Usefulness of intraventricular infusion of antifungal drugs through Ommaya reservoirs for cryptococcal meningitis treatment

Unveiling Drimenol: A Phytochemical with Multifaceted Bioactivities

Drimenol, a phytochemical with a distinct odor is found in edible aromatic plants, such as Polygonum minus (known as kesum in Malaysia) and Drimys winteri. Recently, drimenol has received increasing attention owing to its diverse biological activities. This review offers the first extensive overview of drimenol, covering its sources, bioactivities, and derivatives. Notably, drimenol possesses a wide spectrum of biological activities, including antifungal, antibacterial, anti-insect, antiparasitic, cytotoxic, anticancer, and antioxidant effects. Moreover, some mechanisms of its activities, such as its antifungal effects against human mycoses and anticancer activities, have been investigated. However, there are still several crucial issues in the research on drimenol, such as the lack of experimental understanding of its pharmacokinetics, bioavailability, and toxicity. By synthesizing current research findings, this review aims to present a holistic understanding of drimenol, paving the way for future studies and its potential utilization in diverse fields.

Clinical treatment of cryptococcal meningitis: an evidence-based review on the emerging clinical data

Cryptococcal meningitis (CM) is a fatal fungal central nervous system (CNS) infection caused by Cryptococcus infecting the meninges and/or brain parenchyma, with fever, headache, neck stiffness, and visual disturbances as the primary clinical manifestations. Immunocompromised individuals with human immunodeficiency virus (HIV) infection or who have undergone organ transplantation, as well as immunocompetent people can both be susceptible to CM. Without treatment, patients with CM may have a mortality rate of up to 100% after hospital admission. Even after receiving therapy, CM patients may still suffer from problems such as difficulty to cure, poor prognosis, and high mortality. Therefore, timely and effective treatment is essential to improve the mortality and prognosis of CM patients. Currently, the clinical outcomes of CM are frequently unsatisfactory due to limited drug choices, severe adverse reactions, drug resistance, etc. Here, we review the research progress of CM treatment strategies and discuss the suitable options for managing CM, hoping to provide a reference for physicians to select the most appropriate treatment regimens for CM patients.

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.

Cryptococcal meningitis with atypical paradoxical inflammatory reactions after antifungal treatment in acquired immune deficiency syndrome: A case report

Cryptococcal meningitis (CM) is a life-threatening disease that primarily affects patients with human immunodeficiency virus (HIV). Antifungal therapy with antiretroviral treatment (ART) usually leads to the clinical remission of CM; however, in some cases, these treatments exacerbate intracranial inflammation because of paradoxical inflammatory reaction or immune reconstitution inflammatory syndrome (IRIS). Here we report two CM cases that presented atypical clinical courses attributed to paradoxical inflammatory reactions. The first case was a 43-year-old man with headache and vertigo diagnosed with CM and HIV. The patient's CM not only was refractory to the antifungal combination therapy of liposomal amphotericin B (L-AMB) and fluconazole (FLCZ) but suddenly worsened because of a paradoxical inflammatory reaction after 18 days of treatment. He passed away from brain herniation on day 23. The second case was a 43-year-old man diagnosed with CM and HIV. After receiving antifungal therapy and ART, the patient's status was stable for more than 3 years with undetectable HIV-RNA. He suddenly presented with brain inflammation and was diagnosed with IRIS due to CM (CM-IRIS). His brain lesions were migratory and refractory to various antifungal therapies such as L-AMB, FLCZ, flucytosine, and intrathecal amphotericin B. Although the cryptococcal antigen in the patient's cerebrospinal fluid gradually diminished after continuous antifungal therapies, his cognitive function declined, and right hemiparesis persisted. These two cases of CM presented atypical clinical courses, presumably because of paradoxical inflammatory reactions. It should be noted that the onset of CM-IRIS may not necessarily depend on the timing of ART initiation.

Sustained intrathecal delivery of amphotericin B using an injectable and biodegradable thermogel

Cryptococcal meningitis is a fungal infectious disease with a poor prognosis and high mortality. Amphotericin B (AMB) is the first choice for the treatment of cryptococcal meninges. The blood-brain barrier (BBB) is the major barrier for the effective delivery of drugs to the brain. In this study, AMB was incorporated in a thermosensitive gel for intrathecal injection. We first synthesized AMB-loaded thermogel, investigated its in vitro cumulative release, and in vivo neurotoxicity, and therapeutic effect. The thermosensitive gel was comprised of 25 wt% poly (lactic acid-co-glycolic acid)-poly (ethylene glycol)-poly (lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock polymer aqueous solution. The AMB loaded in the thermosensitive gel (AMB in gel) had low viscosity at low temperature and resulted in the formation of a non-flowing gel at 37 °C (physiological temperature). AMB loading in gel sustained its release for 36 days and the in vitro cumulative release rate was satisfactory. Compared with the AMB solution, intrathecal administration of AMB in gel could reduce the neurovirulence of AMB and get a better treatment effect. The findings of the current study show that the injectable PLGA–PEG–PLGA thermogel is a biocompatible carrier for the delivery of drugs into the intrathecal.

Use of Intraventricular Medications in Critically Ill Patients: A Systematic Review

New evidence and increased use of intracranial devices have increased the frequency of intraventricular (IVT) medication administration in the neurologic intensive care unit. Significant benefits and risks are associated with administration of medications directly into the central nervous system. This review summarizes important literature, along with key information for clinicians regarding the administration, dosing, monitoring, and adverse effects related to IVT medication usage. Multiple medications have supporting literature for their use in critically ill patients including amphotericin B, aminoglycosides, colistimethate, daptomycin, quinupristin/dalfopristin, vancomycin, alteplase, and nicardipine. Sterile preparation and delivery, along with different types of devices that support medication administration, are also reviewed. One randomized, placebo-controlled trial of alteplase demonstrated decreased mortality but no change in good functional outcome. Other reports of IVT medication use are mainly limited to case reports and retrospective case series. There is a need for increased research on the topic; however, several practical barriers decrease the likelihood of a large, placebo-controlled, prospective study for most indications. Providers should consider implementing protocols to maximize safety of IVT medication delivery to ensure optimal patient outcomes.

Clinical characteristic of 15 cases of cryptococcal meningitis treated with Ommaya reservoir

Cryptococcal meningitis is a severe subacute fungal meningoencephalitis. Intracerebroventricular (ICV) injection of antifungal medication and aspiration of cerebrospinal fluid (CSF) through Ommaya reservoir were reported to be useful cryptococcal meningitis treatment method. We want to evaluate the role of Ommaya reservoir in the treatment of refractory cryptococcal meningitis. We retrospectively analyzed clinical records and data of 15 refractory cryptococcal meningitis patients who were treated with Ommaya reservoir in Sir Run Run Shaw hospital from June 2013 to June 2017. Fifteen patients who underwent Ommaya reservoir implanted surgery include eight women and seven men. Headache and fever were the common clinical symptoms. Underlying diseases mainly include diabetes mellitus and hypertension. Three patients occurred renal dysfunction and four patients experienced liver damage. Thirteen patients recovered completely, whereas two patients died. Implant Ommaya reservoir which can serial extract CSF and ICV injection of Amphotericin B is a valuable approach in the treatment of Cryptococcal meningitis, especially for patients with refractory intracranial hypertension.

Intraventricular administration of antibiotics by ommaya reservoir for patients with multidrug-resistant Acinetobacter baumannii central nervous system infection

AIM

To investigate whether the Ommaya reservoir can be used to treat multiple drug-resistant Acinetobacter baumannii (MDR-AB) infections in the central nervous system (CNS).

METHODS

Retrospectively analyzed the clinical records and data of 15 MDR-AB CNS infection patients who were treated in our neuro-ICU. Four patients with MDR-AB CNS infection were involved in this study.

RESULTS

We report the successful treatment of MDR-AB CNS infection by Ommaya reservoirs and intraventricular antibiotic (IVA) administration. Ommaya reservoirs allow serial CSF sampling and IVA injection. Furthermore, debridement can be performed during the operation to insert the Ommaya.

CONCLUSION

Ommaya reservoirs can be used as an effective treatment approach of MDR-AB or other multidrug-resistant Gram-negative bacteria CNS infections.

Intrathecal Antibacterial and Antifungal Therapies

Intrathecal administration of anti-infectives is indicated in central nervous system infections by multiresistant pathogens when drugs that can reach adequate cerebrospinal fluid (CSF) concentrations by systemic therapy are not available. Antibiotics that readily pass the blood-brain and blood-CSF barriers and/or that have low toxicity allowing an increase in the daily dosage should not be used for intrathecal therapy. Intrathecal therapy is accompanied by systemic treatment. Antibacterials indispensable for intrathecal therapy include aminoglycosides, colistin, daptomycin, tigecycline, and vancomycin. Limited experience suggests the utility of the antifungals amphotericin B and caspofungin. Intraventricular administration ensures distribution throughout the CSF compartment, whereas intralumbar dosing often fails to attain adequate antibiotic concentrations in the ventricles. The individual dose is determined by the estimated size of the CSF space and by the estimated clearance from CSF. For moderately lipophilic anti-infectives with a molecular weight above approximately 1,000 g/mol, as well as for hydrophilic drugs with a molecular weight above approximately 400 g/mol, one daily dose is normally adequate. The ventricular drain should be clamped for 15 to 120 min to facilitate the distribution of the anti-infective in the CSF space. Therapeutic drug monitoring of the trough levels is necessary only in cases of therapeutic failure.

Antifungal Drugs: Special Problems Treating Central Nervous System Infections

Treating fungal infections in the central nervous system (CNS) remains a challenge despite the availability of new antifungal agents. Therapy is limited by poor understanding of the kinetic properties of antifungal drugs in the CNS compounded by lack of data for many agents. In some cases, clinical response rates do not correspond to data on drug concentrations in the cerebral spinal fluid and/or brain parenchyma. In order to better characterize the use of antifungal agents in treating CNS infections, a review of the essential principles of neuroPK are reviewed. Specific data regarding antifungal drug concentrations in the cerebral spinal fluid and brain tissue are described from human data where available. Alternative dosing regimens and the role of antifungal drug concentration monitoring in treating fungal infections in the CNS are also discussed. Having a better understanding of these key concepts will help guide clinicians in determining the best treatment courses for patients with these devastating infections.

Fungal infections in pediatric neurosurgery

INTRODUCTION

Invasive mycosis of the central nervous system represent a diverse group of diseases that have gradually emerged as not only opportunistic infections in patients with immune susceptibility due to congenital and acquired deficiency, immunomodulation, solid organ and stem cell transplantation, hematological malignancies, and chronic steroid use but also in selected risk populations such as low weight preterm infants, patients with shunted hydrocephalus and external ventricular drainages, skull base surgery, and head injury.

OBJECTIVES

The purpose of this review is to familiarize the pediatric neurosurgeon with the most common mycosis and their clinical scenarios which can be encountered in the clinical practice, with special emphasis on clinical, radiological, and laboratory diagnosis beyond classical microorganism cultures as well as options in medical and surgical treatment given the high incidence of morbidity and mortality associated with these challenging entities.

METHODS

We conducted an online database review (Ovid, PubMed) gathering relevant English language literature published in the last 20 years with special emphasis on recent breakthroughs in the diagnosis and treatment of invasive mycosis of the CNS as well as reported cases within the pediatric neurosurgical literature and their surgical management.

RESULTS

Fungal agents capable of invading the CNS can behave as aggressive entities with rapid progression manifesting as overwhelming meningoencephalitis with vascular compromise or can lead to space-occupying lesions with abscess formation which require prompt diagnosis by either laboratory identification of the components of these biological agents and their host response or by obtaining tissue specimens for microbiological identification which may not be straightforward due to prolonged culture time.

CONCLUSION

Following a high degree of suspicion with prompt initiation of antifungal agents and reversal of potential immunosuppressant therapies along with neurosurgical evacuation of intracranial collections or removal of infected hardware (CSF shunts) can lead to more optimistic outcomes of these complex clinical scenarios.

Plant bioactive molecules bearing glycosides as lead compounds for the treatment of fungal infection: A review

Despite therapeutic advancement in the treatment of fungal infections, morbidity and mortality caused by these infections are still very high. There are approximately 300 fungal species that are infectious and can cause a variety of diseases. At present, several synthetic antifungal drugs are in clinical practice, many of them, however, are vulnerable to multidrug-resistant strains of microbes, and thus compromising the overall treatment outcomes. Glycosides are naturally occurring plant secondary metabolites with important therapeutic potential and clinical utility. The aim of this review was to focus on the antifungal effects of glycosides in preclinical studies with possible mechanism(s) wherein described. Published research show significant susceptibility of different fungi towards phytoglycosides, mediated through multiple mechanisms. Further detailed studies are needed to explain the clinical applications and limitations of these glycosides.

Ommaya reservoir in the treatment of cryptococcal meningitis

The objective is to study the role of Ommaya reservoir in the treatment of cryptococcal meningitis. The clinical data of 42 patients with cryptococcal meningitis were retrospectively studied. The Ommaya group included 20 patients, who were treated with Amphotericin B (Am B) and Ommaya reservoir implantation. The non-Ommaya group contained 22 patients, who were just treated with Amphotericin B (Am B). In the Ommaya group (surgical group), all 20 patients with Ommaya reservoir were fully recovered, and their average hospital stay period and average treatment period with Amphotericin B were 105.3 ± 18.3 and 75.0 ± 18.1 days, respectively. In the non-Ommaya group (control group), 16 patients were fully recovered and the average hospital stay period and average treatment period with Amphotericin B of these 22 patients were 139.6 ± 29.5 and 150.0 ± 32.2 days, respectively. In the surgical group, average period of cryptococcus disappearance was 20 ± 8 days, while in the control group, that was 35 ± 10 days. The clinical efficacy was better in surgical group than control group (P < 0.05). Ommaya reservoir implantation is a valuable approach in the treatment of cryptococcal meningitis and can improve the cure rate, decrease mortality, and shorten the period of treatment.