CNS infections Flashcards
What is the major causative virus for viral meningitis?
Enterovirus e.g. ECHO virus
Management of viral meningitis
Supportive, as disease is usually self-limiting
Diagnosis of viral meningitis
Viral stool culture
Throat swab
CSF PCR
Presentation of viral encephalitis
Headache; fever; focal neurology e.g. speech, memory symptoms; stupor; coma
Essential features of the history in suspected viral encephalitis
Recent travel (e.g. Japansese encephalitis) Occupational exposure e.g. rabies virus
Treatment of herpes simplex and varicella zoster encephalitis
High dose aciclovir
Which area of the brain does viral encephalitis tend to affect?
Temporal lobe
Main causative organisms of bacterial meningitis in teenagers/adults
Strep pneumonia (pneumococcus) Neisseria meningitides (meningococcus)
Risk factors for bacterial meningitis
Decreased cell-mediated immunity;
Skull trauma e.g. cribriform plate fracure;
Post-neurosurgery;
CSF shunt
Symptoms of meningococcal meningitis are due to the effects of…
Endotoxin
Listeria monocytogenes is more common in what groups of patients?
Neonatal; older patients; immunosuppressed
Antibiotic for listeria
IV ampicillin/amoxicillin
Main four clinical features of bacterial meningitis
Headache
Fever
Neck stiffness
Change in mental state
Meningococcal meningitis may be associated with…
Purpuric (non-blanching) rash
When should performing an LP be avoided?
If there is a possibility of increased ICP
Key findings of LP in bacterial meningitis:
a) cells
b) gram stain
c) protein
d) glucose
a) 10^1 - 10^4. Polymorphs
b) Positive
c) elevated
d) lowered
Indications for CT prior to lumbar puncture
Immunocompromised state History of CNS disease New onset seizue Papilloedema Abnormal level of consciousness Focal neurology
Initial “blind” antibiotic therapy
IV cefotaxime 2g bd. + amoxicllin if 50 years
Role of steroids in bacterial meningitis
Give to all suspected of having bacterial meningitis with the first dose of antibiotic. Reduces unfavourable outcomes particularly in pneumococcal meningitis
Antibiotic for meningococcal meningitis (after CSF/blood cultures)
Benzylpenicillin or ampicillin
Management of tuberculosis meningitis
Isoniazid + rifampicin
Most common cause of meningitis in neonates
Group B strep
When is contact prophylaxis needed and what is given?
In meningococcal meningitis. Oral ciprofloxacin
