Cryptococcus meningitis mimicking cerebral septic emboli, a case report series demonstrating injection drug use as a risk factor for development of disseminated disease

Cryptococcal Meningitis in an Immunocompetent Patient With Underlying Risk Factors

Cryptococcal meningitis, a severe fungal infection of the central nervous system, is usually found in immunocompromised patients, especially those with human immunodeficiency virus/acquired immunodeficiency syndrome. Its occurrence in immunocompetent individuals is rare and the presentation can be nonspecific. We present a case of cryptococcal meningitis in a young, immunocompetent male with a known history of intravenous drug abuse who was also found to have hepatitis C during admission. Induction therapy with amphotericin B and flucytosine was completed for 14 days. This shorter duration was considered as he had a good clinical response with rapid improvement in mental status and intracranial pressure with an extraventricular drain and negative repeat cerebrospinal fluid (CSF) culture. However, during the consolidation phase with fluconazole, the patient developed new neurologic symptoms and the induction phase had to be re-initiated for a total of 28 days. The patient likewise required the re-placement of an extraventricular drain and the creation of a ventriculoperitoneal shunt due to persistent CSF accumulation and increased intracranial pressure. He was eventually discharged on fluconazole for a planned consolidation phase of eight weeks, followed by a prolonged maintenance phase, but the patient was lost to follow-up.

Cryptococcal Meningitis in Young, Immunocompetent Patients: A Single-Center Retrospective Case Series and Review of the Literature

Background

Cryptococcal meningitis is an uncommon but serious infection with high mortality and morbidity. Classically described in immunocompromised patients, including those with solid organ transplants or HIV/AIDS, cryptococcosis has also been reported in young and otherwise healthy patients, albeit rarely.

Methods

We retrospectively searched for all cases of cryptococcal meningitis in young (≤50 years) and previously healthy patients with no known immunocompromising conditions from January 2015 to January 2022 at Indiana University Health (IU Health). Additionally, a PubMed literature review was performed with the keywords "cryptococcal meningitis" and "immunocompetent" from January 1988 to January 2022. Clinical courses, including outcomes and treatment regimens, were evaluated.

Results

We identified 4 local cases of cryptococcal meningitis in otherwise healthy patients age ≤50 years. Three cases were due to Cryptococcus neoformans, with 1 experiencing a postinfectious inflammatory response syndrome (PIIRS). The PubMed search identified 51 additional cases, with 32 (63%) being caused by Cryptococcus neoformans and 8 (17%) by Cryptococcus gattii. Of the 51 cases, only 2 resulted in death directly due to cryptococcosis. Fifteen (29%) had PIIRS, with steroid treatment documented in 11 of 15. Antifungal induction regimens and duration were varied but predominately consisted of amphotericin and flucytosine, with a mean induction duration of 5.0 weeks.

Conclusions

Cryptococcal meningitis in young, previously healthy patients is likely under-recognized. PIIRS (akin to immune reconstitution inflammatory syndrome observed in HIV/AIDS) with prolonged recovery should be of concern. Determining risk factors for cryptococcosis in these patients remains elusive.

Cerebral infarction in HIV-negative patients with cryptococcal meningitis: its predictors and impact on outcomes

Background

Descriptions of the patterns of acute/subacute cerebral infarction (ASCI) in HIV-negative patients with cryptococcal meningitis (CM) are scarce, and the predictors of ischemic stroke and outcomes following ASCI remain unclear.

Aim

To study the clinical characteristics and evaluate the predictors of ASCI in HIV-negative patients with CM and assess the impact of ischemic stroke on the outcomes of the patients.

Methods

We retrospectively analyzed the data of 61 HIV-negative patients with CM treated between January, 2016 and February, 2022, and among them, 53 patients with complete neuroimaging and cerebrospinal fluid (CSF) data were enrolled in this study. The cohort was stratified by the occurrence of ASCI diagnosed based on MRI evidences for comparison of the clinical characteristics (consciousness disturbance, GCS score, duration of symptoms, and treatment), CSF parameters, imaging findings (meningeal inflammation, hydrocephalus, posterior fossa exudates) and outcomes of the patients. A favorable outcome was defined as a modified Rankin scale (mRS) score ≤ 2 and a poor outcome as a mRS score > 2. Logistic regression analysis was used to identify the risk factors of ASCI in the HIV-negative patients with CM.

Results

Of the 53 HIV-negative patients with CM, 14 (26.4%) had ASCI. The incidences of fever, headache, neck stiffness, duration of symptoms, CSF parameters, meningeal enhancement in brain MRI and the treatment regimens were similar between the patients with and those without ASCI. Most of the infarcts (92.9%) were of the lacunar type, involving both the anterior and posterior territories. Basal ganglia-corona radiata and the brainstem-cerebellum were the most frequently involved sites. Univariate logistic regression analysis suggested that consciousness disturbance (P = 0.002), MRI evidence of hydrocephalus (P = 0.042) and posterior fossa exudates (P = 0.028) were predictors of ASCI in these HIV-negative patients with CM. Multivariate analysis identified consciousness disturbance as a significant predictor of ASCI (P = 0.020). Compared with the patients without ASCI, the HIV-negative patients with CM and ASCI had poorer outcomes (P = 0.001).

Conclusion

ASCI can occur in HIV-negative patients with CM, presented commonly as multiple lacunar infarctions involving all the cerebrovascular territories. The presence of consciousness disturbance, hydrocephalus and posterior fossa exudates may increase the risk of ASCI in patients with CM. ASCI is associated with a poor outcome of the HIV-negative patients with CM.

Another case of cryptococcal meningitis in a person without HIV who injects drugs: A possible risk factor in need of further investigation

Cryptococcal meningitis is a fungal central nervous infection typically occurring in patients with severe immunocompromise. We present a case of cryptococcal meningitis occurring in a patient with active injection drug use (IDU) but no immunocompromising condition. This is the seventh case in the recent literature of cryptococcal central nervous involvement in an otherwise healthy young person with IDU, suggesting a possible association in need of further exploration.

Cerebral vasculitis caused by Talaromyces marneffei and Aspergillus niger in a HIV-positive patient: a case report and literature review

Cerebral vasculitis is a long-standing but flourishing and fadeless research topic. Infections are a frequent cause of cerebral vasculitis, vital to diagnose due to involvement of specific anti-infection treatments. A 65-year-old man visited the hospital for his neurological symptoms without obvious inducements. After admission, radiological examination and comprehensive conventional microbiological tests (CMTs) revealed suspected intracranial infectious vasculitis. Metagenomic next-generation sequencing (mNGS) and reverse transcription-polymerase chain reaction further confirmed that his cerebral vasculitis was caused by Talaromyces marneffei (T. marneffei) and Aspergillus niger (A. niger) co-infection. The patient’s final diagnosis changed from initial herpetic encephalitis, due to the past history of cephalosome and facial herpes and non-significant antiviral therapeutic effects, to fungal cerebral vasculitis. The patient was discharged after use of targeted antifungal therapies on day 18 of his admission, and his associated symptoms disappeared completely at follow-up 3 weeks later. We first illustrated the presence of uncommon cerebral vasculitis caused by T. marneffei and A. niger in a human immunodeficiency virus-positive patient. In clinically suspected patients with infectious cerebral vasculitis, mNGS should be performed to detect potential pathogens if CMTs may not provide useful pathogenic clues, highlighting the importance of mNGS in the diagnosis and treatment of infectious diseases.

Associations between Cryptococcus Genotypes, Phenotypes, and Clinical Parameters of Human Disease: A Review

The genus Cryptococcus contains two primary species complexes that are significant opportunistic human fungal pathogens: C. neoformans and C. gattii. In humans, cryptococcosis can manifest in many ways, but most often results in either pulmonary or central nervous system disease. Patients with cryptococcosis can display a variety of symptoms on a spectrum of severity because of the interaction between yeast and host. The bulk of our knowledge regarding Cryptococcus and the mechanisms of disease stem from in vitro experiments and in vivo animal models that make a fair attempt, but do not recapitulate the conditions inside the human host. To better understand the dynamics of initiation and progression in cryptococcal disease, it is important to study the genetic and phenotypic differences in the context of human infection to identify the human and fungal risk factors that contribute to pathogenesis and poor clinical outcomes. In this review, we summarize the current understanding of the different clinical presentations and health outcomes that are associated with pathogenicity and virulence of cryptococcal strains with respect to specific genotypes and phenotypes.