Case report: chronic relapsing cryptococcal meningitis in a patient with low mannose-binding lectin and a low naïve CD4 cell count

Chronic Ventriculitis Caused by Cryptococcus neoformans: A Rare Presentation

Cryptococcus neoformans is a fungus notorious for invading the central nervous system. while Cryptococcus is known to cause meningitis, encephalitis, and meningoencephalitis in immunocompromised patients, especially those with AIDS (CD4 <100), and found to be rapidly fatal, instances of ventricular involvement with chronic sequelae are exceedingly rare. Typical presentations of cryptococcal meningitis involve headache, altered mental status, nuchal rigidity, and vomiting. We report a case of a 58-year-old HIV-positive male who presented with intermittent headaches and changes in gait. The MRI revealed ventriculomegaly and advanced chronic sequela of prior ventriculitis with serum and CSF cryptococcal antigen being positive. The treatment of cryptococcal chronic ventriculitis requires a multidisciplinary approach involving internal medicine, neurosurgery, neurology, and infectious diseases. However, this patient's CSF had no pleocytosis and had very high protein, which is a poor prognostic indicator for this disease and could have been prevented with the prompt recognition of the condition before it had progressed to the chronic stage. We recommend that clinicians maintain a high index of suspicion for opportunistic infections, such as cryptococcal meningitis, in any patient with HIV regardless of typical clinical findings.

Cryptococcus neoformans, a global threat to human health

BACKGROUND

Emerging fungal pathogens pose important threats to global public health. The World Health Organization has responded to the rising threat of traditionally neglected fungal infections by developing a Fungal Priority Pathogens List (FPPL). Taking the highest-ranked fungal pathogen in the FPPL, Cryptococcus neoformans, as a paradigm, we review progress made over the past two decades on its global burden, its clinical manifestation and management of cryptococcal infection, and its antifungal resistance. The purpose of this review is to drive research efforts to improve future diagnoses, therapies, and interventions associated with fungal infections.

METHODS

We first reviewed trends in the global burden of HIV-associated cryptococcal infection, mainly based on a series of systematic studies. We next conducted scoping reviews in accordance with the guidelines described in the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews using PubMed and ScienceDirect with the keyword Cryptococcus neoformans to identify case reports of cryptococcal infections published since 2000. We then reviewed recent updates on the diagnosis and antifungal treatment of cryptococcal infections. Finally, we summarized knowledge regarding the resistance and tolerance of C. neoformans to approved antifungal drugs.

RESULTS

There has been a general reduction in the estimated global burden of HIV-associated cryptococcal meningitis since 2009, probably due to improvements in highly active antiretroviral therapies. However, cryptococcal meningitis still accounts for 19% of AIDS-related deaths annually. The incidences of CM in Europe and North America and the Latin America region have increased by approximately two-fold since 2009, while other regions showed either reduced or stable numbers of cases. Unfortunately, diagnostic and treatment options for cryptococcal infections are limited, and emerging antifungal resistance exacerbates the public health burden.

CONCLUSION

The rising threat of C. neoformans is compounded by accumulating evidence for its ability to infect immunocompetent individuals and the emergence of antifungal-resistant variants. Emphasis should be placed on further understanding the mechanisms of pathogenicity and of antifungal resistance and tolerance. The development of novel management strategies through the identification of new drug targets and the discovery and optimization of new and existing diagnostics and therapeutics are key to reducing the health burden.

Human immune polymorphisms associated with the risk of cryptococcal disease

Cryptococcus neoformans is an opportunistic fungal pathogen that can cause lethal cryptococcal meningitis in immunocompromised individuals such as those with HIV/AIDS. In addition, cryptococcal infections occasionally arise in immunocompetent individuals or those with previously undiagnosed immunodeficiencies. The course of cryptococcosis is highly variable in both patient groups, and there is rapidly growing evidence that genetic polymorphisms may have a significant impact on the trajectory of disease. Here, we review what is currently known about the nature of these polymorphisms and their impact on host response to C. neoformans infection. Thus far, polymorphisms in Fc gamma receptors, mannose‐binding lectin, Dectin‐2, Toll‐like receptors and macrophage colony‐stimulating factor have been associated with susceptibility to cryptococcal disease. Notably, however, in some cases the impact of these polymorphisms depends on the genetic background of the population; for example, the FCGR3A 158 F/V polymorphism was associated with an increased risk of cryptococcal disease in both HIV‐positive and HIV‐negative white populations, but not in Han Chinese patients. In most cases, the precise mechanism by which the identified polymorphisms influence disease progression remains unclear, although impaired fungal recognition and phagocytosis by innate immune cells appears to play a major role. Finally, we highlight outstanding questions in the field and emphasize the need for future research to include more diverse populations in their genetic association studies.

A Rare Presentation of Cryptococcal Meningitis in a Treatment-Naive Patient with Sarcoidosis

Cryptococcus neoformans is an encapsulated, yeast-like fungus that commonly lives in the environment due to soil contamination by the faeces of birds, especially pigeons. Cryptococcus is an opportunistic fungal infection frequently diagnosed in immunocompromised patients with HIV, steroid use, malignancy, history of organ transplantation, or, rarely, sarcoidosis. There have been only a few reports of cryptococcus infection in sarcoidosis patients who were not on steroid treatment. Here, we highlight the importance of considering opportunistic fungal infection in asymptomatic treatment-naive sarcoidosis patients. We present a patient with a history of asymptomatic, treatment-naive sarcoidosis who presented with headache and was diagnosed with cryptococcal meningitis in the presence of an idiopathic T-cell lymphopenia.

LEARNING POINTS

Cryptococcus is an opportunistic fungal infection commonly diagnosed in immunocompromised patients.Sarcoidosis is a multi-systemic disease characterized by the formation of granulomas in various organs, most commonly found in the lungs and mediastinal lymph nodes.

Cryptococcal spondylodiscitis in a non-HIV patient with CD4 lymphocytopenia

Infections that affect the intervertebral discs and vertebrae are known as spondylodiscitis. Such infections are commonly caused by pyogenic organisms, particularly Staphylococcus aureus, and hematogenous spread is the most common route. Non-pyogenic infections include Mycobacterium tuberculosis and Brucellosis. Mycotic infections are becoming more common, in line with the growing number of immunodeficiency disorders. Cryptococcus is included among these mycotic infections. We present a case of such an infection in a non-immunocompromised patient with a known history of treatment with antitubercular therapy. A 52-year-old man came to our hospital with a backache of one-month duration and progressive neurological deficits of the lower limbs of one-week duration. His imaging studies were suggestive of spondylodiscitis at the D10-11 and D11-12 levels with a left paraspinal abscess. The patient underwent anterolateral decompression, biopsy, and instrumented posterior spinal fusion. The pus grew Cryptococcus, and histopathology confirmed Cryptococcal spondylodiscitis. The patient was treated with parenteral amphotericin B and fluconazole. A mycotic infection must be considered in the differential diagnosis of infectious spondylodiscitis.