Subarachnoid small vein occlusion due to inflammatory fibrosis-a possible mechanism for cerebellar infarction in cryptococcal meningoencephalitis: a case report

Divergent neuroimmune signatures in the cerebrospinal fluid predict differential gender-specific survival among patients with HIV-associated cryptococcal meningitis

Introduction

Survival among people with HIV-associated cryptococcal meningitis (CM) remains low, particularly among women, despite the currently optimal use of antifungal drugs. Cryptococcus dissemination into the central nervous system [brain, spinal cord, and cerebrospinal fluid (CSF)] elicits the local production of cytokines, chemokines, and other biomarkers. However, no consistent diagnostic or prognostic neuroimmune signature is reported to underpin the risk of death or to identify mechanisms to improve treatment and survival. We hypothesized that distinct neuroimmune signatures in the CSF would distinguish survivors from people who died on antifungal treatment and who may benefit from tailored therapy.

Methods

We considered baseline clinical features, CSF cryptococcal fungal burden, and CSF neuroimmune signatures with survival at 18 weeks among 419 consenting adults by "gender" (168 women and 251 men by biological sex defined at birth).

Results

Survival at 18 weeks was significantly lower among women than among men {47% vs. 59%, respectively; hazard ratio (HR) = 1.4 [95% confidence interval (CI), 1.0 to 1.9; p = 0.023]}. Unsupervised principal component analysis (PCA) demonstrated divergent neuroimmune signatures by gender, survival, and intragender-specific survival. Overall, women had lower levels of programmed death ligand 1, Interleukin (IL) (IL-11RA/IL-1F30, and IL-15 (IL-15) than men (all p < 0.028). Female survivors compared with those who died expressed significant elevations in levels of CCL11 and CXCL10 chemokines (both p = 0.001), as well as increased T helper 1, regulatory, and T helper 17 cytokines (all p < 0.041). In contrast, male survivors expressed lower levels of IL-15 and IL-8 compared with men who died (p < 0.044).

Conclusions

Survivors of both genders demonstrated a significant increase in the levels of immune regulatory IL-10. In conclusion, the lower survival among women with CM was accompanied by distinct differential gender-specific neuroimmune signatures. These female and male intragender-specific survival-associated neuroimmune signatures provide potential targets for interventions to advance therapy to improve the low survival among people with HIV-associated CM.

Palmitoylethanolamide shows limited efficacy in controlling cerebral cryptococcosis in vivo

Cryptococcus neoformans (Cn) is an encapsulated neurotropic fungal pathogen and the causative agent of cryptococcal meningoencephalitis (CME) in humans. Recommended treatment for CME is Amphotericin B (AmpB) and 5-fluorocytosine (5-FC). Though effective, AmpB has displayed numerous adverse side effects due to its potency and nephrotoxicity, prompting investigation into alternative treatments. Palmitoylethanolamide (PEA) is an immunomodulatory compound capable of promoting neuroprotection and reducing inflammation. To investigate the efficacy of PEA as a therapeutic alternative for CME, we intracerebrally infected mice with Cn and treated them with PEA or AmpB alone or in combination. Our results demonstrate that PEA alone does not significantly prolong survival nor reduce fungal burden, but when combined with AmpB, PEA exerts an additive effect and promotes both survivability and fungal clearance. However, we compared this combination to traditional AmpB and 5-FC treatment in a survivability study and observed lower efficacy. Overall, our study revealed that PEA alone is not effective as an antifungal agent in the treatment of CME. Importantly, we describe the therapeutic capability of PEA in the context of Cn infection and show that its immunomodulatory properties may confer limited protection when combined with an effective fungicidal agent.

Divergent Neuroimmune Signatures in the Cerebrospinal Fluid Predict Differential Gender-Specific Survival Among Patients With HIV-Associated Cryptococcal Meningitis

Survival among people with HIV-associated cryptococcal meningitis (CM) remains low, exceptionally among women with the increased threat of death on current optimal use of antifungal drugs. Cryptococcus dissemination into the central nervous system (CNS) prompts a neuroimmune reaction to activate pathogen concomitant factors. However, no consistent diagnostic or prognostic immune-mediated signature is reported to underpin the risk of death or mechanism to improve treatment or survival. We theorized that the distinct neuroimmune cytokine or chemokine signatures in the cerebrospinal fluid (CSF), distinguish survivors from people who died on antifungal treatment, who may benefit from tailored therapy. We considered the baseline clinical disease features, cryptococcal microbiologic factors, and CSF neuroimmune modulated signatures among 419 consenting adults by gender (biological sex assigned at birth) (168 females and 251 males) by 18 weeks of survival on antifungal management. Survival at 18 weeks was inferior among females than males (47% vs. 59%; hazard ratio HR=1.4, 95% CI: 1.0 to 1.9, and p=0.023). Unsupervised principal component analysis (PCA) demonstrated the divergent neuroimmune signatures by gender, survival, and intragender-specific survival. Overall, females displayed lower levels of PD-L1, IL-1RA, and IL-15 than males (all p≤0.028). Female survivors compared with those who died, expressed significant fold elevations in levels of CSF (CCL11 - myeloid and CXCL10 - lymphoid chemokine (in both p=0.001), and CSF Th1, Th2, and Th17 cytokines. In contrast, male survivors expressed distinctly lower levels of CSF IL-15 and IL-8 compared with those who died. Survivors of either gender demonstrated a significant increase in the levels of immune regulatory element, IL-10. In the finale, we classified divergent neuroimmune key signatures in CSF by gender, survival, and intragender-specific survival among people with HIV-associated cryptococcal meningitis. These intragender-specific survival associated-neuroimmune signatures, suggests the discrete role of gender immune regulating mechanisms as the possible targets for interventions to advance therapy to improve survival among people with HIV-associated cryptococcal meningitis.

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.

Glucuronoxylomannan intranasal challenge prior to Cryptococcus neoformans pulmonary infection enhances cerebral cryptococcosis in rodents

The encapsulated fungus Cryptococcus neoformans is the most common cause of fungal meningitis, with the highest rate of disease in patients with AIDS or immunosuppression. This microbe enters the human body via inhalation of infectious particles. C. neoformans capsular polysaccharide, in which the major component is glucuronoxylomannan (GXM), extensively accumulates in tissues and compromises host immune responses. C. neoformans travels from the lungs to the bloodstream and crosses to the brain via transcytosis, paracytosis, or inside of phagocytes using a "Trojan horse" mechanism. The fungus causes life-threatening meningoencephalitis with high mortality rates. Hence, we investigated the impact of intranasal exogenous GXM administration on C. neoformans infection in C57BL/6 mice. GXM enhances cryptococcal pulmonary infection and facilitates fungal systemic dissemination and brain invasion. Pre-challenge of GXM results in detection of the polysaccharide in lungs, serum, and surprisingly brain, the latter likely reached through the nasal cavity. GXM significantly alters endothelial cell tight junction protein expression in vivo, suggesting significant implications for the C. neoformans mechanisms of brain invasion. Using a microtiter transwell system, we showed that GXM disrupts the trans-endothelial electrical resistance, weakening human brain endothelial cell monolayers co-cultured with pericytes, supportive cells of blood vessels/capillaries found in the blood-brain barrier (BBB) to promote C. neoformans BBB penetration. Our findings should be considered in the development of therapeutics to combat the devastating complications of cryptococcosis that results in an estimated ~200,000 deaths worldwide each year.

Palmitoylethanolamide shows limited efficacy in controlling cerebral cryptococcosis in vivo

Cryptococcus neoformans ( Cn ) is an encapsulated neurotropic fungal pathogen and the causative agent of cryptococcal meningoencephalitis (CME) in humans. Recommended treatment for CME is Amphotericin B (AmpB) and 5-fluorocytosine (5-FC). Though effective, AmpB has displayed numerous adverse side effects due to its potency and nephrotoxicity, prompting investigation into alternative treatments. Palmitoylethanolamide (PEA) is an immunomodulatory compound capable of promoting neuroprotection and reducing inflammation. To investigate the efficacy of PEA as a therapeutic alternative for CME, we intracerebrally infected mice with Cn and treated them with PEA or AmpB alone or in combination. Our results demonstrate that PEA alone does not significantly prolong survival nor reduce fungal burden, but when combined with AmpB, PEA exerts an additive effect and promotes both survivability and fungal clearance. However, we compared this combination to traditional AmpB and 5-FC treatment in a survivability study and observed lower efficacy. Overall, our study revealed that PEA alone is not effective as an antifungal agent in the treatment of CME. Importantly, we describe the therapeutic capability of PEA in the context of Cn infection and show that its immunomodulatory properties may confer limited protection when combined with an effective fungicidal agent.

Cryptococcus neoformans, a global threat to human health

BACKGROUND

Emerging fungal pathogens pose important threats to global public health. The World Health Organization has responded to the rising threat of traditionally neglected fungal infections by developing a Fungal Priority Pathogens List (FPPL). Taking the highest-ranked fungal pathogen in the FPPL, Cryptococcus neoformans, as a paradigm, we review progress made over the past two decades on its global burden, its clinical manifestation and management of cryptococcal infection, and its antifungal resistance. The purpose of this review is to drive research efforts to improve future diagnoses, therapies, and interventions associated with fungal infections.

METHODS

We first reviewed trends in the global burden of HIV-associated cryptococcal infection, mainly based on a series of systematic studies. We next conducted scoping reviews in accordance with the guidelines described in the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews using PubMed and ScienceDirect with the keyword Cryptococcus neoformans to identify case reports of cryptococcal infections published since 2000. We then reviewed recent updates on the diagnosis and antifungal treatment of cryptococcal infections. Finally, we summarized knowledge regarding the resistance and tolerance of C. neoformans to approved antifungal drugs.

RESULTS

There has been a general reduction in the estimated global burden of HIV-associated cryptococcal meningitis since 2009, probably due to improvements in highly active antiretroviral therapies. However, cryptococcal meningitis still accounts for 19% of AIDS-related deaths annually. The incidences of CM in Europe and North America and the Latin America region have increased by approximately two-fold since 2009, while other regions showed either reduced or stable numbers of cases. Unfortunately, diagnostic and treatment options for cryptococcal infections are limited, and emerging antifungal resistance exacerbates the public health burden.

CONCLUSION

The rising threat of C. neoformans is compounded by accumulating evidence for its ability to infect immunocompetent individuals and the emergence of antifungal-resistant variants. Emphasis should be placed on further understanding the mechanisms of pathogenicity and of antifungal resistance and tolerance. The development of novel management strategies through the identification of new drug targets and the discovery and optimization of new and existing diagnostics and therapeutics are key to reducing the health burden.

Phospholipase B Is Critical for Cryptococcus neoformans Survival in the Central Nervous System

Cryptococcus neoformans (Cn) is an opportunistic, encapsulated, yeast-like fungus that causes severe meningoencephalitis, especially in countries with high HIV prevalence. In addition to its well-known polysaccharide capsule, Cn has other virulence factors such as phospholipases, a heterogeneous group of enzymes that hydrolyze ester linkages in glycerophospholipids. Phospholipase B (PLB1) has been demonstrated to play a key role in Cn pathogenicity. In this study, we used a PLB1 mutant (plb1) and its reconstituted strain (Rec1) to assess the importance of this enzyme on Cn brain infection in vivo and in vitro. Mice infected with the plb1 strain survive significantly longer, have lower peripheral and central nervous system (CNS) fungal loads, and have fewer and smaller cryptococcomas or biofilm-like brain lesions compared to H99- and Rec1-infected animals. PLB1 causes extensive brain tissue damage and changes microglia morphology during cryptococcal disease, observations which can have important implications in patients with altered mental status or dementia as these manifestations are related to poorer survival outcomes. plb1 cryptococci are significantly more phagocytosed and killed by NR-9460 microglia-like cells. plb1 cells have altered capsular polysaccharide biophysical properties which impair their ability to stimulate glial cell responses or morphological changes. Here, we provide significant evidence demonstrating that Cn PLB1 is an important virulence factor for fungal colonization of and survival in the CNS as well as in the progression of cryptococcal meningoencephalitis. These findings may potentially help fill in a gap of knowledge in our understanding of cerebral cryptococcosis and provide novel research avenues in Cn pathogenesis. IMPORTANCE Cryptococcal meningoencephalitis (CME) is a serious disease caused by infection by the neurotropic fungal pathogen Cryptococcus neoformans. Due to the increasing number of cases in HIV-infected individuals, as well as the limited therapies available, investigation into potential targets for new therapeutics has become critical. Phospholipase B is an enzyme synthesized by Cn that confers virulence to the fungus through capsular enlargement, immunomodulation, and intracellular replication. In this study, we examined the properties of PLB1 by comparing infection of a Cn PLB1 mutant strain with both the wild-type and a PLB1-reconstituted strain. We show that PLB1 augments the survival and proliferation of the fungus in the CNS and strengthens virulence by modulating the immune response and enhancing specific biophysical properties of the fungus. PLB1 expression causes brain tissue damage and impacts glial cell functions, which may be responsible for the dementia observed in patients which may persist even after resolving from CME. The implications of PLB1 inhibition reveal its involvement in Cn infection and suggest that it may be a possible molecular target in the development of antifungal therapies. The results of this study support additional investigation into the mechanism of PLB1 to further understand the intricacies of cerebral Cn infection.

Infratentorial Cryptococcus neoformans meningoencephalitis with cerebellar infarction: A rare case report

Background

Cryptococcal meningoencephalitis (CM), is a highly fatal fungal infection of the central nervous system (CNS), affecting not only immunocompromised patients, but also apparently immunocompetent patients. CM is mainly caused by Cryptococcus neoformans (C. neoformans), while viral hepatitis B (HBV) tends to be a rare inducement. According to the literature, the most common cerebral area affected by CM was frontal lobe, while infratentorial lesions were rare, especially those complicated with cerebellar infarction.

Methods

This study capitally analyzed the clinical data of an elderly female suffering from infratentorial CM complicated with cerebellar infarction, with a history of chronic HBV.

Results

The patient suffered from the symptoms of dizziness, insanity, low-grade fever, and high cranial pressure throughout the course of the disease. Her MRI findings were hydrocephalus and infratentorial lesions, including bilateral cerebellums and meningeal enhancement. The pathogene was Cryptococcus revealed by both the cytology and ink stain of cerebrospinal fluid, and was confirmed to be C. neoformans by the Next generation sequencing (NGS). After 12 days of intravenous amphotericin B (AMB) treatment, the patient developed oliguria, and 3 days after the termination of AMB treatment, the renal function recovered. Brain MRI reexamination after the treatment showed that the diffused lesions in the cerebellum were significantly decreased, and acute infarction occurred on the left cerebellum although it was asymptomatic. The patient took fluconazole 400mg per day after discharge, without complaints during the follow-up two months later.

Conclusion

C. neoformans infection may be a possible pathogeny in chronic HBV patients with meningoencephalitis. Cerebellar infarction might be a complication of CM, therefore MRI is supposed to be re-examined during antifungal therapy. Additionally, monitoring renal function plays a vital role after AMB treatment, and renal function may recover after termination.

Cerebral infarction in HIV-negative patients with cryptococcal meningitis: its predictors and impact on outcomes

Background

Descriptions of the patterns of acute/subacute cerebral infarction (ASCI) in HIV-negative patients with cryptococcal meningitis (CM) are scarce, and the predictors of ischemic stroke and outcomes following ASCI remain unclear.

Aim

To study the clinical characteristics and evaluate the predictors of ASCI in HIV-negative patients with CM and assess the impact of ischemic stroke on the outcomes of the patients.

Methods

We retrospectively analyzed the data of 61 HIV-negative patients with CM treated between January, 2016 and February, 2022, and among them, 53 patients with complete neuroimaging and cerebrospinal fluid (CSF) data were enrolled in this study. The cohort was stratified by the occurrence of ASCI diagnosed based on MRI evidences for comparison of the clinical characteristics (consciousness disturbance, GCS score, duration of symptoms, and treatment), CSF parameters, imaging findings (meningeal inflammation, hydrocephalus, posterior fossa exudates) and outcomes of the patients. A favorable outcome was defined as a modified Rankin scale (mRS) score ≤ 2 and a poor outcome as a mRS score > 2. Logistic regression analysis was used to identify the risk factors of ASCI in the HIV-negative patients with CM.

Results

Of the 53 HIV-negative patients with CM, 14 (26.4%) had ASCI. The incidences of fever, headache, neck stiffness, duration of symptoms, CSF parameters, meningeal enhancement in brain MRI and the treatment regimens were similar between the patients with and those without ASCI. Most of the infarcts (92.9%) were of the lacunar type, involving both the anterior and posterior territories. Basal ganglia-corona radiata and the brainstem-cerebellum were the most frequently involved sites. Univariate logistic regression analysis suggested that consciousness disturbance (P = 0.002), MRI evidence of hydrocephalus (P = 0.042) and posterior fossa exudates (P = 0.028) were predictors of ASCI in these HIV-negative patients with CM. Multivariate analysis identified consciousness disturbance as a significant predictor of ASCI (P = 0.020). Compared with the patients without ASCI, the HIV-negative patients with CM and ASCI had poorer outcomes (P = 0.001).

Conclusion

ASCI can occur in HIV-negative patients with CM, presented commonly as multiple lacunar infarctions involving all the cerebrovascular territories. The presence of consciousness disturbance, hydrocephalus and posterior fossa exudates may increase the risk of ASCI in patients with CM. ASCI is associated with a poor outcome of the HIV-negative patients with CM.

CNS cryptococcosis presenting with cerebellar stroke and spinal arachnoiditis

A 67-year-old man presented with a low-grade fever for 2 months, weakness of all four limbs for five days and altered sensorium for two days. He was recently diagnosed with AIDS and was treatment-naive. Investigations revealed a CD4 count of 27cells/mm3 MRI brain and spine exhibited bilateral cerebellar lesions with diffusion restriction, and severe arachnoiditis at the level of the lumbar spine. High suspicion of central nervous system tuberculosis in an endemic country like ours, led us to start antitubercular therapy and steroids. Repeated lumbar punctures resulted in a dry tap leading to a delay in diagnosis. Serum cryptococcal antigen detection came positive, following which antifungal treatment was initiated. Later a small amount of cerebrospinal fluid sample was obtained which confirmed the diagnosis of cryptococcosis. However, the patient worsened and succumbed to the illness. This case highlighted the rare presentation of cryptococcal cerebellar stroke and spinal arachnoiditis.

Cryptococcosis Presenting as Cerebrovascular Disease

Infection plays a complex role in cerebrovascular disease and is believed to have both direct and indirect mechanisms on stroke pathogenesis. if not diagnosed and treated promptly, this may have devastating consequences. Management of infection-related strokes focuses on the treatment of the underlying infection with appropriate antimicrobial drugs and the prevention of medical complications. This can lead to devastating neurological deficits. We present two cases of cryptococcal meningoencephalitis that presented with an atypical cerebral infarction. A 55-year-old male with a history of unknown autoimmune disease presented with acute onset cognitive changes and no stroke-like symptoms. A 35-year-old male with no history of autoimmune disease or other existing immunodeficiency presented with breakthrough seizure a long with stroke-like symptoms. Both patients developed multiple cerebral infarcts in multiple vascular territories, with histologic and radiologic findings consistent with a central nervous system cryptococcosis. They were subsequently diagnosed with cryptococcal meningoencephalitis and started on the appropriate anti-fungal regimen with amphotericin B and flucytosine. Prior to discharge to an inpatient rehabilitation facility, both patients were notably improved and near their neurologic baseline. It is important to understand the pathogenesis of cryptococcal infection in the central nervous system because it produces a wide variety of clinico-radiographic features that can be overlooked. Clinicians should keep infection-mediated cerebral infarcts in mind, regardless of risk factors, in order to expedite antimicrobial therapy and minimize adverse events.

Anti-N-methyl-d-aspartate receptor encephalitis associated with intracranial cryptococcal infection: A case report and 2-year follow-up

Anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis is a type of autoimmune encephalitis characterized by the rapid onset of neurologic dysfunction. Several studies have reported the important role of post-infectious effect in its pathogenesis. Herein, we report on a 68-year-old woman diagnosed with anti-NMDA receptor encephalitis with concomitant intracranial cryptococcal infection, who was followed up for two years and demonstrated clinical improvements after effective anti-fungal therapy. This case may help expand the clinical spectrum of post-infectious immune-mediated etiology of anti-NMDA receptor encephalitis. The pathogenic role of both disorders requires further investigation.

The clinical characteristics and outcome of cryptococcal meningitis with AIDS in a tertiary hospital in China: an observational cohort study

BACKGROUND

Despite the profound impact of antiretroviral therapy in the control of AIDS mortality, central nervous system opportunistic infections remains a significant burden in AIDS patients. This retrospective study aims to elucidate the clinical characteristics, outcome and risk factors of cryptococcal meningitis (CM) poor prognosis in AIDS patients from a tertiary hospital in China.

METHODS

Clinical data from 128 patients admitted in Beijing Ditan Hospital, Capital Medical University from November 2008 to November 2017 was collected. The cohort was stratified based on treatment outcome (effective 79%, and ineffective 21%), and Multivariate Logistic regression analysis used to identify risk factors of poor disease prognosis.

RESULTS

Age, incidence of cerebral infarction, the proportion of consciousness disorder, and fasting plasma glucose was higher in the ineffective treatment group than the effective treatment group. The duration of treatment in the induction period of the ineffective group was significantly shorter than that of the effective group. Multivariate Logistic regression analysis indicated that the occurrence of cerebral hernia and consciousness disorder were risk factors for the prognosis of AIDS patients with CM infection, while the duration of treatment in the induction period was a indicative of a better prognosis in AIDS with CM infection complications. Finally, shunt decompression therapy correlated with a better disease outcome.

CONCLUSIONS

This retrospective study exposes the main risk factors associated with worse disease prognosis in AIDS patients with CM infection complications.

Cryptococcus Meningitis Can Co-occur with Anti-NMDA Receptor Encephalitis

We herein report a 50-year-old man with alcoholic cirrhosis who developed loss of consciousness and tremor of the upper limbs. Magnetic resonance imaging findings were suggestive of limbic encephalitis with bilateral hippocampal damage, and a cerebrospinal fluid (CSF) examination confirmed anti-N-methyl-D-aspartate (NMDA) and anti-glutamate receptor antibodies. Despite initial corticosteroid therapy, meningeal irritation symptoms appeared, owing to the development of cryptococcal meningitis (CM), diagnosed by the detection of cryptococcal capsular polysaccharide antigen in the follow-up CSF analysis. Cerebral infarction with reversible stenosis of major cerebral arteries during the clinical course was also observed. Following administration of antifungals and corticosteroids, the number of cells in the CSF gradually declined, and NMDA receptor antibodies disappeared. Our study demonstrates the unique coexistence of CM with anti-NMDA receptor encephalitis in adults.

Landmark clinical observations and immunopathogenesis pathways linked to HIV and Cryptococcus fatal central nervous system co-infection

Cryptococcal meningitis remains one of the leading causes of death among HIV-infected adults in the fourth decade of HIV era in sub-Saharan Africa, contributing to 10%-20% of global HIV-related deaths. Despite widespread use and early induction of ART among HIV-infected adults, incidence of cryptococcosis remains significant in those with advanced HIV disease. Cryptococcus species that causes fatal infection follows systemic spread from initial environmental acquired infection in lungs to antigenaemia and fungaemia in circulation prior to establishment of often fatal disease, cryptococcal meningitis in the CNS. Cryptococcus person-to-person transmission is uncommon, and deaths related to blood infection without CNS involvement are rare. Keen to the persistent high mortality associated with HIV-cryptococcal meningitis, seizures are common among a third of the patients, altered mental status is frequent, anaemia is prevalent with ensuing brain hypoxia and at autopsy, brain fibrosis and infarction are evident. In addition, fungal burden is 3-to-4-fold higher in those with seizures. And high immune activation together with exacerbated inflammation and elevated PD-1/PD-L immune checkpoint expression is immunomodulated phenotypes elevated in CSF relative to blood. Lastly, though multiple Cryptococcus species cause disease in this setting, observations are mostly generalised to cryptococcal infection/meningitis or regional dominant species (C neoformans or gattii complex) that may limit our understanding of interspecies differences in infection, progression, treatment or recovery outcome. Together, these factors and underlying mechanisms are hypotheses generating for research to find targets to prevent infection or adequate therapy to prevent persistent high mortality with current optimal therapy.

Lacunar Stroke in Cryptococcal Meningitis: Clinical and Radiographic Features

OBJECTIVE

Cryptococcal meningitis carries a high mortality, and survivors are left with considerable neurologic sequelae and marked disability. We lack a clear understanding of the pathogenesis of neurologic sequelae and description of stroke features in this population. We aim to describe clinical and radiographic features and predictors of stroke in a cohort of patients with cryptococcal meningitis.

METHODS

We collected key information on patients diagnosed with cryptococcal meningitis at the University of Colorado Hospital between 2000 and 2018 (n = 42). Of those, 32 had neuroimaging studies available. Bivariate and risk ratio estimates regression models were performed to identify predictors of stroke.

RESULTS

We found a 26% ischemic stroke complication rate in individuals with cryptococcal meningitis. Most strokes were acute (75%), lacunar (100%), multiple (88%), bilateral (63%), and involving the basal ganglia (75%). Presence of malignancy (38% versus 8%, P = .085) was higher in stroke in individuals with cryptococcal meningitis, although not statistically significant. Every unit decrease in hemoglobin and serum sodium were predictors for 1.35 and 1.14 times increase in the risk of ischemic stroke, respectively. The presence of hyponatremia carried a RR of 5.7 (95% confidence interval, 1.7-34, P = .005). Cryptococcal meningitis lead to death in 19% of patients and a considerable rate of neurologic sequela among survivors.

CONCLUSIONS

Cryptococcal meningitis carries a high risk of lacunar stroke, particularly in the basal ganglia. Cryptococcal meningitis-associated stroke is common and frequently associated with neurologic disability among survivors. We need to understand the possible role of malignancy, anemia, and hyponatremia in the onset of ischemic stroke.

Cryptococcal meningitis mimicking cerebral infarction: a case report

Cryptococcal meningitis (CM) is the most common type of fungal meningitis. The clinical symptoms of CM are nonspecific, and neuroimaging characteristics are variable. Herein, we present a case of a senile female with CM that was once misdiagnosed as cerebral infarction. Her condition worsened and she developed hydrocephalus. No apparent predisposing factors of CM were reported in this patient. The diagnosis of CM was definitely made after India ink staining of cerebrospinal fluid was positive. This case indicates that clinicians should bear cryptococcal infection in mind when the symptoms are nonspecific and neuroimaging findings are atypical.