meningitis Flashcards
common causes of meningitis? risk factors?
sepsis
otitis media
sinusitis
csf leak from head trauma
risks: close contact with infected person, crowded living or working conditions, immunocompromised state (AIDS, splenia, cancer, old age)
common causes of bacterial meningitis by age? causes of viral? immunocompromised?
> 1 month: group B strep (agalactiae)
1-2 yrs: neisseria meningitidis, strep pneumoniae, hemophilis influenzae (if not vaccinated)
2-50 yrs: neisseria meningitidis, strep pneumoniae
> 50: strep pneumoniae
viral is mostly associated with meningoencephalitis:
enteroviruses are most common in all ages
herrpesviruses (HSV, CMV, EBV, VZV), mumps, measles, HIV, JC
immunocompromised: N. meningitidis, S. pneumoniae, herpesviruses, JC, HIV, cryptococcus, candida
symptoms of meningitis as well as physical exam?
classic triad: fever, altered mental status, meningismus (headache, neck stiffness, photophobia)
can also have N/V
prodrome if cause is viral: malaise, fever, myalgia, upper respiratory symptoms
physical examination:
kernig sign: with hip and knee flexed at 90, passively extending the knee causes pain and resistance of more extension
brudzinki sign: passive flexion of the neck causes flexion of the hips to relieve painful meningeal strain
if sepsis: tahycardia, hypotension
otitis media: swelling and erythema of tympanic membrane
if meningococcemia: non blanching purpuric/ patechial rash
if meningoencephalitis:
focal neurologic signs, seizures, behavioral changes, psychosis
diagnosis?
DO NOT DELAY EMPERIC ANTIBIOTIC THERAPY. start after obtaining blood and csf samples (or after blood sample if LP is delayed).
- blood cultures
- CBC (high WBC or normal, glucose to compare with CSF, high CRP)
- neuroimaging to assess risk of brain herniation after LP ONLY if:
(FAILS)
Focal neurologic deficits, Altered mental status, Immunocompromised or signs of high ICP like papilledema, new onset Seizures
do CT head
CSF analysis findings?
bacterial: cloudy fluid, high PMN, low lymphocytes, high protein, low glucose, high lactic acid, gram stain and culture is positive
N. meningitidis: gram -ve diplococci
S. pneumoniae: gram +ve diplococci
viral: clear fluid, high lymphocytes, low PMN, high protein, normal glucose, variable lactate, gram stain and culture negative
TB: clear fluid, high lymphocytes, low PMN, high protein, low glucose, high lactate, acid fast stain +ve
normal CSF: NO ORGANISMS on stain and culture, cell count low, GLUCOSE IS 2/3 OF SERUM
treatment including choices for emperic?
empiric therapy for bacterial:
18-50 yrs: vancomycin PLUS 3rd generation cephalosporin like ceftriaxone
older than 50: Vancomycin plus 3rd generation PLUS ampicillin to cover listeria
immunocompromised: vancomycin plus AMPICILLIN plus CEFEPIME/ meropenem
empiric for viral: acyclovir
can also give IV dexamethasone to reduce inflammation if due to s. pneumoniae or H. influenzae. given before or with empiric therapy and discontinued if other organism is found.
then treat according to causative organism
complications?
most common: sensorineural hearing loss
focal neurologic deficits, raised ICP cerebral edema, seizures
