Fungal Meningitis Flashcards
What are some common fungal causes of meningitis?
Cryptococcus neoformans
Candida, Aspergillus, Coccidioides, Histoplasma, Blastomyces, Zygomycetes
Exserohilum rostratum
85% of Crytpococcal neoformans meningitis occurs in what patients?
HIV pts.
Crytpococcal neoformans is associated with ___________
pigeon droppings
What is the structure of Crytpococcal neoformans?
Not dimorphic, always an encapsulated yeast
Presentation of Cryptoccocus neoformans
Initial pulmonary infection is asymptomatic
Chronic infection leads to meningitis, fatal if left untreated
How is Cryptococcal meningitis diagnosed?
get CSF of pt, and treat with India ink, look for halos
or CSF testing for antigens
What is the tx for Cryptococcal meningitis?
Amphotericin B and flucytosine combo therapy for CNS cases
Objectives
- Recall that fungal meningitis is typically an opportunistic infection
- Recall the most common cause of fungal meningitis and its key virulence factor
- Recall the predominant fungal cause of steroid-linked meningitis
- Recall diagnostic and treatment procedures for the discussed forms of meningitis
T or F. Fungal meningitis is rare is typically observed only in immunocompromised pts
T.
What is the natural course of Fungal meningitis?
Natural course is spread from blood stream to CNS (Recent outbreaks attributable to epidural injection of contaminated steroids are exceptions to natural courses of fungal meningitis)
As with bacterial meningitis, it is critical to quickly suspect and confirm cases. Some ways to do this include:
- Microscopic observation of yeast forms in CSF samples
- Culture of CSF for fungi
- Antigen detection in CSF for some fungi (Cryptococcus)
- Treat with maximum tolerated doses of amphotericin B for extended times, often in combination with flucytosine which enters the CNS better
The Most common agent in immunocompromised patients is:
Cryptococcus neoformans
- Other fungi include
a. Candida spp. (mostly nosocomial)
b. Aspergillus spp.
c. Coccidioides immitis
d. Histoplasma capsulatum
e. Blastomyces dermatiditis (rare)
f. Zygomycetes spp. (rare)
Cryptococcosis is caused by cryptococcus neoformand or C. gattii
- C. neoformans found in pigeon droppings, is inhaled
a. Worldwide distribution
b. 85% of all cases occur in HIV-infected patients