CNS Infections Flashcards
what are the meninges?
the membranes covering the brain and spinal cord
name the three meninges
dura
arachnoid
pia
what can untreated CNS infection lead to?
brain herniation and death
cord compression and paralysis
what are the two main types of meningitis?
pyogenic/bacterial
aseptic/viral
what is acute encephalitis?
an infection of the brain parenchyma
what is seen on the surface of the brain in bacterial meningitis?
thick layer of suppurative exudate covering the meninges
what is seen microscopically in bacterial meningitis?
neutrophils in the subarachnoid space
name four possible causes of bacterial meningitis
strep pneumoniae
neisseria meningitidis
listeria monocytogenes
haemophilus influenza
what is the management of bacterial meningitis?
ceftriaxone IV 2g BD
dexamethasone IV 10mg
what is the management for bacterial meningitis in someone with a penicillin allergy?
chloramphenicol IV 25mg/kg
when should dexamethasone be given for bacterial meningitis?
with or just before the first dose of antibiotics
when should dexamethsone be continued in bacterial meningitis and for how long?
pneumococcal meningitis
for four days
any other cause = stop
what should be given if listeria cover is required in bacterial meningitis?
add amoxicillin IV 2g 4 hourly
or co-trimoxazole iV 4x a day
what should be added to the management of bacterial meningitis if recent travel to a country with high rates of penicillin resistant pneumococci?
vancomycin or rifampacin
what are the signs and symptoms of bacterial meningitis?
headache vomiting pyrexia neck stiffness photophobia lethargy confusion rash
what bacteria cause bacterial meningitis in neonates?
listeria
group B strep
e coli
what bacteria causes bacterial meningitis in children?
h influenza
what bacteria cause bacterial meningitis in those aged 10-65?
neisseria meningitidis
strep pneumoniae
what bacteria cause bacterial meningitis in those >65?
strep pneumoniae
listeria
what bacteria are associated with bacterial meningitis in the immunocompromised?
listeria
strep pneumoniae
neisseria
pseudomonas
what bacteria are associated with bacterial meningitis in those with head trauma?
staph
gram negative bacilli
what bacteria is associated with bacterial meningitis after fracture of the cribriform plate?
strep pneumoniae
name four possible complications of bacterial meningitis
purulence
invasion
cerebral oedema
hydrocephalus
what causes meningococcal meningitis?
neisseria meningitidis
what causes symptoms in meningococcal meningitis?
endotoxin production
who is most commonly affected by meningococcal meningitis?
young children
what type of h influenzae is the most common cause of meningitis in children <4?
type b
what cause pneumococcal meningitis?
strep pneumoniae
what can be given to provide protection against pneumococcal meningitis?
pneumococcal pneumonia vaccine
what type of bacteria is listeria monocytogenes?
gram positive bacilli
name three risk factors for meningitis due to listeria monocytogenes
neonate
>55
immunosuppression
what antibiotics can be given for meningitis due to listeria monocytogenes?
IV ampicillin/amoxicilli n
what causes tuberculous meningitis?
reactivation of TB
who is more commonly affected by tuberculous meningitis?
the elderly
what is given to treat tuberculous meningitis?
isoniazid and rifampicin
add on pyrazinamide and ethambutol
RI then RIPE
what causes cryptococcal meningitis?
fungal infection
who is most commonly affected by cryptococcal meningitis?
HIV positive patients
how does cryptococcal meningitis present?
subtle neurological presentation
aseptic picture on CSF
how is cryptococcal meningitis managed?
IV amphotericin/flucytosine
fluconazole
when is viral meningitis usually seen?
late summer/autumn
when is viral meningitis usually seen?
late summer/autumn
what usually causes viral meningitis?
enteroviruses e.g. ECHO virus
what investigations are done to diagnose viral meningitis?
viral stool culture
throat swab
CSF PCR
how is viral meningitis managed?
supportive as it is self limiting
how does encephalitis present?
mental state changes
confusion
behaviour/speech disturbances
seizures
what investigations are done for encephalitis?
lumbar puncture
EEG
MRI
what drug should be started if there is a delay to diagnosis or treatment in encephalitis?
aciclovir
what drug is used to manage encephalitis?
aciclovir
how does meningoencephalitis present?
headache
fever
neck stiffness
features of encephalitis
