CNS Infections Flashcards
RFs of bacterial CNS infections
non-intact BBB, very young, elderly, immunocomp
Ways in which bacterial infections spread to CNS?
- hematogenously (most common)
- bone (where thin like mastoiditis, sinusitis, middle ear infx, abscessed tooth)
- interconnecting veins (central facial infections)
- axonal spread
Who is most likely to get bacterial meningitis?
groups of young adults living in crowded conditions
infants
Bacterial meningitis is an infection of ______, _____, and _______ by bacterial.
arachnoid, subarachnoid space, and CSF
Organisms that cause bacterial meningitis?
infants: E. coli, beta-hemolytic strep
children/adults: step pneumo (blood), Neisseria (UTI), H flu (ear infection)
Common symptoms of bacterial meningitis?
fever, severe HA, stiff neck
Positive PE tests in bacterial meningitis
Kernig’s (flex hip/knee)
Brudzinski’s (flex neck)
CSF analysis of bacterial meningitis
- neutrophils with high WBC count
- high proteins
- low glucose
- Gram stain
Bacterial meningitis tx
IMMEDIATE broad spectrum abx
vaccine: Neisseria meningitides and H-flu
Etiology of epidural abscess
- infection in neighboring areas resulting in osteomyelitis or TB of vertebral column
- infection post surgery (staph)
Etiology of subdural abscess
- Infection spread via sinuses or middle ear to subdural space
- staph aureus or strep
Progression of subdural abscess
spinal empyema -> compression of spinal cord -> paralysis/death
Etiology of brain abscess
- extension from sinusitis, otitis, or meningitis
- hematogenous spread
Treatment of epidural, subdural, and brain abscesses
Surgical evacuation and IV abx
Dx imaging of choice for epidural, subdural, and brain abscesses
CT scan
2 types of CNS spirochete infections
Syphilis and Lyme Disease
What organism causes Lyme Disease?
Borrella Burgdoferi in ticks
Signs of syphilis CNS infection
Tabes dorsalis = inflamm/degen of posterior columns; impairs proprioception/vibration; causes shooting pain in legs and Robertson pupil paresthesias
General paresis of the insane = encephalitis due to spirochete invasion of brain; mental and personality changes
How are viral infections of CNS spread?
blood and peripheral nerves
Etiology of viral meningitis?
unidentified virus; possibly enterovirus, HIV, chicken pox, herpes
Possible drug-induced
CSF results of viral meningitis
high cell count
pleocytosis
high protein
normal glucose
How is viral meningitis different from bacterial?
- aseptic/viral has NO neuro deficits
- viral has normal glucose; bacterial is low
- bacterial organism can be identified via Gram stain
definition of encephalitis
infection/inflamm of CNS neurons and glial cells
Etiology of viral encephalitis
- Generalized viral infection (pneumonia, enteritis)
- Primary CNS infection (rabies, West Nile)
