Abstract
Background:
Cryptococcus spp. infection involving the central nervous system (CNS) is associated with poor outcomes. Current guidelines recommend repeating a cerebrospinal fluid (CSF) fungal culture after 2 weeks of treatment to evaluate for clearance. However, this practice has not clearly been associated with outcomes.
Objectives:
We sought to assess the relationship between CSF fungal clearance at 2 weeks and 12-month mortality in patients with CNS cryptococcosis.
Methods:
This is a retrospective cohort study from 2011–2020 of patients with CNS cryptococcosis. Factors associated with 12-month mortality were assessed with Fisher’s exact test for categorical variables and Mann-Whitney test for continuous variables.
Results:
Among 51 patients with CNS cryptococcosis, 42 (82.4%) were initially CSF culture positive. Among 27 patients with follow-up CSF culture at 2 weeks, 6 (22.2%) had a positive result. Factors associated with a positive CSF culture at 2 weeks were an initial CSF cryptococcal antigen titer ≥1:2560, fungemia, and an elevated intracranial pressure requiring therapeutic lumbar punctures. The 12-month mortality rate was 33.3% and this was significantly associated with baseline fungemia, extra-CNS cryptococcal involvement and requirement of intensive care unit level of care. Lack of CSF culture clearance by 2 weeks was not associated with 12-month mortality.
Conclusions:
CNS cryptococcosis has a high mortality rate. A markedly elevated CSF cryptococcal antigen and opening CSF pressure was associated with lack of CSF culture clearance at 2 weeks of treatment. Severe disseminated disease and cryptococcemia were associated with 12-month mortality.
Keywords: Cryptococcus, central nervous system, lumbar puncture, fungemia, mortality
Introduction
Cryptococcus species are a group of environmental yeasts with a propensity for causing infection in immunocompromised patients. This group of opportunistic pathogens, primarily C. neoformans and C. gattii, affects the central nervous system (CNS) in up to 67% of patients.1,2 Factors associated with poor outcomes with cryptococcosis include fungemia, immunocompromised state, active malignancy, end-stage liver disease, use of non-amphotericin B-based therapy, and lack of intracranial pressure management.2–5 Overall, the outcomes of cryptococcosis remain poor, with mortality rates as high as 80% depending on extent of infection and patient factors.1,4,6,7
Patients with CNS cryptococcosis are particularly at increased risk for poor outcomes. Multiple studies have found the rate of cerebrospinal fluid (CSF) fungal clearance to be associated with clinical outcomes.8–10 However, quantitative fungal culture required to measure the rate of CSF fungal clearance is not routinely used in clinical practice. Instead, current guidelines suggest performing a CSF fungal culture after 2 weeks of antifungal therapy to assess for culture clearance.11,12 Studies examining an association between 2-week CSF culture clearance and outcomes have had mixed results.6,7,13 Often, CSF analysis may not be repeated due to difficulties in performing testing in resource-limited settings and in populations at increased risk for coagulopathy, such as those with hematologic malignancies.
We sought to analyze the outcome of patients with CNS cryptococcosis and examine potential associations between outcomes and the initial and 2-week follow-up CSF culture positivity. Additionally, we aimed to evaluate for factors associated with CSF culture clearance at 2 weeks after treatment initiation.
Patients and methods
Study design and setting
This is a retrospective cohort study of patients with CNS cryptococcosis at Mayo Clinic in Arizona, Florida, and Minnesota between 2011 and 2020. Patients were identified by querying our internal microbiology database for patients with either a CSF fungal culture growing a Cryptococcus species or a positive CSF Cryptococcus antigen (CrAg). Inclusion criteria were age ≥18 years at the time of Cryptococcus infection diagnosis, positive CSF fungal culture or CrAg, and a compatible clinical syndrome with CNS cryptococcosis based on symptoms, signs, and radiography. Exclusion criteria were absence of confirmation of CNS involvement by CSF fungal culture or CrAg testing, lack of research authorization, or isolated CSF CrAg that was felt to be a false positive. False positivity was defined as a low-level CSF CrAg titer, typically less than or equal to 1:5 dilutions, with an alternative explanatory diagnosis or those who did not receive therapy and did not develop progressive cryptococcosis.14
Once eligible patients were identified, patient-level data were manually extracted from a review of the electronic medical record. Abstracted data included demographics, medical comorbidities, immunocompromising conditions, cryptococcosis diagnosis and treatment variables, and outcomes. Study data were collected and managed using REDCap electronic data capture tools hosted at Mayo Clinic.15,16 This study was reviewed by our local institutional review board and granted an except status (#19–001020).
Identification and susceptibility testing
The Clinical Microbiology laboratory at Mayo Clinic in Rochester, Minnesota, received specimens for culture, identification, and susceptibility testing from Mayo Clinic sites. Clinical specimens were cultured in inhibitory mold agar and brain-heart infusion agar with chloramphenicol and gentamicin, incubated at 30°C for up to 24 days. Once organism growth is observed, the isolates were identified via matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, real-time polymerase chain reaction, and/or gene sequencing. If requested, susceptibility testing was performed via broth microdilution and interpreted according to Clinical and Laboratory Standards Institute guidelines. CrAg testing was performed by lateral flow assay.
Definitions
Cryptococcal infection was classified as proven or probable according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group guidelines.17 CNS cryptococcosis was defined as CSF fungal culture growth of a Cryptococcus species and/or positive CSF CrAg with compatible clinical symptoms, signs, and/or radiographic testing. The index date of diagnosis was defined as the date the first fungal culture growing a Cryptococcus species or positive CrAg. Sites of Cryptococcus involvement were defined by growth of Cryptococcus species, positive CrAg from the respective site, or compatible clinical symptoms or radiographic findings without an alternative explanation. The exception to this was fungemia, which was defined solely as growth of Cryptococcus from at least one blood culture. Two-week follow-up fungal culture was defined as a CSF fungal culture obtained 12–16 days after treatment initiation, to account for variability in the exact date of follow-up lumbar puncture (LP). The date of CSF clearance was defined as the first date a CSF fungal culture was obtained that did not grow Cryptococcus. Microbiologic recurrence was defined as worsening of signs, symptoms, or radiographic findings of cryptococcosis after initial improvement with microbiologic confirmation of Cryptococcus sp., such as a positive repeated fungal culture, without a plausible alternative explanation. Immune reconstitution inflammatory syndrome (IRIS) was defined as previously published.18 Allograft loss was defined as a loss of transplant organ function requiring transplant re-listing, re-transplantation, or, in the case of kidney transplant recipients, initiation of chronic dialysis therapy. Charlson comorbidity index (CCI) was calculated as previously published.19 In those with a solid organ transplant, their CCI was credited with that transplanted organ’s specific comorbidity (i.e. lung transplantation credited as “chronic lung disease”).
Statistical analysis
The primary outcome was mortality within 12 months of cryptococcosis diagnosis. Secondary outcomes were CSF fungal culture positivity after 2 weeks of therapy, 12-month microbiologic recurrence, 12-month IRIS, and 12-month allograft loss for solid organ transplant (SOT) recipients. Continuous variables are presented as median (interquartile range [IQR] or range) as appropriate. Categorical variables are presented as number (percentage). Fisher’s exact test was used to analyze categorical variables and Mann-Whitney test was used to analyze continuous variables for associations with the primary or secondary outcomes. A Kaplan-Meier curve was constructed and compared utilizing a log-rank test for survival between groups based on 2-week CSF culture clearance. All analyses were performed using BlueSky Statistics version 7.40 software (BlueSky Statistics LLC, Chicago, Illinois).
Results
Fifty-one patients with CNS cryptococcosis were identified during the 10-year study period. The patients had a median age of 64 years (IQR 54–71), were mostly male (66.7%), and predominantly white race (92.2%). Thirty-nine patients (76.5%) had an immunocompromising condition, the most common being SOT. Four patients with human immunodeficiency virus (HIV) infection had a median CD4 count of 26.5 cells/μL (range, 21–54). Median CCI was 5.0 (IQR 4.0–6.5); individual CCI components are displayed in Supplementary Table 1. Twenty-one patients who have completed antifungal therapy were treated for a median of 326 days (IQR 99–522). From the 12 patients without a known immunocompromising condition, 5 had moderate-severe liver disease, 3 had diabetes mellitus, and 3 had a history of cerebrovascular disease. Twenty-six patients had antifungal susceptibility testing performed on their Cryptococcus isolates. Median minimum inhibitory concentrations (MIC) for amphotericin B, 5-flucytosine, and fluconazole were 0.5 (IQR 0.2–0.5), 4.0 (IQR 2.0–4.0), and 4.0 (IQR 2.5–8.0), respectively.
Forty-two (82.4%) patients had a positive CSF fungal culture at diagnosis, while the remaining 9 patients had culture-negative but antigen-positive CSF. The rates of immunocompromising conditions were similar between culture-positive and negative groups, though the culture-negative group had a greater number of SOT recipients (71.4% versus 40.6%) and no patients with HIV infection. The group with an initial positive CSF culture included all of those requiring intensive care unit (ICU) admission (38.1%) or CSF shunt placement (19.0%), had lower initial peripheral blood leukocyte and lymphocyte counts, a higher rate of fungemia (57.1%), a higher initial CSF CrAg titer (median 1:1280 versus 1:10) and a higher initial serum CrAg titer (median 1:2560 versus 1:1280). Nearly all patients received combination liposomal amphotericin B and 5-flucytosine, except for one who received fluconazole monotherapy in each group. Further cohort details are included in Table 1.
Table 1:
Baseline characteristics of 51 patients with central nervous system cryptococcosis, stratified by initial cerebrospinal fluid fungal culture positivity
| CSF culture positive (N=42) | CSF culture negative (N=9) | |
|---|---|---|
| Age, years, median (IQR) | 63.0 (52.2–71.0) | 68.0 (62.0–70.0) |
| Male sex | 26 (61.9) | 8 (88.9) |
| Race | ||
| - American Indian or Alaska Native | 1 (2.4) | 0 (0.0) |
| - Black or African American | 1 (2.4) | 2 (22.2) |
| - White | 40 (95.2) | 7 (77.8) |
| ICU admission | 16 (38.1) | 0 (0.0) |
| Hospital length of stay, days, median (IQR) | 17.5 (12.0–25.0) | 13.0 (9.0–21.0) |
| Immunocompromising condition | 32 (76.2) | 7 (77.8) |
| - Solid organ transplant | 13 (40.6) | 5 (71.4) |
| - Hematologic malignancy | 7 (21.9) | 0 (0.0) |
| - Pharmacologic immunosuppression† | 4 (12.5) | 1 (14.3) |
| - HIV/AIDS | 4 (12.5) | 0 (0.0) |
| - Autologous hematopoietic cell transplant | 2 (6.2) | 1 (14.3) |
| - Idiopathic CD4 lymphopenia | 2 (6.2) | 0 (0.0) |
| Solid organ transplant type (N=18) | ||
| - Kidney | 7 (53.8) | 2 (40.0) |
| - Kidney-pancreas | 2 (15.4) | 0 (0.0) |
| - Pancreas | 1 (7.7) | 0 (0.0) |
| - Liver | 1 (7.7) | 2 (40.0) |
| - Heart | 1 (7.7) | 0 (0.0) |
| - Lung | 1 (7.7) | 0 (0.0) |
| - Heart-kidney | 0 (0.0) | 1 (20.0) |
| Charlson comorbidity index, median (IQR) | 5.0 (4.0–7.0) | 4.0 (4.0–5.0) |
| Diabetes mellitus | 13 (31.0) | 3 (33.3) |
| Leukocyte count, x109, median (IQR) | 6.7 (4.9–10.5) | 9.9 (4.9–11.8) |
| Lymphocyte count, x109, median (IQR) | 0.68 (0.33–0.95) | 0.81 (0.48–1.23) |
| Extra-CNS Cryptococcus disease | 27 (64.3) | 4 (44.4) |
| - Bloodstream | 24 (57.1) | 1 (11.1) |
| - Pulmonary | 11 (26.2) | 3 (33.3) |
| - Pleural | 1 (2.4) | 0 (0.0) |
| - Cutaneous | 1 (2.4) | 1 (11.1) |
| - Other‡ | 4 (9.5) | 1 (11.1) |
| Respiratory culture positivity | 4 (9.5) | 3 (33.3) |
| Other culture positivity§ | 3 (7.1) | 1 (11.1) |
| Cryptococcus species | ||
| - C. neoformans | 38 (90.5) | 3 (33.3) |
| - C. gattii | 2 (4.8) | 1 (11.1) |
| - Unknown | 2 (4.8) | 5 (55.6) |
| Serum CrAg positive | 36 (85.7) | 8 (88.9) |
| Brain mass lesion¶ | 1 (3.0) | 1 (16.7) |
| Hydrocephalus¶ | 2 (6.1) | 1 (16.7) |
| Meningeal enhancement¶ | 9 (27.3) | 2 (33.3) |
| Initial opening pressure, cm H2O, median (IQR) (n=35) | 25.5 (20.0–32.0) | 16.0 (16.0–18.2) |
| Initial protein, mg/dL, median (IQR) (n=50) | 121.0 (79.0–194.0) | 106.0 (44.0–196.0) |
| Initial glucose, mg/dL, median (IQR) (n=49) | 38.0 (20.0–53.0) | 45.0 (33.0–54.2) |
| Initial total nucleated cell count, cells/μL, median (IQR) | 113.5 (32.5–272.8) | 67.0 (4.0–142.0) |
| CSF neutrophil count, cells/μL, median (IQR) (N=47) | 4.8 (0.9–66.0) | 4.7 (0.04–8.5) |
| CSF lymphocyte count, cells/μL, median (IQR) (n=47) | 40.6 (12.8–97.6) | 53.6 (1.9–121.8) |
| Repeated therapeutic LP | 25 (59.5) | 3 (33.3) |
| Shunt placement | 8 (19.0) | 0 (0.0) |
Data are n (%) unless otherwise specified.
Abbreviations: AIDS, acquired immunodeficiency syndrome; CrAg, cryptococcal antigen; CNS, central nervous system; CSF, cerebrospinal fluid; HIV, human immunodeficiency virus; ICU, intensive care unit; IQR, interquartile range; IRIS, immune reconstitution inflammatory syndrome; LP, lumbar puncture.
Pharmacologic immunosuppression included prednisone (3), prednisone with azathioprine (1), and tumor necrosis factor-α inhibitor (1). This group did not include those receiving immunosuppression for a solid organ transplant.
Other non-CNS sites of Cryptococcus disease includes intra-abdominal (2), ocular (1), prostate (1), and sinus (1).
Other sites of culture growth includes abdominal fluid (2), sinus (1), and urine (1).
n = 39, excluding 12 patients who did not undergo magnetic resonance imaging of the brain.
From the 42 patients with initial CSF culture positivity, only 31 (73.8%) had a follow-up CSF fungal culture at any time point. The median time to CSF culture clearance from the 31 patients with any follow-up LP was 14 days (range, 1–69 days). A positive CSF fungal culture was noted at any point during follow-up in 15 patients at a median of 9 days from treatment initiation (IQR 6–13).
Twenty-seven (64.3%) patients underwent a 2-week follow-up CSF analysis. Among them, 6 (22.2%) had a positive CSF fungal culture at 2 weeks, while 21 (77.8%) had achieved CSF clearance. Factors significantly associated with lack of CSF culture clearance were higher initial serum and CSF CrAg, initial CSF CrAg ≥1:2560, higher initial CSF opening pressure, fungemia, and lower initial CSF neutrophil count (Table 2). Patients with 2-week CSF clearance had a shorter duration of induction antifungal treatment (median 20 days versus 52 days; p = 0.002). The MICs for amphotericin B and 5-flucytosine were not associated with lack of CSF clearance.
Table 2:
Comparison of 27 patients with central nervous system cryptococcosis and initial cerebrospinal fluid fungal culture positivity who had repeated lumbar puncture performed 2 weeks after treatment initiation
| CSF culture clearance by 2 weeks (N=21) | Lack of CSF culture clearance by 2 weeks (N=6) | p value | |
|---|---|---|---|
| Charlson comorbidity index | 5.0 (3.0–6.0) | 6.0 (4.5–6.0) | 0.423 |
| Time from symptom onset to treatment initiation, days | 16.0 (7.0–22.0) | 16.0 (11.5–50.5) | 0.748 |
| Leukocyte count, x109/L | 6.7 (5.1–9.8) | 4.0 (2.6–12.0) | 0.232 |
| Absolute lymphocyte count, x109/L | 0.8 (0.4–1.1) | 0.6 (0.3–1.0) | 0.502 |
| CSF CrAg titer ≥1:2560†,‡ | 5 (23.8) | 5 (100.0) | 0.004 |
| Opening pressure, cm H2Oa (n=15) | 23.0 (13.5–25.5) | 32.5 (27.8–40.2) | 0.029 |
| Protein, mg/dL† (n=26) | 141.5 (105.5–240.8) | 127.5 (36.2–208.2) | 0.301 |
| Glucose, mg/dL† (n=26) | 40.0 (26.8–50.0) | 22.5 (20.0–26.5) | 0.094 |
| Total CSF nucleated cell count, cells/μLa | 224.0 (49.0–273.0) | 75.5 (37.8–397.5) | 0.771 |
| CSF neutrophil count, cells/μL† | 10.1 (2.0–78.8) | 1.1 (0.2–3.6) | 0.047 |
| CSF lymphocyte count, cells/μL† | 42.0 (13.8–188.4) | 60.3 (28.2–139.0) | 0.793 |
| Immunocompromising condition, N (%) | 16 (76.2) | 5 (83.3) | 1 |
| - Solid organ transplant | 6 (37.5) | 0 (0.0) | 0.119§ |
| - Hematologic malignancy | 3 (18.8) | 3 (60.0) | |
| - Pharmacologic immunosuppression | 3 (18.8) | 0 (0.0) | |
| - Idiopathic CD4 lymphopenia | 2 (12.5) | 0 (0.0) | |
| - HIV/AIDS | 1 (6.2) | 2 (40.0) | |
| - Hematopoietic cell transplant | 1 (6.2) | 0 (0.0) | |
| Fungemia, N (%) | 8 (38.1) | 6 (100.0) | 0.016 |
| Repeated therapeutic LP, N (%) | 9 (42.9) | 6 (100.0) | 0.020 |
Data are median (IQR) unless otherwise specified. Bold values indicate p < 0.05.
Abbreviations: AIDS, acquired immunodeficiency syndrome; CrAg, cryptococcal antigen; CSF, cerebrospinal fluid; HIV, human immunodeficiency virus; IQR, interquartile range; LP, lumbar puncture.
Referring to the initial lumbar puncture.
N=26, excluding one patient with lack of CSF culture clearance by 2 weeks who did not have an initial CSF CrAg titer performed.
Test for differences in specific immunocompromising conditions.
Overall, 17 patients (33.3%) died within 12 months of cryptococcosis diagnosis. This included 2 (22.2%) patients with initial CSF culture-negativity and 15 (35.7%) with initial culture positivity. After univariable analysis, factors associated with 12-month mortality included lower initial CSF lymphocyte percentage, requirement of ICU level of care, presence of extra-CNS cryptococcal disease, and fungemia (Table 3). CSF fungal culture clearance at 2 weeks was not associated with 12-month mortality (Figure 1). Likewise, initial CSF culture positivity, ascertainment of 2-week CSF culture status, initial serum or CSF CrAg titer, and MICs for amphotericin B, 5-flucytosine, or fluconazole were not significantly associated with mortality. One patient experienced microbiologic recurrence, 1 developed IRIS, and 2 SOT recipients lost their kidney allografts within 12 months after diagnosis.
Table 3:
Univariable testing for association with 12-month mortality
| 12-month survival (N=34) | 12-month mortality (N=17) | p value | |
|---|---|---|---|
| Initial total nucleated cell count, cells/μL, median (IQR) | 87.0 (32.5, 248.8) | 131 (16.0, 229.0) | 0.780 |
| Initial CSF lymphocyte percentage, median (IQR) | 70.0 (41.75, 81.0) | 35.0 (19.0, 53.0) | 0.003 |
| ICU admission | 7 (20.6) | 9 (52.9) | 0.027 |
| Non-CNS cryptococcal involvement | 17 (50.0) | 14 (82.4) | 0.035 |
| Fungemia | 12 (35.3) | 13 (76.5) | 0.008 |
| CSF culture clearance by 2 weeks (N=27) | 16 (80.0) | 5 (71.4) | 0.633 |
| Performance of follow-up LP (N=38) | 20 (74.1) | 7 (63.6) | 0.696 |
| Initial CSF culture positivity | 27 (79.4) | 15 (88.2) | 0.699 |
Data are n (%) unless otherwise specified. Bold values indicate p < 0.05.
Abbreviations: CNS, central nervous system; CSF, cerebrospinal fluid; ICU, intensive care unit; LP, lumbar puncture
Figure 1:
Kaplan-Meier curve comparing 27 patients with central nervous system cryptococcosis based on follow-up cerebrospinal fluid fungal culture clearance. The p value was calculated by log-rank testing.
Discussion
CNS cryptococcosis is associated with high mortality rate. One in three patients with CNS cryptococcosis in our cohort died within 12 months after diagnosis – a rate that is consistent with prior reports in immunocompromised populations.1,3,4,20,21 Factors associated with mortality were fungemia, extra-CNS involvement, requirement of ICU level of care, and initial low CSF lymphocyte percentage – all measures that reflect the extent of involvement, clinical severity, or degree of immunocompromise at presentation. One recent report found non-CNS extrapulmonary involvement to have a similarly high 90-day mortality rate as CNS cryptococcosis.21 This is consistent with our cohort, where most patients had multifocal disseminated disease and nearly half were fungemic on presentation. The initial serum and CSF CrAg were also numerically higher among patients who died, suggesting a higher burden of infection, although these markers did not reach statistical significance.
The median time to CSF culture negativity is 2 weeks. CSF culture clearance was achieved at 2 weeks in the majority (78%) of patients who received induction therapy with combination amphotericin B and 5-flucytosine. All evaluable SOT recipients in our cohort had achieved CSF clearance by 2 weeks. This is in contrast with a prior study of SOT recipients, where 47.6% had not cleared their CSF by 2 weeks.6 Similarly, a randomized clinical trial evaluating early versus late antiretroviral therapy initiation in HIV patients with CNS Cryptococcus infection found 43% did not clear their CSF by 2 weeks.7 The differences in the rate of CSF clearance may be related to the choice of induction therapy. In the SOT study, most patients received an amphotericin B product; however, less than half received this with 5-flucytosine.6 In the HIV study, all patients received combination amphotericin B and fluconazole per their protocol.7 The combination of amphotericin B and 5-flucytosine has been shown to have enhanced fungicidal activity and improved survival as compared to amphotericin B monotherapy.9 Nearly all patients in the present cohort received amphotericin B plus 5-flucytosine combination therapy, and this could account for the higher rate of CSF culture clearance in our cohort.9,22
While most patients had achieved CSF culture clearance by 2 weeks, about 20% had persistent culture positivity at this time point. Several factors were identified to be associated with the lack of CSF clearance at 2 weeks including fungemia, markedly elevated serum or CSF CrAg, elevated CSF opening pressure, and lower initial CSF neutrophil count. All these factors reflect higher fungal burden at diagnosis and a higher degree of immunosuppression. All patients who did not clear their CSF culture by 2 weeks also had required multiple therapeutic LPs (due to elevated CSF opening pressure), which allowed for the collection of CSF samples for repeated fungal cultures. However, repeated CSF analysis may not be easily performed in many patients, especially if there are no indications for therapeutic LPs. Our study demonstrated high rates of CSF culture clearance at 2 weeks among patients with lower microbiologic burden. The utility of repeated CSF culture is questionable in these low fungal burden cases, especially since analyses of routine follow-up CSF fungal culture have not been able to redemonstrate its impact on survival outcomes.7–10 Moreover, there are risks associated with repeated LP, including LP-associated hematoma among patients with coagulopathy or thrombocytopenia.23,24 These issues disproportionately affect those with hematologic malignancies, stem cell transplants, and SOT populations.20,25,26 Our study findings suggest that there may be a group of patients (those with low fungal burden) that may forego follow-up CSF testing, particularly if they have elevated risk for procedural complications.
Repeat CSF cultures have been used to guide the duration of induction antifungal therapy. Consistent with the guidelines, patients with persistently positive CSF cultures in our study had longer courses of induction therapy.11,12 While we did not find 2-week CSF culture positivity to be associated with mortality, this may have been due to the longer durations of induction therapy in this population. Prior studies have also not found an association with mortality, though one did show a non-significant increase in mortality in those that had not cleared their CSF at 2 weeks.6 However, this is in contrast to the study of patients with HIV, where high-dose fluconazole consolidation therapy was utilized for 3 weeks or until CSF clearance was demonstrated.7 Those who had not cleared their CSF culture in that study did have a longer duration of consolidation (median 40 days versus 23 days), though the length of induction therapy was equal. Current guidelines recommend 8 weeks of high-dose fluconazole consolidation,11,12 which surpasses the length utilized for most of those patients.
This study has several limitations of note. It was performed retrospectively and is susceptible to inherent sources of bias. CNS cryptococcosis is a relatively uncommon disease and we only had a small absolute number of patients, particularly those who did not clear their CSF. This limited our ability to adjust for potential confounders, and the factors associated with outcomes in the univariable analyses should be interpreted with caution. Antifungal susceptibility testing was only performed in about half of the cohort, limiting our ability to test for associations between MICs and outcomes. Given that length of antifungal induction therapy correlated with CSF clearance, we were unable to evaluate its independent effect on outcomes. Finally, not all patients had a follow-up LP within our 2-week timeframe and there may have been prognostic factors that also affected the decision to pursue this testing.
In conclusion, this study identifies several factors associated with 12-month mortality and CSF clearance at 2 weeks in patients with CNS cryptococcosis. The majority of patients had achieved CSF culture negativity after 2 weeks of induction treatment with amphotericin B and 5-flucytosine. However, two-week CSF clearance was not significantly associated with 12-month survival. The high rate of CSF clearance at 2 weeks suggests that there may be a subgroup of patients with CNS cryptococcosis that do not necessarily require follow-up CSF evaluation, particularly those with evidence of low initial fungal burden and those not requiring therapeutic LPs. Further study with larger cohorts is necessary to confirm these findings and to better define the populations that would benefit most from having a 2-week follow-up CSF analysis.
Supplementary Material
Funding
This work was supported by the National Institutes of Health [UL1TR002377]. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
Footnotes
Conflicts of interest
All authors have no conflicts of interest to report.
Ethics statement: This study was reviewed by our local institutional review board and granted an except status (#19–001020).
References
- 1.Baddley JW, Chen SCA, Huisingh C, et al. MSG07: An International Cohort Study Comparing Epidemiology and Outcomes of Patients With Cryptococcus neoformans or Cryptococcus gattii Infections. Clin Infect Dis. 2021;73(7):1133–1141. doi: 10.1093/cid/ciab268 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Lui G, Lee N, Ip M, et al. Cryptococcosis in apparently immunocompetent patients. QJM - Mon J Assoc Physicians. 2006;99(3):143–151. doi: 10.1093/qjmed/hcl014 [DOI] [PubMed] [Google Scholar]
- 3.Zhao H, Zhou M, Zheng Q, et al. Clinical features and Outcomes of Cryptococcemia patients with and without HIV infection. Mycoses. 2021;64(6):656–667. doi: 10.1111/myc.13261 [DOI] [PubMed] [Google Scholar]
- 4.Spec A, Raval K, Powderly WG. End-Stage Liver Disease Is a Strong Predictor of Early Mortality in Cryptococcosis. Open Forum Infect Dis. 2016;3(1):1–5. doi: 10.1093/ofid/ofv197 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Rolfes MA, Hullsiek KH, Rhein J, et al. The effect of therapeutic lumbar punctures on acute mortality from cryptococcal meningitis. Clin Infect Dis. 2014;59(11):1607–1614. doi: 10.1093/cid/ciu596 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Singh N, Lortholary O, Alexander BD, et al. Antifungal Management Practices and Evolution of Infection in Organ Transplant Recipients with Cryptococcus Neoformans Infection. Transplantation. 2005;80(8):1033–1039. doi: 10.1097/01.tp.0000173774.74388.49 [DOI] [PubMed] [Google Scholar]
- 7.Rolfes MA, Rhein J, Schutz C, et al. Cerebrospinal Fluid Culture Positivity and Clinical Outcomes After Amphotericin-Based Induction Therapy for Cryptococcal Meningitis. Open Forum Infect Dis 2015;2(4):2633851. doi: 10.1093/ofid/ofv157 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Beardsley J, Wolbers M, Kibengo FM, et al. Adjunctive Dexamethasone in HIV-Associated Cryptococcal Meningitis. N Engl J Med. 2016;374(6):542–554. doi: 10.1056/NEJMoa1509024 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Day JN, Chau TTH, Wolbers M, et al. Combination Antifungal Therapy for Cryptococcal Meningitis. N Engl J Med. 2013;368(14):1291–1302. doi: 10.1056/NEJMoa1110404 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Bicanic T, Brouwer AE, Meintjes G, et al. Relationship of cerebrospinal fluid pressure, fungal burden and outcome in patients with cryptococcal meningitis undergoing serial lumbar punctures. AIDS. 2009;23(6):701–706. doi: 10.1097/QAD.0b013e32832605fe [DOI] [PubMed] [Google Scholar]
- 11.Perfect JR, Dismukes WE, Dromer F, et al. Clinical Practice Guidelines for the Management of Cryptococcal Disease: 2010 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(3):291–322. doi: 10.1086/649858 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Baddley JW, Forrest GN. Cryptococcosis in solid organ transplantation—Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clin Transplant. 2019;33(9). doi: 10.1111/ctr.13543 [DOI] [PubMed] [Google Scholar]
- 13.Chang CC, Dorasamy AA, Gosnell BI, et al. Clinical and mycological predictors of cryptococcosis-associated immune reconstitution inflammatory syndrome. AIDS. 2013;27(13):2089–2099. doi: 10.1097/QAD.0b013e3283614a8d [DOI] [PubMed] [Google Scholar]
- 14.Dubbels M, Granger D, Theel ES. Low Cryptococcus Antigen Titers as Determined by Lateral Flow Assay Should Be Interpreted Cautiously in Patients without Prior Diagnosis of Cryptococcal Infection. Gilligan P, ed. J Clin Microbiol. 2017;55(8):2472–2479. doi: 10.1128/JCM.00751-17 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)—A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–381. doi: 10.1016/j.jbi.2008.08.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Harris PA, Taylor R, Minor BL, et al. The REDCap consortium: Building an international community of software platform partners. J Biomed Inform. 2019;95:103208. doi: 10.1016/j.jbi.2019.103208 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Donnelly JP, Chen SC, Kauffman CA, et al. Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium. Clin Infect Dis. 2019;(Xx):1–10. doi: 10.1093/cid/ciz1008 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Sun H-Y, Alexander BD, Huprikar S, et al. Predictors of Immune Reconstitution Syndrome in Organ Transplant Recipients With Cryptococcosis: Implications for the Management of Immunosuppression. Clin Infect Dis. 2015;60(1):36–44. doi: 10.1093/cid/ciu711 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. J Chronic Dis. 1987;40(5):373–383. doi: 10.1016/0021-9681(87)90171-8 [DOI] [PubMed] [Google Scholar]
- 20.Dioverti M V, Parikh SA, Osmon DR, Habermann TM, Tande AJ. Cryptococcus neoformans infections in patients with lymphoproliferative neoplasms. Leuk Lymphoma. 2019;60(4):920–926. doi: 10.1080/10428194.2018.1508666 [DOI] [PubMed] [Google Scholar]
- 21.Mejia-Chew C, Sung A, Larson L, Powderly WG, Spec A. Treatment and mortality outcomes in patients with other extrapulmonary cryptococcal disease compared with central nervous system disease. Mycoses. 2021;64(2):174–180. doi: 10.1111/myc.13199 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Bicanic T, Wood R, Meintjes G, et al. High-Dose Amphotericin B with Flucytosine for the Treatment of Cryptococcal Meningitis in HIV-Infected Patients: A Randomized Trial. Clin Infect Dis. 2008;47(1):123–130. doi: 10.1086/588792 [DOI] [PubMed] [Google Scholar]
- 23.Domingues R, Bruniera G, Brunale F, Mangueira C, Senne C. Lumbar puncture in patients using anticoagulants and antiplatelet agents. Arq Neuropsiquiatr. 2016;74(8):679–686. doi: 10.1590/0004-282X20160098 [DOI] [PubMed] [Google Scholar]
- 24.Domenicucci M, Mancarella C, Santoro G, et al. Spinal epidural hematomas: personal experience and literature review of more than 1000 cases. J Neurosurg Spine. 2017;27(2):198–208. doi: 10.3171/2016.12.SPINE15475 [DOI] [PubMed] [Google Scholar]
- 25.Tang F-F, Sun Y-Q, Mo X-D, et al. Incidence, Risk Factors, and Outcomes of Primary Prolonged Isolated Thrombocytopenia after Haploidentical Hematopoietic Stem Cell Transplant. Biol Blood Marrow Transplant. 2020;26(8):1452–1458. doi: 10.1016/j.bbmt.2020.03.024 [DOI] [PubMed] [Google Scholar]
- 26.Madisetty J, Wang C. Transfusion Medicine and Coagulation Management in Organ Transplantation. Anesthesiol Clin. 2017;35(3):407–420. doi: 10.1016/j.anclin.2017.04.004 [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.