lower glucose level of CSF(P = 0.001), and Pearson’s χ2 analysis confirmed that unfavorable outcome was associated with opening pressure of CSF(>300mmH20, P = 0.038), impaired consciousness (P = 0.001), hydrocephalus(P = 0.045), and Shunt surgery (P = 0.045), and then multiple logistic regression analysis confirmed that impaired consciousness(P = 0.015) and lower glucose concentration of CSF(P = 0.012) increased the likelihood of unfavorable outcome in CM patients.

Conclusion

Impaired consciousness and decreased glucose concentration of CSF were independently prognostic factors which predict the unsatisfactory outcome in immunocompetent patients with CM.

Central Nervous System Cryptococcal Infections in Non-HIV Infected Patients

Central nervous system (CNS) cryptococcosis in non-HIV infected patients affects solid organ transplant (SOT) recipients, patients with malignancy, rheumatic disorders, other immunosuppressive conditions and immunocompetent hosts. More recently described risks include the use of newer biologicals and recreational intravenous drug use. Disease is caused by Cryptococcus neoformans and Cryptococcus gattii species complex; C. gattii is endemic in several geographic regions and has caused outbreaks in North America. Major virulence determinants are the polysaccharide capsule, melanin and several ‘invasins’. Cryptococcal plb1, laccase and urease are essential for dissemination from lung to CNS and crossing the blood–brain barrier. Meningo-encephalitis is common but intracerebral infection or hydrocephalus also occur, and are relatively frequent in C. gattii infection. Complications include neurologic deficits, raised intracranial pressure (ICP) and disseminated disease. Diagnosis relies on culture, phenotypic identification methods, and cryptococcal antigen detection. Molecular methods can assist. Preferred induction antifungal therapy is a lipid amphotericin B formulation (amphotericin B deoxycholate may be used in non-transplant patients) plus 5-flucytosine for 2–6 weeks depending on host type followed by consolidation/maintenance therapy with fluconazole for 12 months or longer. Control of raised ICP is essential. Clinicians should be vigilant for immune reconstitution inflammatory syndrome.

Cryptococcosis in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of cryptococcosis in the pre- and post-transplant period. The current update now includes a discussion of cryptococcosis, which is the third most common invasive fungal infection in SOT recipients. Infection often occurs a year after transplantation; however, early infections occur and donor-derived infections have been described within 3 months after transplant. There are two main species that cause infection, Cryptococcus neoformans and C gattii. Clinical onset may be insidious, but headaches, fevers, and mental status changes should warrant diagnostic testing. The lateral flow cryptococcal antigen assay is now the preferred test from serum and cerebrospinal fluid due to its rapidity, accuracy, and cost. A lumbar puncture with measurement of opening pressure is recommended for patients with suspected or proven cryptococcosis. Lipid amphotericin B plus 5-flucytosine is used as initial treatment of meningitis, disseminated infection, and moderate-to-severe pulmonary infection, followed by fluconazole as consolidation therapy. Fluconazole is effective for mild-to-moderate pulmonary infection. Immunosuppression reduction as part of management may lead to immune reconstitution syndrome that may resemble active disease.

Infection in Kidney Transplant Recipients

In organ transplant recipients, impaired inflammatory responses suppress the clinical and radiologic findings of infection. The possible etiologies of infection are diverse, ranging from common bacterial and viral pathogens that affect the entire community to opportunistic pathogens that cause invasive disease only in immunocompromised hosts. Antimicrobial therapies required to treat established infection are often complex, with accompanying risks for drug toxicities and drug interactions with the immunosuppressive agents used to maintain graft function. Rapid and specific diagnosis is essential for successful therapy. The risk of serious infections in the organ transplant patient is largely determined by the interaction between two factors: the patient’s epidemiologic exposures and the patient’s net state of immunosuppression. The epidemiology of infection includes environmental exposures and nosocomial infections, organisms derived from donor tissues, and latent infections from the recipient activated with immunosuppression. The net state of immune suppression is a conceptual framework that measures those factors contributing to risk for infection: the dose, duration, and temporal sequence of immunosuppressive drugs; the presence of foreign bodies or injuries to mucocutaneous barriers; neutropenia; metabolic abnormalities including diabetes; devitalized tissues, hematomas, or effusions postsurgery; and infection with immunomodulating viruses. Multiple factors are present in each host. A timeline exists to aid in the development of a differential diagnosis for infection. The timeline for each patient is altered by changes in prophylaxis and immunosuppressive drugs. For common infections, new microbiologic assays, often nucleic acid based, are useful in the diagnosis and management of opportunistic infections.

Prevention and Treatment of Yeast and Endemic Fungal Infections

Invasive fungal infections (IFIs) remain an important complication of solid organ transplantation owing to their significant morbidity and mortality and include infections due to Candida, Cryptococcus, endemic mycosis, and other rare yeasts and molds. IFIs occur in different intervals posttransplantation and depend on a number of extrinsic and intrinsic risk factors, some of which are specific to the type of organs transplanted, surgical techniques, and type of immunosuppressive medications. Donor-derived IFIs and emergence of new multidrug-resistant yeasts have been reported in various healthcare settings. Clinical manifestations of yeast and endemic fungal infections vary in different types of organ transplants. Diagnosis of IFIs in SOT recipients is challenging due to their nonspecific signs and symptoms owing to the impaired inflammatory responses as a result of immunosuppression and the lack of highly sensitive and specific diagnostic modalities. Early diagnosis is key to successful therapy, and physicians should have a high index of suspicion based on risk factors and epidemiology of these pathogens. Antifungal treatment strategies for yeast infections have been outlined in various society guidelines. Management of complications that arise before or during antifungal therapy is critical for optimizing clinical response.

Cryptococcal disease in the solid organ transplant setting: review of clinical aspects with a discussion of asymptomatic cryptococcal antigenemia

PURPOSE OF REVIEW

Cryptococcal infections are an important cause of morbidity and mortality in solid organ transplant patients. Here, we review the microbiology, epidemiology, clinical course, treatment, and outcomes of Cryptococcus in solid organ transplant recipients.

RECENT FINDINGS

We identify the unique findings in solid organ transplant patients when compared to other immunocompromised patients such as those with HIV. We also describe our experience and outcomes with regard to solid organ transplant patients who do not have positive fungal cultures, but cryptococcal antigen positivity and concern for cryptococcal disease.

SUMMARY

Our review will highlight the importance of these new diagnostic techniques in those with Cryptococcus and solid organ transplant, which will be the subject of new research.

Unique characteristics of cryptococcosis identified after death in patients with liver cirrhosis: comparison with concurrent cohort diagnosed antemortem

Characteristics of cirrhosis-associated cryptococcosis first diagnosed after death are not fully known. In a multicenter study, data generated as standard of care was systematically collected in 113 consecutive patients with cirrhosis and cryptococcosis followed for 80 patient-years. The diagnosis of cryptococcosis was first established after death in 15.9% (18/113) of the patients. Compared to cases diagnosed while alive, these patients had higher MELD score (33 vs. 22, P = .029) and higher rate of cryptococcemia (75.0% vs. 41.9%, P = .027). Cases diagnosed after death, in comparison to those diagnosed during life were more likely to present with shock (OR 3.42, 95% CI 1.18-9.90, P = .023), require mechanical ventilation at admission (OR 8.5, 95% CI 2.74-26.38, P = .001), less likely to undergo testing for serum cryptococcal antigen (OR 0.07, 95% CI 0.02-0.21, P < .001) and have positive antigen when the test was performed (OR 0.07, 95% CI 0.01-0.60, P = .016). In a subset of cirrhotic patients with advanced liver disease cryptococcosis was first recognized after death. These patients had the characteristics of presenting with fulminant fungemia, were less likely to have positive serum cryptococcal antigen and posed a diagnostic challenge for care providers.

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.

Spectrum of neuroimaging findings in cryptococcal meningitis in immunocompetent patients in China - A series of 18 cases

PURPOSE

Cryptococcosis is a devastating opportunistic disease commonly encountered in organ transplant recipients and patients with acquired immunodeficiency syndrome (AIDS). Few studies have profiled the disease in immunocompetent patients. We sought to characterize the neuroimaging findings of cryptococcal meningitis among immunocompetent patients in China.

MATERIALS AND METHODS

Retrospective review of all patients diagnosed with cryptococcal meningitis at our institute, on the basis of CSF culture or India Ink test, between November 2011 and February 2016, was performed. Only apparently immunocompetent patients, for whom at least one brain MRI examination was performed, were included in the analysis. The MRI results were available for all these patients before CSF diagnosis. Data related to variables such as patient demographics, clinical features, neuroimaging characteristics and CSF findings were analyzed.

RESULTS

Eighteen apparently immunocompetent patients, for whom brain MRI radiographs were available, were included in the analysis. Abnormal MRI findings were observed in 16 patients. These included multiple intraparenchymal lesions with or without enhancement, prominent basal ganglia involvement, miliary distribution of parenchymal nodules, multiple dilated Virchow-Robin spaces and leptomeningeal enhancement. Six patients had ventriculomegaly.

CONCLUSION

In our study, intraparenchymal findings were more common than leptomeningeal enhancement and perivascular lesions. Cryptococcal meningitis should be considered in the differential diagnosis of immunocompetent patients with brain MRI findings of prominent parenchymal involvement such as bilateral patchy lesions in basal ganglia or miliary distribution of parenchymal nodules.

[Invasive yeast diseases in solid organ transplant recipients]

Invasive yeast diseases are uncommon nowadays in solid organ transplant recipients. Invasive candidiasis (2%) usually presents during the first month after transplantation in patients with risk factors. Both common and transplant-specific risk factors have been identified, allowing very efficacious targeted prophylaxis strategies. The most common clinical presentations are fungaemia and local infections near the transplantation area. Cryptococcosis is usually a late infection. Its incidence remains stable and the specific risk factors have not been identified. When cryptococcosis is detected very early, transmission with the allograft should be considered. The most common clinical presentations include meningitis, pneumonia, and disseminated infection. Intracranial hypertension and immune reconstitution syndrome have to be considered. No therapeutic clinical trials have been conducted in solid organ transplant recipients, thus treatment recommendations are derived from data obtained from the general population. It is particularly important to consider the possibility of drug-drug interactions, mainly between azoles and calcineurin inhibitors. Both invasive candidiasis and cryptococcosis increase the mortality significantly in solid organ transplant recipients.

Favorable Evolution of Cryptococcal Meningitis in the Context of Flucytosine Resistance

Cryptococcal meningitis is a critical illness affecting 0.2% to 5% solid-organ transplant recipients with a 40% to 50% mortality. We report the case of a 48-year-old lung transplant recipient, who, 15 months after a right lung graft, kept parakeets and developed meningitis due to Cryptococcus neoformans. Immunosuppressive treatment was based on a quadruple sequential immunosuppressive therapy that included induction therapy with thymoglobulin, followed by corticosteroids, calcineurin inhibitors, and mycophenolate mofetil. Antifungal susceptibility testing of Cryptococcus neoformans showed resistance to flucytosine and intermediate sensitivity to fluconazole. Initial treatment adhered to international guidelines; however, the patient could not tolerate an effective double-antifungal therapy during the first 2 months of treatment. Despite this delayed treatment for an aggressive infection in an immunocompromised patient, the patient survived without relapse and received maintenance treatment with fluconazole during the course of 3 years. Administration of calcineurin inhibitors as immunosuppressive treatment may partly explain this outcome, as this therapeutic class is known to protect from severe forms of cryptococcal meningitis.

Severe cryptococcal-associated neurological immune reconstitution inflammatory syndrome in a renal transplant recipient treated with adalimumab

Cryptococcosis is a major concern in organ transplant recipients. A decrease in immunosuppressants following the initiation of antifungal therapy is currently recommended, but can occasionally be complicated by the onset of immune reconstitution inflammatory syndrome (IRIS). We report on a case of cryptococcosis in a kidney transplant recipient, compounded by severe neurological IRIS, the outcome of which was unfavorable despite the use of anti-tumor necrosis factor-alpha monoclonal antibodies.

Dramatic improvement of severe cryptococcosis-induced immune reconstitution syndrome with adalimumab in a renal transplant recipient

In solid organ transplant recipients, immune reconstitution inflammatory syndrome (IRIS) is a rare complication of cryptococcosis, which may require steroids in its most severe forms. Here, we report the case of a renal transplant recipient who developed severe cryptococcal meningitis-associated IRIS 1 week after immunosuppression reduction. High-dose steroids failed to improve the disease. Finally, a recombinant human monoclonal tumor necrosis factor-α (TNF-α) antagonist, adalimumab, was prescribed, and the patient rapidly experienced dramatic neurological improvement. No IRIS relapse occurred within 14 months following adalimumab discontinuation.

Predictors of immune reconstitution syndrome in organ transplant recipients with cryptococcosis: implications for the management of immunosuppression

BACKGROUND

Risk factors including how changes in immunosuppression influence the occurrence of immune reconstitution syndrome (IRS) in solid organ transplant (SOT) recipients with cryptococcosis have not been fully defined.

METHODS

SOT recipients with cryptococcosis were identified and followed for 12 months. IRS was defined based on previously proposed criteria.

RESULTS

Of 89 SOT recipients, 13 (14%) developed IRS. Central nervous system (CNS) disease (adjusted odds ratio [AOR], 6.23; P = .03) and discontinuation of calcineurin inhibitor (AOR, 5.11; P = .02) were independently associated with IRS. Only 2.6% (1/13) of the patients without these risk factors developed IRS compared with 18.8% (6/32) with 1 risk factor, and 50% (6/12) with both risk factors (χ(2) for trend, P = .0001). Among patients with CNS disease, those with neuroimaging abnormalities (P = .03) were more likely to develop IRS, irrespective of serum or CSF cryptococcal antigen titers and fungemia. Graft rejection after cryptococcosis was observed in 15.4% (2/13) of the patients with IRS compared with 2.6% (2/76) of those without IRS (P = .07).

CONCLUSIONS

We determined variables that pose a risk for IRS and have shown that discontinuation of calcineurin inhibitors was independently associated with 5-fold increased risk of IRS in transplant recipients with cryptococcosis.

Cryptococcosis in kidney transplant recipients in a Chinese university hospital and a review of published cases

BACKGROUND

Cryptococcosis is a severe fungal infection with a high mortality rate among solid-organ transplant recipients. Today, China is among the countries performing the most kidney transplants worldwide, however data on the association of cryptococcosis with kidney transplantation in mainland China remain scarce and fragmented.

METHODS

We retrospectively analyzed cases of culture-confirmed cryptococcosis following kidney transplantation that have occurred at our hospital and reviewed the published cases in China over the last 30 years.

RESULTS

Cryptococcosis in kidney transplant recipients was mainly caused by Cryptococcus neoformans var. grubii VNI strains and occurred most frequently in patients aged 41-50 years (37.9%, 11/29). The average time to infection after kidney transplantation was 5.16 ± 3.97 years. The clinical manifestations were found to be diverse, with slight to moderate headache and fever, meningeal irritation, and high cerebrospinal fluid pressure being relatively common. Physicians should be alert to these symptoms among kidney transplant recipients.

CONCLUSIONS

Cryptococcosis is a serious infection among kidney transplant recipients in mainland China. It has unique characteristics, such as a relatively long time to onset after kidney transplantation, and diverse clinical manifestations. Treatment with intrathecal injection of amphotericin B is considered effective for central nervous system involvement. The findings of this study also highlight the urgent need for multicenter, prospective, and multidisciplinary clinical studies and education on cryptococcosis in kidney transplant recipients in China.

Fungal central nervous system infections: prevalence and diagnosis

Fungal infections of the central nervous system (CNS) are rare but they pose a significant challenge. Their prevalence spans a wide array of hosts including immunosuppressed and immunocompetent individuals, patients undergoing neurosurgical procedures and those carrying implantable CNS devices. Cryptococcus neoformans and Aspergillus spp. remain the most common pathogens. Magnetic resonance imaging can help localize the lesions, but diagnosis is challenging since invasive procedures may be needed for the retrieval of tissue, especially in cases of fungal abscesses. Antigen and antibody tests are available and approved for use in the cerebrospinal fluid (CSF). PCR-based techniques are promising but they are not validated for use in the CSF. This review provides an overview on the differential diagnosis of the fungal CNS disease based on the host and the clinical syndrome and suggests the optimal use of diagnostic techniques. It also summarizes the emergence of Cryptococcus gatti and an unanticipated outbreak caused by Exserohilum rostratum.

Neurological complications of solid organ transplantation

Solid organ transplantation (SOT) is the preferred treatment for an expanding range of conditions whose successful therapy has produced a growing population of chronically immunosuppressed patients with potential neurological problems. While the spectrum of neurological complications varies with the type of organ transplanted, the indication for the procedure, and the intensity of long-term required immunosuppression, major neurological complications occur with all SOT types. The second part of this 2-part article on transplantation neurology reviews central and peripheral nervous system problems associated with SOT with clinical and neuroimaging examples from the authors' institutional experience. Particular emphasis is given to conditions acquired from the donated organ or tissue, problems specific to types of organs transplanted and drug therapy-related complications likely to be encountered by hospitalists. Neurologically important syndromes such as immune reconstitution inflammatory syndrome (IRIS), posterior reversible encephalopathy syndrome (PRES), and posttransplantation lymphoproliferative disorder (PTLD) are readdressed in the context of SOT.

Invasive fungal infections in solid organ transplant recipients

Invasive fungal infections are a major problem in solid organ transplant (SOT) recipients. Overall, the most common fungal infection in SOT is candidiasis, followed by aspergillosis and cryptococcosis, except in lung transplant recipients, where aspergillosis is most common. Development of invasive disease hinges on the interplay between host factors (e.g., integrity of anatomical barriers, innate and acquired immunity) and fungal factors (e.g., exposure, virulence and resistance to prophylaxis). In this article, we describe the epidemiology and clinical features of the most common fungal infections in organ transplantation. Within this context, we review recent advances in diagnostic modalities and antifungal chemotherapy, and their impact on evolving prophylaxis and treatment paradigms.

Comparison and temporal trends of three groups with cryptococcosis: HIV-infected, solid organ transplant, and HIV-negative/non-transplant

BACKGROUND

The Infectious Disease Society of America (IDSA) 2010 Clinical Practice Guidelines for the management of cryptococcosis outlined three key populations at risk of disease: (1) HIV-infected, (2) transplant recipient, and (3) HIV-negative/non-transplant. However, direct comparisons of management, severity and outcomes of these groups have not been conducted.

METHODOLOGY/PRINCIPAL FINDINGS

Annual changes in frequency of cryptococcosis diagnoses, cryptococcosis-attributable mortality and mortality were captured. Differences examined between severe and non-severe disease within the context of the three groups included: demographics, symptoms, microbiology, clinical management and treatment. An average of nearly 15 patients per year presented at Duke University Medical Center (DUMC) with cryptococcosis. Out of 207 study patients, 86 (42%) were HIV-positive, 42 (20%) were transplant recipients, and 79 (38%) were HIV-negative/non-transplant. HIV-infected individuals had profound CD4 lymphocytopenia and a majority had elevated intracranial pressure. Transplant recipients commonly (38%) had renal dysfunction. Nearly one-quarter (24%) had their immunosuppressive regimens stopped or changed. The HIV-negative/non-transplant population reported longer duration of symptoms than HIV-positive or transplant recipients and 28% (22/79) had liver insufficiency or underlying hematological malignancies. HIV-positive and HIV-negative/non-transplant patients accounted for 89% of severe disease cryptococcosis-attributable deaths and 86% of all-cause mortality.

CONCLUSIONS/SIGNIFICANCE

In this single-center study, the frequency of cryptococcosis did not change in the last two decades, although the underlying case mix shifted (fewer HIV-positive cases, stable transplant cases, more cases with neither). Cryptococcosis had a relatively uniform and informed treatment strategy, but disease-attributable mortality was still common.

[Immune reconstitution syndrome]

The immune reconstitution inflammatory syndrome (IRIS) represents a heterogeneous group of conditions. Whilst they typically present in HIV-infected patients with advanced immunodeficiency, IRIS have also been described in HIV-negative patients with immune reconstitution due to other causes of immunosuppression. Frequently IRIS results from an immune response against underlying infection (pathogen-associated IRIS). However, IRIS might become evident during immune reconstitution without an underlying pathogen such as a sarcoid-like illness or an autoimmune thyropathy. Here we report on the epidemiology and risk factors of IRIS along with diagnosis and management of this clinically important inflammatory syndrome.

Opportunistic infection-associated immune reconstitution syndrome in transplant recipients

Reversal of pathogen-induced immunosuppression upon employment of effective antimicrobial therapy and withdrawal of iatrogenic immunosuppression has the potential to shift the host immune repertoire towards pathologic inflammatory responses conducive to immune reconstitution syndrome (IRS). Posttransplant IRS has been observed with fungi, M. tuberculosis, cytomegalovirus, and polyoma virus nephropathy. This review discusses the existing state of knowledge regarding IRS and the immune mechanisms that underlie its pathogenesis, with significant implications for developing reliable diagnostic biomarkers and optimal management strategies for post-transplant opportunistic infection-associated IRS.

Cutaneous cryptococcosis in solid organ transplant recipients

Clinical manifestations, treatment, and outcomes of cutaneous cryptococcosis in solid organ transplant (SOT) recipients are not fully defined. In a prospective cohort comprising 146 SOT recipients with cryptococcosis, we describe the presentation, antifungal therapy, and outcome of cutaneous cryptococcal disease. Cutaneous cryptococcosis was documented in 26/146 (17.8%) of the patients and manifested as nodular/mass (34.8%), maculopapule (30.4%), ulcer/pustule/abscess (30.4%), and cellulitis (30.4%) with 65.2% of the skin lesions occurred in the lower extremities. Localized disease developed in 30.8% (8/26), and disseminated disease in 69.2% (18/26) with involvement of the central nervous system (88.9%, 16/18), lung (33.3%, 6/18), or fungemia (55.6%, 10/18). Fluconazole (37.5%) was employed most often for localized and lipid formulations of amphotericin B (61.1%) for disseminated disease. Overall mortality at 90 days was 15.4% (4/26) with 16.7% in disseminated and 12.5% in localized disease (P = 0.78). SOT recipients who died were more likely to have renal failure (75.0% vs. 13.6%, P = 0.028), longer time to onset of disease after transplantation (87.5 vs. 22.6 months, P = 0.023), and abnormal mental status (75% vs. 13.6%, P = 0.028) than those who survived. Cutaneous cryptococcosis represents disseminated disease in most SOT recipients and preferentially involves the extremities. Outcomes with appropriate management were comparable between SOT recipients with localized and disseminated cryptococcosis.

Identifying predictors of central nervous system disease in solid organ transplant recipients with cryptococcosis

BACKGROUND

Cerebrospinal fluid (CSF) analysis is often deferred in patients with cryptococcal disease, particularly in the absence of neurologic manifestations. We sought to determine whether a subset of solid organ transplant (SOT) recipients with high likelihood of central nervous system (CNS) disease could be identified in whom CSF analysis must be performed.

METHODS

Patients comprised a multicenter cohort of SOT recipients with cryptococcosis.

RESULTS

Of 129 (88%) of 146 SOT recipients with cryptococcosis who underwent CSF analysis, 80 (62%) had CNS disease. In the overall study population, abnormal mental status, time to onset of cryptococcosis more than 24 months posttransplantation (late-onset disease), serum cryptococcal antigen titer more than 1:64, and fungemia were independently associated with an increased risk of CNS disease. Of patients with abnormal mental status, 95% had CNS cryptococcosis. When only patients with normal mental status were considered, three predictors (serum antigen titer >1:64, fungemia, and late-onset disease) independently identified patients with CNS cryptococcosis; the risk of CNS disease was 14% if none, 39% if one, and 94% if two of the aforementioned predictors existed (chi for trend P<0.001).

CONCLUSIONS

CSF analysis should be strongly considered in SOT recipients with cryptococcosis who have late-onset disease, fungemia, or serum cryptococcal antigen titer more than 1:64 even in the presence of normal mental status.

Lipid formulations of amphotericin B significantly improve outcome in solid organ transplant recipients with central nervous system cryptococcosis

BACKGROUND

Whether outcome of central nervous system (CNS) cryptococcosis in solid organ transplant recipients treated with lipid formulations of amphotericin B is different from the outcome of the condition treated with amphotericin B deoxycholate (AmBd) is not known.

METHODS

We performed a multicenter study involving a cohort comprising consecutive solid organ transplant recipients with CNS cryptococcosis.

RESULTS

Of 75 patients treated with polyenes as induction regimens, 55 (73.3%) received lipid formulations of amphotericin B and 20 (26.7%) received AmBd. Similar proportions of patients in both groups had renal failure at baseline (P = .94 ). Overall, mortality at 90 days was 10.9% in the group that received lipid formulations of amphotericin B and 40.0% in the group that received AmBd. In univariate analysis, nonreceipt of calcineurin inhibitors (P = .034), renal failure at baseline (P = .016), and fungemia (P = .003) were significantly associated with mortality. Compared with AmBd, lipid formulations of amphotericin B were associated with a lower mortality (P = .007). Mortality did not differ between patients receiving lipid formulations of amphotericin B with or without flucytosine (P = .349). In stepwise logistic regression analysis, renal failure at baseline (odds ratio [OR], 4.61; 95% confidence interval [CI], 1.02-20.80; P = .047) and fungemia (OR, 10.66; 95% CI, 2.08-54.55; P = .004 ) were associated with an increased mortality, whereas lipid formulations of amphotericin B were associated with a lower mortality (OR, 0.11; 95% CI, 0.02-0.57; P = .008).

CONCLUSIONS

Lipid formulations of amphotericin B were independently associated with better outcome and may be considered as the first-line treatment for CNS cryptococcosis in these patients.

Concomitant cryptococcosis and burkholderia infection in an asymptomatic lung transplant patient with cystic fibrosis

Concomitant pulmonary infections with Cryptococcus neoformans and Burkholderia cepacia in lung transplant recipients are very rare and create unique diagnostic and therapeutic dilemmas. Herein, we present a double lung transplant patient with cystic fibrosis who was found to have coinfection with these two rare organisms, though he was completely asymptomatic.

Immune reconstitution inflammatory syndrome in non-HIV immunocompromised patients

PURPOSE OF REVIEW

In the era of highly active antiretroviral therapy, immune reconstitution inflammatory syndrome has become well recognized in the HIV-infected population. However, little is known about its occurrence in non-HIV immunocompromised hosts. The present review aims to propose the pathogenesis of immune reconstitution inflammatory syndrome, summarize its occurrence in immunocompromised patients without HIV infection, and suggest potential treatment options.

RECENT FINDINGS

Immune reconstitution inflammatory syndrome is exuberant and dysregulated inflammatory responses to invading microorganisms. It manifests when an abrupt shift of host immunity from an anti-inflammatory and immunosuppressive status towards a pathogenic proinflammatory state occurs as a result of rapid decreases or removal of factors promoting immunosuppression or inhibiting inflammation. In addition to HIV-infected patients, immune reconstitution inflammatory syndrome has also been observed in solid organ transplant recipients, women during the postpartum period, neutropenic patients, and tumor necrosis factor antagonist recipients. Corticosteroids are the most commonly employed treatment, whereas other potential agents based on its pathogenesis deserve further investigation.

SUMMARY

Non-HIV immunocompromised hosts develop immune reconstitution inflammatory syndrome when the sudden change in the dominant T helper responses to inflammation is not well balanced by anti-inflammatory responses. Judicious manipulation of host immunity and timely recognition of immune reconstitution inflammatory syndrome as we deal with the infections in these populations is critical to limit or avoid the harm by immune reconstitution inflammatory syndrome.

Managing cryptococcosis in the immunocompromised host

PURPOSE OF REVIEW

Expanding access to antiretroviral treatment has dramatically improved the long-term prognosis of patients with HIV-associated cryptococcal disease who survive the acute infection. However, the incidence and acute mortality of HIV-associated cryptococcal meningitis remain high. In this context, this review summarizes urgently needed recent work aimed at improving the acute management of cryptococcal infection in immunocompromised hosts.

RECENT FINDINGS

Studies have started to optimize antifungal regimens and address the complications of raised cerebrospinal fluid pressure and cryptococcal immune reconstitution syndrome. Amphotericin B at 1 mg/kg per day has been shown to be more rapidly fungicidal than the standard dose of 0.7 mg/kg per day, and new data support the importance of combination therapy with flucytosine. Amphotericin B and fluconazole at 800 mg is an alternative combination that appears superior to amphotericin B alone. At a dosage of 400 mg per day, fluconazole alone is much less rapidly fungicidal than amphotericin B and is associated with the development of secondary resistance.

SUMMARY

Recent findings support the use of rapidly fungicidal initial antifungal therapy with amphotericin B-based combination treatment. Where amphotericin B treatment is not yet feasible, studies are needed to optimize oral regimens. Based on accumulating data on rate of clearance of infection, the most promising new regimens in terms of fungicidal activity and safety could be selected for clinical endpoint trials.

Cryptococcosis in solid organ transplant recipients: current state of the science

Cryptococcosis remains a significant opportunistic infection in solid organ transplant recipients. Disease presentation and outcomes may be affected by, among other factors, the use of calcineurin inhibitor immunosuppressive agents. It is being increasingly recognized that rapid reversal of immunosuppression in transplant recipients treated for cryptococcosis incurs the risk of immune reconstitution inflammatory syndrome, which resembles worsening disease or relapse. This review summarizes the current state of knowledge regarding cryptococcosis in transplant recipients and highlights areas where future investigations are needed to further optimize outcomes for these patients.