Infections of the CNS Flashcards
What are some common organisms causing bacterial and viral Meningitis?
Bacterial: Neisseria Mengitidis, Haemophilus Influenzae B, Streptococcus Pneumonia, Group B Streptococci
Fungal
Viral: Enterovirus, HIV, VZV, Mumps, Measels
What’re the common organism causes of Encephalitis, Abscesses, Myelitis?
Encephalitis - viral
Abscesses - bacterial (streptococci)
Myelitis - viral (poliomyelitis, rabies)
What’re clinical features of Meningitis? How would they differ from Encephalitis?
Fever, Headache, Neck stiffness, Photophobia, Purpuric rash, Reduced consciousness (GCS), Focal CNS signs from raised ICP
Confusion and Seizures more common in Encephalitis
Purpuric rash occurs only in Meningococcal Meningitis
What are the most common forms of Meningitis and for each age group
Meningococcal B most common, Meningococcal disease peaks before 1 year old and then again around university age
Meningococcal - children and young adults
Pneumococcal - URTI, immunocompromised
Group B Streptococci - neonates
Listeriosis - elderly, neonates and immunocompromised
Tuberculous -high CSF protein, rapid onset of fever/confusion/coma
Brain abscess - chronic URTIs, may present with seizures
What are the investigations of Meningitis?
FBC
Inflammatory markers
U and E
Coagulation tests (APTT and PT)
2x blood cultures and blood for PCR tests
HIV test?
CT scan if raised ICP or lesion risk - not common
Lumbar puncture for CSF sample is gold standard
Outline analysis of CSF sample in Meningitis
What’s a risk of performing lumbar puncture with ICP is raised?
Take 3 LP samples and compare sample 1 and 3 for RBCs
Measure CSF opening pressure (>18cm indicates raised ICP)
CSF shouldn’t have many proteins in, few cells (WCCs), should be clear
Be careful as risk of coning - when pressure is relieved from LP so brain herniates through foramen magnum
How does CSF change in bacterial, viral and tuberculous Meningitis:
WCC
WBC type
Protein
Glucose (vs serum)
Bacterial: High WCC, mainly Neutrophils, high proteins and low glucose compared to serum, organisms may be seen
Viral: Slightly high WCC, mainly lymphocytes, slightly high protein and normal glucose
Tuberculous: High WCC, mainly lymphocytes, very high proteins and low glucose compared to serum
If CSF glucose is <50% of blood serum glucose, then likely to be bacterial or TB meningitis
What’re the preventative measures for Meningitis?
Immunoprophylaxis - vaccination programmes, now have against all Meningococcal strains, pneumococcus, HIB and viral vaccinations in development
Chemoprophylaxis - single dose of Ciprofloxacin or Rifampicin for those in household of someone affected by Meningitis
Outline the management of Meningitis
Bacterial: Cetrifaxone (good at penetrating BBB -> CSF)
Listeriosis: Amoxicillin
Viral: Aciclovir IV
TB: Combination of antibiotics
Management of sepsis six
Define Meningitis and Encephalitis
M = Inflammation of the meninges E = Inflammation of the brain Meningoencephalitis = inflammation of the meninges and brain
What’s myelitis?
Inflammation of the spinal cord
What are the most common symptoms of Meningitis for a diagnosis? (95% of the time)
Any 2 of: Headache Neck stiffness Fever (>38) GCS <14
What’s turbid CSF in a sample likely to indicate?
Neisseria Meningitidis
What’s the treatment for suspected bacterial meningitis? (which antibiotics)
Ceftriaxone
Or if Penicillin allergy: Vancomycin + Meropenem
Antibiotics + Dexamethasone (glucocorticoid receptor agonist)
Sepsis six if necessary
Which drug is used for viral encephalitis?
Aciclovir (inhibits viral DNA synthesis)
