CNS Infections II Flashcards
where does Haemophilus influenzae get its virulence
pili, LPS, capsule (polyribitol phosphate)
biology of heamophilus influenzae
non motile gram neg rod, fastidious [uses X (heme) and V (NAD) factor]
clinical features of h. influenzae
- slower onset (3-4 days)
- follows: nasopharyngitis, sinusitus, otitis media
- 1/3 survivors have neurological sequel
prevention of haemophilus influenzae
vaccine: herbix
problem with vaccination of h. influenzae
it is specific for the capsule of h. influenzae but new strains are now unencapsulated
who gets the listeria monocytogenes strain of meningitis
– Infants
– Adults >60y, alcoholics, cancer patients, renal transplant
-those who drink unpasteurized milk
biology of listeria monocytogenes (include virulence factor)
gram positive rod
virulence factors: internalin A and B, listeriolysin O
functions of internalin A and B and listeriolysin O
internalins - helps bacteria attach to host
listerolysin - form spores that help bacteria invade cells
clinical features of listeria monocytogenes
– Subclinical-gastrointestinal like
– Neonatal
– Immunocompromised
transmission of strep agalactiae
it is seen in newborns so vertical transmission from pregnant women who 15-35% of them are asymptomatic
Facultative Gram-negative bacilli
Klebsiella, E. coli, S. marcescens, P. aeruginosa
how does one get the facultative gram neg bacilli
head trauma or neurosurgery
how does one get a staphylococci CNS infection
early post neurosurgical/post-trauma hence why it is so uncommon
underlying conditions that lead to staphylococci CNS infections
– Diabetes mellitus
– Alcoholism
– Chronic renal failure (hemodialysis)
how does staph epidermidis get to the CNS
uses CSF shunts
what is a health care related CNS infection
MRSA
treponema pallidum can lead to what CNS infections
syphilis and spirocheteal meningitis
clinical neurosyphilis
– Syphilitic meningitis (0.3-2.4% untreated cases)
– Meningovascular syphilis
– Parenchymatous neurosyphilis
– Gummatous neurosyphilis (rare)
Borrelia burgdorferi can lead to what infection
Lyme infection
special feature of borrelia burgodorferi
clinical features of borrelia burgodorferi
spirochete
2-10 weeks post erythema migrans
symptoms of viral causes of meningitis
- acute benign, self limiting, monophasic
- cranial neuropathy and raised intracranial pressure
most common cause of viral meningitis in US
enterovirus
pathogenesis of viral causes of meningitis
mucosal surface colonization RTI/GIT –> viremia –> CNS invasion –> virus spread within the CNS
who gets non polio enterovirus
infants and young children with no previous exposure and immunity
thought it is part of adult normal flora
who gets mump virus
non immunized population (meningoencephalitis)
feature of mump virus
benign and self limiting
what are the late viruses
herpes
most common herpes virus in CNS infection
HSV 2
what are the herpes virus associated with CNS infections
HSV, VZV, CMV, EBV, HHV 6, 7, 8
virus associated with roseola infantum
HHV6
arbovirus (arthropod borne) leads to
encephalitis
what virus is associated with rodents and excreta (hamsters, rats, mice)
Lymphocytic choriomeningitis virus
so you see this in lab workers, houses with poor hygiene, pet owners
most fungal cause of CNS infections
cryptococcus neoformans (cryptococcus gatti)
what does c. neoformans cause in immunocompromised and previous healthy individuals
encephalitis
how do you diagnose c. neoformans
PCR, india ink (capsule)
what does c. gattii colonize
wood
geographical location of histoplasma capsulatum
Ohio, Mississippi river valley
who is commonly affected with histoplasma capsulatum
• Immunosuppressed
– AIDS
– Solid organ transplants
how do you diagnose histoplasmosis
PCR (best), histoplasma antigen in CSF, culture (grows slowly)
what is seen in blastomyces
brain abscesses
geographical location of coccoides
Central & Southern Arizona + Central Valley of California
symptoms of coccoides and diagnosis method
pneumonia like
eosinophil in CSF, complement fixation test
how does one get candida
common in neonatal ICU through the use of IV catheters
most common cause of chronic meningitis
mycobacterium tuberculosis due to rupture of subarachnoid space
general features of encephalitis
- Irritability
- Altered personality
- Drowsiness
- Ataxia
- Excessively brisk tendon reflexes
CSF findings of encephalitis
same as viral since it is due to viruses
diagnostic method of encephalitis
MRI
most common sporadic encephalitis
herpes virus
clinical features of herpes virus
– Incubation period uncertain • Rapid onset – several days – Fever (90-100%) – Altered consciousness (97-100%) – Headache (70-81%)
vector born viruses
• Arboviruses – Togaviridae – Flaviviridae – Bunyaviridae – Reoviridae
