Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

PHAR255 > Meningitis > Flashcards

Meningitis Flashcards

1
Q

What is meningitis?

A

inflammation around the membranes that surround the brain and spinal cord
-involves arachnoid, pia mater, CSF
-inflammatory process in the subarachnoid space can extend around the brain, spinal cord and ventricles
-inflammation due to infection, stroke, tumors, trauma, etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What proportion of people develop some type of neurologic sequelae due to meningitis?

A

1/3 to 1/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Differentiate bacterial and aseptic meningitis.

A

bacteria:
-acute meningeal inflammation caused by bacterial infection
-usually evokes a PMN response within the CSF
aseptic:
-meningeal inflammation without evidence of bacteria
-there is no readily identifiable organism on routine culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can cause aseptic meningitis?

A

could be anything that is not bacterial BUT also includes some bacterial causes not easily grown
could be viral, fungal, syphilis, TB, Lyme, atypical bacteria
could also be chemical irritation, malignancy or drug induced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some protective barriers to the brain?

A

the meninges
skull
the blood brain barrier
the blood-CSF barrier
once past these barriers, there is a lack of host defense mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three ways that meningitis can be acquired?

A

hematogenous: spread from the blood
contiguous: from an URTI
direct inoculation: surgery or trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the series of events leading up to bacterial meningitis.

A
  1. mucosal colonization and bacterial invasion of the host and CNS
  2. bacterial replication in the subarachnoid space
  3. inflammation/pathophysiologic changes
  4. increased intracranial pressure, cerebral edema and neuronal damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is special about bacteria that commonly cause meningitis?

A

they have properties that can enhance their virulence
-H. influenzae, S. pneumoniae, and N. meningitidis make IgA protease which allows them to colonize nasopharyngeal mucosa by cleaving antibodies
-N.meningitidis can adhere to cells by means of pili
-all 3 are encapsulated by a polysaccharide capsule which inhibits phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Does the CSF have strong host defenses?

A

poor host defenses in the CSF
-low complement levels, low antibody levels
-bacteria are able to quickly multiply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the result of the inflammatory cascade which occurs to someone with meningitis?

A

cytokines are released = promotes migration of neutrophils into the CSF
neutrophils release PGs, MMPs, etc which cause edema and swelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the risk factors for bacterial meningitis?

A

congenital or traumatic defects
previous viral infection
age (elderly, young children, infants)
low SES
crowding
exposure to pathogens
-recent colonization
-contact with meningitis pts
-IV drug use
-bacterial endocarditis
-immunosuppression
-surgery or trauma
-splenic dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the CSF.

A

most is produced in ventricles by choroid plexus
flows unidirectionally from ventricles to subarachnoid space then down through spinal cord
-drug admin in lumbar area does not result in sig conc above that point
normally clear with few WBCs; protein < 500mg/ml; glucose conc approx 50-60% of simultaneous peripheral glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the most common pathogens that cause meningitis?

A

S. pneumonia
N. meningitidis
Group B streptococcus
Listeria monocytogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

True or false: the causative pathogens of meningitis vary by age

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which pathogen used to account for ~50% of meningitis cases?

A

H. influenzae
-vaccination has almost completely eliminated
S. pneumoniae now predominates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which organisms are most likely to cause meningitis in premature infants and neonates ( < 1 month)?

A

E. coli
Strep agalactiae
L. monocytogenes
Klebsiella species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which organisms are most likely to cause meningitis in infants and kids (1-23 months)?

A

S. pneumoniae
N. meningitidis
(H. influenzae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which organisms are most likely to cause meningitis in people aged 2-50 years old?

A

S. pneumoniae
N. meningitidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which organisms are most likely to cause meningitis in people older than 50 years old?

A

S. pneumoniae
N. meningitidis
L. monocytogenes
gram negative enterics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which organisms are most likely to cause meningitis in patients receiving surgery or due to trauma?

A

Staph infection
gram negative bacilli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which organisms are most likely to cause meningitis in patients with a brain abscess?

A

polymicrobial (aerobic and anaerobic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the components in the diagnosis of meningitis?

A
  1. physical exam
  2. laboratory tests
  3. age of patient (clue to organism)
  4. history of presenting illness
  5. past medical history (IV drug use, asplenic, immunocomp)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the signs and symptoms of meningitis?

A

classic triad: fever, headache, neck stiffness
altered mental status
vomiting
seizures
malaise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What percentage of patients experience the classic triad of symptoms?

A

25-50%
-stiff neck only present ~30% of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Who are some patients that might not have the classic features of meningitis?
infants, elderly, immunosuppressed infants: non-specific -irritable, lethargy, poor feeding, fever, seizures, rash, breathing changes, bulging fontanelle elderly: often only confusion or altered mental status
26
What are some laboratory tests that will be conducted for meningitis?
lumbar puncture CSF gram stain and culture CSF chemistry CSF WBC count
27
What is the use of the lumbar puncture for meningitis?
obtain fluid for cell counts for gram stain and C & S
28
When must we be careful with a lumbar puncture?
elevated intracranial pressure
29
What should be done while waiting to identify the infecting pathogen of meningitis?
medical emergency -start empiric antibiotics within 1hr of diagnosis
30
What is the expected CSF chemistry of someone with bacterial meningitis?
low glucose elevated protein
31
What are the expected CSF WBC counts in someone with bacterial meningitis?
normally < 5 x 10 to the 6/L; most monocytes will often be > 500 x 10 to the 6/L; mostly PMNs
32
What are some acute complications of bacterial meningitis?
shock resp failure abscess seizures altered mental status apnea increased intracranial pressure death
33
What are some sequelae of bacterial meningitis?
seizure disorder impaired cognition/intellect personality changes gait disturbances dizziness focal neurologic deficit (blindness, paralysis, paresis)
34
What are the mortality rates of bacterial meningitis?
4-10% in children 25% in adults 50% in elderly
35
What increases the risk of mortality from bacterial meningitis?
decreased consciousness at admission signs of increased ICP seizures within 24h of admission infants and older than 50yrs delay in treatment need for mechanical ventilation
36
What are some treatment considerations for bacterial meningitis?
1. adequate concentration of antibiotic in the CSF 2. activity of antibiotic in CSF 3. direct (focal) antibiotic administration
37
Why cant all drugs cross the BBB?
BBB consists of tightly joined capillary endothelial tissue which prevents drug passage drug must go through endothelial cells rather than between them
38
What happens to BBB efflux pumps with inflammation?
inhibited may also be blocked with probenicid
39
What determines concentration of antibiotic in the CSF?
lipid solubility plasma protein binding molecular weight ionization
40
What happens to antibiotic penetration with inflammation?
penetration increases careful not to decrease dose as patient gets better -penetration will decrease
41
Which antimicrobials can achieve therapeutic levels in CSF without inflammation?
acyclovir chloramphenicol FQs fluconazole linezolid metronidazole sulfonamides, trimethoprim pyrazinamide, rifampin, isoniazid
42
Which antibiotics can achieve therapeutic levels in CSF with meningeal inflammation?
ampicillin, pen G, piperacillin aztreonam cefotaxime, ceftriaxone, cefepime, ceftazidime, cefuroxime imipenem, meropenem vancomycin
43
Which antibiotics show nontherapeutic levels in CSF with or without inflammation?
aminoglycosides 1st gen cephalosporins 2nd gen cephalosporins doxycycline intraconazole amphotericin B beta-lactamase inhibitors
44
What kind of antibiotics are needed for bacterial meningitis?
bactericidal agents
45
What are the routes of administration for bacterial meningitis?
intralumbar intracisternal intraventricular
46
What are some considerations with antibiotic administration for bacterial meningitis?
drug may cause chemical meningitis -use preservative free may introduce nosocomial infection less volume the better
47
What are some general considerations for treatment of bacterial meningitis?
start antibiotics immediately empiric therapy based on age, hx, underlying dx, gram stain generally IV admin give full doses for entire course of therapy rpt lumbar puncture in 1-2d to ensure CSF sterilization -may not be done if common pathogen and pt response
48
When is treatment of bacterial meningitis extended?
subdural abscess prolonged fever delayed sterilization of CSF persistent symptoms and signs
49
What is the duration of therapy of bacterial meningitis if the patient is responding well ?
S. pneumoniae: 14 days N. meningitidis: 5-7 days H. influenzae: 7-14 days Group B strep: 14-21 days gram negative bacilli: 21 days abscess: 4-6 weeks
50
List the empiric antibiotic therapy of choice for bacterial meningitis for the following groups: - < 1 month old - 1 month - 50 years old - > 50 years old - trauma or neurosurgery
< 1 month: ampicillin + cefotaxime or AMG 1 mo-50yrs: vancomycin + 3rd gen ceph (ceftriaxone or cefotaxime) > 50yrs: vancomycin + ampicillin + 3rd gen ceph trauma or surgery: vancomycin + cefepime/ceftazidime/meropenem
51
What is the therapy for bacterial meningitis if caused by S. pneumoniae?
vancomycin + 3rd gen ceph pen G or ampicillin if pen susceptible alt: FQ, meropenem
52
What is the therapy for bacterial meningitis if caused by N. meningitidis?
3rd gen ceph, ampicillin, pen G alt: FQ, ampicillin
53
What is the therapy for bacterial meningitis if caused by L. monocytogenes?
ampicillin or pen G +/- AMG alt: TMP/SMX, meropenem
54
What is the therapy for bacterial meningitis if caused by strep agalactiae?
ampicillin or pen G alt: 3rd gen ceph
55
What is the therapy for bacterial meningitis if caused by H. influenzae?
3rd gen ceph alt: cefepime, meropenem, FQ
56
What is the therapy for bacterial meningitis if caused by E. coli?
3rd gen ceph cefepime, meropenem, FQ, TMP/SMX
57
How should AMGs be given for bacterial meningitis?
directly into CSF (except neonates) due to poor penetration synergistic with penicillins in IV form
58
Which cephalosporins can penetrate the CSF?
1st gen: inadequate CNS penetration 2nd gen: penetrate but delayed sterilization, failure, resistance 3rd gen: standard empiric therapy for meningitis and DOC for gram negative bacilli
59
What are some supportive therapies to prevent/treat edema, hydrocephalus and inflammation?
mannitol: osmotic diuretic that can decrease ICP shunts: drain excess fluid from brain steroids
60
What is an example of a corticosteroid regimen for meningitis?
dexamethasone 0.15mg/kg q6h for 2-4d
61
Why is corticosteroid use in meningitis controversial?
decreasing inflammation will decrease antibiotic penetration BUT killing organisms results in release of inflammatory mediators
62
When should corticosteroids be discontinued in bacterial meningitis?
d/c within 48h if S. pneumoniae or H. influenzae not cultured
63
How should corticosteroids be administered in bacterial meningitis?
before or within 2h of antimicrobials
64
What are the benefits of corticosteroids in bacterial meningitis?
can decrease hearing loss in kids (esp if H. influenzae) sig decrease in mortality and reduced hearing loss in adults
65
When are corticosteroids recommended for bacterial meningitis?
> 6 weeks old and H. influenzae infection consider if > 6 weeks old and pneumococcal infection
66
Describe appropriate monitoring parameters for bacterial meningitis.
check C & S results lab: CBC rpt lumbar puncture signs and symptoms q4h antibiotic AE complications
67
Who should receive prophylaxis for meningitis?
high risk contacts: start ASAP -household or close contacts -intimate non-household contacts -direct exposure to secretions -school/daycare *HCP do not need unless contact with secretions*
68
What are the options for prophylaxis of meningitis?
meningococcal: -rifampin -alt: ciprofloxacin, ceftriaxone H. influenzae: rifampin not given if pneumococcal

PHAR255 (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions