Cryptococcal meningoencephalitis in HIV/AIDS: when to start antiretroviral therapy?

Elevated Intracranial Pressure in Cryptococcal Meningoencephalitis: Examining Old, New, and Promising Drug Therapies

Despite the availability of effective antifungal therapy, cryptococcal meningoencephalitis (CM) remains associated with elevated mortality. The spectrum of symptoms associated with the central nervous system (CNS) cryptococcosis is directly caused by the high fungal burden in the subarachnoid space and the peri-endothelial space of the CNS vasculature, which results in intracranial hypertension (ICH). Management of intracranial pressure (ICP) through aggressive drainage of cerebrospinal fluid by lumbar puncture is associated with increased survival. Unfortunately, these procedures are invasive and require specialized skills and supplies that are not readily available in resource-limited settings that carry the highest burden of CM. The institution of pharmacologic therapies to reduce the production or increase the resorption of cerebrospinal fluid would likely improve clinical outcomes associated with ICH in patients with CM. Here, we discuss the potential role of multiple pharmacologic drug classes such as diuretics, corticosteroids, and antiepileptic agents used to decrease ICP in various neurological conditions as potential future therapies for CM.

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.

Multiple intracranial cryptococcomas in an immunocompetent patient with pulmonary involvement

Opportunistic infections affecting central nervous system (CNS) have high prevalence in developing countries and cryptococcosis is one of them. It is associated with myriad of signs symptoms and clinical behavior. Though commonly associated with AIDS/HIV infection, it has been reported to be pathogenic in immunocompetent patients. Leptomeningitis is most common presentation in CNS, but unusual tumor like mass lesions have been reported. Lungs are primary site of infection, but it can affect different organs with varied clinical presentations. Therefore, correct diagnosis and proper management is essential in such cases excluding the differentials as fatality rate can be quite high. We report such an unusual case of multiple cryptococcal mass lesions in brain in a healthy immune competent individual with bilateral pulmonary involvement.

CNS infections in HIV

PURPOSE OF REVIEW

Central nervous system (CNS) infections associated with HIV remain significant contributors to morbidity and mortality, particularly among people living with HIV (PLWH) in resource-limited settings worldwide. In this review, we discuss several recent important scientific discoveries in the prevention, diagnosis, and management around two of the major causes of CNS opportunistic infections-tuberculous meningitis (TBM) and cryptococcal meningitis including immune reconstitution syndrome (IRIS) associated with cryptococcal meningitis. We also discuss the CNS as a possible viral reservoir, highlighting Cerebrospinal fluid viral escape.

RECENT FINDINGS

CNS infections in HIV-positive people in sub-Saharan Africa contribute to 15-25% of AIDS-related deaths. Morbidity and mortality in those is associated with delays in HIV diagnosis, lack of availability for antimicrobial treatment, and risk of CNS IRIS. The CNS may serve as a reservoir for replication, though it is unclear whether this can impact peripheral immunosuppression.

SUMMARY

Significant diagnostic and treatment advances for TBM and cryptococcal meningitis have yet to impact overall morbidity and mortality according to recent data. Lack of early diagnosis and treatment initiation, and also maintenance on combined antiretroviral treatment are the main drivers of the ongoing burden of CNS opportunistic infections. The CNS as a viral reservoir has major potential implications for HIV eradication strategies, and also control of CNS opportunistic infections.

Dexamethasone and Methylprednisolone Promote Cell Proliferation, Capsule Enlargement, and in vivo Dissemination of C. neoformans

Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, who often have some inflammatory condition and, therefore, end up using glucocorticoids, such as dexamethasone and methylprednisolone. Although the effects of this class of molecules during cryptococcosis have been investigated, their consequences for the biology of C. neoformans is less explored. Here, we studied the effects of dexamethasone and methylprednisolone on the metabolism and on the induction of virulence factors in C. neoformans. Our results showed that both glucocorticoids increased fungal cell proliferation and surface electronegativity but reduced capsule and secreted polysaccharide sizes, as well as capsule compaction, by decreasing the density of polysaccharide fibers. We also tested whether glucocorticoids could affect the fungal virulence in Galleria mellonella and mice. Although the survival rate of Galleria larvae increased, those from mice showed a tendency to decrease, with infected animals dying earlier after glucocorticoid treatments. The pathogenesis of spread of cryptococcosis and the interleukin secretion pattern were also assessed for lungs and brains of infected mice. While increases in the spread of the fungus to lungs were observed after treatment with glucocorticoids, a significant difference in brain was observed only for methylprednisolone, although a trend toward increasing was also observed for dexamethasone. Moreover, increases in both pulmonary and cerebral IL-10 production, reduction of IL-6 production but no changes in IL-4, IL-17, and INF-γ were also observed after glucocorticoid treatments. Finally, histopathological analysis confirmed the increase in number of fungal cells in lung and brain tissues of mice previously subjected to dexamethasone or methylprednisolone treatments. Together, our results provide compelling evidence for the effects of dexamethasone and methylprednisolone on the biology of C. neoformans and may have important implications for future clinical treatments, calling attention to the risks of using these glucocorticoids against cryptococcosis or in immunocompromised individuals.

Iron Assimilation during Emerging Infections Caused by Opportunistic Fungi with emphasis on Mucorales and the Development of Antifungal Resistance

Iron is a key transition metal required by most microorganisms and is prominently utilised in the transfer of electrons during metabolic reactions. The acquisition of iron is essential and becomes a crucial pathogenic event for opportunistic fungi. Iron is not readily available in the natural environment as it exists in its insoluble ferric form, i.e., in oxides and hydroxides. During infection, the host iron is bound to proteins such as transferrin, ferritin, and haemoglobin. As such, access to iron is one of the major hurdles that fungal pathogens must overcome in an immunocompromised host. Thus, these opportunistic fungi utilise three major iron acquisition systems to overcome this limiting factor for growth and proliferation. To date, numerous iron acquisition pathways have been fully characterised, with key components of these systems having major roles in virulence. Most recently, proteins involved in these pathways have been linked to the development of antifungal resistance. Here, we provide a detailed review of our current knowledge of iron acquisition in opportunistic fungi, and the role iron may have on the development of resistance to antifungals with emphasis on species of the fungal basal lineage order Mucorales, the causative agents of mucormycosis.

AIDS-associated Talaromyces marneffei central nervous system infection in patients of southwestern China

Background

The clinical and laboratory characteristics of AIDS-associated Talaromyces marneffei infection, a rare but a fatal mycosis disease of the central nervous system, remain unclear.

Case presentation

Herein, we conducted a retrospective study of ten AIDS patients with cerebrospinal fluid culture-confirmed central nervous system infection caused by Talaromyces marneffei. All 10 patients were promptly treated with antifungal treatment for a prolonged duration and early antiviral therapy (ART). Among them, seven patients were farmers. Nine patients were discharged after full recovery, while one patient died during hospitalization, resulting in a mortality rate of 10%. All patients initially presented symptoms and signs of an increase in intracranial pressure, mainly manifesting as headache, dizziness, vomiting, fever, decreased muscle strength, diplopia or even altered consciousness with seizures in severe patients. Nine patients (90%) showed lateral ventricle dilatation or intracranial infectious lesions on brain CT. Cerebrospinal fluid findings included elevated intracranial pressure, increased leukocyte count, low glucose, low chloride and high cerebrospinal fluid protein. The median CD4⁺ T count of patients was 104 cells/μL (IQR, 36–224 cells/μL) at the onset of the disease. The CD4⁺ T cell counts of three patients who eventually died were significantly lower (W = 6.00, p = 0.020) than those of the patients who survived.

Conclusions

The common clinical symptoms of T. marneffei central nervous system infection are associated with high intracranial pressure and intracranial infectious lesions. Earlier recognition and diagnosis and a prolonged course of amphotericin B treatment followed by itraconazole combined with early ART might reduce the mortality rate.

Antifungal activity of eugenol on Cryptococcus neoformans biological activity and Cxt1p gene expression

Background and Purpose

The present study was targeted toward investigating the effects of eugenol on Cryptococcus neoformans biological activity and Cxt1p gene expression.

Materials and Methods

For the purpose of the study, the growth, urease, synergism activity, and disk diffusion of C. neoformans were assessed in eugenol-treated culture. The minimum inhibitory concentration (MIC) was determined by the Clinical and Laboratory Standards Institute M27-A3 method at a concentration range of 0.062-2 mg/mL. Subsequently, the expression of Cxt1p genes was studied at the MIC₅₀ concentration of eugenol using real-time polymerase chain reaction.

Results

The obtained results showed that eugenol at the concentrations of 125 and 500 µg/mL resulted in 50% and 100% growth inhibition in C. neoformans, respectively. In terms of urease activity, the results showed that the addition of MIC₅₀ of eugenol and fluconazole to urea medium reduced urease activity in C. neoformans. In the culture treated with eugenol, the inhibition zone of antifungal drugs, namely amphotericin B, itraconazole, and fluconazole, was increased to 36±0.002, 22±0.001, and 12±0.002 mm, respectively. The expression levels of Cxt1p in the eugenol-treated, fluconazole-treated, and non-treated samples were estimated at 46%, 58%, and 100%, respectively.

Conclusion

The findings of the current study revealed that eugenol could cause C. neoformans growth inhibition and reduce Cxt1p expression in this species. As the results indicated, the susceptibility of C. neoformans to fluconazole was increased when combined with eugenol.

Cryptococcal meningitis after ART: Need for proper baseline evaluation in the era of 'Test & Treat'

Cryptococcal meningitis (CM) contributes significantly to high early mortality in the setting of advanced HIV. In resource poor settings, the current HIV disease management approach is focused on commencing antiretroviral therapy (ART) on the same day of HIV diagnosis (‘Test and Treat’). The HIV program in Nigeria does not currently provide CrAg screening for patients with newly diagnosed and advanced HIV disease. We report a case of severe cryptococcal meningitis presenting following the commencement of ART. There is clear benefit in the early commencement of ART among HIV infected patients and to prevent patients lost to follow-up as aimed with the ‘Test & Treat’ approach. However, this approach needs to be balanced against the risk of IRIS and its associated morbidity and mortality when those patients are not being properly evaluated for opportunistic infections being present without overt symptoms.

Occam's razor need not apply: Advanced HIV infection presenting with five simultaneous opportunistic infections and central nervous system lymphoma

Patients with Human Immunodeficiency Virus (HIV) infection and Acquired Immunodeficiency Syndrome (AIDS) are at risk for multiple infectious and oncologic complications. In such cases, Occam's razor need not apply: multiple infections and malignancies are often present concurrently upon presentation to care. A patient off anti-retroviral therapy (ART) for several years developed advanced HIV infection (CD4 count 19 cells/uL) and presented with five simultaneous opportunistic infections including Pneumocystis jiroveci pneumonia (PJP), cytomegalovirus (CMV) retinitis, Mycobacterium avium complex (MAC) bloodstream infection, chronic hepatitis B virus (HBV), and Epstein-Barr virus (EBV) viremia. Simultaneously, he was found to have primary central nervous system (CNS) B-cell lymphoma. Treatment decisions for such patients are often complex, as ideal therapy for one disease may directly counter or interact with therapy for another. For instance, methotrexate for primary CNS lymphoma and trimethoprim/sulfamethoxazole for PJP is a strictly contraindicated medication combination. It is important to understand not just the management of any single opportunistic disease in patients with advanced HIV, but how to balance management for patients with a variety of concurrent processes. In an era when HIV care is becoming increasingly simplified, patients presenting with advanced infection highlight the lack of data on how best to manage patients with multiple concurrent disease processes. Significant further research is needed to clarify ideal comparative therapy.

Opportunistic Invasive Mycoses in AIDS: Cryptococcosis, Histoplasmosis, Coccidiodomycosis, and Talaromycosis

PURPOSE OF REVIEW

The goal of this review is to provide an update on the epidemiology, diagnosis, and treatment of opportunistic fungal infections in patients with human immunodeficiency virus (HIV) infection including Cryptococcus spp., Histoplasma spp., Coccidioides spp., and Talaromyces marneffei, formerly Penicillium marneffei.

RECENT FINDINGS

In many settings, despite increasing roll out of antiretroviral therapy (ART), opportunistic invasive mycoses produce a substantial burden of disease. The prevalence of specific fungal pathogens depends on their endemicity. Viral suppression achieved by greater access to ART and increased the availability of point-of-care testing with rapid diagnostic tests (RDTs) aid to curtail the associated fungi morbidity. RDTs allow earlier screening to preemptively initiate treatment of opportunistic fungal pathogens. Identifying asymptomatic cryptococcal infection before starting ART is crucial in reducing the risk of the immune reconstitution inflammatory syndrome (IRIS). There is an urgent need to decrease the burden of opportunistic invasive fungal infections in individuals with HIV/AIDS through different interventions: (a) continue to expand the deployment of ART to the most affected populations to achieve viral suppression; (b) ensure early diagnosis of fungal pathogen with point-of-care testing;