Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era. Clin Radiol. 2016;71:9-17. [PMID: 26564776 DOI: 10.1016/j.crad.2015.10.005]

Cryptococcus neoformans: Brain Preference, Gender Bias, and Interactions with Mycobacterium tuberculosis and Toxoplasma gondii in HIV-Positive Patients

Cryptococcus neoformans, a high-priority pathogen (WHO, 2022) and ubiquitous fungus, is responsible for hundreds of thousands of meningoencephalitis cases annually, with a high fatality rate. Its distribution is uneven: it primarily affects immunocompromised individuals (especially HIV-positive patients). Our study aims to explore the Cryptococcus' brain tropism in immunosuppressed patients, its gender preference and the possible interactions with other opportunistic neurotropic microorganisms, such as Mycobacterium tuberculosis (MTB) and the brain microbiota, with a particular focus on Toxoplasma gondii (T. gondii).

METHODS

We conducted a retrospective descriptive analysis of all cases diagnosed with central nervous system cryptococcosis (Crypto-CNS) in HIV-positive patients admitted over 10 years (2010-2019) in a tertiary Romanian hospital. We examined their demographic, clinical, immunobiological, and imaging data, as well as their medical history, comorbidities, and coinfections.

RESULTS

Forty-two cases were admitted, with a male predominance (3.6:1) and a mean age of 33.3 years; 24% were diagnosed concomitantly with HIV infection and Crypto-CNS. All patients were severely immunosuppressed, with CD4 counts <200 cells/mm3 (median = 20.5 [1-163], mean = 31.6). Recent/concomitant tuberculosis was found in 10 (27.7%). T. gondii-seropositive patients developed Crypto-CNS at a lower immunological state than seronegative ones (27.1 CD4 cells/mm3 vs. 46.7 cells/mm3, means). Of 25 cases with available brain imagery, 28% had high intracranial pressure. Twelve patients (28.5%) died during the hospitalization within 26.3 days (mean, SD = 21.4); 1-year mortality increased to 50%. In-hospital mortality was associated with lower CD4 counts, increased intracranial pressure, and T. gondii-seropositivity.

CONCLUSIONS

Crypto-CNS in HIV-positive patients mainly affects men and may be promoted by concomitant or recent tuberculosis. T. gondii may confer some protection even at low immune levels but increases mortality when immunity is critically low.

Analysis of intracranial lesions in patients with HIV-associated cryptococcal meningitis

Background

Intracranial imaging abnormalities are commonly observed in patients suffering from HIV-associated cryptococcal meningitis, both before and during the treatment period. This study aims to analyze the prevalence, origins, radiological characteristics, treatments, and prognosis of intracranial lesions in patients with HIV-associated cryptococcal meningitis, thereby providing references for future clinical decision-making.

Methods

The clinical data of patients diagnosed with HIV-associated cryptococcal meningitis and admitted to the Shanghai Public Health Clinical Centre between 2013 and 2019 were collected. Logistic regression analysis was subsequently conducted to identify potential risk factors associated with the development of intracranial lesions in this patient group.

Results

Of 211 patients analyzed, 64.5% (136/211) had intracranial lesions during treatment and follow-up. Initial cranial imaging showed 60% had lesions pre-treatment. Throughout treatment, 32.7% (52/159) developed new or worsened lesions. Mortality rates at 2 weeks, 8 weeks, and 2 years for those with detected lesions were 3%, 7.6%, and 13.2%, respectively. Lesions were primarily caused by Cryptococcus (70.5%) and Mycobacterium (24.3%). Lacunar infarcts, especially in the basal ganglia, were the most common type. Patients aged 50 years or older, and those presenting with altered mental status upon admission, were found to be more likely to have intracranial lesions at baseline, with adjusted odds ratios of 5.364 (95% CI: 1.468-19.591, P=0.011) and 7.970 (95% CI: 2.241-28.337, P=0.001), respectively. Patients with lesion progression showed higher levels of IFN-γ, IL-4, IL-5, IL-6, IL-1Ra, IL-1β, GM-CSF, Eotaxin, and Basic FGF in cerebrospinal fluid after four weeks of treatment.

Conclusion

Intracranial lesions in HIV-associated cryptococcal meningitis patients are mostly due to Cryptococcus and Mycobacterium infections. They often appear as lacunar infarcts, predominantly in the basal ganglia, and can worsen with treatment initiation, possibly due to higher baseline cytokine levels in cerebrospinal fluid.

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.

Diffuse Leptomeningeal Glioneuronal Tumor with FGFR1 Mutation in a 29-Year-Old Male

This study reports on diffuse leptomeningeal glioneuronal tumor (DL-GNT) in a 29-year-old male. DL-GNT is a rare central nervous system (CNS) tumor mostly seen in children and only few cases have been reported in adult patients. Our patient presented with a chronic headache that lasted for five months. MR imaging showed mild hydrocephalus, multiple rim-enhancing nodular lesions in the suprasellar cistern, diffuse leptomeningeal enhancement in the lumbosacral area, and multiple small non-enhancing cyst-appearing lesions not suppressed on fluid attenuated inversion recovery (FLAIR) images in the bilateral basal ganglia, thalami, and cerebral hemispheres. Under the impression of germ cell tumor with leptomeningeal seeding, the patient underwent trans-sphenoidal tumor removal. DL-GNT was pathologically confirmed and FGFR1 mutation was detected through a next-generation sequencing test. In conclusion, a combination of leptomeningeal enhancement and multiple parenchymal non-enhancing cyst-appearing lesions not suppressed on FLAIR images may be helpful for differential diagnosis despite overlapping imaging features with many other CNS diseases that have leptomeningeal enhancement.

Expression of the α7 nAChR Subunit Duplicate Form (CHRFAM7A) Was Down-Regulated in Patients with Intracranial Infection and Reduced Inflammation in in vitro Model by p38 MAPK

OBJECTIVE

In this study, we investigated that the effects and possible mechanisms of the α7 nAChR subunit duplicate form (CHRFAM7A) affected inflammation in the model of intracranial infection.

METHODS

Mice of the model group were injected (intracranial injection) with Staphylococcus aureus. Mouse microglial BV2 cell was exposed with 200 ng of LPS for 4 h.

RESULTS

CHRFAM7A mRNA expressions were reduced in patients with intracranial infection. CHRFAM7A mRNA and protein expressions were suppressed in mice with intracranial infection in a time-dependent manner. CHRFAM7A reduced inflammation in mice with intracranial infection. The inhibition of CHRFAM7A reduced inflammation in mice with intracranial infection. CHRFAM7A suppressed p38 MAPK in mice with intracranial infection. The inhibition of p38 MAPK shows the effects of CHRFAM7A in intracranial infection.

CONCLUSION

Our data demonstrate that the expression of the CHRFAM7A was down-regulated in patients with intracranial infection and reduced inflammation in in vitro model by p38 MAPK, which suggests the potential role of CHRFAM7A as a diagnostic biomarker for intracranial infection.

The neurological sequelae of pandemics and epidemics

Neurological manifestations in pandemics frequently cause short and long-term consequences which are frequently overlooked. Despite advances in the treatment of infectious diseases, nervous system involvement remains a challenge, with limited treatments often available. The under-recognition of neurological manifestations may lead to an increase in the burden of acute disease as well as secondary complications with long-term consequences. Nervous system infection or dysfunction during pandemics is common and its enduring consequences, especially among vulnerable populations, are frequently forgotten. An improved understanding the possible mechanisms of neurological damage during epidemics, and increased recognition of the possible manifestations is fundamental to bring insights when dealing with future outbreaks. To reverse this gap in knowledge, we reviewed all the pandemics, large and important epidemics of human history in which neurological manifestations are evident, and described the possible physiological processes that leads to the adverse sequelae caused or triggered by those pathogens.

Application value analysis of magnetic resonance imaging and computed tomography in the diagnosis of intracranial infection after craniocerebral surgery

BACKGROUND

Intracranial infection is a common clinical disease. Computed tomography (CT) and magnetic resonance imaging (MRI) have certain sensitivity and have good diagnostic efficacy.

AIM

To study the application value of MRI and CT in the diagnosis of intracranial infection after craniocerebral surgery.

METHODS

We selected 82 patients who underwent craniocerebral surgery (including 40 patients with intracranial infection and 42 patients without infection) during the period from April 2016 to June 2019 in our hospital. All 82 patients received CT and MRI examinations, and their clinical data were reviewed. A retrospective analysis was performed, and the coincidence rate of positive diagnosis and the overall diagnosis coincidence rate of different pathogenic infection types were measured with the two examination methods. The diagnostic sensitivity and specificity as well as the positive and negative predictive values of the two examination methods were compared.

RESULTS

For all types of pathogenic infections (Staphylococcus aureus, Staphylococcus hemolyticus, Staphylococcus epidermidis, and others), MRI scans had higher positive diagnostic coincidence rates than CT scans; the overall diagnostic coincidence rate, sensitivity, specificity, positive predictive value, and negative predictive values were significantly higher with MRI examinations than with CT examinations, and the differences were statistically significant (P < 0.05).

CONCLUSION

MRI examination can accurately diagnose intracranial infection after clinical craniocerebral surgery. Compared with CT, MRI had higher diagnostic efficiency. The diagnostic sensitivity and specificity, the diagnostic coincidence rate, and the positive and negative predictive values were significantly higher with MRI than with conventional CT, which can be actively promoted.

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.

Intracranial calcifications on CT: an updated review

Intracranial calcifications are frequently encountered in non-contrast computed tomography scan in both adult and pediatric age groups. They refer to calcifications within the brain parenchyma or vasculature and can be classified into several major categories: physiologic/age-related, dystrophic, congenital disorders/phakomatoses, infectious, vascular, neoplastic, metabolic/endocrine, inflammatory and toxic diseases. In this updated review, we present a wide spectrum of intracranial calcifications from both pediatric and adult populations focusing on their pattern, size and location.

The antifungal and Cryptococcus neoformans virulence attenuating activity of Pelargonium sidoides extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Limitations of clinical antifungal treatments and drug-resistance are drivers of the search for novel antifungal strategies. Extracts prepared from the tubers of the medicinal plant, Pelargonium sidoides, are known for their antiviral and antibacterial activities and are used in ethnomedicine for the treatment of acute respiratory infections. Their impact on fungi has not been well characterised. Here, we provide a first report on the antifungal activity of a P. sidoides aerial tissue extract against Cryptococcus neoformans as well as the effects of both tuber and aerial tissue extracts on selected virulence factors.

AIM OF THE STUDY

Novel antimicrobial strategies that target multiple cellular pathways or make use of anti-pathogenic compounds that inhibit virulence factors have been proposed. This work aimed to evaluate P. sidoides plant parts for their anticryptococcal activity and antipathogenic properties on selected virulence factors.

MATERIALS AND METHODS

The antifungal activity of crude P. sidoides tuber and aerial tissue extracts (15% m/m ethanol) were compared using a modified colourimetric antifungal susceptibility test. Fungicidal activity of the extracts was confirmed by plate counts. To test yeast resistance to the extracts, it was conditioned by multiple passages in sub-lethal doses followed by antifungal susceptibility testing. Cytotoxicity of the extracts was tested with a blood agar haemolysis assay. Extracts were evaluated for the presence of multiple bioactive compounds by solid-phase fractionation and visualisation by thin-layer chromatography in combination with bioassays. The influence of extracts on the production of the polysaccharide capsule, ergosterol content as well as laccase and urease activities were also evaluated. Cell surface variations after extract exposure were visualised by scanning electron microscopy (SEM).

RESULTS

Both tuber and aerial tissue extracts were fungicidal and contained multiple bioactive compounds which constrained the development of antifungal resistance. No haemolytic activity was observed, and the extracts did not appear to target ergosterol biosynthesis. However, the extracts displayed anti-pathogenic potential by significantly inhibiting laccase and urease activity while also significantly reducing capsule size. SEM revealed notable cell surface variations and provided support for the observed reduction in capsule size.

CONCLUSIONS

Our results provide support to the exploration of medicinal plants as sources of alternative antifungal therapies and the potential use of multicomponent inhibition and or virulence attenuation for next-generation treatment strategies. Our data also provide relevant information that may support the further use of P. sidoides in traditional medicines as well as in commercialised phytopharmaceuticals.

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.

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.

Neuroimaging in Central Nervous System Infections

Radiologic imaging is often employed to supplement clinical evaluation in cases of suspected central nervous system (CNS) infection. While computed tomography (CT) is superior for evaluating osseous integrity, demineralization, and erosive changes and may be more readily available at many institutions, magnetic resonance imaging (MRI) has significantly greater sensitivity for evaluating the cerebral parenchyma, cord, and marrow for early changes that have not yet reached the threshold for CT detection. For these reasons, MRI is generally superior to CT for characterizing bacterial, viral, fungal, and parasitic infections of the CNS. The typical imaging features of common and uncommon CNS infectious processes are reviewed.

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.