Cryptococcal Meningitis
To view the entire topic, please log in or purchase a subscription.
Pediatrics Central™ is an all-in-one application that puts valuable medical information, via your mobile device or the web, in the hands of clinicians treating infants, children, and adolescents. Explore these free sample topics:
-- The first section of this topic is shown below --
PATHOGENS
- Two main species complexes of Cryptococcus are important for human disease.
- Cryptococcus neoformans
- This is the predominant pathogen (~80% of human cryptococcosis cases) and is the most common cause of non-viral meningitis in people.
- Worldwide distribution. Particularly prevalent in soil contaminated by guano.
- Nomenclature is in flux with some arguing for two species (C. neoformans and C. deneoformans) while others arguing for a more comprehensive term C. neoformans complex.
- Cryptococcus gattii:
- Responsible for approximately 20% of human cases of cryptococcosis.
- Understanding of distribution is evolving, but predominantly seen in tropical and subtropical climates (e.g., Australia, Oceania and parts of Africa, Asia, Europe and the Americas).
- In North America, it has been associated with outbreaks in the Pacific Northwest (Vancouver Island, Washington, Oregon).
- Nomenclature in flux with some arguing for 5 species (C. gattii, C deuterogattii, C. bacillisporus, C. tetragattii and C. decagattii) while others for a comprehensive C. gattii complex.
- Unlike C. neoformans, is more commonly seen in healthy hosts.
- Has reduced sensitivity to fluconazole and appears to be more virulent.
- Cryptococcus neoformans
- Pathogenesis:
- Acquisition of organism:
- The most common form of exposure is via inhalation of the fungal spore into airways.
- Other forms of exposure are direct inoculation into the skin or transmission via organ transplant.
- Cryptococcus has multiple virulence factors.
- Foremost amongst those is the polysaccharide capsule that impairs immune response to the fungus and contributes to CNS disuse manifestations.
- An effective immune response is critical to protection from infection, but an over-exuberant response is also responsible for neurological symptoms in both HIV and non-HIV patients.
- Fate of infection:
- Controlled via immune response and cleared--or remains in a chronic latent form (with the possibility of future reactivation).
- Localized to the site of exposure (e.g., lung or skin).
- May disseminate to various other sites including CNS (virtually any organ can be involved but most common also include bloodstream, skin, reticuloendothelial system, prostate).
- Acquisition of organism:
-- To view the remaining sections of this topic, please log in or purchase a subscription --
PATHOGENS
- Two main species complexes of Cryptococcus are important for human disease.
- Cryptococcus neoformans
- This is the predominant pathogen (~80% of human cryptococcosis cases) and is the most common cause of non-viral meningitis in people.
- Worldwide distribution. Particularly prevalent in soil contaminated by guano.
- Nomenclature is in flux with some arguing for two species (C. neoformans and C. deneoformans) while others arguing for a more comprehensive term C. neoformans complex.
- Cryptococcus gattii:
- Responsible for approximately 20% of human cases of cryptococcosis.
- Understanding of distribution is evolving, but predominantly seen in tropical and subtropical climates (e.g., Australia, Oceania and parts of Africa, Asia, Europe and the Americas).
- In North America, it has been associated with outbreaks in the Pacific Northwest (Vancouver Island, Washington, Oregon).
- Nomenclature in flux with some arguing for 5 species (C. gattii, C deuterogattii, C. bacillisporus, C. tetragattii and C. decagattii) while others for a comprehensive C. gattii complex.
- Unlike C. neoformans, is more commonly seen in healthy hosts.
- Has reduced sensitivity to fluconazole and appears to be more virulent.
- Cryptococcus neoformans
- Pathogenesis:
- Acquisition of organism:
- The most common form of exposure is via inhalation of the fungal spore into airways.
- Other forms of exposure are direct inoculation into the skin or transmission via organ transplant.
- Cryptococcus has multiple virulence factors.
- Foremost amongst those is the polysaccharide capsule that impairs immune response to the fungus and contributes to CNS disuse manifestations.
- An effective immune response is critical to protection from infection, but an over-exuberant response is also responsible for neurological symptoms in both HIV and non-HIV patients.
- Fate of infection:
- Controlled via immune response and cleared--or remains in a chronic latent form (with the possibility of future reactivation).
- Localized to the site of exposure (e.g., lung or skin).
- May disseminate to various other sites including CNS (virtually any organ can be involved but most common also include bloodstream, skin, reticuloendothelial system, prostate).
- Acquisition of organism:
There's more to see -- the rest of this entry is available only to subscribers.