meningitis (exam 1) Flashcards
meningitis is inflammation predominantly of the __ space, most commonly due to __
- subarachnoid space
- infection
meningitis: etiology can be
- viral (aseptic)
- bacterial
- fungal (less common)
__ meningitis is a medical emergency and must be distinguished from the more common __ meningitis
- bacterial
- viral
incidence of bacterial meningitis in the US has been __
declining
meningitis has an overall mortality of __%
15-25%
bacterial meningitis: 3 types of infection
- community acquired: etiologic organisms vary with age
- nosocomial: primarily a disease of neurosurgical pts
- recurrent: most common in pts with nosocomial meningitis with compromised meningeal integrity
bacterial meningitis: major causes of community acquired bacterial meningitis are
- S. pneumoniae (pneumococcal)
- N. meningitides (meningococcal)
- H. influenzae
- Listeria monocytognes
bacterial meningitis: major causes of healthcare associated bacterial meningitis are
- staphylococci
2. aerobic gram negative bacilli
pt population: infants <1 mo
likely pathogens, antimicrobial therapy:
- S. agalactiae
- L. monocytogenes
- E. coli
- gram negative bacilli
- Ampicillin plus Cefotaxime OR
- Amplicillin plus an aminoglycoside
pt population: children 1-23 mos
likely pathogens, antimicrobial therapy:
- S. pneumoniae
- N. meningitidis
- S. agalactiae
- H. influenzae
- E. coli
- Vancomycin (gram + coverage!) and ceftriaxone (3rd generation cephalosporin)
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: children and adults 2-50 years
likely pathogens:
- N. meninditidis
- S. pneumoniae
- Vancomycin and ceftriaxone
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: >50 yo
likely pathogens:
- S. pneumoniae
- N. meningitidis
- L. monocytogenes
- aerobic gram negative bacilli
- Vancomycin, ceftriaxone, and ampicillin
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: pt with basilar skull fx or cochlear implant
likely pathogens:
- S. pneumoniae
- H. influenzae
- GABHS
- Vancomycin plus (ceftriaxone) 3rd generation cephalosporin
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: pt with penetrating trauma or s/p neurosurgery
likely pathogens:
- S. aureus
- P. aeruginosa
- aerobic gram negative bacilli
- coagulase negative staphylococci
- Vancomycin plus cefepime OR
- Vancomycin plus ceftazidime OR
- Vancomycin plus meropenem
pt population: pt with CSF shunt
likely pathogens:
- coagulase negative staphyloccus
- S. aureus
- aerobic gram negative bacilli
- P. aeruginosa
- Propionibacterium acnes
- Vancomycin and cefepime
bacterial meningitis: __ organism depends on __ of entry and __ factors
- etiological
- route/site
- host
bacterial meningitis, 3 mechanisms of entry:
- colonization of __ with subsequent __ invasion followed by __ invasion
- invasion of the CNS following __ due to localized source/infection (GI; endocarditis)
- __ entry into the CNS from __ infection (otitis media, mastoiditis, sinusitis), __, __, or medical __
- nasopharynx
- bloodstream
- CNS
-bacteremia
- direct
- contiguous
- trauma
- neurosurgery
- devices (shunt)
bacterial meningitis host factors that can predispose to meningitis
- asplenia
- complement deficiency
- glucocorticoid excess
- diabetes mellitus
- alcoholism
- hypogammaglobulinemia (not producing immunoglobulins)
- HIV
- recent infection (respiratory, ear)
- recent exposure to someone with meningitis
- IVDA (IV drug user)
- recent head trauma
- otorrhea or rhinorrhea
- recent travel to area with endemic meningococcal disease (Africa)
bacterial meningitis: classic triad of symptoms are
- fever: often high (>38C or 100.4F)
- nuchal rigidity = pathognomonic sign of meningitis
- change in mental status (delirium, confusion; test by mini-mental; level of consciousness)
bacterial meningitis clinical presentation
- fever: often high (>38C or 100.4F)
- nuchal rigidity = pathognomonic sign of meningitis
- change in mental status (delirium, confusion; test by mini-mental; level of consciousness)
- headache (common, typically severe and generalized)
- pts are very ill and often present soon after onset of symptoms (24 hrs)
- course of illness varies from progression over hours to several days
- photophobia
- nausea
- vomiting
- seizures (more in kids)
- focal neurological deficits (including cranail nerve palsies)
- papilledema (edges of optic disc are blurred)
- myalgias
- maculopapular rash that progresses to petechiae and palpable purpura in meningococcal meningitis
95% sensitivity for clinical features of 2 of the following symptoms
- fever
- neck stiffness
- altered mental status
- headache
93% sensitivity for lab features of
cerebrospinal fluid with WBC count > or = 100 per microL
87% sensitivity for this clinical feature
headache
83% sensitivity for this clinical feature
neck stiffness
77% sensitivity for this clinical feature
fever > or + 100.4F (38C)
44% sensitivity for this clinical feature
triad of fever, neck stiffness, and altered mental status
69% sensitivity for this clinical feature
altered mental status (Glascow Coma Scale <14)
Glasgow coma scale: worst, best, mild brain injury, moderate brain injury, and sever brain injury
-3 = worst score
-greater than or equal to 8 = severe brain injury
-9-12 = moderate brain injury
13 or higher = mild brain injury
15 = best score
Glasgow coma scale: signs and scores
-eye opening: spontaneous (4), to command (3), to pain (2), none (1)
verbal response: oriented (5), confused/disoriented (4), inappropriate words (3), incomprehensible sounds (2), none (1)
motor response: obeys commands (6), localizes pain (5), withdraws (4), abnormal flexion to pain (3), abnormal extension to pain (2), none (1)
signs of meningeal irritation: Kernig’s sign - maneuver and positive test
- maneuver: place pt supine with hip flexed at 90 degrees; attempt to extend the leg at the knee
- positive test: when there is resistance to extension at the knee to >135 degrees or pain in the lower back or posterior thigh
- (usually develops in late stage of meningitis)
signs of meningeal irritation: Brudzinski’s sign - maneuver and positive test
- maneuver: place pt in the supine position and passively flex the head towards the chest
- positive test: when there is flexion of the knees and hips of the pt
- (usually develops in late stage of meningitis)
signs of meningeal irritation: jolt accentuation headache - maneuver and positive test
- maneuver: pt rotates his head horizontally 2-3 times per second
- positive test: when the pt reports exacerbation of his headache with this maneuver
bacterial meningitis labs
- CBC with differential: WBC usually elevated with a left shift; can also have leukopenia with severe infection; platelet count may be decreased (over 10,000 is high) (left shift = bands and neutrophils)
- coagulation studies
- serum electrolytes (sodium, potassium, chloride, CO2, glucose, check metabolic state by pH)
- blood cultures (2 from peripheral; do when pt febrile because bacteremic)
- CSF EVALUATION IS KEY (lumbar puncture)
bacterial meningitis: not uncommon for LP to be delayed while a CT is performed to rule out __ or __; done to minimize risk of __
- mass lesion
- increased intracranial pressure
- cerebral herniation
indications for CT prior to LP include
- immunocompromised
- history of CNS disease
- new onset seizure
- papilledema (sing of increased cranial pressure)
- abnormal level of consciousness
- focal neurological deficit
if LP delayed
get blood cultures and treat empirically with Abx and dexamethasone (0.15 mg/kg IV q6hrs) within 30 min of encountering pt
csf analysis, bacteria: CSF opening pressure, cell count, protein, glucose
> 20 (7-18 cm H2O)
1000 (5 WBCs)
100 (<10 (50-80 mg/dL)
csf analysis, mycobacterium tuberculosis: CSF opening pressure, cell count, protein, glucose
> 20 (7-18 cm H2O)
100-500 (5 WBCs)
100 (<50 mg/dL)
10-45 (50-80 mg/dL)
csf analysis, fungi: csf opening pressure, cell count, protein, glucose
< 20 (7-18 cm H2O)
5-500 (5 WBCs)
>100 (<50 mg/dL)
10-45 (50-80 mg/dL)
csf analysis, viruses: csf opening pressure, cell count, protein, glucose
< 20 (7-18 cm H2O)
5-500 (5 WBCs)
50-150 (<50 mg/dL)
normal (50-80 mg/dL)
csf gram stain: gram positive diplococci
pneumococcal infection
csf gram stain: gram negative diplococci
meningococcal infection
csf gram stain: small pleomorphic gram negative coccobacilli
Haemophilus influenzae infection
csf gram stain: gram positive rods and coccobacilli
listerial infection
PCR (not routinely available in bacterial meningitis but very sensitive and specific) is the standard of care for detection of
enteroviruses, Herpesviridae (HSV, VZV, CMV, and EBV)
2 general principles for antibiotic treatment for bacterial meningitis
- agent used must be bacteriocidal against the infecting organism
- agent used must be able to penetrate the blood brain barrier in order to reach sufficient concentration in the CSF
pt population: immunocompromised state
likely pathogens, antimicrobial therapy:
- S. pneumoniae
- N. meningitidis
- L monocytogenes
- aerobic gram-negative bacilli (P. aeruginosa)
- Vancomycin plus amplicillin plus cefepime OR
- Vancomycin plus ampicillin plus meropenem
good concentrations in CSF with and without meningitis
- chloramphenicol
- sulfonamides
- cephalosporins
- cefotaxime
- ceftriaxone
- ceftazidime
- moxalactam
- cefepime
- metronidazole
- trimethoprimsulfamethoxazole
- isoniazid
adequate concentrations in csf in meningitis
- penicillin
- ampicillin
- methicillin
- oxacillin
- nafcillin
- carbenicillin
- ticarcillin
- tetracycline
- erythromycin
- ethambutol
- rifampin
- vancomycin
- meropenem
fair to poor concentrations in csf in meningitis
- early cephalosporins
- cephalothin
- cefoxitin
- aminoglycosides
- gentamicin
- tobramycin
- amikacin
- clindamycin
- benzathine penicillin
antibiotic penetration of csf largely depends on status of the __; with meningeal inflammation, separation of intercellular __ and increased numbers of __ in cerebral microvascular endothelial cells; as inflammation subsides, decrease in Abx penetration into csf; therefore, __ IV doses used throughout course to Tx to maintain adequate CSF levels of Abx
- blood brain barrier
- tight junctions
- pinocytotic vesicles
- maximum
Streptococcus pneumoniae: recommended therapy and alternative therapies
-Vancomycin plus a 3rd generation cephalosporin
[Ceftriaxone or cerotaxime]
[some experts would add rifampin if dexamethasone given]
-Fluoroquinolone
[moxifloxacin, recommended given its excellent CSF penetration and in vitro activity against S. pneumoniae; if used many would combine moxifloxacin with vancomycin, or a 3rd generation cephalosporin (ceftraizone or cefotaxime)]
Neisseria meningitidis: recommended therapy and alternative therapies
- 3rd generation cephalosproin (ceftriaxone or cerotaxime)
- Chloramphenicol, fluoroquinolone, aztrenam
Listeria monocytogens: recommended therapy and alternative therapies
- ampicillin OR penicillin [addition of an aminoglycoside should be considered
- Trimethoprim-sulfamethoxazole
Haemophilus influenzae: recommended therapy and alternative therapies
- 3rd generation cephalosporin (ceftraixone or cerotaxime)
- chloramphenicol, cefepime, meropenem, fluoroquinolone
suspicion of bacterial meningitis –> immunocompromised, history of CNS disease, new onset seizure, papilledema, altered consciousness, or focal neurologic deficit; or delay in performance of diagnostic lumbar puncture –>
blood culture STAT –> Dexamthasone + empiric antimicrobial therapy –> negative CT scan of head –> perform lumbar puncture –> CSF findings consistent with bacterial meningitis –> positive CSF gram stain –> Dexamethasone + trageted (or empiric if no) antimicrobial therapy
suspicion of bacterial meningitis –> = NO immunocompromised, history of CNS disease, new onset seizure, papilledema, altered consciousness, or focal neurologic deficit; or delay in performance of diagnostic lumbar puncture –>
blood culture and lumbar culture STAT –> Dexamthasone + empiric antimicrobial therapy –> CSF findings consistent with bacterial meningitis –> positive CSF gram stain –> Dexamethasone + trageted (or empiric if no) antimicrobial therapy
bacterial meningitis: importatnt things to consider and labs/tests
- ABCs
- CBC with diff, coagulation studies
- 2 sets of blood cultures
- LP for CSF cell count and differential, glucose, and protein; gram stain; culture and senitivities
- begin dexamethason (if organism unknown or suspected pneumococcus) and appropriate IV antibiotics
__ can be added in pt receiving dexamethasone and Vancomycin ( to increase CSF concentrations of Vancymycin)
rifampin (dexamtheasone decreases inflammation and thus reduces vancomycin csf penetration)
prevention: these 2 vaccines have reduced incidence of bacterial meningitis
- H. influenza type B vaccine
2. S. pneumoniae vaccine
__ vaccine recommended for children ages 11-18, freshmen entering college dormitories, travelers to regions in which __ disease is endemic (e.g. sub-Saharan Africa)
- N. meningitidis
- meningococcal
aseptic meningitis: __ process involving the meninges with no evidence of __ on gram stain or culture; most commonly __ in etiology; other causes include __, __, __, and __
- inflammatory
- bacteria
- viral
- neoplasms
- fungal
- TB
- medications
most common cause of aseptic meningitis
enteroviruses (coxsackie and echovirus)
aspetic meningitis: enteroviruses occur mstly during
late summer or fall
aseptic meningitis enteroviruses: symptoms
(abrupt onset)
- fever
- headache
- nausea
- vomiting
- photophobia
- rash
- diarrhea
- URI symptoms
aseptic meningitis enterovirus: __ can help establish diagnosis (it is the standard of care for detection of ___)
- PCR
- enteroviruses, HErpesviridae (HSV, VZV, CMV, EBV)
aseptic meningitis enterovirus: treatment is
supportive
