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24 Cards in this Set
- Front
- Back
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Anatomy of central nervous system(CNS)
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Consist of brain, spinal cord.
Encased by 3 membranes -Dura mater: outer -Arachnoid mater: middle -Pia mater: inner Subarachnoid space -between arachnoid mater and pia mater -contains cerebrospinal fluid (CSF) |
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Anatomy of peripheral nervous system(PNS)
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-Consists of crainial nerves, spinal nerves.
-Axons and dendrites of adjacent neurons communicate via the synapse. -Neurotransmitters released from one cell and act on adjacent cell. |
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CNS Defenses
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Mostly structural
-skull, vertebral column, CSF -blood-brain barrier: blood vessels surround and inside the brain have low permeability. prevents many microbes from entering. Immune defense are iminiaml- IMMUNE PRIVILEGED SITE -even mild reactions are detrimental to CNS |
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Meningitis
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Infection and inflammation of the meninges
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Encephalitis
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Infection and inflammation of the brain.
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Acute
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disease with rapid onset and short duration.
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Chronic
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dieases with prolonged onset and long duration
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Subacute
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Disease with onset/duration between acute and chronic.
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Microbes that causes meningitis
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-Neisseria meningitidis
-Streptococcus pneumonia -Listeria monocytogenes -Cryptococcus neoformans -Enteroviruses |
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Meningitis caused by Neisseria meningitidis**
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-most serious form of acute bacterial meningitis.
-virulence factors: capsule, endotoxin, IgA protease -treatment: penicillin G (through IV) or cefotaxime. -transmission: person-to-person via respiratory droplets. |
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Meningitis caused by Neisseria meningitidis: Pathogenisis
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-Bacteria uses pili and thin capsule to attach to epithelium in nasopharynx.
-Uses siderophores to steal iron from host cells, enabling fast replication. -Invade epithelial cells, enter bloodstream, migrate to meninges. -Release endotoxin in CSF and bloodstream, causing inflammation and indirect damage to meninges. |
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Meningitis caused by Neisseria meningitidis: Diagonosis
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-Sample CSF via spinal tap.
-Microscopic observation/Gram stain* -Direct antigen test for capsule antigens* -PCR* -Cultivation and biochemical tests- oxidase test. |
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Meningitis caused by Streptococcus pneumonia
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Virulence factors: capsule, induction of apoptosis, hemolysin and hydrogen peroxide production.
Treatment- antibiotics (cephalosporin) ->cefotaxime, vancomycin if resistant. |
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Meningitis caused by Listeria monocytogenes
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Virulence factors: intracellular growth
Treatment:antibiotics; ampicillin, sulfa drugs. Mortality rate 20-25% |
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Meningitis caused by Cryptococcus neoformans**
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-Most common cause of fungal meningitis.
-Virulence factors: capsule, melanin production. -Treatment: antibiotics; amphotericin B, fluconazole. Treatment required for weeks-months. Immediate treatment necessary. -Transmission: via bird feces. |
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Meningitis caused by Cryptococcus neoformans: Pathogenesis
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-Uses thick capsule to bind to respirator epithelium.
-Invades epithelium, enters bloodstream and migrates to meninges and brain. -Capsule prevents phagocytosis. -Multiplies rapidly and forms tumor-like mases in meninges and brain. -The masses cause direct damage, inflammation causes indirect damage |
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Meningitis caused by Cryptococcus neoformans: Diagnosis
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-Sample CSF via spinal tap.
-Microscopic observation- look for budding, stain for capsule. -Direct ELISA, DFA, FISH, PCR. |
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Meningitis caused by viruses
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Virulence factors: lytic infection of host cells.
Treatment: usually none --> unles virus identified. -Enteroviruses; none -HHVs; acyclovir |
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Encephalitis caused by Easter Equine Encephalitis Virus (EEEV)
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ACUTE
Virulence Factors: attachment, fusion, invasion capabilities. Treatment: none Fatality; 30-70% |
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Encephalitis caused by West Nile Virus
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ACUTE
Virulence Factors: attachment, fusion, invasion capabilities. Treatment: none |
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Encephalitis caused by Toxoplasma gondii
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SUBACUTE
Virulence factors: intracellular growth Treatment: Drugs that inhibit protozoal folate synthesis. Pyrimtheamine and/or/ leucovorin and/or sulfadiazine. |
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Encephalitis caused by Rabies
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Virulence factors:
Treatment: immunoglobulin injected into wound and intramuscularly. |
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Tetanus
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Virulence factors: tetanospasm exotoxin.
Treatment:Immunoglobulin (anti-toxin)- antibodies neutralize the toxins and prevent it from interaction with neurons |
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Botulism
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Virulence factors: botulinum exotoxin
Treatment:Immunoglobulin (anti-toxin), antibodies bind to toxin and netralize it. - mechanical ventilators |
