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35 Cards in this Set
- Front
- Back
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Local immune response in CNS (3)
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No lymphatics, but CSF and brain fluids flow to lympathics
Can synthesize complement, but levels are low Generally low MHC expression |
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2 key neuroglial cells and main functions
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Astrocytes-BBB
Microglia-macrophage activity (originate in bone marrow) |
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Resident innate immune cells in CNS
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Astrocytes express TLR4, produce TGF-Beta
Microglia-highly phagocytic, poor APCs, express TLR4 Mast cells produce TNF to inc permeability. |
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What makes mediators that inc permeability of BBB? What is the outcome of this?
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Mast cells make mediators; outcome is lymphocytes allowed through
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What kind of T cells can enter the nervous system?
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Only those stimulated by antigen
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What happens to most T cells that enter the brain?
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die via apoptosis (unless they encounter antigen in CNS)
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What causes B cells to enter BBB?
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Flow of lymph drainage to lymph node; enters in response to inflammationif encounter antigen, it expands and multiplies w/ antibodies
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Which component of the immune arcs are unable to respond in CNS?
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afferent arm: cellular route like DCs
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Inflammation of brain parenchyma
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encephalitis
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Inflammation of spinal cord tissue
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myelitis
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Acute causes of meningitis
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-encapsulated bacteria (Strep pneumo, N. meningitidis)
-Arbovirus (West Nile) -Enteroviruses -HSV2 |
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Chronic causes of meningitis
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M. tuberculosis
Cryptococcus neoformans other fungi |
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Viral causes of acute encephalitis
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herpes
Adenovirus Influenza A Enteroviruses, poliovirus Rabies Arboviruses |
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Acute microbial cause of brain abscess
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Staphylococci
Mixed anaerobic & aerobic flora Group A strep |
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Chronic causes of brain abscess
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M. tuberculosis
C. neoformans Taenia solium Toxoplasma gondii |
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General entry routes for CNS infections
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Hematogenous
Neural pathways direct inoculation |
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What is a possible entrance of pathogens into the brain past the BBB?
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Through the choroid plexus
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What causes a greater likelihood of penetration into the CNS?
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More organisms in the blood
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Which viruses traffic along peripheral nerves?
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Rabies
HSV VZV |
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Concerns of bacterial meningitis at 0-3 months
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Group B strep, E. coli, Listeria
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Concerns for bacterial meningitis in immunocompetent adults
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S. pneumoniae or N. meningitidis
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What two characteristics of settings can indicate an increased risk of CNS infections?
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Geographic location (distribution of vectors, exposure to some fungal pathogens is restricted)
Time of year (seasonal) |
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3 potential results of CNS damage
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death of CNS cells
Tissue destruction Cerebral edema |
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Frontal lobe abscess symptoms
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fontal sinusitis
HA memory defects attention loss diminished intellectual performance |
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Temporal Lobe encephalitis symptoms
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personality changes
visual field defects hemiparesis with large lesions focal seizures |
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Basilar meningitis symptoms
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HA, suboccipital
Neck stiffness diplopia CN palsies |
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Kernig's sign
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lift legs, neck flexes or pain increases
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Brudzinski's sign
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Lift neck, legs flex or pain increases
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Dx of CNS infections
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Obtain blood cultures
CT LP |
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Normal WBC count of CSF
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0-6 cells/uL
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Viral meningitis CSF findings for WBC
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10-1,000 cells/uL
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Bacterial meningitis CSF findings for WBC
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1,000-5,000 cells/uL
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When do the glucose levels change in meningitis?
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bacterial meningitis (or Tb); provides food for neutrophils and oxidative burst
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Difference between bacterial meningits and Tb meningitis
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Tb has lower WBC (100-500) than bacterial, mononuclear response
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What is a rule for CSF glucose as it relates to blood glucose
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Normal CSF glucose is at or greater than 2/3 blood glucose
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