Cryptococcal choroid plexitis: rare imaging findings of central nervous system cryptococcal infection in an immunocompetent individual

Infectious Diseases of the Brain and Spine: Fungal Diseases

Advances in treatments of autoimmune diseases, acquired immunodeficiency syndrome, organ transplantation, and the use of long-term devices have increased the rates of atypical infections due to prolonged immune suppression. There is a significant overlap in imaging findings of various fungal infections affecting the central nervous system (CNS), often mimicking those seen in neoplastic and noninfectious inflammatory conditions. Nonetheless, there are imaging characteristics that can aid in distinguishing certain atypical infections. Hence, familiarity with a wide range of infectious agents is an important part of diagnostic neuroradiology. In this article, an in-depth review of fungal diseases of the CNS is provided.

Entrapment Syndrome in a Kidney Transplant Recipient with Cryptococcal Meningitis

Cryptococcus neoformans primarily affects immunocompromised individuals and the central nervous system (CNS) is the most common site of dissemination. Entrapped temporal horn syndrome (ETH) remains a rare CNS manifestation and has not previously been described in solid organ transplant recipients. Here, we present a case of ETH in a 55-year-old woman with history of renal transplant and prior treated Cryptococcal meningitis.

Cryptococcus neoformans Infection in the Central Nervous System: The Battle between Host and Pathogen

Cryptococcus neoformans (C. neoformans) is a pathogenic fungus with a global distribution. Humans become infected by inhaling the fungus from the environment, and the fungus initially colonizes the lungs. If the immune system fails to contain C. neoformans in the lungs, the fungus can disseminate to the blood and invade the central nervous system, resulting in fatal meningoencephalitis particularly in immunocompromised individuals including HIV/AIDS patients. Following brain invasion, C. neoformans will encounter host defenses involving resident as well as recruited immune cells in the brain. To overcome host defenses, C. neoformans possesses multiple virulence factors capable of modulating immune responses. The outcome of the interactions between the host and C. neoformans will determine the disease progression. In this review, we describe the current understanding of how C. neoformans migrates to the brain across the blood–brain barrier, and how the host immune system responds to the invading organism in the brain. We will also discuss the virulence factors that C. neoformans uses to modulate host immune responses.

Obstructive Hydrocephalus Secondary to Cryptococcal Meningitis in an Immunocompetent Adult

Cryptococcal infections of the central nervous system (CNS) are common opportunistic infections in immunocompromised hosts. They can occur in immunocompetent hosts, and this has been documented in isolated case reports. Rapid neurological deterioration can be seen, particularly with hydrocephalus, and diagnosis can be difficult without a high index of suspicion. Treatment arms include prolonged antifungal therapy and cerebrospinal fluid (CSF) diversion procedures.

We present a case of a middle-aged immunocompetent male, who presented with an acute confusional state and papilledema. An urgent computed tomography (CT) and magnetic resonance imaging (MRI) revealed obstructive hydrocephalus, and an external ventricular drain was placed. CSF samples were collected, and analysis revealed cryptococcal infection. He was treated with antifungal therapy but failed external ventricular drain challenging. A ventriculoperitoneal shunt was placed after negative CSF studies were obtained.

While uncommon, cryptococcal meningitis in immunocompetent hosts can present with obstructive hydrocephalus. It can result in rapid neurological decline and death. Emergent CSF diversion and antifungal therapy are the primary treatment modalities. CSF diversion may be permanently required in some cases.

[A patient with recurrent multiloculated hydrocephalus after Cryptococcal ventriculitis]

We report here a rare case of adult-onset multiloculated hydrocephalus (MLH) after Cryptococcal meningitis. A 63-year-old man had Cryptococcal ventriculitis in 2011, and he recovered with treatment of antimycotic drugs. However, he was admitted again because of disorientation and amnesia, and brain MRI showed dilation of the inferior horn of the left lateral ventricle. He underwent a ventriculoperitoneal shunt (VPS) for noncommunicating hydrocephalus in 2019, and the disorientation and amnesia improved. One year after the VPS, he was admitted because of urinary dysfunction and gait disturbance. Brain MRI showed dilation of the bilateral anterior horns of the lateral ventricles. He underwent an additional VPS into the space in 2020, and urinary dysfunction and gait disturbance improved. This case was supposed that the symptom in agreement with the dilated ventricle by MLH was shown.

Cryptococcal Choroid Plexitis and Non-Communicating Hydrocephalus

Cryptococcus neoformans is a fungus that commonly invades the central nervous system. While the choroid plexus, the site of the blood-cerebrospinal fluid barrier, serves as one potential entry point for the pathogen, disease involvement of the choroid plexus itself remains a very rare manifestation of Cryptococcus infection. In cases in which choroid plexus involvement blocks cerebrospinal fluid flow, obstructive hydrocephalus may occur. Here we report the case of a 63-year-old woman who presented with choroid plexitis causing obstructive hydrocephalus at the foramen of Monro. Endoscopic biopsy confirmed Cryptococcus neoformans, and the patient was successfully treated with amphotericin, flucytosine, and fluconazole. With proper recognition and treatment of this pathology, patients can fully recover from this condition.

Choroid plexus and the blood-cerebrospinal fluid barrier in disease

The choroid plexus (CP) forming the blood-cerebrospinal fluid (B-CSF) barrier is among the least studied structures of the central nervous system (CNS) despite its clinical importance. The CP is an epithelio-endothelial convolute comprising a highly vascularized stroma with fenestrated capillaries and a continuous lining of epithelial cells joined by apical tight junctions (TJs) that are crucial in forming the B-CSF barrier. Integrity of the CP is critical for maintaining brain homeostasis and B-CSF barrier permeability. Recent experimental and clinical research has uncovered the significance of the CP in the pathophysiology of various diseases affecting the CNS. The CP is involved in penetration of various pathogens into the CNS, as well as the development of neurodegenerative (e.g., Alzheimer´s disease) and autoimmune diseases (e.g., multiple sclerosis). Moreover, the CP was shown to be important for restoring brain homeostasis following stroke and trauma. In addition, new diagnostic methods and treatment of CP papilloma and carcinoma have recently been developed. This review describes and summarizes the current state of knowledge with regard to the roles of the CP and B-CSF barrier in the pathophysiology of various types of CNS diseases and sets up the foundation for further avenues of research.

Cerebellar Cryptococcoma in an Immunocompetent Adult: A Rare Occurrence Report of a Case and Review of Literature

This study reports a rare case of cryptococcoma of the brain and review the related literature. An intracranial lesion, in a healthy, middle-aged adult who underwent surgery with a preoperative diagnosis of neoplastic/metastatic lesion, which turned out to be cryptococcoma, is being reported. Histopathological examination revealed that this immunocompetent patient had cryptococcoma of the cerebellum. He responded to antifungal chemotherapy (amphotericin B initially for 2 weeks and later oral fluconazole for 10 weeks) very well. Occurrence of cryptococcomas in immunocompetent patients is rare and responds to antifungal chemotherapy very well. Only six cases (including this) have been reported in literature till now.

Magnetic resonance imaging findings in central nervous system cryptococcosis: comparison between immunocompetent and immunocompromised patients

Objective

To assess the magnetic resonance imaging (MRI) patterns associated with central nervous system infection with Cryptococcus sp. in relation to patient immune status.

Materials and Methods

This was a retrospective study of MRI data for 19 patients with neurocryptococcosis who underwent the examination between January 2000 and March 2014. The MRI characteristics examined included lesion topography, aspects of diffusion, T1-weighted images, T2-weighted images, and contrast enhancement patterns.

Results

In all cases, cryptococcal infection was confirmed by cerebrospinal fluid analysis. Of the 19 patients, 10 were immunocompromised and 9 were immunocompetent. Abnormal imaging patterns occurred alone or in conjunction with other manifestations. The imaging patterns found in immunocompromised patients included the following: leptomeningeal enhancement, in 6; pachymeningeal enhancement, in 3 (due to intracranial hypotension in 2); perivascular space involvement, in 4; granulomas, in 2; hydrocephalus, in 2; miliary nodules, in 1; and plexitis, in 1. In immunocompetent patients, the following imaging patterns were observed: leptomeningeal enhancement, in 5; perivascular space involvement, in 3; granulomas, in 3; cryptococcoma, in 1; ventriculitis, in 1; and hydrocephalus, in 1. In 2 immunocompetent patients, diffusion-weighted imaging showed diffusion restriction in cerebral cryptococcal granuloma.

Conclusion

In both groups, the most common imaging finding was leptomeningeal enhancement, followed by dilatation of perivascular spaces with the presence of mucoid material. Rare presentations, such as miliary nodules, plexitis, ventriculitis, and pachymeningeal enhancement, were also observed. None of the imaging patterns common to immunocompetent and immunocompromised patients differed significantly in frequency between them.

The diverse cellular responses of the choroid plexus during infection of the central nervous system

The choroid plexus (CP) is responsible for the production of a large amount of the cerebrospinal fluid (CSF). As a highly vascularized structure, the CP also presents a significant frontier between the blood and the central nervous system (CNS). To seal this border, the epithelium of the CP forms the blood-CSF barrier, one of the most important barriers separating the CNS from the blood. During the course of infectious disease, cells of the CP can experience interactions with intruding pathogens, especially when the CP is used as gateway for entry into the CNS. In return, the CP answers to these encounters with diverse measures. Here, we will review the distinct responses of the CP during infection of the CNS, which include engaging of signal transduction pathways, the regulation of gene expression in the host cells, inflammatory cell response, alterations of the barrier, and, under certain circumstances, cell death. Many of these actions may contribute to stage an immunological response against the pathogen and subsequently help in the clearance of the infection.

Innate immune evasion strategies against Cryptococcal meningitis caused by Cryptococcus neoformans

As an infectious fungus that affects the respiratory tract, Cryptococcus neoformans (C. neoformans) commonly causes asymptomatic pulmonary infection. C. neoformans may target the brain instead of the lungs and cross the blood-brain barrier (BBB) in the early phase of infection; however, this is dependent on successful evasion of the host innate immune system. During the initial stage of fungal infection, a complex network of innate immune factors are activated. C. neoformans utilizes a number of strategies to overcome the anti-fungal mechanisms of the host innate immune system and cross the BBB. In the present review, the defensive mechanisms of C. neoformans against the innate immune system and its ability to cross the BBB were discussed, with an emphasis on recent insights into the activities of anti-phagocytotic and anti-oxidative factors in C. neoformans.

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.

Cerebral cryptococcoma mimicking glioblastoma

Cryptococcus neoformans and C. gattii cause invasive fungal disease, with meningitis being the most common manifestation of central nervous system (CNS) disease. Encapsulated cryptococcomas occur rarely, predominantly in immunocompetent hosts, usually related to C. gattii Our patient was an immunocompetent man who presented with headache and a large cystic CNS lesion thought to be glioblastoma. Biopsy of a concomitant lung lesion confirmed cryptococcoma and empiric antifungal therapy was started for presumed CNS cryptococcoma. Antifungal therapy failed to shrink the CNS lesion, and surgical excision confirmed C. gattii CNS cryptococcoma. Following surgery he had complete resolution of symptoms. This case highlights that cryptococcoma cannot be distinguished from tumour on clinical or imaging findings. A combined medical and surgical approach is optimal for the management of large or surgically accessible cryptococcomas, as antifungal therapy alone is unlikely to penetrate large lesions sufficiently to lead to a cure.

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.

Refractory Cryptococcus neoformans Meningoencephalitis in an Immunocompetent Patient: Paradoxical Antifungal Therapy-Induced Clinical Deterioration Related to an Immune Response to Cryptococcal Organisms

We present a case of refractory Cryptococcus neoformans meningoencephalitis in an immunocompetent woman. Her clinical symptoms did not improve with 6 months of antifungal therapy, and MRI abnormalities, indicating severe meningeal and cerebral inflammation, persisted despite a decreasing cryptococcal antigen titer. The patient continued to deteriorate despite antifungal therapy, and her condition clearly improved following treatment with adjunctive corticosteroid. We postulate that the paradoxical antifungal therapy-related clinical deterioration was due to an immune response to cryptococcal organisms, which responded to corticosteroids. These observations provide rationale for a further evaluation of corticosteroids in the management of select cases of C. neoformans central nervous system infection.

Acutely Trapped Ventricle: Clinical Significance and Benefit from Surgical Decompression

BACKGROUND

Focal ventricular obstruction--trapped ventricle--results in cerebrospinal fluid accumulation, mass effect and possible clinical deterioration. There are no systematic studies on the benefit of surgical decompression in adults.

METHODS

We reviewed patients admitted with acutely trapped ventricle on brain imaging to assess their prognosis and the effect of surgical intervention on 30-day mortality.

RESULTS

Of the 392 patients with trapped ventricle, the most common causes were brain tumor (45%), intracerebral hemorrhage (ICH) (20%), and subdural hematoma (SDH) (14%). Lateral ventricle trapping accounted for 97% of cases. Two hundred and twenty-one patients (56%) received a surgical intervention for trapped ventricle or its causes; 126 (83%) were treated with craniotomy, 26 (17%) with craniectomy, 30 (14%) with external ventricular drain (EVD) alone, 23 (10%) with ventriculoperitoneal shunt alone, and 16 (7%) with endoscopic fenestration of the septum pellucidum. Surgical intervention was associated with mortality reduction from 95% (n = 54) to 48% (n = 11) in the ICH group, from 47% (n = 27) to 12% (n = 15) in the tumor group and from 90% (n = 18) to 20% (n = 7) in the SDH group (p < 0.001 for all comparisons). Univariate logistic analysis showed that surgical intervention and tumor etiology were associated with decreased mortality while age, ICH etiology, intraventricular hemorrhage, midline shift, and anticoagulation were associated with increased mortality. On multivariate logistic regression, surgical intervention remained associated with decreased mortality (p < 0.0001; OR 0.20, 95% CI 0.09-0.42). On subgroup analysis of the ICH cohort, surgical intervention was also associated with decreased mortality (p = 0.028).

CONCLUSIONS

Neurosurgical intervention for decompression in patients with trapped ventricle can have a measurable beneficial effect on early mortality.

The choroid plexus-a multi-role player during infectious diseases of the CNS

The choroid plexus (CP) is the source of cerebrospinal fluid (CSF) production and location of the blood-CSF barrier (BCSFB), which is constituted by the epithelial cells of the CP. Several infectious pathogens including viruses, bacteria, fungi and parasites cross the BCSFB to enter the central nervous system (CNS), ultimately leading to inflammatory infectious diseases like meningitis and meningoencephalitis. The CP responds to this challenge by the production of chemokines and cytokines as well as alterations of the barrier function of the BCSFB. During the course of CNS infectious disease host immune cells enter the CNS, eventually contributing to the cellular damage caused by the disease. Additional complications, which are in certain cases caused by choroid plexitis, can arise due to the response of the CP to the pathogens. In this review we will give an overview on the multiple functions of the CP during brain infections highlighting the CP as a multi-role player during infectious diseases of the CNS. In this context the importance of tools for investigation of these CP functions and a possible suitability of the CP as therapeutic target will be discussed.

[A case of cryptococcal ventriculitis with slowly progressive gait disturbance and memory impairment as initial symptoms]

A 54-year-old man was admitted due to progressive gait disturbance and cognitive impairment. On MRI, a hyperintense region was observed in the periventricular white matter on FLAIR imaging, with Gd-enhancement in the choroid plexus and periventricular wall. Cerebrospinal fluid (CSF) examination showed marked abnormalities including a high white blood cell count (WBC, 360 cells/mm(3). 83% lymphocytes), an elevated protein level (1,416 mg/dl), a low glucose level (12 mg/dl), and elevated cryptococcal antigen with positive Indian ink staining. Cryptococcal ventriculitis was diagnosed. The patient was initially treated with liposomal amphotericin B, fluconazole, voriconazole, and flucytosine for 38 weeks, followed by administration of itraconazole and fluconazole with some improvement. The brain MRI after one month showed septum formation in the posterior horn, which was suggestive of ventriculitis. Although ventriculitis is rare, we should pay attention to the presence of ventriculitis due to cryptococcal infection in the central nervous system.

Extensive Central Nervous System Cryptococcal Disease Presenting as Immune Reconstitution Syndrome in a Patient with Advanced HIV: Report of a Case and Review of Management Dilemmas and Strategies

One of the complications of the use of antiretroviral therapy (ART), immune reconstitution inflammatory syndrome (IRIS), is particularly problematic in the management of cryptococcal meningitis. We present the case of a 35-year-old male with acquired immune deficiency syndrome diagnosed with extensive central nervous system (CNS) cryptococcal disease, including meningitis and multiple intracranial cysts, diagnosed eight weeks after the initiation of ART. The patient experienced a relapsing and remitting clinical course despite repeated courses of potent antifungal therapy and aggressive management of raised intracranial pressure. This review highlights therapeutic dilemmas and strategies in the management of CNS cryptococcosis complicated with IRIS and highlights gaps in available treatment guidelines.

Chronic meningitis: a diagnostic challenge highlighted in a case of cryptococcal meningoencephalitis in an apparently immunocompetent older woman

Chronic meningitis can be difficult to diagnose. The authors report the case of an older Caucasian lady, with no underlying immunocompromising factors, who presented with a 2 month history of confusion. Due to the non-specific symptoms on presentation, a diagnosis was only obtained after a repeat CT scan of the brain, which showed hydrocephalus. Subsequent cerebrospinal fluid analysis showed biochemical abnormalities and Cryptococcus neoformans on staining.

Involvement of the Choroid Plexus in Neurotuberculosis: MR Findings in Six Cases

The majority of intracranial infections that cause meningitis are considered to start in the choroid plexus of the ventricles, but lesions involving the choroid plexus are rare. There are isolated case reports of the involvement of choroid plexus in tuberculous meningitis. The main imaging findings are abnormal enhancement of the thickened choroid plexus, asymmetric hydrocephalus with sequestrated temporal horn, periventricular edema and intraventricular septae formation. Six patients having tubercular involvement of choroid plexus were treated at our institution. This is probably the largest series of tubercular involvement of choroid plexus highlighting the imaging features of this rare manifestation of CNS tuberculosis.