Meningitis Flashcards
What are the signs of neurological sequelae?
Seizures
Hearing loss
Hydrocephalus
What are the meninges?
Membranes that surround the brain and spinal cord
What are the 3 layers of the meninges?
Dura mater - attached to the skull.
Arachnoid - middle.
Pia mater - covering the brain tissue.
What is the CSF?
Fluid within the CNS that suspends the brain and other CNS structures.
Where is the CSF produced?
In choroids plexus
What are the normal contents of the CSF?
WBC < 5 cells/m3
Protein < 50 mg/dL
Glucose 50-66% simultaneous serum value
BBB
Natural barrier.
Exchange of drugs and endogenous compounds among the blood, brain and CSF.
Consists of tightly joined endothelial cells.
What is the definition of meningitis?
Inflammation of the subarachnoid space or spinal fluid
What are the types of Meningitis?
Bacterial
Aseptic
What are the causes of aseptic meningitis?
NSAIDs
Bactrim
OKT3-anti-rejection monoclonal antibody
Azathioprine
What is the definition of encephalitis?
Inflammation of the brain
What type of bacteria are able to gain entry into the subarachnoid space?
Bacteria that have a polysaccharide capsule ad other cell surface structures are able to evade host defenses and gain entry
What are the steps for bacterial meningitis infection?
Hematogenous spread of organisms.
Contiguous spread from parameningeal focus.
Direct bacterial inoculation.
What are predisposing risk factors for meningitis?
Immunosuppression Head trauma Neurosurgical patients Local infection Exposure to someone with meningitis Anatomicial or functional asplenia Complement deficiency Recent travel to area with endemic meningococcal disease
What are the 3 classical triad s/sx for meningitis?
Fever
Nuchal rigidity
Altered mental status
What are the classic s/sx for meningitis?
Fever Nuchal rigidity Altered mental status Severe HA Photophobia Petechial rash (N. meningitidis only) Kernig sign (+) Brudzinski sign (+)
What are the ways to diagnose meningitis?
History and physical exam Lumbar puncture CSF gram stain and culture Rapid-identification latex agglutination PCR CT scan
What does a rapid identification agglutination detect?
H. influenzae S. pneumonia N. meingitides E. coli group B streptococci
What is different in the lumbar puncture in the differential?
> 80 PMNs
How many serotypes are there of N. meningitides?
5: A, B, C, Y, W135
What symptoms occur in ~50% of the population in N. meiningitides infections?
Petechiae
Purpuric lesions
What are the post infection immunologic reactions for patients with N. meningitides?
~10-14 days after onset of disease.
Fever, arthritis, pericarditis.
Even with successful treatment.
Which bacteria is the leading cause of mengintis?
S. pneumoniae
What are the risk factors of meningitis caused by S. pneumoniae?
Repeated episodes of otitis media, CSF leaks, fracture of sinuses, COPD
What kinds of complications are common in S. pneumonia meningitis?
Neurologic (coma, seizures)
What are the risk factors for meningitis caused by H. influenzae?
Otitis media
Paranasal sinus infections
CSF leak
What vaccination has decreased the incidence of H. influenzae pneumoniae?
Hib vaccine
What populations are primarily affected by Listeria monocytogenes meningitis?
Neonates
Alcholics
Immunocompromised adults
The elderly
What people are at risk for G- meningitis?
People with CNS trauma
What are the treatment goals for bacterial meningitis?
Eradicate invading organism
Alleviate symptoms
Prevent neurologic sequelae
What happens once meingitis is suspected?
NEUROLOGIC EMERGENCY! DO NOT delay once meningitis is suspected.
How long do we treat meningitis?
48-72 hours or until it is ruled out
What are antibiotic characteristics that affect penetration of antibiotics into the CSF?
Low molecular weight > high
Non-ionized at physiologic pH > ionic
Highly lipid soluble > water soluble
Non-protein bound > protein bound
What are the common pathogens for < 1 month of age?
S. agalactiae
E. coli
L. monocytogenes
Klebsiella spp.
What is the empiric therapy for < 1 month old?
Cefotaxime + ampicillin
OR
Ampicillin + aminoglycoside
What are the common pathogens for 1-23 month olds?
S. pneumonia N. meningitideis S. agalaciae H. influenzae E. coli
What is the empiric therapy for 1-23 month olds?
Vancomycin + ceftriaxone (or cefotaxime)
What are the common pathogens for 2-50 year olds?
S. pneumoniae
N. meningitidis
What is the empiric therapy for 2-50 year olds?
Vancomcin + ceftriaxone (or cefotaxime)
What are the common pathogens for > 50 year olds?
S. pneumoniae
N. meningitidis
L. monocytogenes
Aerobic G- bacilli
What is the empiric therapy for > 50 year olds?
Vancomycin \+ Ceftriaxone (or cefotaxime) \+ Ampicillin
What is the duration of therapy for N. meningitidis?
7 days
What is the duration of therapy for H. influenzae?
7 days
What is the duration of therapy for S. pneumoniae?
10-14 days
What is the duration of therapy for S. agalactiae
14-21 days
What is the duration of therapy for aerobic G- bacilli?
21 days
What is the duration of therapy for L. monocytogenes?
> /= 21 days
When do you administer adjunctive dexamethasone therapy?
10-20 minutes before or at the same time as 1st dose of antibiotic, for 2-4 days
What is the current thoughts on use of adjunctive dexamethasone therapy?
Controversial with conflicting data.
Evidence of decreased neurologic sequelae in:
-infants and children with H. influenzae type b meningitis.
-Adults with suspected S. pneumoniae meningitis
What are the disadvantages in the use of adjunctive dexamethasone therapy?
Decreased inflammation which leads to decreased amount of drug that penetrates the CNS
How do you prevent H. influenzae type b (Hib)
Hib conjugate vaccin
Routine vaccination starting at 2 months of age
How do you prevent N. meningitidis?
Meningococcal conjugate vaccines
Hib-MenCY (infants), Menactra (MCV4-D), Menveo (MCV4-CRM)
Routine vaccination: MCV4 at age 11-18yo, with a booster at age 16
When do you prophylax for N. meningitidis?
Chemoprophylaxis
Close contacts - persons with prolonged contact to the infected person or their secretions within 1 week before symptoms being until 24 h after antibiotics are initiated. Those who frequently sleep and ear in the same dwelling with the index case
What is the N. meningitidis chemoprophylaxis treatment?
Rifampin for 2 days
Adults: 600mg q12h x 4 doses
Children > 1 month of age: 10mg/kg/d x 2 days
Who should receive chemoprophylaxis?
Household members
Day care center contacts
Any person directly exposed to the patient’s secretions (coughing, sneezing, kissing)
How do you prevent S. pneumoniae?
PCV13 - routine vaccination series starting at 2 months
PPSV23 - routine vaccination in persons >/= 65 yo
