Crash course: CNS infections + STIs Flashcards
What is meningitis?
Inflammation of the meninges
Can be bacterial, viral or fungal (or TB)
Presents with meningism
What are the signs of meningism?
Stiff neck (nuchal rigidity)
Kernig’s sign
Brudzinski’s sign
List 5 symptoms of meningitis
Headache
Photophobia
Fever
N+V
Drowsiness
Give 4 signs of meningococcal disease
Non-blanching petechial rash
Altered mental status
Skin mottling
Cold + painful extremities
What is encephalitis?
Inflammation of brain parenchyma
Usually viral, rarely AI
Presents systemically unwell, altered mental state- personality change
What is a brain abscess?
Infective collection in the brain parenchyma
Presents with swinging fevers + SOL
What are the most common causes of meningitis in neonates?
Group B Strep
Listeria monocytogenes
E. coli
What are the most common causes of meningitis in adults?
Neisseria meningitidis
Streptococcus pneumoniae
What are the other causes of meningitis in the elderly in addition to Neiserria and Steptococcus?
Group B Strep
Listeria monocytogenes
What can cause meningitis in the
immunocompromised?
TB
What are the three classifications of meningitis? What are the usual causative organisms?
Acute: bacterial
Chronic: TB, Spherocytes, Cryptococcus
Aseptic: acute viral
Which organism causes meningococcal meningitis?
Neiserria Meningitidis
What are the 3 most common causes of meningitis in children/ young adults?
Neiserria Meningitidis
Haemophilus influenzae (rare in vaccinated countries)
Streptococcus pneumoniae
What are the viral causes of meningitis?
Enterovirus: Adenovirus, Cocksackie
HSV-2
HIV seroconversion (rarely)
Name 2 fungal causes of meningitis. In which patients?
Cryptococcus neoformans: HIV
Cryptococcus gattii: immunocompetent
How is meningitis diagnosed?
LP
Ideally LP before abx, but like with cultures, don’t delay abx
If any Sx consistent with raised ICP or SOL, need brain imaging first
Give 4 signs of raised ICP
Focal neurology
Papiloedema
Reduced GCS
Seizures
What analytics are used on CSF in meningitis?
Biochemical analysis
Gram stain for bacteria
PCR for viruses
Ziehl-Neelson stain forTB
India ink stain for Cryptococcus
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in BACTERIAL meningitis?
Cloudy + turbid
↑↑↑ WCC
Massive neutrophilia
↑↑ Protein
↓ glucose (<40% plasma glucose, as bacteria consuming)
↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in VIRAL meningitis?
Clear
↑ WCC
Lymphocytosis
N/ ↑ protein
N glucose (>60% plasma glucose)
N/ ↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in FUNGAL meningitis?
Fibrin web
N/ ↑ WCC
Lymphocytosis
N/ ↑ protein
N/ ↓ glucose (<40% plasma glucose)
↑ / ↑↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in TB meningitis?
Cloudy + viscous
↑ WCC
Lymphocytosis
↑↑ protein
↓↓ glucose (<30% plasma glucose)
↑ opening pressure
What is normal opening CSF pressure?
10-20
Describe management of meningitis
In community: IM Benzylpenicillin
In hospital:
IV Ceftriaxone/ Cefotaxime
(+ Amoxcillin/ Ampicillin if baby or >50y)
+ Acyclovir if can’t exclude encephalitis