Infections of the Nervous System Flashcards
What is meningitis?
Inflammation of the brain meninges.
What is encephalitis?
Inflammation of the brain parenchyma.
What are the most common bacterial organisms in CNS infection?
Strep. pneumoniae
Neisseria meningitidis
Listeria monocytogenes
What is used to treat meningitis if caused by strep. pneumoniae and neisseria meningitidis?
Ceftriaxone and dexamethasone.
How are treatments for CNS infections administered?
Intravenously
What is given to those with listeria monocytogenes infection?
Ceftriaxone, dexamethasone and amoxicillin.
In those with history of recent travel to a country with known penicillin-resistance, what is given?
Vancomycin and ceftriaxone.
In what individuals are steroids contraindicated?
Immunocompromised
Septic shock
Post-surgery
Steroid hypersensitivity
What is the most common cause of viral meningitis?
Enterovirus
What time of year is viral meningitis most commonly seen?
Late summer/autumn
How is viral meningitis diagnosed?
CSF PCR
Stool culture
Throat swab
How is viral meningitis treated?
Symptomatic only as the virus will be self-limiting.
How is bacterial meningitis diagnosed?
Lumbar puncture
What will a lumbar puncture show in an individual with bacterial meningitis?
High WBCs
High protein
Low glucose
Culture may not be positive for bacteria if antibiotics given prior to the sample being obtained.
What are the key symptoms of meningitis?
Headache
Fever
Neck stiffness
What are features of encephalitis?
Headache
Fever
Neck stiffness
What conditions may precede bacterial meningitis?
Endocarditis
Pneumonia
UTI
Involves a haematogenous route of spread.
What virus is commonly involved in encephalitis?
HSV
What is seen on an MRI in an individual with encephalitis?
Hyperdense areas.
What is meningo-encephalitis?
A crossover condition involving features of both meningitis and encephalitis.
Is trauma of the cribriform plate a risk factor for strep. pneumoniae meningitis?
Yes
Does a CSF pleocytosis indicate meningitis?
No, only confirmed when bacteria is identified.
What does pleocytosis mean?
An increased WBC count.
What individuals must get CT prior to lumbar puncture?
Immunosuppressed New onset seizure History of CNS disease Papilloedema Abnormal LOC
What cells are raised in bacterial meningitis?
Neutrophils
What cells are raised in viral meningitis?
Lymphocytes
In relation to CSF sample glucose level, what differs between viral and bacterial meningitis?
Bacteria consumes glucose, meaning it will be low in bacterial meningitis.
Viruses do not consume glucose, meaning it will be normal in viral meningitis.
What is aseptic meningitis?
Meningitis with no pus.
Can be caused by a virus, malignancy or sarcoidosis.
In those over 60, what bacteria is a risk?
Listeria monocytogenes
Give amoxicillin alongside ceftriaxone to cover this.
Is meningitis a medical emergency?
Yes
