Infections Caused by Yeast and Yeast-Like Fungi Flashcards
What types of cryptococcis cause disease?
Neoformans and gattii
What does crypto require for virulence?
Polysaccharide capsule.
Risk factors for crypto?
HIV, transplant, long-term steroids, cirrhosis
CD4 counts risk for crypto?
<100
What is neoformans associated with?
Pigeon poop and rotting trees
What is gatti associated with?
Eucalyptus in endemic areas [Candida, Pacific Northwest]
How does cryptococcis CSF infections present?
1/4 to 1/3 of patients may not have typical meningeal signs and symptoms. Fever in 50%. May have lethargy and encephalopathy due to increased ICP and direct neuroinvasion. CN palsies will occur later in disease typically involving the optic nerves.
What is a cryptococcoma
It is a space occupying CNS lesion.
What are the skin lesions of crypto?
Looks like molluscum. May be direct innoculation or more likely disseminated.
How does crypto effect the prostate?
Can cause chronic prostatitis. Usually subclinical but may serve as a reservoir leading to relapse in inadequately treated patients with disseminated crypto.
What is the most common bone related crypto presentation?
Vertebral osteomyelitis
Describe the CSF findings of crypto
Mild protein elevation, low to normal glucose, lymphocytic pleocytosis
Work up of suspected crypto
CSF antigen and fungal culture.
What media is needed to grow crypto?
Grows on most aerobic and fungal media.
What is a method to enhance isolation of crypto from the blood?
Lysis centrifugation
How is gatti and neoformans differentiated?
Concanavalin-glycine-thymol agar turns blue for C. gattii but not C. neoformans. Also (MALDI-TOF).
What does H and E stain show for crypto?
4–10 μm yeasts which appear to have a large clearing around them because the large polysaccharide capsule does not stain.
What do fungal stains show in crypto?
Narrow-based budding and variable sizes on Grocott’s methenamine silver (GMS) or periodic acid–Schiff (PAS)
What is the purpose of a Mucicarmine stain and a Alcian blue stain?
Can help in the differentiation from other fungi of similar size and morphology, which lack capsules. Alcian stains the capsule blue, mucicarmine stains the capsule red.
How is crypto antigen detected?
Lateral flow assay is preferred over older methods as it is more sensitive, specific and less expensive.
Who should have routine CrAg testing? Why?
People with HIV with CD4 ≤100 cells/μL in countries with high incidences of cryptococcal meningitis as the antigen is positive months before signs and symptoms of disease
What should you do if CrAg screen in an HIV patient with CD4 <100 is positive?
CSF examination to rule out meningitis. If active CM ruled out, pre-emptive fluconazole 400 mg PO daily × ≥12 months.
Do CrAg titers correlate to fungal burden?
No. They should not be trended to monitor response as patients can stay positive years following infection.
What is the utility of CrAG testing for pulmonary crypto?
It is specific but sensitivity is low.
What are the 3 phases of treatment for crypto meningitis?
Induction, consolidation, maintenance.
