Meningitis Flashcards
Hib vaccination had a profound population-wide effect in all-age incidence of H. influenzae meningitis reducing it by _____% between 1986 and 2007 to a near elimination level.
97%
1) The meninges are made up of three separate membranes, which are what?
2) Meningitis refers to inflammation of what?
1) Dura mater, arachnoid, and pia mater
2) The subarachnoid space or spinal fluid
The ependymal cells of the choroid plexus function as a ____________ system to form the blood-CSF barrier
active-transport
CNS bacterial pathogens produce an extensive polysaccharide capsule resistant to neutrophil phagocytosis and __________________ ________________.
complement opsonization.
The development of bacterial meningitis involves four main processes, list them
1) Mucosal colonization
2) Bacteria in SA space
3) ^ ICP
4) Cerebral edema leading to neuron damage
The effects of meningitis, namely ______________ within the subarachnoid space and the ensuing neurologic damage, are not necessarily a direct result of the pathogens themselves.
inflammation
True or false: The inflammation from meningitis is not necessarily a direct result of the pathogens themselves.
True
1) Vasogenic edema causes what?
2) What does this lead to?
1) Increased ICP
2) O2 depletion
What 2 signs will be positive?
Brudzinski and Kernig’s
1) What happens if you give abx before you get samples?
2) Should you still give abx if unable to get samples within an hour?
1) Sensitivity and specificity decrease
2) Yes
True or false: Neuroimaging should not delay initiation of appropriate antibiotic therapy as doing so can result in a poor outcome in this disease.
True
1) What test may be useful in differentiating between bacterial and other types of meningitis?
2) Is this test still useful if abx already given?
1) CSF lactate
2) Reduces sensitivity, suggesting the usefulness is compromised in those pts
____________________________ techniques can rapidly diagnose CNS infections and may be particularly useful in patients who have received antimicrobial therapy before lumbar puncture, have negative cultures, or when the organism is fastidious or fails to grow in conventional culture.
Polymerase chain reaction (PCR)
Diagnosis of tuberculous meningitis employs what?
Acid-fast stain, culture, and PCR of the CSF.
1) Administration of what 3 things may be indicated for patients presenting with a possible CNS infection?
2) What else may be needed?
1) Fluids, electrolytes, antipyretics, and analgesics
2) Venous thromboembolism prophylaxis, antiepileptic therapy, and ICP monitoring may be needed.
Patients may require the administration of __________ ___________ such as mannitol 25% or hypertonic 3% saline to maintain an ICP of less than 15 mm Hg (2 kPa) and a cerebral perfusion pressure of 60 mm Hg (8 kPa) or more.
osmotic diuretics
In meningitis, abx penetration is increased through inflamed meninges. Why?
Due to:
1) damage to tight junctions between capillary endothelial cells and
2) reduction of the activity of energy-dependent efflux pumps in the choroid plexus responsible for movement of penicillins
1) Are only ionized or nonionized antibiotics at physiologic or pathologic pH are capable of diffusion?
2) Antibiotics not extensively bound to____________ provide a larger free fraction of drug capable of passing into the CSF.
1) Nonionized
2) plasma proteins
Neonates w. meningitis: What are the 2 onsets?
1) Early onset
Term: within 7 days
Preterm: within 72 hours
2) Community-acquired late onset
Term: > 7 days
Preterm: > 72 hours
Define kernicterus
Displacement of bilirubin from albumin binding sites that cause brain damage
What may you see the use of when treating neonate pts?
1) May see triple therapy
2) May see use of vancomycin
Is gentamicin ionized or unionized?
Polarized (ionization); limits diffusion into CNS
1) With vancomycin, what should you consider if Tx not working? What do you need to do regardless?
2) What is a downside of it?
1) Direct CNS administration; monitor serum drug levels
2) Nephro and ototoxic
How is Macrotube minimum inhibitory concentration (MIC) determined?
The first clear tube read is the MIC
1) When using Colastin, what should you consider?
2) What is recommended for gentamicin, tobramycin, or vancomycin use?
3) When dosing trimethoprim-sulfamathoxazole, which part do you base it on?
1) Intraventricular doses
2) TDM (therapeutic drug monitoring)
3) The trimethoprim
Slide 36
Streptococcus pneumoniae (Pneumococcus or Diplococcus):
What things may predispose the patient to the development of pneumococcal meningitis?
Pneumonia, endocarditis, CSF leak secondary to head trauma, splenectomy, alcoholism, sickle cell disease, and bone-marrow transplantation
Coma, hearing impairment, and seizures are common neurologic complications due to which kind of meningitis?
S. pneumoniae
For Streptococcus pneumoniae (Pneumococcus or Diplococcus) Tx:
1) What is the empiric therapy?
2) What may substitute an abx in empiric therapy?
3) What may be used as monotherapy?
1) Ceftriaxone & vancomycin
2) Rifampin may be substituted for vancomycin
3) Ceftaroline may be used as monotherapy
For Streptococcus pneumoniae (Pneumococcus or Diplococcus) meningitis Tx:
1) What is an alternative to a third-generation cephalosporin in penicillin resistant isolates?
2) Some caution is warranted with the use of ______________ for CNS infections given the risk of drug-induced seizures
3) How is this form of meningitis prevented?
1) Meropenem
2) imipenem
3) Vaccines
Neisseria meningitidis (Meningococcus):
1) Incidence peaks in <_______yr(s) old; second peak in adolescents and young adults ________ to _______ years of age
2) The presence of what may be the primary clue that this is the pathogen?
1) <1 year old; 16 to 23
2) Petechiae
Neisseria meningitidis (Meningococcus):
1) Empiric therapy (pre-culture)?
2) Once you get cultures back, what should you be looking to use if they’re susceptible to it?
3) How is this form of meningitis prevented?
1) Ceftriaxone or cefotaxime
2) Penicillin G or ampicillin
3) Vaccines
Neisseria meningitidis: Use meropenem for _____________ and ____________ resistant cultures
penicillin and cephalosporin
Haemophilus influenzae type b meningitis:
1) What is the empiric therapy?
2) What is beneficial for treatment of infants and children with Hib meningitis to diminish the risk of hearing loss, if given before or concurrently with the first dose of antimicrobial agent(s)?
3) For prophylaxis, ______________ should be administered orally, once a day for 4 days (20 mg/kg/dose; maximum, 600 mg).
1) Ceftriaxone or cefotaxime
2) Dexamethasone
3) rifampin
1) What should you do for prophylaxis for a person exposed to Haemophilus influenzae type b who can’t take rifampin?
2) Can Haemophilus influenzae type b be prevented?
1) Consultation with an expert in infectious diseases is recommended; may consider ceftriaxone or cefotaxime.
2) Yes; Hib vaccine
Streptococcus agalactiae (Streptococcus Group B): Recommended agents for_________________ are penicillin, ampicillin, cefazolin (if penicillin allergy and not at high risk for anaphylaxis), or vancomycin (if penicillin allergy and at high risk for anaphylaxis)
intrapartum prophylaxis
Streptococcus agalactiae (Streptococcus Group B): Recommended agents for intrapartum prophylaxis include what?
1) Penicillin
2) Ampicillin
3) Cefazolin (if penicillin allergy and not at high risk for anaphylaxis) or
4) Vancomycin (if penicillin allergy and at high risk for anaphylaxis)
Streptococcus agalactiae (Streptococcus Group B):
1) Empiric therapy for a newborn with early onset?
2) What abt for a newborn with late onset?
3) What abt for adults?
4) When should you use Vancomycin?
1) Ampicillin plus an aminoglycoside
2) Ampicillin and an aminoglycoside or cefotaxime
3) Ampicillin or penicillin G
4) Type I PCN allergy
Listeria monocytogenes:
1) What are the empiric therapy options?
2) What is the duration of therapy?
1) Ampicillin or penicillin G + aminoglycoside
2) 21 days (minimum)
Dexamethasone (steroid):
1) Associated with lower rates of what 2 sequelae in adults and children?
2) Potential concern is that adjunctive dexamethasone therapy may reduce what?
1) HL and short-term neurological
2) The penetration of antibiotics (i.e., vancomycin & pneumococcal meningitis caused by penicillin- or cephalosporin-resistant strains) into the CSF by inhibiting or reducing meningeal inflammation
Dexamethasone:
1) What are the recommendations by the IDSA?
2) What is the recommendation for pneumococcal meningitis?
1) Call for the use of adjunctive dexamethasone in infants and children (6 weeks of age and older – may see recommendations for 2 months and older) with H. influenzae meningitis
2) Pediatrics: consider risk vs. benefit
Adults: give regardless if suspected or proven
European guidelines recommend initiating dexamethasone in all patients (adults and children) presenting with suspected or proven community-acquired bacterial meningitis and consider discontinuation only if pathogens other than __________________ or ___________________ are identified.
H. influenza or S. pneumoniae
Dexamethasone (Decadron)
1) What is the biggest takeaway of the MOA?
2) What is are 2 common SEs? (>10%)
3) What is a less common SE (that may or may not be linked; 1-10%)?
3) List rare SEs [don’t think rare ones are important] (<1%)
1) Anti-inflammatory
2) Hypertension, GI upset
3) Atrophic condition of skin
4) Primary adrenocortical insufficiency, Cushing syndrome, decreased body growth, increased risk of infection
Rifampin:
1) What is the MOA?
2) What 2 things can it Tx besides meningitis?
3) What are some side effects?
4) What are some significant interactions?
1) Binds to the beta subunit of bacterial RNA-polymerase and inhibits transcription of DNA to RNA
2) TB and leprosy
3) Flu-like sx; rare hepatotoxicity, shock, hemolytic anemia, or acute renal failure
4) Increased risk of oral contraceptive failure via CYP450 enzyme induction; need to give HIV patients rifabutin instead (increased elimination of protease inhibitors)
Rifampin:
1) What are 2 major downsides for female patients with the ability to reproduce?
2) What is a weird side effect?
1) Teratogenic + Increased risk of oral contraceptive failure via CYP450 enzyme induction
2) May turn urine and other secretions orange-red
