Fungal Infections of CNS

Question 1

fungal infections of CNS

Answer 1

• most diverse phylogenetic group
• common environmental organisms
• inhabit all ecosystems
• neglected by press and society
• hard to treat

Question 2

fungal infections mortality and morbidity

Answer 2

highest mortality and morbidity

Question 3

what are fungi

Answer 3

• eukaryotic organisms
• Estimated to be ~3 million species -only ~120,000 have been described
• ~40 are frequent human pathogens
• Far fewer invade the CNS
• Always posed threat to public health but increasing recently

Question 4

5 broad classification categories for Mycoses

Answer 4

• Based on site
• requirements to cause systemic disease in humans
• based on fungal virulence

Question 5

Classification of mycoses based on site (3)

Answer 5

1. superficial: skin, hair, nails
2. subcutaneous: lower levels of skin; fat; mucous membranes
3. systemic or invasive: internal organs

Question 6

what are the 4 requirements to cause systemic disease in humans

Answer 6

1. high temp tolerance
2. ability to invade
3. ability to obtain nutrients and grow
4. resistance to the immune system

Question 7

classification of mycoses based on fungal virulence

Answer 7

1. primary: can infect healthy immunocompetent individuals
2. opportunistic: only infect the immunocompromised

Question 8

Primary CNS fungi infections are:

Answer 8

uncommon, limited niches, usually treatable

Question 9

opportunistic CNS fungi infections are:

Answer 9

more frequent, ubiquitous, usually fatal

Question 10

4 main ways to diagnose fungal infections

Answer 10

1. direct visualization w/ w/o staining
   - calcofluor white
   - india ink
2. blood/CSF cultures
   - most readily cultivable
3. tissue cultures
   - requires crushing/processing of tissue which destroys molds
4. Serology (antibody based assays)
   - CrAg test, allowed for cryptococcal screening

Question 11

what is the most common endemic fungal infection in Americas

Answer 11

histoplasma

Question 12

why is the medical burden of mycoses increasing

Answer 12

1. Delayed diagnosis
   * Know if you live in endemic area for fungal pathogens
   * Know if you have conditions that put you at risk
2. Few antifungals
3. Toxic side effects

• New opportunities! For many, accidental hosts
• New platforms and niches! Appearance of
  superbugs!
• New land! Ease of travel, climate change, etc.