CNS infection and meningitis Flashcards
Which broad category of organisms is most commonly responsible for acute meningitis?
Bacteria
How does chronic meningitis present and which organisms are more likely to be the cause?
Headaches for months
Likely to be TB or cryptococcus
Which broad category of organisms is most commonly responsible for aseptic meningitis?
Viruses
What is the most common Gram -ve cause of bacterial meningitis in otherwise healthy adults?
Neisseria meningitidis
What is the most common Gram +ve cause of bacterial meningitis in otherwise healthy adults?
Strep pneumoniae
List 3 causes of bacterial meningitis in neonates
Group B strep
Listeria monocytogenes
E coli
(All GI flora)
List 3 causes of bacterial meningitis in the elderly
Group B strep
Listeria monocytogenes
Mycobacterium tuberculosis (subacute)
List 4 viral causes of meningitis
Coxsackie
Mumps
HSV2
Echovirus (in children
Name a fungal cause of chronic meningitis
Cryptococcus neoformans
Describe the aetiology of bacterial meningitis?
Spread of infection either systemically (eg from mucosa) or locally (eg from skull fracture)
List 3 risk factors for Neisseria meningitidis meningitis
Complement deficiency
Hyposplenism (susceptible to encapsulated organisms)
Hypogammaglobulinaemia
List 6 risk factors for Strep pneumoniae meningitis
Complement deficiency Hyposplenism Immune defect (eg alcoholics) Infection (ie pneumonia) Entry fracture Previous head trauma w/CSF leak
How does acute bacterial meningitis present?
Headache Vomiting Photophobia Irritability Fever Focal neuro signs Rash
How is bacterial meningitis diagnosed?
Clinical features Blood cultures Serum-Ag EDTA-PCR Throat swab CSF - WCC (polymorphs)↑ Protein ↑ Glucose ↓
What is the treatment for bacterial meningitis?
Resuscitate (ABC)
Ceftriaxone
Corticosteroids
*If listeria suspected cover with ampicillin
Which scoring system is used to predict the need for intensive care in children with bacterial meningitis?
Glasgow Meningococcal Septicaemia Prognostic Score
>8 usually fatal
How can viral meningitis be distinguished from viral encephalitis?
In viral meningitis there is no change in consciousness or focal neurology
What are the normal ranges for WCC, protein and glucose in adult CSF?
WCC: 0-5
Protein: 0.15-0.4
Glucose: 2.2-3.3 (>50% serum)
What is the most likely type of infection in a patient with the following CSF results: -
Glucose: low
WCC: high with polymorphs
Bacterial infection
?turbid
What is the most likely type of infection in a patient with the following CSF results: -
Glucose: normal
WCC: high with polymorphs
Partially treated bacterial infection
What is the most likely type of infection in a patient with the following CSF results: -
Glucose: normal
WCC: high with mononuclear cells
Viral meningitis/encephalitis
What is the most likely type of infection in a patient with the following CSF results: -
Protein: high
WCC: high with mononuclear cells
Mycobacterium TB or cryptococcus
Name 2 CNS infections in which the CSF results can be normal
Cerebral abscess (Streptococci) Viral encephalitis (Herpes)
What is the treatment for meningoencephalitis?
Acyclovir and ceftriaxone
