CNS Infections Flashcards
CNS is ___ ____ against infection
well protected - has mechanical and immunological barriers
Brain - immune response
Brain has limited immune responses once infection occurs
Brain - limited compliance to acute infections therefore
Permanent damage or death can occur quickly
Brain - chronic infections
Cause significant displacement with few s/s
Chronic infections cause s/s that mimic other things so hard to diagnose until there is significant displacement of brain structures
Various pathogens are responsible - name them
Bacteria
Viruses
Prions
Fungi
CNS infection - define
Inflammation of structures within the CNS as a result of a pathogen
Meningitis - define
Inflammation of the pia and arachnoid in the subarachnoid space
Encephalitis - define
inflammation of the brain parenchyma
Empyema - define
Accumulation of pus in the epidural or subdural spaces
Difference between bacterial and viral inflammatory response
Bacterial infection has a bigger inflammatory response than viral
Abscess or Granuloma - definition
Localized inflammation of the brain or spinal cord parenchyma
Myelitis - definition
Inflammation of the spinal cord parenchyma
Encephalomyelitis - define
inflammation of the brain and spinal cord
Ependymitis - define
inflammation of the ventricles and ventricular lining
Routes of entry or spread
Hematogenous spread
Direct inoculation
Direct spread/extension
Spread of viruses along nerves
Bacterial meningitis AKA
septic meningitis
Bacterial meningitis - what is often the primary clue of which bacteria
The age of onset
Bacterial meningitis - what is the most common route
Hematogenous (blood system spread)
Bacterial meningitis - Other routes that are common
congenital defects
acquired
Bacterial meningitis - Pathogen if age less than 3 months
Group B strep
E coli
Listeria
S pneumoniae
Bacterial meningitis - Pathogen if age 3 months to 50 years
S pneumoniae
Neisseria meningitidis
H influenza
Bacterial meningitis - Pathogen - greater than 50 years
S pneumoniae
Bacterial meningitis - Pathogen - or impaired cellular immunity
L monocytogenes
Gam - bacilli
Bacterial meningitis - Pathology
1 Dramatic loss of capillary integrity secondary to release of endotoxins
2 Purulent rxn with polymorphonuclear leukocytes and necrosis
3 Vascular occlusion - cerebral edema
Bacterial meningitis - Pathology - Antibiotics in the immediate acute stages
Might increase release of endotoxins - you are getting rid of some endotoxins but also letting more come
Bacterial meningitis - Pathology - Inflammation results in
CSF blockage Communication hydrocephalus (reuptake) Obstructive hydrocephalus (block) Cortical ischemia Inc ICP
Bacterial meningitis - Pathology - Communication hydrocephalus (reuptake)
The system is not taking up the CSP as it should so it is sitting there and not being taken up
Bacterial meningitis - Pathology - Obstructive hydrocepahlus (block)
More common kind where there is a blockage of the CSF pathways
Bacterial meningitis - Pathology - Cortical ischemia results
Because the vascular system is blocked if it is severe enough
Bacterial meningitis - increase ICP and cerebral perfusion pressures
When we have an increase in ICP we start to lose brain perfusion
Bacterial meningitis - Diagnosis
CSF changes
Clinical tests