CNS Infections Flashcards
Name some anatomical infections of the CNS?
- Myelitis
- Abscess
- Meningitis
- Encephalitis
What are the 3 most important bacterial causes of CNS infections?
- Listeria
- Pneumococcus
- Meningococcus
What are the most common viral causes of CNS infections?
- HSV
- VZV
- Enterovirus
What is the most common fungal cause of CNS infections?
Cryptococcosis
What is the most common protozoal cause of CNS infections?
Toxoplasmosis
What is meningitis?
What is diagnosis based on?
Inflammation of meninges +/- cerebrum (meningo-encephalitis)
Inflammation presence in the CSF
What are the types of meningitis and what causes them?
- Acute
- Bacterial/viral
- Sub-acute
- Bacterial (Listeria/TB)
What are the signs and symptoms of meningitis?
- Most will have 2 of:
- Fever
- Headache
- Neck stiffness
- Reduced GCS
- Rash
- Kernigs sign
- Brudzinskis sign
What meningitis symptom is indicative of cerebritis/encephalitis?
Confusion
What type of rash is present in meningitis?
- Purpuric +/
- Petechial
- What are each of the following?
- Gram positive diplococci
- Gram negative diplococci
- Gram positive rods
- Streptococcus pneumoniae
- Neisseria meningitidis
- Listeria monocytogenes
What should be considered if someone who has meningitis has recently travelled?
- May be resistant meningitis
- South East Asia
What are the risk factors for a pneumococal meningitis?
- Mostly caused by an underlying disorder
- Alcohol
- Head injury
- Immunosuppression
What are the risk factors for a listeria meningitis?
- Pregnancy
- Immunosuppression
- Eating cheese and pate
Name some signs which make meningitis more likely to have a pneumococcal cause?
- Seizures
- CN VIII palsy
- Endocarditis
- Focal neurological signs
What is pictured here?
- Typical signs of meningococcal meningitis
- Purpuric rashes
- Digital vasculitis
Name 4 prognostic indicators of a adverse outcome in bacterial meningitis?
- Reduced GCS
- Pneumococcal cause
- CN palsy (pneumococcal)
- Bleeding (meningococcal)
Name some investigations for a suspected meningitis?
- History/ exam
- Throat culture
- Blood cultures
- Lumbar puncture
- FBC, U&Es, LFTs, CRP
Describe the use of a lumbar puncture as an investigation for a suspected meningitis?
- Gram stain, Culture, PCR
- Protein and Glucose
- Viral PCR
What might you examine if there is a suspected meningitis?
- Throat
- Cervical lymph nodes
When would you perform a CT scan for a suspected meningitis?
- To exclude mass lesion and gross cerebral oedema
- Give antibiotics pre-scan
What can a CT not exclude?
Raised intracranial pressure
When would you perform a CT before a lumbar puncture?
- GCS <= 12
- CNS signs
- Papilloedema
- Sezisures
- Immunocompromised
When is a LP contraindicated?
- Brin shift
- Severe sepsis
- Coagulopathy
- GCS deterioration
- Infection at LP site
- Rapidly evolving rash
What would be the CSF findings from LP if there was a bacterial meningitis?
- Raised protein
- Glucose reduced <50%
- Neutrophils / Lymphocytes
What would be the CSF findings from LP if there was a TB meningitis?
- Lymphocytes
- Raised protein
- Glucose reduced <50%
What would be the CSF findings from LP if there was a viral meningitis?
- Lymphocytes (neutrophils early)
- Raised protein
- Normal glucose
What would be the CSF findings from LP if there was a fungal meningitis?
- Lymphocytes
- Raised protein
- Glucose reduced <50%
What investigations could be used to differentiate between a TB and a fungal cause of meningitis post-LP?
- TB
- Culture, PCR
- Fungal
- India ink, CrAG
Describe the treatment of a suspected bacterial meningitis?
- IV antibiotics
- Treat for all possible causes
- IF there is a high possibility of pneumo cause:
- Add steroids
What drug does everyone with a suspected bacterial meningitis get?
- Ceftriaxone
- Covers all possible causes
- Add Amoxicillin if there is signs of Listeria cause
What is the definitive antibiotic therapy for meningococcal bacterial meningitis?
- IV Ceftriazone or Benzyl Penicillin
- 5 days
What is the definitive antibiotic therapy for pneumococcal bacterial meningitis?
- IV Ceftriaxone or Benzyl Penicillin
- 14 days
What is the definitive antibiotic therapy for listerial bacterial meningitis?
- IV Amoxicillin (stop Ceftriaxone)
- 21 days
Describe the use of secondary bacterial meningitis prevention?
- Give close contacts of someone with BM prophylactic treatment
- Ciprofloxacin or Rifampicin
Look at the meningococcal vaccine schedule
What are the special circumstances for bacterial meningitis vaccinations?
- Asplenic patients
- Cochlear implants
- Complement deficiency
- Travelling to Sub-Saharan Africa
Describe Viral Meningitis?
- Diagnosed only after bacterial exclusion
- No confusion
- Supportive treatment
- Consider Aciclovir ONLY if immunocompromised
When is Aciclovir only considered as a treatment of viral meningitis?
- Immunocompromised
- ?HIV
Describe the signs of Viral Encephalitis and what causes it?
- Confusion, Fever +/- Seizures
- HSV
What are the CSF signs of viral encephalitis?
- Lymphocytes
- Normal glucose
What is the treatment of Viral Encephalitis?
IV Aciclovir for 3 weeks
Describe intra-cerebral TB?
- Sub-acute
- Associated with TB in another site
- CN lesions usual
- CSF may be normal
Describe the treatment for intra-cerebral TB?
‘RIPE’ + steroids
Describe HIV brain disease?
Consequence of untreated infection and marked immunodeficiency
What does PMLE stand for?
Progressive multifocal leucoencephalopathy
Describe PMLE?
- Progressive motor dysfunction
- Immunocompromised
- No specific treatment
Describe Intra-cerebral toxoplasmosis?
- Caused by Toxoplasma gondii
- Immunocompromised
- Headache, seizures, focal CNS signs
- Multiple enhancing lesions
Name a diagnostic sign of intra-cerebral toxoplasmosis?
IgG and IgM in the blood
What is the treatment for intra-cerebral toxoplasmosis?
- Sulphadiazine
- Pyramethamime
Describe Cryptococcal meningitis?
- Caused by fungus cryptococcus neoformans
- Immunodeficiency usually (HIV)
How do you treat cryptococcal meningitis?
- Amphotericin B + Flucytosine
- Shunt if raised ICP
