CNS Infections - Bacterial & Fungi Flashcards
What should you always give for suspected bacterial infection in child with stiff neck (suspected meningitis)?
Ceftriaxone (3rd generation cephalosporin)
What do you always want to do before giving drugs or doing LP?
Do a culture!
What will you see in the LP of bacterial meningitis?
High opening pressure (200-500) High WBC (100-20,000) - 18,000 High PMN (polymorphonuclear neutrophils) High/Elevated Protein (100-500) Low Glucose (bacteria is eating it all!) - under or equal to 40
What might cloudy CSF mean?
Infection
What are the most likely causes/etiologies of bacterial meningitis?
- Streptococcus pneumonia - (can start as sinusitis or otitis media and become meningitis) - most common in adults
- Neisseria meningiditis - teenage
- Haemophilus influenza type b - most often in unvaccinated infants & young children
What are the traits of Haemophilus influenza type b?
Gram -, rod
What does viral CSF look like?
Normal Glucose No change in pressure upon opening WBC elevated just a little (5-500) Elevated protein (30-150) Mostly normal glucose (maybe a little lower) Small amt. PMN, some Leukocytes NO BACTERIA ON GRAM STAIN
What does fungal CSF look like?
High opening pressure (>250) WBC elevated (20-2,000) No PMN (only leukocytes) Elevated protein (a little) Normalish glucose
What do Nisseria, Strep. pneumo and H. influenza look like on a gram stain?
Nisseria - gram -, diplococci
Strep. pneumo - gram +, diplococci, lancet shape
H. influenzae - gram -, rod
If gram stain looks ambiguous, what do you look for with meningitis?
- Check for X factor (hematin) and V factor (NAD) on chocolate agar = positive means H. influenzae
- Check for Latex agglutination with antibodies specific to polyribitol phosphate capsule = H. influenzae
What other organisms could cause meningitis?
- E. coli
- Listeria monocytogenes
- Mycobacterium tuberculosis
- Treponem pallidum
What virulence factors doe H. influenzae have?
Capsule, pili, outer membrane proteins, IgA protease and endotoxin.
What people are very susceptible to Haemophilus influenzae infection?
Unvaccinated people (especially infants) Immunocompromised
What other organisms are associated with ear infections (otitis media) - other than H. influenzae?
- Strep. pneumo.
- M. catorrhiasis
What infection are associated with H. influenzae?
- Often secondary to the flu
- Can be associated with ear & eye infections
- Meningitis, Otitis media, sinusitis, epiglottitis, tracheobronchitis, bacteremia, pneumonia
What is Type B H. influenzae?
Most virulent (meningitis, epiglottitis, bacteremia), polyribitol phosphate capsule antigens used for the vaccine
What kind of resistance does H. influenzae have?
Beta-lactamases are expressed!
What do you treat with?
Ceftriaxone + Clavulanate
What organism can cause headache, fever, joint pain and dry cough and is carried in soil in southwest regions?
Coccidioides immitis - Valley fever!
What type of fungi is Coccidioides immitis?
Dimorphic fungi:
- mold with hypea in soil
- produce arthroconidia that are inhaled into lung
- In lung: divides into huge spherule, which can rupture to release endospores!
What drugs could be used to treat Coccidiodes immitis?
Azoles - used for Fungi
Flucytosine - is a nucleotide analog that disrupts DNA and RNA synthesis (converted to 5-fluorouracil)
What other fungi are associated with development of meningitis in immunocompromised individuals (HIV) and what is its major virulence factor?
Crytococcus neoformins - Fungi that also has a capsule on it!! - manage it similarly to coccidiodes immitis
What does listeria look like on the gram stain?
Gram + (purple) , rods!
What does a wet mount of streptococcus pneumoniae or corynebacterium show?
Tumbling motility
