CNS infections Flashcards
What are the 4 causes of CNS infection?
Direct innoculation
Local spread from adjacent structures
Spread from a distant focus of infection
Trauma to the skull
Just a statement really…
Time is neural tissue, untreated infection may cause brain herniation and death, cord compression and necrosis with subsequent permanent paralysis
PREACH IT BROTHA
Encephalopathy
Irritation but not inflammation
Encephalitis
Infection of the brain parenchyma
Aseptic meningitis
Non-pyogenic bacterial meningitis (i.e. not found a bacterium but think there is an infection involved often virus but not always)
Meningitis
Inflammation of layers covering brain parenchyma
If meninges inflamed it becomes like injecting pus into the CNS, all the cranial nerves as they exit can be effected
What are the trio of symptoms that represent meningitis?
Headache, Photophobia and Neck stiffness
What does pyogenic mean?
Pus forming organism
Bacterial meningitis frequently causes severe oedema and ——- —–
Raised ICP
What is the common causative organism for bacterial meningitis in those age 10-21
Meningococcus
What is the common causative organism for bacterial meningitis in those 21+
Pneumococcus
Most common causative organism for bacterial meningitis in elderly?
Listeria Monocytogenes
Most common causative organism for bacterial meningitis in infants
H.Influenza
Most common causative organism for bacterial meningitis in neonates
E.Coli
What are the two common gram + bacteria that can cause meningitis?
Strep pneumonia ( diplococci in chains) Listeria Monocytogenes (bacilli)
What are the three gram - bacteria that can cause meningitis?
E.coli (bacilli)
H.Influenza (cocco bacilli)
Nisseria Meningitis (diplococci, intracellular)
What is the likely causative bacterium in meningitis if there is a fractured cribriform plate, diabetic/alcoholic, hospitalised patient?
Strep Pneumonia
Likely causative organism in meningitis if there is neurosurgery or head trauma?
Staph A or staph epidermis
Likely causative organism if pregnant, over 55, neonates or immunosuppressed?
Listeria monocytogenes
What is Waterhouse-Friderichsen syndrome?
A form of fulminant meningococcal disease in which severe septicaemia is complicated by the development of bilateral haemorrhage into the adrenal glands and disseminated intravascular coagulation (DIC)
What does the LP look like for bacterial meningitis?
Cloudy turbid CSF
Polymorphs present
Low glucose
Raised protein
Treatment of community acquired meningitis
IV Cefriaxone and Dexamethasone
is listeria is suspected what should be added to the treatment regime?
Amoxicillin (for 21 days)
If recent travel to a country with high rates of penicillin resistant pneumococcus add in…
Vancomycin
What is the prophylactic therapy for those in close contact to those with meningitis
Ciprofloxacin (single dose)
What are two specific tests that are positive in meningitis?
Kernig’s sign
Brudzinksis sign
What are the indications for hospital admission in those with acute adult bacterial meningitis
Meningeal irritation
Impaired conscious level
Petechial rash
Those who are febrile or unwell and have had a recent fit
Ill and had recent close contact with someone with meningococcal infection
When does viral meningitis commonly occur?
After a viral illness (late summer/autum)
What are the common viruses that cause viral meningitis?
Enteroviruses e.g. echovirus (or coxsackie)
If the viral meningitis is severe what is the most likely causative organism
HSV
What does LP look like for patients with viral meningitis?
Clear fluid
Lymphocytes
Low/Normal glucose
Normal/ Slightly raised protein
TRUE/FALSE
Viral meningitis is often self-limiting
TRUE
If severe then IV Acyclovir may be used
Findings of TB meningitis on LP?
Low glucose
High protein
Presence of fibrin webs
Which disease is cryptococcal meningitis common with?
HIV disease
What is the treatment of TB meningitis?
RIPE
When does neonatal meningitis present?
1st 4wks of life
What are the 3 organisms that can cause neonatal meningitis?
Group B strep
E Coli
Listeria Monocytogenes
What is the treatment of neonatal meningitis caused by group B strep?
Benzylpenicillin and gentamicin
What drugs are used to treat E.Coli causing neonatal meningitis?
Cefotaxime and gentamicin
What is used to treat neonatal meningitis caused by Listeria monocytogenes?
Amoxicillin and gentamicin
What is encephalitis?
Inflammation of the brain parenchyma commonly due to viral infection
What is the most common cause of encephalitis?
HSV
What are the two ways that HSV can spread to the brain to cause encephalitis?
- Through CN1
- Reactivation in trigeminal root ganglia
How does encephalitis present?
Acute onset headache and fever
Altered consciousness
Focal neurological deficit
Seizures with focal neurological deficits
Herpes simplex encephalitis
Parotitis in an unvaccinated patient
Mumps encephalitis
Skin lesions/vesicles in a dermatomal pattern
VZV encephalitis
What is an uncommon serious sequel of measles virus
Subacute sclerosing panencephalitis
How does subacute sclerosing pan encephalitis present?
Change in personality
Cognitive decline
Myoclonus
Speech and memory problems is more common in encephalitis or meningitis?
Encephalitis`
