meningitis Flashcards
meningism
symptom complex
headache
photophobia
vomiting with muscle spasm
neck stiffness: stiffness on passive neck flexion is key
causes of meningism
meningitis
SAH
infection w bacteraemia
meningitis
infection of meninges
inflammation and meningeal irritation
can cause death, permanent disability
meningitis pathophysiology
- attachment to mucosal epithelial cells e.g.bacteria to nasopharynx mucosa, enterovirus to gut mucosa
- transgression of mucosal barrier
- survival in bloodstream
- entry into CNS
- production of overt infection in meninges +/- encephalopathy
common bacterial causes meningitis
neisseria meningitis
streptococcus pneumoniea
neonates: e.coli, group b strep
common viral causes meningitis
enterovirus parechovirus coxasackie A, B mumps HSV
common non-infectious causes meningitis
tumour cells in CSF
drugs
SLE, sarcoid
aseptic meningitis
CSF elevated lymphocytes and protein
no organism cultured/detected
when should meningeal infection be suspecter
every pt with Hx URTI and one meningeal symtpoms
acute meningitis
signs/symptoms <24hrs and rapidly progressive e.g. meningococcal
subacute meningitis
signs/symptoms 1-7days e.g. viral
acute meningitis risk factors
recent skull trauma
DM
alcoholism
exposure to meningococcus
meningitis Ix
LP - CSF testing
blood cultures
CT if focal signs or papilloedema
FBC, U&Es, LFTs
CSF testing
biochem: Glc, protein
microbio: gram stain, differential cell count, bacterial culture, antigen detection test
normal adult CSF features
clear small number cells <5 mostly lymphocytes normal Glucose (60% blood level) normal protein
bacterial meningitis CSF features
turbid inc cell number mostly neutrophils reduced Glc inc proteins
viral meningitis CSF features
clear to turbid inc cell number mostly lymphocytes glucose normal increased proteins
TB meningitis CSF features
clear to turbid inc cell numbers lymphocytes or mixed reduced Glc inc protein
greatest risk factor for bacterial meningitis
colonisation
reducing death rate of acute meningitis
early clinical recognition
rapid antigen detection
rapid initiation bacteriocidaal antimicrobial Rx
early treatment of sequelae: DIC, acidosis
antibiotic prophylaxis for contacts
bacterial meningitis antibiotic therapy
benzylpenicillin only reaches CSF in sufficient amount if meningeal inflammation and 4hrly doses
ceftriazone reaches CSF in efficient quanitities only if inflammed meninges
meningococcal meningitis
neisseria meningitis
children and young adults
gram stain shows gram negative diplococci
meningococcal meningitis features
+/- septicaemia
petechial skin rash
meningeal symptoms
systemic upset
fulminant meningococcal septicaemia
very sudden onset purpuric skin rash reduced consciousness, fever septicaemic shock, renal failure CSF CSF sterile 50% die first 24hrs
MX meningococcal meningitis
if GP suspects it give parenteral penicillin prior to hosp transmission
ceftriazone prior to LP but after taking blood cultures
benzylpenicillin or ceftriaoxne
supportive management
rifampicin or ciprofloxacin at discharge to erradicate neisseria meningitidis carriage
meningococcal meningitis bad prognostic markers
clinical: delay antib, extremes age, purpuric lesions, hyperpyrexia
lab: DIC, metabolic acidosis, absence polymorph leucocytosis
what is most frequent cause bacterial meningitis in adults
pneumococcal meningitis - strep pneumoniae
pneumococcal meningitis microbiology
gram positive diplococci
alpha haemolytic
pneumococcal meningitis predisposing factors
pnuemonia sinusitis alcoholism head trauma endocarditis splenectomy
pneumococcal meningitis clinical
acute onset - 1/2 days
more likely to have reduced consciousness/focal neuro signs than meningococcal and hameophilus
petechiae uncommon
concurrent sinus/ear infection
pneumococcal meningitis complications
death hearing loss CN deficits hemiparesis hydrocephalus seizures
dexamethasone reduces likehood of complications occuring
pneumococcal meningitis management
early administration high dose ceftriaxone
Hib meningitis clinical features
young kids
mild URTI then rapid detioration
fever, drowsy, lethargy
nuchal rigitidy often absent
late disaese: coma, seizures
Hib meningitis microbiology
gram negative cocci and bacilli
Hib meningitis treatment
ceftriaxone +/- dexamethasone
rifampicin prophylaxis to close contancts
TB meningitis
meningitis follows rupture of subependymal tubercle into subarachnoid space
kids assoc w miliary TB or effusion
TB meningitis clinical
subacute onset
lethargy
headache
change in mentation
TB meningitis poor prognostic markers
extremes age
illness >2mo
neuro defiict
leptospirosis and lyme disease
caused by spirochates
may cause apparent aseptic meningitis
leptospirosis features
septicaemic illness fever, rigors myalgia, vomiting conjunctical effusion meningism rash liver and renal damage
lyme disease features
skin rash
neurological symptoms inc meningitis
peripheral or cranial neuropathies
most common causes viral meningitis
enteroviruses - echovirus, coxsackie
viral meningitis features
non-specific prodromal ilness
rapid onset: headache, photophobia, stiff neck, fever
rash if enteroviral
pt usually lucid and alert
viral meningitis Ix
CSF PCR
- enteroviruses
- mumps
- HSV
viral meningitis prevention
MMR
good hand hygeine
viral meningitis treatment
enterovirus and parechovirus: supportive Rx, usually recover 72hrs
chronic infection (immunocompromised): IVIg
HSV: aciclovir
cryptococcal meningitis
cryptococcus neoformans
HIV, immunosuppressed, lymphoma, DM
fungal meningitis microbiology
organism is yeast with a polysacharride capsule
gram stain shows yeast cells
culture C. neoformans
serum cryptococcal polysacharide antigen
fungal meningitis clinical features
subacute onset fever headache nausea lethargy confuson abdo pain mengism less common but can develop
fungal meningitis Mx
parenteral amphocetin +/- flucytosine
high dose fluconazole as alternative
fungal meningitis prevention
if HIV pt gets cryptococcal meningitis then prophylaxis with fluconazole
how does neonatal meningitis differ from adult
features non-specific, not well localices
GBS, e.coli, l. monocytogenes
neonatal meningitis predisposing factors
low birth wait
PROM
maternal DM
group b strep
gram +ive cocci
benzylpenicillin, amoxycillin
e.coli
gram - bacilli
cefotaxamine
l.monocytogenes
g + bacilli
ampicillin and gentamicin
neonatal meningitis early onset
within 3days birth
resp distress, ,bactermia
assoc w prematurity, difficult/prolonged birth
neonatal meningitis late onset
> 1wk after birth
pulm involvement rare
diagnosing neonatal meningitis
bacterial: CSF, blood cultures
viral: CSF, EDTA blood, faecal + nasopharyngeal secretions
