Pulmonary cryptococcosis misdiagnosed as smear-negative pulmonary tuberculosis with fatal consequences

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.

Metagenomic next-generation sequencing contributes to the diagnosis of mixed pulmonary infection: a case report

BACKGROUND

Pulmonary cryptococcosis (PC) and mixed pulmonary infection are difficult to be diagnosed due to the non-specificity and their overlapping clinical manifestations. In terms of the clinical diagnosis of PC and mixed pulmonary infection, conventional tests have limitations such as a long detection period, a limited range of pathogens, and low sensitivity. Metagenomics next-generation sequencing (mNGS) is a nascent and powerful method that can detect pathogens without culture, to diagnose known and unexplained infections in reduced time.

CASE PRESENTATION

A 43-year-old female was admitted to the hospital after suffering from a cough for one month. At the time of admission, a contrast-enhanced chest CT revealed multiple nodules and plaques in her right lung, as well as the formation of cavities. The blood routine assays showed evidently increased white blood cell count (mainly neutrophils), CRP, and ESR, which suggested she was in the infection phase. The serum CrAg-LFA test showed a positive result. Initially, she was diagnosed with an unexplained pulmonary infection. Bronchoalveolar lavage fluid (BALF) samples were collected for microbial culture, immunological tests and the mNGS. Microbial culture and immunological tests were all negative, while mNGS detected Corynebacterium striatum, Pseudomonas aeruginosa, Streptococcus pneumoniae, and Cryptococcus neoformans. The diagnosis was revised to PC and bacterial pneumonia. Lung infection lesions were healed after she received targeted anti-infection therapy with mezlocillin and fluconazole. In a follow-up after 2 months, the patient's symptoms vanished.

CONCLUSIONS

Here, we demonstrated that mNGS was capable of accurately distinguishing Cryptococcus from M. tuberculosis in pulmonary infection, and notably mNGS was capable of swiftly and precisely detecting pathogens in mixed bacterial and fungal pulmonary infection. Furthermore, the results of mNGS also have the potential to adjust anti-infective therapies.

Pulmonary and Extrapulmonary Manifestations of Fungal Infections Misdiagnosed as Tuberculosis: The Need for Prompt Diagnosis and Management

Fungal infections commonly present with myriad symptoms that mimic other clinical entities, notable amongst which is tuberculosis. Besides histoplasmosis and chronic pulmonary aspergillosis, which can mimic TB, this review has identified several other fungal infections which also do. A total of 80 individual cases misdiagnosed as TB are highlighted: aspergillosis (n = 18, 22.5%), histoplasmosis (n = 16, 20%), blastomycosis (n = 14, 17.5%), cryptococcosis (n = 11, 13.8%), talaromycosis (n = 7, 8.8%), coccidioidomycosis (n = 5, 6.3%), mucormycosis (n = 4, 5%), sporotrichosis (n = 3, 3.8%), phaeohyphomycosis (n = 1, 1.3%) and chromoblastomycosis (n = 1, 1.3%). Case series from India and Pakistan reported over 100 cases of chronic and allergic bronchopulmonary aspergillosis had received anti-TB therapy before the correct diagnosis was made. Forty-five cases (56.3%) had favorable outcomes, and 25 (33.8%) died, outcome was unclear in the remainder. Seventeen (21.3%) cases were infected with human immunodeficiency virus (HIV). Diagnostic modalities were histopathology (n = 46, 57.5%), culture (n = 42, 52.5%), serology (n = 18, 22.5%), cytology (n = 2, 2.5%), gene sequencing (n = 5, 6.3%) and microscopy (n = 10, 12.5%) including Gram stain, India ink preparation, bone marrow smear and KOH mount. We conclude that the above fungal infections should always be considered or ruled out whenever a patient presents with symptoms suggestive of tuberculosis which is unconfirmed thereby reducing prolonged hospital stay and mortalities associated with a delayed or incorrect diagnosis of fungal infections.

It is not always Tuberculosis! A case of pulmonary cryptococcosis in an immunocompetent child in Uganda

Pulmonary cryptococcosis is rare in immunocompetent individuals. Limited data exist regarding its occurrence in children, especially in developing countries. This case report describes an 8-year-old HIV-negative child with pulmonary cryptococcosis, previously diagnosed and treated for tuberculosis twice without improvement. Fine needle aspiration biopsy confirmed the diagnosis of pulmonary cryptococcosis and serum cryptococcal antigen test was positive. The child improved on amphotericin and fluconazole treatment. Despite the limited diagnostic capacity in many resource-constrained settings like Uganda, this case report highlights the need to investigate other causes of pneumonia in immunocompetent children that are not improving on conventional antimicrobial treatments.

The development and validation of a diagnostic scoring system to differentiate pulmonary tuberculosis from non-tuberculosis pulmonary infections in HIV-infected patients with severe immune suppression

Background

It remains challenging to differentiate tuberculosis (TB) from non-TB pulmonary infections in HIV-infected patients. Herein, we developed a scoring system aimed to rapidly determine the likelihood of TB or non-TB pathology in HIV-infected patients presenting with pulmonary infections.

Methods

We collected and collated data of hospitalized HIV-infected patients with pulmonary infections, followed by univariate and multivariate data analyses to determine risk variables that were significantly different between HIV/TB patients and HIV/non-TB patients. Subsequently, a regression coefficient was calculated for each variable, and a score was assigned to each variable in line with its regression coefficient. The sum of the scores for each variable in our scoring model was used to predict the likelihood of TB or non-TB pulmonary infection in each patient. Finally, we tested the diagnostic accuracy of the scoring system in our retrospective cohort, as well as in a prospective cohort.

Results

A total of 598 HIV-infected patients were enrolled in our retrospective cohort, among whom 288 had TB and 310 had non-TB pulmonary infections. Eight variables, including fever, highest body temperature, erythrocyte sedimentation rate (ESR), cervical lymphadenopathy, hilar and/or mediastinum lymphadenopathy, pulmonary cavitation, pleural effusion, and miliary nodules, were found to be mathematically significantly different via univariate analysis and multivariate logistic regression analysis. After regression coefficient calculation followed by score assignment, a receiver operating characteristic (ROC) curve was plotted, and the area under the curve (AUC) was calculated to be 0.902. When the total score for a patient is > 12, the sensitivity and specificity for TB prediction using our scoring system were 76.4% and 87.7% respectively in the retrospective cohort, and its diagnostic accuracy was 82.7% in the prospective cohort.

Conclusions

Our results demonstrate that our proposed diagnostic scoring system could be helpful in differentiating pulmonary TB from non-TB pulmonary infections in HIV-infected patients.

A 34-Year-Old Man With HIV/AIDS and a Cavitary Pulmonary Lesion

A 34-year-old man presented to a community hospital with fever and fatigue for 3 days and was found to be febrile and tachycardic with a cavitary pulmonary lesion and paratracheal adenopathy on CT imaging. One month before, he had presented to his primary care provider with a palmar rash; he had been diagnosed and treated for syphilis and was also diagnosed with HIV. He had a CD4 count of 106 cells/μL and an HIV viral load of 1,290,000 copies/mL. Pneumocystis prophylaxis with trimethoprim-sulfamethoxazole and antiretroviral treatment with only tenofovir and emtricitabine therapy were started 2 weeks before presentation.

Examination of a Chinese-made cryptococcal glucuronoxylomannan antigen test in serum and bronchoalveolar lavage fluid for diagnosing pulmonary cryptococcosis in HIV-negative patients

BACKGROUND

We presented the performance of a Chinese-made cryptococcal glucuronoxylomannan (GXM) antigen test using serum and bronchoalveolar lavage fluid (BALF) samples in the HIV-negative Chinese population.

METHODS

Between February 2017 and January 2019, HIV-negative patients with pulmonary cryptococcosis were recruited and followed-up every three months, including completion of a chest CT examination and collection of serum and BALF samples.

RESULTS

Here, thirty-seven confirmed and ten clinically diagnosed patients were recruited. Furthermore, samples from 174 noncryptococcosis patients that may cause false positives were also collected. The sensitivity of a lateral flow assay (LFA) for detecting cryptococcal GXM antigen in serum and BALF samples from confirmed cases was 97% and 95%, respectively, and the specificity was 98.2% and 93%, respectively, and the differences in these values between the BALF and serum samples were not significant. The serum cryptococcal GXM antigen value showed a positive correlation (r: 0.581, p < 0.001) with pulmonary lesion size, while the BALF value showed no correlation (r: 0.253, p: 0.13). The positivity rate of BALF was higher than that of serum when the diameter of the pulmonary lesion was small (diameter less than 20 mm). Moreover, the serum cryptococcal GXM antigen levels showed an overall decreasing trend with the decrease in pulmonary lesion size after antifungal therapy in patient follow-up.

CONCLUSIONS

The Chinese-made cryptococcal GXM antigen test has better sensitivity and specificity for diagnosing pulmonary cryptococcosis in the HIV-negative Chinese population, and it could be used to diagnose and to monitor this disease.

Comparison of cryptococcal meningitis in HIV-negative patients with and without lung infections

Objective

To investigate the clinical features and outcomes of cryptococcal meningitis (CM) in HIV-negative patients with and without lung infections.

Methods

We retrospectively reviewed the medical records of HIV-negative patients with CM admitted to two university hospitals in Southwest China over the past 5 years.

Results

Seventy-one patients were included, of whom 35 (49.3%) had lung disease. Compared with patients without lung infection, CM patients with lung infection tended to be male and younger (≤30 years), experienced more fever, less vomiting and fewer central nervous system symptoms; more often had low white blood cell (WBC) counts (<20 × 10⁶/L), and fewer often had ethmoid sinusitis, maxillary sinusitis, paranasal sinusitis, and otitis media. Cryptococcus neoformans isolates from these patients were sensitive to itraconazole, voriconazole, fluconazole, and amphotericin B but resistant to flucytosine. CM patients with lung infection had higher mortality at discharge compared with patients without lung infection (8.6% vs. 0%). Multivariable analyses showed that a WBC count <20 × 10⁶/L was significantly associated with poor treatment outcome (odds ratio 0.01, 95% confidence interval 0–0.83).

Conclusion

HIV-negative CM patients with lung infections tended to be male and younger. Fever, fewer central nervous system symptoms, and WBC counts <20 × 10⁶/L were characteristic of this patient group.

An AIDS patient with urine retention

Background

Cryptococcal prostatitis is a rare clinical disease and has never been reported in China.

Case presentation

We report on a male HIV-infected patient with pulmonary and prostate cryptococcosis that was misdiagnosed (as tuberculosis) and delayed diagnosed. Although the patients accepted anti-fungal treatment and anti-retroviral treatment finally, the physician’s mistakes reflect the rarity of this condition in China.

Conclusion

Cryptococcal prostatitis is a rare disease that unusually presents in immunodeficient patients. Physicians should have a heightened awareness of this particular infection in the immunodeficient population.

Pulmonary cryptococcosis: A review of pathobiology and clinical aspects

Pulmonary cryptococcosis is an important opportunistic invasive mycosis in immunocompromised patients, but it is also increasingly seen in immunocompetent patients. The main human pathogens are Cryptococcus neoformans and C. gattii, which have a worldwide distribution. In contrast to cryptococcal meningitis, pulmonary cryptococcosis is still underdiagnosed because of limitations in diagnostic tools. It can mimic lung cancer, pulmonary tuberculosis, bacterial pneumonia, and other pulmonary mycoses both clinically and radiologically. Pulmonary nodules are the most common radiological feature, but these are not specific to pulmonary cryptococcosis. The sensitivity of culture of respiratory samples for Cryptococcus is poor and a positive result may also reflect colonisation. Cryptococcal antigen (CrAg) with lateral flow device is a fast and sensitive test and widely used on serum and cerebrospinal fluid, but sera from patients with pulmonary cryptococcosis are rarely positive in the absence of disseminated disease. Detection of CrAg from respiratory specimens might assist the diagnosis of pulmonary cryptococcosis but there are very few data. Molecular detection techniques such as multiplex reverse transcription polymerase chain reaction (RT-PCR) could also provide better sensitivity but these still require validation for respiratory specimens. The first line of treatment for pulmonary cryptococcosis is fluconazole, or amphotericin B and flucytosine for those with central nervous system involvement. Pulmonary cryptococcosis worsens the prognosis of cryptococcal meningitis. In this review, we summarize the biological aspects of Cryptococcus and provide an update on the diagnosis and management of pulmonary cryptococcosis.

Opportunistic infections and immune reconstitution inflammatory syndrome in HIV-1-infected adults in the combined antiretroviral therapy era: a comprehensive review

Despite the availability of effective combined antiretroviral treatment, many patients still present with advanced HIV infection, often accompanied by an AIDS-defining disease. A subgroup of patients starting antiretroviral treatment under these clinical conditions may experience paradoxical worsening of their disease as a result of an exaggerated immune response towards an active (but also subclinical) infectious agent, despite an appropriate virological and immunological response to the treatment. This clinical condition, known as immune reconstitution inflammatory syndrome, may cause significant morbidity and even mortality if it is not promptly recognized and treated. This review updates current knowledge about the incidence, diagnostic criteria, risk factors, clinical manifestations, and management of opportunistic infections and immune reconstitution inflammatory syndrome in the combined antiretroviral treatment era.

Cryptococcosis in HIV-infected hospitalized patients in Germany: Evidence for routine antigen testing

OBJECTIVES

To investigate the diagnostic value of routine cryptococcal antigen (CRAG) testing in HIV-infected patients in a low prevalence setting.

METHODS

Retrospective single centre cohort study of a 10-year period (2005-2014).

RESULTS

5461 patients tested for CRAG were included. Cryptococcal antigenaemia was found in 1.6% and 1.1% of patients with CD4 counts of ≤100/μl and 101-200/μl, respectively. The positive predictive values for identifying clinically relevant cryptococcal disease was 96% and 100%, respectively. Half of the patients had a non-specific presentation and median time-to-diagnosis was high (5 days, range 1-44 days). The median time-to-diagnosis in direct admissions to our centre with routine CRAG testing was significantly shorter: 1 day (range: 1-17) vs. 7 days (range: 2-44), p = 0.003. Prevalence of cryptococcal antigenaemia was 2.8% in patients with pneumocystis pneumonia and median time-to-diagnosis of cryptococcosis was significantly longer in this subgroup (15 days; range: 1-44 vs. 3 days; range: 1-17; p = 0.008). CRAG titres ≥1:512 were associated with disseminated disease (OR 21.3, p = 0.0008, 95% CI 1.64-277), however, 10% of patients with disseminated cryptococcosis had CRAG titres <1:16.

CONCLUSION

Our data support routine CRAG testing in hospitalized HIV-infected patients with CD4 counts ≤200/μl, and/or pneumocystis pneumonia.

Lack of IL-4 receptor expression on T helper cells reduces T helper 2 cell polyfunctionality and confers resistance in allergic bronchopulmonary mycosis

T helper (Th)1 and Th2 cells play decisive roles in the regulation of resistance vs. susceptibility to pulmonary cryptococcosis. To study the function of interleukin (IL)-4 receptor (IL-4R) on Th cells in pulmonary cryptococcosis, we infected mice specifically lacking IL-4Rα on CD4(+) T cells (Lck(Cre)IL-4Rα(-/lox) mice) and IL-4Rα(-/lox) controls. Lck(Cre)IL-4Rα(-/lox) mice developed enhanced resistance accompanied by reduced pulmonary allergic inflammation and diminished production of the Th2 cytokines IL-4, IL-5, and IL-13 as compared with IL-4Rα(-/lox) mice. Polyfunctional antigen-specific Th2 cells producing simultaneously two or three Th2 cytokines were reduced in infected Lck(Cre)IL-4Rα(-/lox) mice, pointing to a critical role of polyfunctional Th2 cells for disease progression. Reduced Th2 polyfunctionality was associated with fewer pulmonary alternatively activated macrophages. This work is the first direct evidence for a critical contribution of the IL-4R on Th cells to Th2-dependent susceptibility during allergic bronchopulmonary mycosis. Moreover, the data demonstrate that the quality of the Th2 response has an impact on type 2 inflammation. The analysis of polyfunctional Th2 cells may be useful for monitoring the course of the disease.

CrAg lateral flow assay for cryptococcosis

Importance of field: Cryptococcal meningitis is a leading cause of death globally among people with AIDS. In sub-Saharan Africa, cryptococcosis is estimated to kill more people than tuberculosis. Cryptococcosis is also an important infectious disease among immunosuppressed patients in countries with advanced medical care. Early diagnosis is the key to effective treatment, particularly in patients in resource-limited settings. A new lateral flow immunoassay (LFA) for cryptococcal antigen (CrAg) allows for rapid and inexpensive diagnosis of cryptococcosis at or near the point of patient contact.

AREAS COVERED

This article reviews the need for improved diagnostics for cryptococcal meningitis and describes the features of an ideal diagnostic. The design of a new LFA for CrAg is described as well as the results of initial clinical evaluation of the CrAg LFA.

EXPERT OPINION

The CrAg LFA is recommended for use with serum, plasma or CSF for diagnosis of cryptococcal meningitis or non-meningeal cryptococcal disease in symptomatic patients. There is a need for further evaluation of LFA for screening of asymptomatic patients. However, the LFA is emerging as a valuable tool for screening of serum or plasma in ART-naive adults with CD4 counts less than 100 cells/mm(3) in geographic regions with a high prevalence of cryptococcal antigenemia. CrAg screening has the potential to identify patients with asymptomatic cryptococcal infection who should receive preemptive antifungal therapy.

IL-23 dampens the allergic response to Cryptococcus neoformans through IL-17-independent and -dependent mechanisms

The cytokines IL-23 and IL-17 have been implicated in resistance to cryptococcal disease, but it is not clear whether IL-23-mediated production of IL-17 promotes fungal containment following pulmonary challenge with Cryptococcus neoformans. We used mice lacking IL-23 (IL-23p19(-/-)) or IL-17RA (IL-17RA(-/-)), and wild type (WT) C57BL/6 mice to examine the IL-23/IL-17 axis after intranasal infection with the C. neoformans strain 52D. The absence of IL-23 or IL-17RA had no effect on pulmonary or brain fungal burden at 1 or 6 weeks after infection. However, survival of IL-23p19(-/-) mice was reduced compared to IL-17RA(-/-) mice. IL-I7 production by CD4 T cells and natural killer T (NKT) cells was impaired in IL-23p19(-/-) lungs, but was not completely abolished. Both IL-23p19(-/-) and IL-17RA(-/-) mice exhibited impaired neutrophil recruitment, increased serum levels of IgE and IgG2b, and increased deposition of YM1/YM2 crystals in the lung, but only IL-23p19(-/-) mice developed persistent lung eosinophilia. Although survival of IL-17RA(-/-) and WT mice was similar after 17 weeks of infection, only surviving IL-17RA(-/-) mice exhibited cryptococcal dissemination to the blood. These data demonstrate that IL-23 dampens the allergic response to cryptococcal infection through IL-17-independent suppression of eosinophil recruitment and IL-17-dependent regulation of antibody production and crystal deposition. Furthermore, IL-23, and to a lesser extent IL-17, contribute to disease resistance.

Evaluation of a newly developed lateral flow immunoassay for the diagnosis of cryptococcosis

This study, evaluating the performance of a novel cryptococcal lateral flow immunoassay, shows that the assay performs as well as available diagnostic methods is economical, rapid, and easy to perform; and as such can be a point of care test in resource limited settings.

Background. Cryptococcosis is a common opportunistic infection of human immunodeficiency virus (HIV)–infected individuals mostly occurring in resource-limited countries. This study compares the performance of a recently developed lateral flow immunoassay (LFA) to blood culture and enzyme immunoassay (EIA) for the diagnosis of cryptococcosis.

Methods. Archived sera from 704 HIV-infected patients hospitalized for acute respiratory illness in Thailand were tested for cryptococcal antigenemia using EIA. All EIA-positive and a subset of EIA-negative sera were tested by LFA, with results recorded after 5 and 15 minutes incubation. Urine from patients with LFA- and EIA-positive sera was tested by LFA. Antigen results from patients with positive cryptococcal blood cultures were compared.

Results. Of 704 sera, 92 (13%) were positive by EIA; among the 91 EIA-positive sera tested by LFA, 82 (90%) and 87 (96%) were LFA positive when read after 5 and 15 minutes, respectively. Kappa agreement of EIA and LFA for sera was 0.923 after 5 minutes and 0.959 after 15 minutes, respectively. Two of 373 EIA-negative sera were LFA positive at both time points. Of 74 urine specimens from EIA-positive patients, 52 (70.3%) were LFA positive. EIA was positive in 16 of 17 sera from blood culture–positive patients (94% sensitivity), and all sera were positive by LFA (100% sensitivity).

Conclusions. A high level of agreement was shown between LFA and EIA testing of serum. The LFA is a rapid, easy-to-perform assay that does not require refrigeration, demonstrating its potential usefulness as a point-of-care assay for diagnosis of cryptococcosis in resource-limited countries.