Fungal and parasitic CNS infections Flashcards
Which agent has terminal, “tennis racket” like spores?
Clostridium Tetani
What population is at the largest risk for C. tetani, esp in underdeveloped countries?
newborns and IV drug users
What is the key VF in C. Tetani?
Tetanospasmin, a potent exotoxin
What does tetanospasmin toxin activity result in?
disruption of CNS control, autonomic dysfunction, and NM junction dysfunction
What are the signs of tetanus?
Trismus, risus sardonicus, opisthotonos, and flexion of the arms and extension of the lower extremities, pneumonia, hypo/hypertension, tachycardia (death due to resp/cardiac failure)
What is used to neutralize the tetanus exotoxin and for passive immunization?
Human Tetanus Immune Globulin (HTIG)
What is the DOC for Tetanus?
PCN plus antitoxin (HTIG)
What agent produces the most potent toxin known, has subterminal spores, and is greatly heat resistant?
Clostridium botulinum
What is the reason for GI distrubance in food poisoning with c. botulinum? Infant botulism?
Neurotoxin; spores and neurotoxin
What antibiotic should be used with C. botulinum?
NONE! Use antitoxin only
Cryptococcus neoformans is to ___ as cryptococcus gattii is to___
Immunocompromised; immunocompetent (fatal)
What does cryptococcus neoformans result in in immunocompromised hosts?
meningoencephalitis, all cases are fatal
Thick capsule that produces creamy, mucoid colonies
Cryptococcus neoformans
What medium does cryptococcus neoformans grow on?
Saboroud’s dextrose agar or potato dextrose agar
What two serotypes are found in c. neoformans? c. gattii?
A/D; B and C
What is the CP of cryptococcosis?
Fever, HA, stiff neck, change in mental status, LOW GLUCOSE
What stain is used if you suspect C. Neoformans?
India Ink
How do you differentiate between C. neoformans and C. gattii?
C. neoformans will grow on CGB medium
What is the DOC for crypto neoformans?
ampho B + flucytosine, fluconazole following acute tx in AIDS pts.
What does toxoplasma gondii cause?
the third leading cause of death in the US due to FBI, most are asymptomatic in immunocompetent hosts
Where do we see severe complications of toxoplasma gondii?
in immunocompromised hosts and women NEWLY infected in PGN
What is the name of the tissue cyst that contains bradyzoites in toxoplasmosis?
zoitocyst
What is the triad of sx that suggest congenital toxoplasmosis?
Chorioretinitis, hydrocephalus, intracranial calcifications
What is the CP of postnatal toxoplasmosis?
Fever, myalgia, blurred vision
How does transmission of toxoplasma gondii usually occur?
foodborne (usually zoitocysts), zoonotic (oocysts), and rarely through blood transfusion and organ transplantation
What is the test of choice for diagnosing toxoplasmosis?
PCR to evaluate DNA or ELISA to evaluate IgG or IgM in amniotic fluid, DIFFICULT TO OBTAIN CSF SAMPLE
What is the treatment for toxoplasmosis?
pyrimethamine and sulfadiazine (parasite still stays in tissues)
What is considered the business end of the naegleria fowleri?
amoeboid
What is the causitive agent that results in primary acute meningoencephalitis in HEALTHY individuals? How many days post exposure?
Naegleria Fowleri, 1-14 days post exposure, death occurs in two days of becoming symptomatic!
Why is Naegleria caught so late?
Because we treated them for bacterial and fungal meningitis first!
Summer months, southern states, freshwater, cannot be contracted from drinking contaminated water, and by using tap water in Neti pots
Naegleria fowleri
What is the combination therapy for naegleria fowleri?
Amphotericin B, rifampin, and miconazole
Which protozoan possesses spiked pseudopodia?
acanthamoeba
Which agent causes pain and blurred vision following trauma to the eye that can resemble corneal herpes?
acanthamoeba
How can you control infection of acanthamoeba?
wear gloves while gardening, properly clean lesions
What is the treatment of choice for keratitis?
oral itraconazole, topical miconazole + corticosteroid
