Ch 23 CNS infections Flashcards
Meningitis
infection or inflammation that is confined to the meninges
common causes of meningitis
bacteria or virus
which outcome is worse in meningitis? bacterial or virus?
bacteria etiology is worse than viral
3 bacterial forms of meningitis (accounts for 95% of bacterial forms of meningitis)
haemopilus meningitis
meningococcal meningitis - 2nd most common cause
pneumococcal meningitis - most common cause
how is bacteria spread to meninges
can be spread from an adjacent infected area (eg ears or sinuses), from the environment (e.g. congenital defect, penetrating injury) through the bloodstream
primary cause of bacterial meningitis
inflammation
- leads to tissue and vascular injury, septic thrombosis, smaller infarcts
TB can also develop meningitis
complications of bacterial meningitis
brain edema and increased ICP - hypoxic ischemic encephalopathy (HIE)
what happens when there is bacterial meningitis in children
cranial nerve defects (reversible)
- mostly in children (5-11 % cases)
which cranial nerve is most affected by bacterial meningitis?
cranial nerve 8 (auditory)
- results in sensorineural hearing loss
Cranial nerve 6 (abducens)
- longest intracranial route
- most vulnerable to compression
CN 3, 4, 7 may also be affected
how does TB bacteria spread?
to brain and spine from lung
rates of bacterial meningitis
0.6-4/100,000 annually
rates of neonatal bacterial meningitis
0.25-1/1000
rate of TB meningitis?
rare, only in poor regions
bacterial meningitis mortality rate
5-10%
significantly improved
highest in 1st year of life, decline mid life, then increase in older adults
mortality rate highest in which type of meningitis?
pneumococcal (10-30%)
TB (15-30%)
mortality rate lowest in which type of meningitist?
meningococcal (4-5%)
% of people with long term consequences of bacterial meningitis
15-25%
common consequences of bacterial meningitis
hearing loss 11%
ID 4%
spasticity 4%
seizure disorders 4%
cognitive impairment/ADHD in 50% of childhood survivors
determinants of severity - age
most cases happen in children <5 years or > 60 years
medical risk factor for bacterial meningitis
immunosuppression - increased risk for infections
e.g. HIV, autoimmune etiology, cystic fibroids, DM, hypoarathyroidism
SES risk factors
resources
Types of bacterial meningitis and NP outcomes
pneumococal meningitis show greater cognitive impairments than meningococcal meningitis
viral or bacterial meningitis have better outcomes?
viral
other medical risk factors for bacterial meningitis
complications (prolonged seizures, hemiparesis, b/l hearing loss)
Low CSF glucose level
strep pneumonia infection
younger age - worse language outcome
male or female worse behavioral outcome for bacterial meningitis
MALES
acute vs gradual presentation
acute:
sudden fever
severe HA
stiff neck
gradual:
non specific flu like symptoms
common presenting sx in children of bacterial meningitis
hyperthermia lethargy anorexia vomiting respiratory distress convulsion irritability jaundice diarrhea stiff neck
assessment of bacterial meningitis
lumbar puncture - diagnostic, check CSF to see if there’s blood or white blood cells, protein levels, low glucose
brain imaging - CT/MRI do NOT help with diagnosis!
even if scans do not show meningeal enhancement, it does not r/o diagnosis
MRI is used for TB meningitis
treatment for bacterial meningitis
antibiotics vaccine corticosteroids - inflammation and swelling, - prevents hearing loss
TB meningitis
- anti TB drugs
NP outcomes overall in bacterial meningitis
MORE cognitive impairments than physical impairments
NP IQ in bacterial meningitis
adults - average IQ
peds - low average to average IQ
NP academic in bacterial meningitis
2x more likely to need special ed, grade retention
no consistent academic deficit in certain domains
NP attention in bacterial meningitis
adults - trails B and stroop
peds - ADHD rates higher than average
NP processing speed in bacterial meningitis
adults - simple reaction time slower
MAIN DEFICIT
NP language in bacterial meningitis
adults - no problem
peds - kids dx before age 1 have impairment
NP visuospatial in bacterial meningitis
no consistent finding
NP memory in bacterial meningitis
adults - mixed
NP Executive function in bacterial meningitis
adults - problems more common
peds - not severe impaired but below expectation
NP sensorimotor in bacterial meningitis
hearing loss - consistent finding (usually in pneumococcal than meningococcal)
hemiparesis
cortical blindness
ataxia
spasticity
Meningitis is the cause of ?% of deaf and hard of hearing in youth in USA?
3-6%
NP mood in bacterial meningitis
peds - ADHD, behavioral changes and other MH issues in adolescence
NP work in bacterial meningitis
adults - can work normally
peds - in peds onset, lower economic sufficiency in adulthood
Aseptic Forms of meningitis - aseptic means?
non bacterial forms of bacterial meningitis
Cause of aseptic meningitis?
virus
fungi
parasite
enterovirus (through intestine)
most common cause of aseptic meningitis
enterovirus
examples of fungi that can cause aseptic meningitis
crytococcus histoplasma blastomyces coccidioides candida - acquired usually in hospital
which one is more common? viral or bacterial forms of meningitis
viral forms
how many cases of viral aseptic meningitis
10,000 reported
possibly 75,000
fungal meningitis happens in which population?
rare
usually in immunocompromised eg HIV positive
most common form of fungal meningitis
crytococcus
mortality of viral meningitis
< 1%
morbidity of viral meningitis
less common long term neurological consequences than bacterial meningitis, usually benign outcomes
recovery of viral meningitis?
7-10 days
no residual effects
persistent effects are mild
presenting problem in viral meningitis?
headache - most common sx
fever irritability nausea and vomiting stiff neck rash fatigue
assessment and dx of viral meningitis
lumbar puncture - examine blood and CSF to isolate viral pathogen
CT, MRI, EEG - clarify dx
treatment of viral meningitis
antibiotics - USELESS
mostly supportive - rest, fluids, anti inflammatory meds
some antiviral meds
treatment of fungal meningitis
antifungal meds
NP in fungal meningitis
mostly mild
but long lasting deficits can be seen in motor speed, gross motor, and EF
Definition of Encephalitis
infection of the brain tissue/parenchyma
most common cause of Encephalitis
virus
other causes of Encephalitis
(besides virus #1)
bacteria, fungi, parasites
autoimmune
two types of Encephalitis
primary Encephalitis = acute viral Encephalitis
secondary Encephalitis = post-infective Encephalitis
what is primary Encephalitis / acute viral Encephalitis
direct infection of brain through direct invasion of pathogen
what is secondary Encephalitis/post-infective Encephalitis
results from previous viral infection (e.g. chickenpox, mumps, measles) or immunization (measles vaccine)