Opportunistic infections of the CNS

Question 1

Toxoplasma gondii

Answer 1

obligate intracellular parasite –> macro
most common xsmission in ingestion from infected intermediate host
Dx with serology

Question 2

Toxoplasma gondii patho

Answer 2

predilection for heart, lung, brain, and the eye
self-limiting mono-like Sx
remain dormant in cysts in various tissue after immune response
can be reactivated in immunocomp
primary dz while prego = congenital disease

Question 3

Toxoplasma life cycle

Answer 3

oocyst –> sexual cycle in cat
tachyzoite –>replicating form that disseminates
bardyzoite –> dormant form in cyts

Question 4

Cryptococcus Neoformans

Answer 4

leading cause of fungal meningitis
budding yeast at hot and cold
mucopolysaccharide capsule –> antiphago
grows well in nitrogen rich environments; pigeon poop
NO PTP xsmission
lung (nodule) –> CNS (meningitis; most common)

Question 5

C. Neoformans Dx and Tx

Answer 5

staining of capsules by India ink
latex agglutination
culture on SDA
self limiting; removal of nodule

Question 6

Pneumocystis Carinii

Answer 6

primitive fungus; but lacks ergosterol
when CD4+ <200 and malnourished children
fight infection via CMI
stain via Gomeri stain (cysts)
stain via Giemsa (trophozoite)

Question 7

P. Carinii patho

Answer 7

inhaled as sporozoite–> trophozoite –> cyst
droplet inhalation
Sx dz = reactivation or carrier state
bilateral diffuse interstitial pneumonitis w/ plasma cell infiltrates

Question 8

CMV

Answer 8

env linear ds DNA virus
early, interm, late proteins
replicates in epith and shed in secretions
latent inf in lymph and macro