CNS Infections - Kozel Flashcards
Glucose concentrations in the CSF are what percent of the serum level?
60%
What are some specific tests you can order based on clinical suspicion?
Nucleic acid amplification Stain and culture for AFB VDRL test India ink negative stain Cryptococcal polysaccharide antigen Fungal culture Viral culture
What are the following CSF findings for viral infections? WBC count WBC cell type Glucose Protein
WBC: 50-1000
Mononuclear
Glucose >45
Protein <200
What are the following CSF findings for bacterial infections? WBC count WBC cell type Glucose Protein
WBC: 1000-5000
Neutrophilic
Glucose <40
Protein 100-500
What are the following CSF findings for tuberculous infections? WBC count WBC cell type Glucose Protein
WBC: 50-300
Mononuclear
Glucose <45
Protein 50-300
What are the following CSF findings for cryptococcal infections? WBC count WBC cell type Glucose Protein
WBC: 20-500
Mononuclear
Glucose 45
Basically what is the only type of CNS infection that will raise glucose above 45?
viral
What is the only type of CNS infection that will have a neutrophilic infiltrate?
bacterial
What is the normal range of glucose in the CSF?
50-80
What is the normal WBC count in the CSF
0-5
what is the effect of blood in the CSF on the WBC count?
need to adjust the count
What are the reasons for decrased glucose in the CSF?
- Increased glycolysis by leukocytes and bacteria
- Increased metabolic rate of brain and spinal cord
- Altered glucose transport between blood and CSF
What are the reasons for increased protein in the CSF?
disruption of BBB; must also be adjusted if there is blood in the CSF
what are the contraindications for LP?
papilledema; increased ICP
neurological suggestion of intracranial mass
What are the three things you need to do in the initial management of acute meningitis?
- Lumbar puncture and CSF analysis
- Empiric antimicrobial therapy based on patient age
- Adjunctive dexamethasone if appropriate
What is the most common cause of viral meningitis?
enterovirus
What is the most common cause of bacterial meningitis?
Strep pneumo
What are the two causes of spirchetal meningitis
Treponema pallidum
Borrelia burgdorferii
T/F: you can get helminths in the brain
true
what is the invasion process of bacterial meningitis?
Mucosal/nasopharyngeal colonization
Local invasion
Intravascular survival
Meningeal invasion – Moxon experiment
Induction of subarachnoid space inflammation
Alterations of blood-brain barrier
Cerebral edema and increased intracranial pressure
what are the three types of cerebral edema?
- vasogenic from increased BBB permeability
- cytotoxic from swelling of cellular elements of the brain
- interstitial from obstruction of normal flow of CSF
what are the common bacterial pathogens for meningitis of the neonate?
Strep agalactiae
E. coli
Listeria monocytogenes
Klebsiella spp.
What are the common bacterial pathogens for meningitis of the 1-23 month old?
S. agalactiae E. coli H. flu Strep pneumo N. meningitidis
What are the common bacterial pathogens for meningitis of the 2-50 year old?
S. pneumo
N. meningitidis
What are the common bacterial pathogens for meningitis of the >50 year old?
S. pneumo
N. meningitidis
Listeria monocytogenes
Aerobic gram-negative bacilli
What allows disruption of the BBB that allows Abx to reach the brain?
inflammation
what effect do corticosteroids have on abx penetration of the brain?
they reduce inflamm so they also reduce abx penetration of the bbb
What are the features of abx with good CNS penetration in the absence of meningeal inflammation?
- Low molecular weight
- Low degree of ionization at 3. physiological pH
- High lipid solubility
- Low degree of protein binding
- Absence of active efflux systems
What is the Tx for meningitis in the 1 month old?
ampicillin plus ceftoxamine
or
ampicillin plus an aminoglycoside
What is the Tx for meningitis in the 1-23 month old?
Vancomycin plus a third gen cephalosporin
What is the Tx for meningitis in the 2-50 year old?
Vancomycin plus a third gen cephalosporin
What is the Tx for meningitis in the >50 year old?
vancomycin plus ampicillin plus third gen cephalosporin
What is the recommended drug for strep pneumo meningitis?
vancomycin plus third gen cephalosporin
What is the alternative tx for strep pneumo?
Meropenem
Fluoroquinolone
What is the tx for N. meningitidis?
Third gen cephalosporin
what is the alt. tx for N. meningitidis?
PCN G
Ampicillin
fluoroquinolone
What is the tx for listeria monocytogenes?
ampicillin
PCN G
What is the alt. tx for listeria monocytogenes?
TMP-SMX
Meropenem
What is the tx for strep. agalactiae?
Ampicillin
PCN G
What is the alternative tx for strep agalactiae?
third gen cephalosporin
What is the tx for h flu?
third gen cephalosporin
what is the alt. tx for h flu?
cefepime
meropenem
fluoroquinolone
What is the tx for E. coli?
third gen cephalosporin
what is the alt. tx for E. coli?
Cefepime meropenem aztreonam fluoroquinolone TMP-SMX
what are the two things that define chronic meningitis?
indolent onset of greater than four weeks
signs of chronic inflamm in CSF
What are the early symptoms of chronic meningitis?
HA
nausea
decreased memory and comprehension
What are the differences you see in chronic meningitis vs. acute?
onset is more gradual
fever is lower
assc’d with lethargy and disability
pt is often immunocompromised
What are the mycoses that can cause chronic meningitis?
Cryptococcosis
Coccidioidomycosis
Histoplasmosis
Candidiasis
what are the bacteria that can cause chronic meningitis?
Mycobacterium tuberculosis
Treponema pallidum
Borrelia burgdorferii
what are the parasites that can cause chronic meningitis?
Acanthamebiasis
Cysticerosis
Angiostrngylus cantonensis
what are the two defining features of encephalitis?
inflamm in the brain parenchyma
clinical or lab evidence of neuro dysfunction
What are the symptoms of encephalitis?
fever and HA
altered mental status–EARLIER than meningitis
Describe the CSF profile in enceph?
normal glucose
elevated protein
Lymphocytic pleocytosis (elevated lymphs)–magnitude changes with etiology
What are the most common viral etiologies of enceph?
HSV-1 and HSV-2 Varicella-Zoster virus CMV HHV-6 Arboviruses HIV enterovirus ---polio rabies virus
(Vira/bacterial) sources are most common for enceph
viral
What are the possible bacterial causes of enceph?
Listeria monocytogenes Rickettsia spp. Ehrlichia spp. Bartonella spp. Mycoplasma pneumoniae
Is the capsule of a brain abscess well or poorly vascularized?
well vascularized
What are the three sources of a brain abscess?
- Contiguous spread from sinusitis, otitis media, or mastoiditis
- hematogenous spread
- trauma
What are the symptoms of a brain abscess?
HA, N/V, FOCAL NUERO FINDINGS BASED ON SIDE OF ABSCESS
Are brain abscesses singular or mixed in their etiology?
MIxed
What are the two most common sources of brain abscesses?
Strep spp. 70%
Staph aureus 10-20%
What are the most common fungal brain abscesses?
Aspergillus Candida Cryptococcus Mucorales Coccidioides
What is the most common protozoal/helminthic brain abscess?
toxoplasma gondii
Neurocysticercosis is caused by the larval form of (blank)
Taenia solium
What are some other notable causes of helminthic brain abscesses?
Trypanosoma cruzi, Entamoeba histolytica, Shistosoma spp.
What are isolates from a brain abscess caused by sinus and dental infection?
Aerobic and aneorbic streptococci Bacteroides Prevotella spp. Enterobacterieriae Staph aurues
What are isolates from a brain abscess caused by penetrating trauma?
Staph aureus
Aerobic streptococci
Enterobacteriae
Clostridium
What are isolates from a brain abscess caused by pulmonary infection?
Fusobacterium Actinomyces Bacterioides Prevotella Nocardia Streptococci
What are isolates from a brain abscess caused by congenital heart disease?
Streptococci
Staph aureus
What are isolates from a brain abscess caused by HIV infection?
TOXOPLASMA GONDII Nocardia Mycobacterium Listeria monocytogenes Cryptococcus neoformans
What are isolates from a brain abscess caused by transplantation?
Aspergillus Candida Mucorales Nocardia Toxoplasma Gondii
What are isolates from a brain abscess caused by neutropenia?
Aerobic gram-neg bacilli
Aspergillus
Candida
Mucorales
Which bug is this? Gram negative cocci Fastidious pathogen; A) grows on blood, chocolate, and Thayer-Martin Medium B) can only culture on Thayer-Martin
Neisseria
Neisseria produces (blank) oxidase which can be used to ID it
indphenol oxidase
T/F: Neisseria is easily killed by sunlight, heat, and chemicals
true
Neisseria has a (blank)-specific CPS
group specific
Which group of neisseria is the epidemic strain?
group A
Groups B, C, Y, and W-135 are which type of Neisseria strains?
endemic
Which group of Neisseria is a polymer of sialic acid?
Group B
Group B Neisseria is (poorly/stronlgy) immunogenic
poorly; seen as self
Group B Neisseria ag is expressed in what specific tissue?
neonatal!
Which group of the endemic Neisseria strains can occasionally become epidemic?
group C
Neisseria has (group/type) specific outer membrane protiens and lipooligosacchardies
type specific
T/F: Meningococcemia can occur with or without meningitis
true
What are the general findings in a meningococcal infection?
Meningococcemia
Meningitis
Petechial lesions
Petechiae correlate with the degree of (blank) due to DIC
thrombocytopenia
T/F: patients with fulminant sepsis and meningitis show purpura, petechia, and echymoses
true
what part of neiserria makes it antiphagocytic?
the capsule
What part of neiserria is extremely toxic and produces inflamm?
LOS
LOS contains lipid (A/C) and the core oligosaccharaide
lipid A
T/F: LOS has the O antigen
false; lacks the O ag
How is LOS released from neisseria?
from the bacterial surface as the membrane blebs
Neisseria has (pili/flagella)
pili
Neiserria first gains access to the body where?
nasopharynx
Neiserria uses its (blank) to adhere to the epi cells of the nasopharynx
pili
besides prevent phagocytosis, what else does the capsule of neiserria do?
prevents complement mediated lysis
Which part of Neisseria causes tissue damage?
LOS
DIC from Neisseria is caused by what toxic part of the bacteria?
LOS
Multiple attacks of Neisseria is associated with depletion of which complement factors?
C5,6,7,8
What types of specimens do you need to collect to Dx Neisseria?
blood
CSF
NP secretions in the carriers
How do you visualize Neisseria?
Direct exam with gram stain of the CSF
What type of culture and special conditions are needed to culture Neisseria?
Culture IMMEDIATELY
incubate in CO2
Use Thayer-martin agar
What is the gram stain and general appearance of Neisseria?
gram negative diplococci
What is the oxidase status of Neisseria?
oxidase positive
Neisseria oxidatively produces acid from what?
sugars, eg glucose and maltose
How is Neisseria spread man to man?
airborne transmission via respiratory droplets
Which populations are most susceptible to Neisseria?
young kids (no Abs) college students and military recruits (crowding and fatigue)
What is the carrier rate of Neisseria?
1-40%; few carriers develop disease
T/F: Neisseria only happens in outbreaks
false; may occur sporadically or in epidemics, hence the multiple strains
immunity to meningococcus is due to what?
anticapsular AB
what are the MOA’s of immunity to Neisseria?
complement mediated lysis and opsonization
Anticapsular Ab is the major factor that determines (blank vs. blank)
resistance vs. susceptibility
What explains the risk of Neisseria in kids between 6-24 months?
lack of anticapsular Ab
Naturally ocurring Abs to Neisseria are probably due to the carrier state and to cross reacting with what other bacteria?
E. coli
The tetravalent meninogcoccal vaccine has which four Neisseria strains?
A
C
Y
W-135
What part of the bacteria does the meningococcal vaccine contain?
purified polysaccharide only
T/F: The tetravalent vaccine is one of two vaccines used for adults older than 56
false; the only one
The (polysacc/polysacc-protein) vaccine is used to vaccinate adolescents against meningitis
polysacc-protein conjugate
Which four strains does the polysacc-protein conjugate vaccine against meningitis have?
A
C
Y
W-135