Cryptococcal neuroradiological lesions correlate with severity during cryptococcal meningoencephalitis in HIV-positive patients in the HAART era

Spectrum of cryptococcal manifestations in a young male with human immunodeficiency virus

We present the case of a young male with human immunodeficiency virus and a history of nonadherence to antiretroviral therapy who developed cryptococcal meningitis. This case highlights the diverse medical and clinical presentations of central nervous system cryptococcosis in an immunocompromised individual from a radiology perspective. CT and MR imaging demonstrated basal ganglia enhancement and leptomeningeal involvement, characteristic of this pathogen. This report underscores the significance of advanced imaging modalities, in particular MRI, in diagnosing cryptococcal meningitis. Additionally, other manifestations of cryptococcus, including within the thorax, are highlighted in the same patient. The combination of these findings, along with confirmatory cerebral spinal fluid analysis, are crucial to the rapid initiation of an appropriate antifungal regimen for treatment.

Global guideline for the diagnosis and management of cryptococcosis: an initiative of the ECMM and ISHAM in cooperation with the ASM

Cryptococcosis is a major worldwide disseminated invasive fungal infection. Cryptococcosis, particularly in its most lethal manifestation of cryptococcal meningitis, accounts for substantial mortality and morbidity. The breadth of the clinical cryptococcosis syndromes, the different patient types at-risk and affected, and the vastly disparate resource settings where clinicians practice pose a complex array of challenges. Expert contributors from diverse regions of the world have collated data, reviewed the evidence, and provided insightful guideline recommendations for health practitioners across the globe. This guideline offers updated practical guidance and implementable recommendations on the clinical approaches, screening, diagnosis, management, and follow-up care of a patient with cryptococcosis and serves as a comprehensive synthesis of current evidence on cryptococcosis. This Review seeks to facilitate optimal clinical decision making on cryptococcosis and addresses the myriad of clinical complications by incorporating data from historical and contemporary clinical trials. This guideline is grounded on a set of core management principles, while acknowledging the practical challenges of antifungal access and resource limitations faced by many clinicians and patients. More than 70 societies internationally have endorsed the content, structure, evidence, recommendation, and pragmatic wisdom of this global cryptococcosis guideline to inform clinicians about the past, present, and future of care for a patient with cryptococcosis.

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.

Cryptococcal meningitis in apparently immunocompetent patients

Cryptococcal meningitis (CM) is an invasive fungal disease that currently poses a threat to human health worldwide, with high morbidity and mortality, particularly in immunocompromised patients. Although CM mainly occurs in HIV-positive patients and other immunocompromised patients, it is also increasingly seen in seemingly immunocompetent hosts. The clinical characteristics of CM between immunocompromised and immunocompetent populations are different. However, few studies have focussed on CM in immunocompetent individuals. This review summarizes the clinical characteristics of apparently immunocompetent CM patients in terms of aetiology, immune pathogenesis, clinical presentation, laboratory data, imaging findings, treatment strategies and prognosis. It is of great significance to further understand the disease characteristics of CM, explore new treatment strategies and improve the prognosis of CM in immunocompetent individuals.

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 a Mexican Neurological Center

BACKGROUND

Cryptococcal meningitis, one of the most severe infections affecting the central nervous system, often involves severe neurological sequels and high mortality.

METHODS

A retrospective review was performed, including 76 cases admitted in a 10-year period at a neurological referral center in Mexico City. From 68 isolates, 52 fungal specimens were identified as part of the Cryptococcus neoformans var. neoformans complex, 15 as C. neoformans var gattii complex, and one as Cryptococcus non-neoformans/gattii.

RESULTS

Higher cryptococcal meningitis incidence and severity were found in HIV-infected men; other risk factors frequently observed were diabetes mellitus and labor exposure to poultry. The main clinical manifestations were subacute headache, cognitive alterations, and photophobia (exclusively in HIV patients). MRI was highly sensitive for pathologic findings such as meningeal enhancements and cryptococcomas, most of them associated to C. neoformans complex. Eleven patients developed severe brain vasculitis, as observed by transcranial Doppler. Hydrocephalus with intracranial hypertension was the most frequent complication.

CONCLUSIONS

One-half of the population died, and the rest had neurological sequels, mainly neuropsychiatric manifestations and secondary headaches. These patients developed severe functional limitations in performing daily activities in an independent manner.

Headache Attributed to Non-vascular Intracranial Disorder: Neoplasms, Infections, and Substance Abuse

Evaluation of headaches warrants a careful history and neurologic assessment to determine the need for further workup and imaging. Identifying patients who are at risk for underlying pathology is important and this includes individuals with known or suspected malignancy and those who are immunocompromised and at increased risk for intracranial infection. While CT is helpful in the acute setting and to screen for intracranial hypertension, MRI is the modality of choice for the evaluation of underlying pathologies. Imaging in substance abuse may show injury related to direct toxicity or secondary to vascular complications.

New strategies for combating fungal infections: Inhibiting inositol lipid signaling by targeting Sec14 phosphatidylinositol transfer proteins

Virulent fungi represent a particularly difficult problem in the infectious disease arena as these organisms are eukaryotes that share many orthologous activities with their human hosts. The fact that these activities are often catalyzed by conserved proteins places additional demands on development of pharmacological strategies for specifically inhibiting target fungal activities without imposing undesirable secondary effects on the host. While deployment of a limited set of anti-mycotics has to date satisfied the clinical needs for treatment of fungal infections, the recent emergence of multi-drug resistant fungal 'superbugs' now poses a serious global health threat with rapidly diminishing options for treatment. This escalating infectious disease problem emphasizes the urgent need for development of new classes of anti-mycotics. In that regard, Sec14 phosphatidylinositol transfer proteins offer interesting possibilities for interfering with fungal phosphoinositide signaling with exquisite specificity and without targeting the highly conserved lipid kinases responsible for phosphoinositide production. Herein, we review the establishment of proof-of-principle that demonstrates the feasibility of such an approach. We also describe the lead compounds of four chemotypes that directly target fungal Sec14 proteins. The rules that pertain to the mechanism(s) of Sec14 inhibition by validated small molecule inhibitors, and the open questions that remain, are discussed - as are the challenges that face development of next generation Sec14-directed inhibitors.

Cerebral Cryptococcomas: A Systematic Scoping Review of Available Evidence to Facilitate Diagnosis and Treatment

Background: Recommendations for managing patients with cerebral cryptococcomas are scarce across multiple clinical guidelines. Due to the deficiency of high-quality data coupled with an increasing number of at-risk patients, the purpose of this review is to describe the demographic characteristics, causative pathogen, intracranial imaging, surgical and/or pharmacological interventions, as well as outcomes of patients with cerebral cryptococcomas to improve recognition and management. Methods: We conducted a scoping review in accordance with the PRISMA guidelines using PubMed and Web of Science. Reports were included if the following details were presented: (1) site of infection; (2) treatment details which at least include the specific antifungal therapy administered, if applicable; and (3) patient outcome. Results: A total of 40 records representing 47 individual patients were included, of which the median age was 48.5 years, 75% were male, and 60% reported a significant past medical, surgical, or social history. C. neoformans was isolated more often than C. gattii (74% vs. 26%, respectively). Patients most often presented with headache, altered mental status and/or confusion, and vomiting occurring over a median of 30 days; though few were noted to have significant findings on physical examination. More than 50% of patients had a single cerebral cryptococcoma lesion, whereas perilesional edema was present in 73% of cases. Surgical intervention occurred in 49% of patients. An amphotericin B-based formulation was administered as “induction” therapy to 91% of patients, but combined with flucytosine or fluconazole in only 58%, for an overall median of 42 days. Fifty two percent of patients received “maintenance” therapy for a median of 126 days, in which fluconazole was most often used. Corticosteroids were administered to approximately 30% of patients for a median of 31.5 days. Overall, mortality was 34%. Conclusion: Based on our findings, management should include antifungal therapy for a minimum of 6 months with considerations for concomitant corticosteroids in the setting of perilesional edema, as well as surgical intervention. Emphasis should be placed on providing well-documented treatment details in future case reports and series to allow for the development of more concise evidence-based recommendations.

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.

Approach to Neurologic Complications in the Immunocompromised Patient

Neurologic complications are common in immunocompromised patients, including those with advanced human immunodeficiency virus, transplant recipients, and patients on immunomodulatory medications. In addition to the standard differential diagnosis, specific pathogens and other conditions unique to the immunocompromised state should be considered in the evaluation of neurologic complaints in this patient population. A thorough understanding of these considerations is critical to the inpatient neurologist in contemporary practice, as increasing numbers of patients are exposed to immunomodulatory therapies. In this review, we provide a chief complaint-based approach to the clinical presentations and diagnosis of both infectious and noninfectious complications particular to immunocompromised patients.

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

•

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

•

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

•

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

•

The CryptoCEST contrast can differentiate cryptococcal brain lesions from gliomas.

•

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.

Emerging Prospects for Combating Fungal Infections by Targeting Phosphatidylinositol Transfer Proteins

The emergence of fungal “superbugs” resistant to the limited cohort of anti-fungal agents available to clinicians is eroding our ability to effectively treat infections by these virulent pathogens. As the threat of fungal infection is escalating worldwide, this dwindling response capacity is fueling concerns of impending global health emergencies. These developments underscore the urgent need for new classes of anti-fungal drugs and, therefore, the identification of new targets. Phosphoinositide signaling does not immediately appear to offer attractive targets due to its evolutionary conservation across the Eukaryota. However, recent evidence argues otherwise. Herein, we discuss the evidence identifying Sec14-like phosphatidylinositol transfer proteins (PITPs) as unexplored portals through which phosphoinositide signaling in virulent fungi can be chemically disrupted with exquisite selectivity. Recent identification of lead compounds that target fungal Sec14 proteins, derived from several distinct chemical scaffolds, reveals exciting inroads into the rational design of next generation Sec14 inhibitors. Development of appropriately refined next generation Sec14-directed inhibitors promises to expand the chemical weaponry available for deployment in the shifting field of engagement between fungal pathogens and their human hosts.

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.

Enlarged periventricular space and periventricular lesion extension on baseline brain MRI predicts poor neurological outcomes in cryptococcus meningoencephalitis

In Cryptococcus neoformans meningoencephalitis, brain MRI findings might reflect the phathomechanism of disease progression that is fungal accumulation in the peri-venular space and consequent invasion into the parenchyma. This study analyzed serial brain MRI findings of 76 patients with cryptococcus meningoencephalitis in association with the disease progression and outcomes. MRI parameters included the enlarged periventricular space (ePVS) score (range 0-8), periventricular lesion extension, cryptococcoma, and hydrocephalus. Clinical outcomes at 2-week, 10-week, and 6-month were evaluated using modified Rankin scale (mRS). At 6 months, 15 (19.7%) patients died and 34 (44.1%) had poor neurological outcomes (mRS scores > 2). At baseline, an ePVS score of ≥ 5 (Odds-ratio [OR]: 94.173, 95% confidence-interval [95%CI]: 7.507-1181.295, P < .001), periventricular lesion extension (OR: 51.965, 95%CI: 2.592-1041.673, P = .010), and presence of encephalitis feature (OR: 44.487, 95%CI: 1.689-1172.082, P = .023) were associated with 6-month poor outcomes. Presence of two or more risk factors among encephalitis feature, ePVS score ≥ 5, and periventricular lesion extension at baseline, was associated with 6-month poor outcomes (area under the curve [AUC]: 0.978, P < .001) and mortality (AUC: 0.836, P < .001). Disease progression was associated with interval development of cryptococcoma and hydrocephalus. Brain MRI findings might be useful in predicting outcomes and monitoring the progression of cryptococcus meningoencephalitis.

Clinical features and treatment outcomes of human immunodeficiency virus-associated cryptococcal meningitis: a 2-year retrospective analysis

BACKGROUND

Cryptococcal meningitis (CM) is one of the most common opportunistic infections caused by Cryptococcus neoformans in human immunodeficiency virus (HIV)-infected patients, and is complicated with significant morbidity and mortality. This study retrospectively analyzed the clinical features, characteristics, treatment, and outcomes of first-diagnosed HIV-associated CM after 2-years of follow-up.

METHODS

Data from all patients (n = 101) of HIV-associated CM hospitalized in Shanghai Public Health Clinical Center from September 2013 to December 2016 were collected and analyzed using logistic regression to identify clinical and microbiological factors associated with mortality.

RESULTS

Of the 101 patients, 86/99 (86.9%) of patients had CD4 count <50 cells/mm, 57/101 (56.4%) were diagnosed at ≥14 days from the onset to diagnosis, 42/99 (42.4%) had normal cerebrospinal fluid (CSF) cell counts and biochemical examination, 30/101 (29.7%) had concomitant Pneumocystis (carinii) jiroveci pneumonia (PCP) on admission and 37/92 (40.2%) were complicated with cryptococcal pneumonia, 50/74 (67.6%) had abnormalities shown on intracranial imaging, amongst whom 24/50 (48.0%) had more than one lesion. The median time to negative CSF Indian ink staining was 8.50 months (interquartile range, 3.25-12.00 months). Patients who initiated antiretroviral therapy (ART) before admission had a shorter time to negative CSF Indian ink compared with ART-naïve patients (7 vs. 12 months, χ = 15.53, P < 0.001). All-cause mortality at 2 weeks, 8 weeks, and 2 years was 10.1% (10/99), 18.9% (18/95), and 20.7% (19/92), respectively. Coinfection with PCP on admission (adjusted odds ratio [AOR], 3.933; 95% confidence interval [CI], 1.166-13.269, P = 0.027) and altered mental status (AOR, 9.574; 95% CI, 2.548-35.974, P = 0.001) were associated with higher mortality at 8 weeks.

CONCLUSION

This study described the clinical features and outcomes of first diagnosed HIV-associated CM with 2-year follow-up data. Altered mental status and coinfection with PCP predicted mortality in HIV-associated CM.

A Sec14-like phosphatidylinositol transfer protein paralog defines a novel class of heme-binding proteins

Yeast Sfh5 is an unusual member of the Sec14-like phosphatidylinositol transfer protein (PITP) family. Whereas PITPs are defined by their abilities to transfer phosphatidylinositol between membranes in vitro, and to stimulate phosphoinositide signaling in vivo, Sfh5 does not exhibit these activities. Rather, Sfh5 is a redox-active penta-coordinate high spin Fe^III hemoprotein with an unusual heme-binding arrangement that involves a co-axial tyrosine/histidine coordination strategy and a complex electronic structure connecting the open shell iron d-orbitals with three aromatic ring systems. That Sfh5 is not a PITP is supported by demonstrations that heme is not a readily exchangeable ligand, and that phosphatidylinositol-exchange activity is resuscitated in heme binding-deficient Sfh5 mutants. The collective data identify Sfh5 as the prototype of a new class of fungal hemoproteins, and emphasize the versatility of the Sec14-fold as scaffold for translating the binding of chemically distinct ligands to the control of diverse sets of cellular activities.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

Do Intracerebral Cytokine Responses Explain the Harmful Effects of Dexamethasone in Human Immunodeficiency Virus-associated Cryptococcal Meningitis?

Background

The CryptoDex trial showed that dexamethasone caused poorer clinical outcomes and slowed fungal clearance in human immunodeficiency virus–associated cryptococcal meningitis. We analyzed cerebrospinal fluid (CSF) cytokine concentrations from participants over the first week of treatment to investigate mechanisms of harm and test 2 hypotheses: (1) dexamethasone reduced proinflammatory cytokine concentrations, leading to poorer outcomes and (2) leukotriene A4 hydrolase (LTA4H) genotype influenced the clinical impact of dexamethasone, as observed in tuberculous meningitis.

Methods

We included participants from Vietnam, Thailand, and Uganda. Using the Luminex system, we measured CSF concentrations of the following: interferon γ, tumor necrosis factor (TNF) α, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant 1, macrophage inflammatory protein 1α, and interleukin 6, 12p70, 8, 4, 10, and 17. We determined the LTA4H genotype based on the promoter region single-nucleotide polymorphism rs17525495. We assessed the impact of dexamethasone on cytokine concentration dynamics and the association between cytokine concentration dynamics and fungal clearance with mixed effect models. We measured the influence of LTA4H genotype on outcomes with Cox regression models.

Results

Dexamethasone increased the rate TNF-α concentration’s decline in (−0.13 log2pg/mL/d (95% confidence interval, −.22 to −.06 log2pg/mL/d; P = .03), which was associated with slower fungal clearance (correlation, −0.62; 95% confidence interval, −.83 to −.26). LTA4H genotype had no statistically significant impact on outcome or response to dexamethasone therapy. Better clinical outcomes were associated with higher baseline concentrations of interferon γ.

Conclusions

Dexamethasone may slow fungal clearance and worsen outcomes by increasing TNF-α concentration’s rate of decline.

17-β-Estradiol increases macrophage activity through activation of the G-protein-coupled estrogen receptor and improves the response of female mice to Cryptococcus gattii

Cryptococcus gattii (Cg) is one of the agents of cryptococcosis, a severe systemic mycosis with a higher prevalence in men than women, but the influence of the female sex hormone, 17-β-estradiol (E2), on cryptococcosis remains unclear. Our study shows that female mice presented delayed mortality, increased neutrophil recruitment in bronchoalveolar lavage fluid, and reduced fungal load after 24 hr of infection compared to male and ovariectomised female mice (OVX). E2 replacement restored OVX female survival. Female macrophages have more efficient fungicidal activity, which was increased by E2 and reversed by the antagonist of G-protein-coupled oestrogen receptor (GPER), which negatively modulates PI3K activation. Furthermore, E2 induces a reduction in Cg cell diameter, cell charge, and antioxidant peroxidase activity. In conclusion, female mice present improved control of Cg infection, and GPER is important for E2 modulation of the female response.

Cryptococcal infections in children: retrospective study and review from Australia

Aim: Cryptococcosis causes significant morbidity and mortality worldwide, but pediatric data are limited. Methods: A retrospective literature review of Australian pediatric cryptococcosis and additional 10-year audit of cases from a large pediatric network. Results: 22 cases of cryptococcosis in children were identified via literature review: median age was 13.5 years (IQR 7.8-16 years), 18/22 (82%) had meningitis or central nervous system infection. Where outcome was reported, 11/18 (61%) died. Of six audit cases identified from 2008 to 2017, 5 (83%) had C. gattii disease and survived. One child with acute lymphoblastic leukemia and C. neoformans infection died. For survivors, persisting respiratory or neurological sequelae were reported in 4/6 cases (67%). Conclusion: Cryptococcosis is uncommon in Australian children, but is associated with substantial morbidity.

Imaging of Human Neurolisteriosis: A Prospective Study of 71 Cases

Background

Neurolisteriosis ranks among the most severe neurological infections. Its radiological features have not been thoroughly studied. We describe here the neuroradiological features of neurolisteriosis and assess their prognostic value.

Methods

Patients with microbiologically proven neurolisteriosis were enrolled from November 2009 to October 2013 in MONALISA study. Magnetic resonance and computed tomography images were studied by 2 independent neuroradiologists. Predictors of 3-month mortality were determined using logistic regression.

Results

Seventy-one patients were included; 42 were men (59%). Mean age was 64 years. Sixty patients (85%) reported signs of encephalitis, with clinical brainstem involvement in 16 (23%). Images were abnormal in 87% of cases (62/71). Main neuroradiological images were meningeal enhancement (25/71, 35%), abscess(es), or nodular image(s) evocative of abscess (10/71, 14%), hemorrhages (11/71, 15%), contrast-enhancing ventricles, or hydrocephalus (7/71, 10%). White-matter images (42/71, 59%), dilated Virchow-Robin spaces (22/71, 31%), and cerebral atrophy were also reported (34/71, 48%). Brainstem involvement (meningeal enhancement, abscess) was reported in only 7/71 cases (10%). Three-month survival was lower in patients with hydrocephalus or contrast-enhancing ventricles (1/7 [14%] than without [47/64, 73%], P = .005) and in patients with parenchymal images (abscess[es], nodule[s]\, or white matter images; 25/46 [54%] vs 23/25 without [92%], P = .004). Parenchymal images were associated with lower 3-month survival in the multivariable model (odds ratio 5.60, 95% confidence interval [1.42-29.6], P = .02).

Conclusions

Neurolisteriosis presents as a combination of neuroradiological images, none being specific. Radiological signs of rhombencephalitis are uncommon, whereas, unexpectedly, hemorrhagic images are frequent. The negative prognostic value of parenchymal neuroradiological images was evidenced.

Clinical Trials Registration

NCT01520597.

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.

Neurological manifestations, laboratory and neuroimaging features in HIV-infected patients

Objectives:

To present detailed information regarding these aspects in Human Immunodeficiency Virus (HIV)-infected patients making an effort to improve the recognition of neurological complications of HIV infection.

Methods:

This retrospective study analyzed the clinical manifestations, laboratory and neuroimaging results of HIV-infected patients with neurological complications at Xuanwu hospital, Beijing, China from January 2011 to December 2014, one of top-rated hospitals in Beijing, China.

Results:

A diverse range of clinical diagnoses was identified, including encephalopathy, meningoencephalitis, peripheral neuropathy, multiple sclerosis, cerebral infarction and lymphoma associated with HIV infection. The mostly observed neurological disorders were motor/sensory deficits in the limbs (75%), cognitive impairments (42%) and fever (33%). Non-specific results of laboratory tests, including elevated erythrocyte sedimentation rate (ESR), cerebrospinal fluid (CSF) protein concentration and IgG, were found. Brain Magnetic Resonance Imaging (MRI) abnormalities displayed a variety of patterns and distributions due to diverse clinical profiles.

Conclusion:

The clinical scenarios of HIV-infected patients are remarkably diverse and complex. Etiological tests would be cardinal to make more definitive diagnosis for HIV-infected patients. Prospective studies with follow-up were needed to bring more accurate information.

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.

Comparison and Correlation of Magnetic Resonance Imaging and Clinical Severity in Nonhuman Immunodeficiency Virus Patients with Cryptococcal Infection of Central Nervous System

Background:

The incidence of cryptococcal meningitis among immunocompetent patients increases, especially in China and imaging plays an important role. The current study was to find the correlation between magnetic resonance imaging (MRI) manifestation and clinical severity in nonhuman immunodeficiency virus patients with cryptococcal infection of central nervous system (CNS).

Methods:

A total of 65 patients with CNS cryptococcal infection from August 2014 to October 2016 were retrospectively included in this study. All the patients had MRI data and clinical data. The patients were divided into two groups according to whether the patients were confirmed with identifiable underlying disease. Comparison and correlation of MRI and clinical data in both groups were investigated using independent sample t-test, Chi-square test, Mann-Whitney test and Spearman rank correlation analysis.

Results:

In all 65 patients, 41 cases (41/65, 63.1%; Group 1) had normal immunity and 24 cases (24/65, 36.9%; Group 2) had at least one identifiable underlying disease. Fever, higher percentage of neutrophil (NEUT) in white blood cell (WBC), and increased cell number of cerebral spawell correlated with the number of cells andil fluid (CSF) were much common in patients with underlying disease (Group 1 vs. Group 2: Fever: 21/41 vs. 21/24, χ² = 8.715, P = 0.003; NEUT in WBC: 73.15% vs. 79.60%, Z = −2.370, P = 0.018; cell number of CSF: 19 vs. 200, Z = −4.298, P < 0.001; respectively). Compared to the patients with normal immunity, the lesions are more common in the basal ganglia among patients with identifiable underlying disease (Group 1 vs. Group 2: 20/41 vs. 20/24, χ² = 7.636, P = 0.006). The number of the involved brain areas in patients with identifiable underlying disease were well correlated with the number of cells and pressure of CSF (r = −0.472, P = 0.031; r = 0.779, P = 0.039; respectively).

Conclusions:

With the increased number of the involved brain areas in patients with identifiable underlying disease, the body has lower immunity against the organism which might result in higher intracranial pressure and more severe clinical status.

Dual infection of the central nervous system caused by Cryptococcus and Toxoplasma in a patient with AIDS: a case report and literature review

Dual infection of the central nervous system secondary to Cryptococcus and Toxoplasma is very uncommon, even in the setting of acquired immunodeficiency syndrome (AIDS). We report the case of a 52-year-old patient who was admitted with multiple cranial nerve deficits. Magnetic resonance imaging showed supratentorial and infratentorial enhancing lesions. He was newly diagnosed with HIV infection with a CD4 count of 59 cells/uL and HIV viral load of 299,619 copies/mL. Diagnosis of Cryptococcus meningitis was made by Cryptococcal antigen in cerebrospinal fluid (CSF). The high clinical suspicion for Toxoplasmosis prompted an early empiric treatment for this condition. The diagnosis of Toxoplasmosis was later confirmed by PCR in CSF. Despite an adequate treatment for these two pathologies, his condition deteriorated and eventually expired. We reviewed the English language literature for cases of Cryptococcus and Toxoplasma co-infection of the central nervous system in patients with AIDS. To our knowledge, our patient is the third case of simultaneous infection described in the literature. Clinicians must be aware that focal brain lesions in patients with cryptococcal meningitis should prompt a full evaluation to search for concomitant pathologies of which Toxoplasmosis is the most important. Our case illustrates the utility of PCR in CSF for an early diagnosis of toxoplasmosis, reserving brain biopsy for cases of anti-toxoplasma therapy failure.

EQUAL Cryptococcus Score 2018: A European Confederation of Medical Mycology Score Derived From Current Guidelines to Measure QUALity of Clinical Cryptococcosis Management

Cryptococcocis is an opportunistic fungal infection with high morbidity and mortality. Guidelines to aid clinicians regarding diagnosis, management, and treatment can be extensive and challenging to comply with. There is no tool to measure guideline adherence. To create such a tool, we reviewed current guidelines from the Infectious Diseases Society of America, the World Health Organization, the American Society of Transplantation, and recent significant publications to select the strongest recommendations as vital components of our scoring tool. Items included diagnostic tests (blood, tissue, and cerebrospinal fluid cultures, Cryptococcus antigen, India ink, histopathology with special fungal stains, central nervous system imaging), pharmacological (amphotericin B, flucytosine, azoles) and nonpharmacological treatments (intracranial pressure management, immunomodulation, infectious disease consultation), and follow-up of central nervous system complications. The EQUAL Cryptococcus Score 2018 weighs and aggregates the recommendations for the optimal management of cryptococcosis. Providing a tool that could measure guideline adherence or facilitate clinical decision-making.

HIV-associated opportunistic CNS infections: pathophysiology, diagnosis and treatment

Nearly 30 years after the advent of antiretroviral therapy (ART), CNS opportunistic infections remain a major cause of morbidity and mortality in HIV-positive individuals. Unknown HIV-positive disease status, antiretroviral drug resistance, poor drug compliance, and recreational drug abuse are factors that continue to influence the morbidity and mortality of infections. The clinical and radiographic pattern of CNS opportunistic infections is unique in the setting of HIV infection: opportunistic infections in HIV-positive patients often have characteristic clinical and radiological presentations that can differ from the presentation of opportunistic infections in immunocompetent patients and are often sufficient to establish the diagnosis. ART in the setting of these opportunistic infections can lead to a paradoxical worsening caused by an immune reconstitution inflammatory syndrome (IRIS). In this Review, we discuss several of the most common CNS opportunistic infections: cerebral toxoplasmosis, progressive multifocal leukoencephalopathy (PML), tuberculous meningitis, cryptococcal meningitis and cytomegalovirus infection, with an emphasis on clinical pearls, pathological findings, MRI findings and treatment. Moreover, we discuss the risk factors, pathophysiology and management of IRIS. We also summarize the challenges that remain in management of CNS opportunistic infections, which includes the lack of phase II and III clinical trials, absence of antimicrobials for infections such as PML, and controversy regarding the use of corticosteroids for treatment of IRIS.

Computerised tomography findings in HIV-associated cryptococcal meningoencephalitis at a tertiary hospital in Pretoria

Objective

Computerised tomography (CT) scans of 30 patients, admitted with HIV-associated cryptococcal meningoencephalitis (CM), were retrospectively reviewed and the different neuroradiological findings categorised. In addition to the characterisation of the cohort, we looked at whether positive CT scans can indicate negative outcomes when compared with normal imaging.

Methods

We identified all patients admitted with CM to Kalafong Hospital in Pretoria, South Africa, over a 2-year period and selected those who underwent brain CT. Abnormal findings were divided into cryptococcal-related lesions and other pathological findings. Clinical data, as well as laboratory data and information about the outcomes were collected.

Results

Thirty-nine (44.8%) out of 87 patients had a CT done during the hospital admission, of which 30 were reviewed and independently reported by the authors. The majority of CT scans were non-contrasted (n = 21). Four patients (13.3%) had normal imaging. Amongst the 26 patients with abnormal CTs, we found 16 brain scans (53.3%) with changes most likely attributed to CM. Dilated Virchow–Robin (VR) spaces, found on eight scans (26.7%), were the most common CT finding related to neurocryptococcosis. Global cerebral atrophy, present in 17 patients (56.7%), was the prevailing generalised abnormality. The mortality of all patients who underwent imaging was similar (33.3%) to the mortality in the total cohort of patients with cryptococcal meningitis (31%). In the group with cryptococcal-related changes on imaging, the mortality was higher (53.3%) than in both groups and a subgroup of five patients with hydrocephalus showed 100% mortality.

Conclusion

Computerised tomography brain imaging was performed in 44.8% of all patients admitted with CM into our hospital. More than half of the images showed cryptococcal-related pathological findings, of which dilated VR spaces were the most common. Only 13.3% of scans were normal. Mortality was higher in the patients with cryptococcal-related pathology (53.3% vs. 31%), with hydrocephalus being associated with a 100% mortality. No scan in our cohort showed any pathology requiring neurosurgical intervention or contraindicating the procedure of a lumbar puncture.

Choroid Plexitis and Ependymitis by Magnetic Resonance Imaging are Biomarkers of Neuronal Damage and Inflammation in HIV-negative Cryptococcal Meningoencephalitis

CNS cryptococcal meningoencephalitis in both HIV positive (HIV+) and HIV negative (HIV−) subjects is associated with high morbidity and mortality despite optimal antifungal therapy. We thus conducted a detailed analysis of the MR imaging findings in 45 HIV− and 11 HIV+ patients to identify imaging findings associated with refractory disease. Ventricular abnormalities, namely ependymitis and choroid plexitis were seen in HIV− but not in HIV+ subjects. We then correlated the imaging findings in a subset of HIV− subjects (n = 17) to CSF levels of neurofilament light chain (NFL), reflective of axonal damage and sCD27, known to best predict the presence of intrathecal T-cell mediated inflammation. We found that ependymitis on brain MRI was the best predictor of higher log(sCD27) levels and choroid plexitis was the best predictor of higher log(NFL) levels. The availability of predictive imaging biomarkers of inflammation and neurological damage in HIV− subjects with CNS cryptococcosis may help gauge disease severity and guide the therapeutic approach in those patients.

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.

The absence of microbiota delays the inflammatory response to Cryptococcus gattii

The inflammatory response plays a crucial role in infectious diseases, and the intestinal microbiota is linked to maturation of the immune system. However, the association between microbiota and the response against fungal infections has not been elucidated. Our aim was to evaluate the influence of microbiota on Cryptococcus gattii infection. Germ-free (GF), conventional (CV), conventionalized (CVN-mice that received feces from conventional animals), and LPS-stimulated mice were infected with C. gattii. GF mice were more susceptible to infection, showing lower survival, higher fungal burden in the lungs and brain, increased behavioral changes, reduced levels of IFN-γ, IL-1β and IL-17, and lower NFκBp65 phosphorylation compared to CV mice. Low expression of inflammatory cytokines was associated with smaller yeast cells and polysaccharide capsules (the main virulence factor of C. gattii) in the lungs, and less tissue damage. Furthermore, macrophages from GF mice showed reduced ability to engulf, produce ROS, and kill C. gattii. Restoration of microbiota (CVN mice) or LPS administration made GF mice more responsive to infection, which was associated with increased survival and higher levels of inflammatory mediators. This study is the first to demonstrate the influence of microbiota in the host response against C. gattii.

A Retrospective Cohort Study of Lesion Distribution of HIV-1 Infection Patients With Cryptococcal Meningoencephalitis on MRI: Correlation With Immunity and Immune Reconstitution

The objective of this paper is to correlate the MRI distribution of cryptococcal meningoencephalitis in HIV-1 infection patients with CD4 T cell count and immune reconstitution effect.A large retrospective cohort study of HIV patients from multi-HIV centers in China was studied to demonstrate the MRI distribution of cryptococcal meningoencephalitis and its correlation with the different immune status.The consecutive clinical and neuroimaging data of 55 HIV-1-infected patients with cryptococcal meningoencephalitis collected at multi-HIV centers in China during the years of 2011 to 2014 was retrospectively analyzed. The enrolled patients were divided into 2 groups based on the distribution of lesions. One group of patients had their lesions at the central brain (group 1, n = 34) and the other group of patients had their lesions at the superficial brain (group 2, n = 21). We explored their MRI characterization of brain. In addition, we also compared their CD4 T cell counts and immune reconstitution effects between the 2 groups based on the imaging findings.No statistical difference was found in terms of age and gender between the 2 groups. The medians of CD4 T cell counts were 11.67 cells/mm (3.00-52.00 cells/mm) in group 1 and 42.00 cells/mm (10.00-252.00 cells/mm) in group 2. Statistical difference of CD4 T cell count was found between the 2 groups (P = 0.023). Thirteen patients in group 1 (13/34) and 12 patients in group 2 (12/21) received highly active antiretroviral treatment (HAART). Patients of group 2 received HAART therapy more frequently than patients of group 1 (P = 0.021).Central and superficial brain lesions detected by MR imaging in HIV-1-infected patients with cryptococcal meningoencephalitis are in correlation with the host immunity and HAART therapy.

Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era

Cryptococcus neoformans infection is the most common fungal infection of the central nervous system (CNS) in advanced human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients, but remains a relatively uncommon CNS infection in both the immunocompromised and immunocompetent patient population, rendering it a somewhat elusive and frequently overlooked diagnosis. The morbidity and mortality associated with CNS cryptococcal infection can be significantly reduced by early recognition of the imaging appearances by the radiologist in order to focus and expedite clinical management and treatment. The emergence and evolution of anti-retroviral therapy have also impacted significantly on the imaging appearances, morbidity, and mortality of this neuro-infection. The constellation of varied imaging appearances associated with cryptococcal CNS infection in the HIV and AIDS population in the era of highly active anti-retroviral therapy (HAART) will be presented in this review.

A paradoxical decline: intracranial lesions in two HIV-positive patients recovering from cryptococcal meningitis

Cryptococcal immune reconstitution inflammatory syndrome (C-IRIS) is an increasingly important manifestation among patients with HIV/AIDS, especially as the use of antiretroviral therapy (ART) is expanding worldwide. Cryptococcus and associated C-IRIS are common causes of meningitis. While intracranial lesions are common in HIV/AIDS, they are rarely due to cryptococcosis or C-IRIS. We describe two cases of paradoxical C-IRIS associated with the development of intracranial cryptococcomas in HIV/AIDS. Both patients had an initial episode of cryptococcal meningitis treated with antifungal therapy. At the time, they had initiated or modified ART with subsequent evidence of immune reconstitution. Two months later, they developed aseptic meningitis with intracranial lesions. After exhaustive work ups, both patients were diagnosed with paradoxical C-IRIS and biopsy confirmed intracranial cryptococcomas. We review the important clinical, diagnostic and therapeutic features of cryptococcomas associated with C-IRIS in HIV/AIDS.

LATERAL FLOW ASSAY FOR CRYPTOCOCCAL ANTIGEN: AN IMPORTANT ADVANCE TO IMPROVE THE CONTINUUM OF HIV CARE AND REDUCE CRYPTOCOCCAL MENINGITIS-RELATED MORTALITY

AIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is useful for the diagnosis of disease caused by Cryptococcus species. The CrAg LFA has better analytical sensitivity for C. gattii than CrAg-latex or EIA. Prevention of cryptococcal disease is new application of CrAg LFA via screening of blood for subclinical infection in asymptomatic HIV-infected persons with CD4 counts < 100 cells/mL who are not receiving effective antiretroviral therapy. CrAg screening of leftover plasma specimens after CD4 testing can identify persons with asymptomatic infection who urgently require pre-emptive fluconazole, who will otherwise progress to symptomatic infection and/or die.

Imaging of the brain in patients with human immunodeficiency virus infection

Neurologic disease in acquired immunodeficiency syndrome (AIDS) patients is related either to opportunistic pathogens or to direct central nervous system (CNS) invasion by the human immunodeficiency virus. Despite the increasing availability of antiretroviral therapy, opportunistic infections continue to afflict patients in the developing world and in other populations with limited access to appropriate treatment. Classic CNS infections in the setting of AIDS include toxoplasmosis, cryptococcosis, progressive multifocal leukoencephalopathy, and cytomegalovirus encephalitis. Additionally, AIDS patients are far more susceptible to acquiring CNS tuberculosis and neurosyphilis, both of which exhibit altered disease characteristics in the setting of immunosuppression. Neuroimaging is a crucial component of the diagnostic work-up of these conditions, and findings include, but are not limited to, intracranial mass lesions, white matter disease, meningoencephalitis, vascular complications, and hydrocephalus. Though various disease processes can produce imaging findings that overlap with one another, certain characteristic patterns may suggest a particular pathogen, and advanced imaging techniques and laboratory tests allow for definitive diagnosis. Knowledge of the imaging patterns seen in the setting of AIDS-related CNS disease is vital to the neuroradiologist, whose interpretation may guide decisions related to treatment and further work-up.