Bacterial Infections of CNS Flashcards
70% of all bacterial infections in 2000 were due to what 3 infections?
- streptococcus pneumoniae
- haemophilus influenzue
- Neisseria meningitidis
What are the two main types of bacterial meningitis
- community acquired meningitis
- nosocomial bacterial meningitis
community acquired bacterial meningitis
acquired spontaneously from exposure to environment
3 examples of community acquired bacterial meningitis
- h. influenza
- s. pneumonia
- n. meningitidis
aka the 3 most common bacterial infections
nosocomial bacterial menigitis
acquired in the hospital or as a result of an invasive medical procedure
3 examples of nosocomial bacterial menigitis
- e. coli
- other streptococcus spp
- staphylococcus spp
Epidemiology of bacterial infections
- has changed since introduction of vaccines
- highest burden is seen in africa
- the meningitis belt in africa
what is the meningitis belt
- region of sub-saharan africa that experiences recurring outbreaks
what are some factors that contribute to the recurring outbreaks seen in the meningitis belt
- weather related
- social/cultural influences
- health infrastructure
7 common themes from community acquired bacterial infections
- extracellular organisms
- express virulence factors that allow them to survive in bloodstream <- prerequisite
- can target endothelia of the brain
(most direct interactions) - cross at areas that are considered leaky
- can be prevented through vacccinations
- similar groups are at risk
Vaccines in the US
- no federal requirements, CDC can only make recommendations
- each state establishes vaccination requirements for school children
- this only applies to kids attending schools (public, private, and day care)
Classic triad for meningitis
Headache/fever, malaise, and neck pain
Listeria monocytogenes is normally contracted through
contaminated food
Treponema pallidum is generally contracted how?
sexually transmitted
Borrelia burgdorferi is generally contracted how
tick borne
Burkholderia pseudomallei is generally contracted how?
tropical climate associated with water
Commonalities of listeria monocytogenes, borrelia burgdorferi, and burkholderia pseudomallei
- these infections, in addition to meningitis, can also cause encephalitis and/or myelitis
- Occurrence should raise the suspicion of an immune deficiency or an unusual source of infection
- They are not normal commensals, must be acquired from external sources
- They all have specialized surfaces
- Can use multiple or unique ways to cross the CNS barriers
- L. monocytogenes can invade BMECs directly, then infect contiguous tissue, or use Trojan horse.
- The spirochetes use unique shape and motility to “drill” a hole between cellular barriers, including BBB
- B. pseudomallei can invade nerves peripherally and spread cell-to-cell back into the CNS.
- Big challenge, diagnosis!
Myelitis
infection of the nerves and/or glia of the spinal cord that result in the inflammation of the spinal cord
2 broad types of myelitis
acute and transverse
Examples of most infectious diseases that cause myelitis
b. burgdorferi, s. aureus, b. pseudomallei, m. leprae, and most viruses
most autoimmune diseases cause what type of myelitis
transverse myelitis
example of viruses that can cause transverse myelitis
polio or herpes
Transverse myelitis is mostly idiopathic because?
the cause is not known
