CNS infections Flashcards
Define meningitis
Inflammation of the subarachnoid space or spinal fluid
What are the two types of meningitis?
- Bacterial
- Aseptic
What is the cause of aseptic meningitis?
- TMP/SMX
- OKT3 antirejection monoclonal Ab
- Azathioprine
- NSAIDs
Define encephalitis
Inflammation of the brain
What are the predisposing risk factors for CNS infections?
- Immunosuppression
- Head trauma
- Neurosurgical patients
- Local infection
- Exposure to someone with meningitis
- Anatomical or functional asplenia
- Complement deficiency
- Recent travel to area with endemic meningococcal disease
What are the early classical signs/Sx of meningitis?
- Fever
- Nuchal rigidity
- Altered mental status
- Severe HA
- Positive Brudzinski’s and Kernig’s sign
- Photophobia
- Petechial rash
Which early sign/Sx is only found when patient is exposed to N. meningitidis organism?
Petechial rash
What are the late classical signs/Sx of meningitis?
- Irritability
- Drowsiness
- Seizures
- Coma
What are the diagnostic tests or procedures for meningitis?
- History and physical exam
- Lumbar puncture
- CSF gram stain and culture
- Rapid identification latex-agglutination
- Polymerase chain reaction (PCR)
- CT scan
Rapid identification latex agglutination is helpful to detect which organism antigens in the CSF?
- H. influenzae
- S. pneumoniae
- N. meningitidis
- E. coli
- Group B streptococci
(T/F) - Rapid identification latex agglutination is not useful if the gram stain comes out negative
FALSE - it is useful
When doing a lumbar puncture there are 5 things that need to be checked in order to diagnose a bacterial or viral meningitis. What are they?
- Opening pressure (mmHg)
- WBC count (cells/mm^3)
- Differential (%)
- Proteins (mg/dL)
- Glucose (mg/dL)
What is a normal opening pressure in a patient?
75-175
What is a normal WBC count in a patient?
< 5
What is a normal differential in a patient?
> 90 monos
What is a normal protein in a patient?
< 50
What is a normal glucose in a patient?
50-66% simultaneous serum value
What is the bacterial opening pressure value in a patient?
Elevated
What is the bacterial WBC value in a patient?
1000-5000
What is the bacterial differential value in a patient?
> 80 PMNs
What is the bacterial protein value in a patient?
100-500
What is the bacterial glucose value in a patient?
< 40-60
What is the viral opening pressure value in a patient?
Elevated
What is the viral WBC count value in a patient?
100-1000
What is the viral differential value in a patient?
50 lymphs
What is the viral proteins value in a patient?
30-100
what is the viral glucose value in a patient?
< 30-70
Bacterial meningitis is treated depending on the age group and bacterial organism that is contributing to it. What are the divided age groups?
< 1 month
1-23 months
2-50 yo
> 50 yo
Which is the only age group that is not affected by N. meningitidis?
< 1 month
Which is the only age group that is not affected by S. pneumoniae?
< 1 month
Which age groups can be affected by L. monocytogenes?
< 1 month
> 50 yo
Which age groups can be affected by Streptococcus. agalactiae?
< 1 month
1-23 months
Which age group is affected by H. influenzae?
1-23 months
Which age group is affected by Klebsiella spp?
< 1 month
Which age group is affected by aerobic gram (-) bacilli?
> 50 yo
Which age groups are affected by E. coli?
< 1 month
1-23 months
What are the favorable characteristics of antibiotics that penetrate the CSF well?
- LMW
- Non-ionized at physiologic pH
- Non-protein bound
- Lipid soluble
What is the empiric treatment for < 1-month patients with bacterial meningitis?
- Ampicillin + cefotaxime OR
- Ampicillin + aminoglycoside
What is the empiric treatment for 1-23 months patients with bacterial meningitis?
Ceftriaxone (or cefotaxime) + vancomycin
What is the empiric treatment for 2-50 yo patients with bacterial meningitis?
Ceftriaxone (or cefotaxime) + vancomycin
What is the empiric treatment for > 50 yo patients with bacterial meningitis?
Ceftriaxone (or cefotaxime) + vancomycin + ampicillin
(T/F) - The duration of empiric treatments for bacterial meningitis depends on the pathogen in the patient
TRUE
How long should an empiric treatment be given for H. influenzae?
7 days
How long should an empiric treatment be given for N. meningitidis?
7 days
How long should an empiric treatment be given for S. pneumoniae?
10-14 days
How long should an empiric treatment be given for S. agalactiae?
14-21 days
How long should an empiric treatment be given for aerobic gram-negative bacilli?
21 days
How long should an empiric treatment be given for L. monocytogenes?
At least 21 days
(T/F) - Adjunctive dexamethasone is highly controversial for the use in meningitis
TRUE
(T/F) - Dexamethasone can decrease the neurologic sequelae in some patients
TRUE
Which patients can dexamethasone decrease neurologic sequelae?
- Infants and children with H. influenzae type B meningitis
- Adults with suspected S. pneumoniae meningitis
How is dexamethasone administered and for how long?
Either 10-20 mins before the 1st dose of the antibiotic OR at the same time as the 1st dose of the antibiotic for 2-4 days
(T/F) - There is a disadvantage to the use of dexamethasone with antibiotics because it could reduce the amount of drug penetrating the CSF
TRUE
How can H. influenzae type B meningitis be prevented?
Vaccination - Hib conjugate vaccine (starts at 2 months)
How can N. meningitidis meningitis be prevented?
- Chemoprophylaxis: Use of rifampin for 2 days
- Vaccination: Hib-MenCY, Menactra, Menveo
Which meningococcal vaccine is given to infants?
Hib-MenCY
How can S. pneumoniae meningitis be prevented?
Vaccination - PPSV23 or PCV13
(T/F) - PPSV23 is given to patients ages 55 and older
FALSE - given to 65 and older
(T/F) - PCV13 is given to patients starting at 2 months old
TRUE