MMG Nervous System Diseases
Terms
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What are the three parts of the brain?
What does each control? -
-Cerebrum; voluntary muscles, perception, and thinking
-Cerebellum; many incoluntary body movements
-Brain Stem; breathing, heart rate, blood pressure -
What are three types of nerves?
Where do each carry signals? -
-Sensory: to CNS
-Motor: away from CNS
-Mixed: to and from CNS - Whay type of environment is the CNS? What does this mean?
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-axenic
*no normal flora - How can pathogens enter the CNS?
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-breaks in bones and meninges
-medical procedures
-travel through peripheral neurons to CNS
-infect/kill cells of meninges resulting in meningitis - How do bacteria cause disease of the nervous system?
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-infect NS cells (meningitis and leprosy)
-release toxins that affect neurons (botulism, tetanus) - What are the signs and symptoms of Meningitis?
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-sudden high fever and severe meningeal inflammation
-severe headache, vomiting, pain
-stiff neck, altered muscle control
-brain infection result in behavioral changes, coma, death
*may be rapid development -
How can you diagnose meningitis?
How can it be treated? -
-CSF Tap
-Treat with antimicrobial srugs
*some vax available - What type of people should avoid high risk foods for meningitis?
- -individuals at risk for listeriosis
- What are the airborne-transmitted bacteria that cause meningitis?
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-S. pneumoniae
-N. meningitidis
-H. influenzae - Describe S. pneumoniae in terms of bacterial meningitis.
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-leading cuase of meningitis in adults
-only enxapsulated strains are virulent
-secretory IgA protease
-pneumolysin supresses phagocytosis - Describe Neisseria meningtidisis (meningococus) in terms of bacterial meningitis.
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-causes meningococcal meningitis
-fimbria, capsule, and lipooligosaccharide required for virulence - Describe Haemophilus influenzae in terms of meningitis.
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-leading cuase of bacterial meningitis PRIOR to vaccine
-thought to cuase flu epidemics
-classified by antigens on capsule (95% of diseases are type b). - Describe Listeria monocytogenes in terms of meningitis.
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-enters body through contaminated food or water
-cuases listeriosis in fetuses, imm. compro people, elderly
-listeriolysin O breaks down phagosome before lysosome can fuse
-can move from cell to cell using host's actin network (actin tails) - Describe Streptococus agalactiae in terms of meningitis.
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-"Group B Strep"
-cuases most cases of newborn meningitis (passed through infected birth canal) - What are the signs and symptoms of Leprosy (Hansen's Disease)?
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-tuberculoid leprosy: nonprogressive; patients have strong cell-mediated immune system
-lepromatous leprosy; progressive tissue destruction, patients have weak cell-mediated immune system -
How do you confirm leprosy?
What is the etiological agent of leprosy? -
-acid-fast rods in samplesQ
-Mycobacterium leprae - Describe M. leprae.
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-Gram + bacillus with mycolic acid in cell wall
-transmitted via person to person contact or via breaks in skin
-M. leprae grows best in cooler regions of body - How do you treat leprosy?
- -multiple antibiotics becuase of drug resistance
- How does one acquire botulism?
- -from intoxication from ingested toxin rather than infection
- What are the signs and syptoms of Botulism?
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-double or blurred vision
-drooping eyelids
-slurred speech
-difficulty swallowing
-dry mouth
-muscle weakness - What are the different types of Botulism and what are these symptoms?
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-food-borne: progressive paralysis of all voluntary muscles
-infant: bacteria grow in intestines, non-specific symptoms
-wound: like food-borne botulism - Describe the etiological agent of botulism?
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-Clostridium botulinum
-Gram + bacillus that forms endospores
-different strains produce one of seven neurotoxins
*deadliest toxins known - How can you treat botulism?
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-wash intestinal tract to remove bacteria
-administer botulism immune globulin (against toxins)
*antimicrobials not affective becuase it was an ingested toxin not cell! - What are the signs and symptoms of Tetanus?
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-rigid paralysis in face
-then fever, muscle spasms, and respiratroy failure - Describe the etiological agent that cuases tetanus.
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-Clostridium tetani
-found in soil
-endospores enter contaminated wounds (deep puncture)
-incubates 5 days to 15 weeks! - How do you treat tetanus?
- -tetanus immunoglobulin, penicillin
- How do you prevent tetanus?
- -vaccinate with tetanus toxoid
- What are the signs and symptoms of viral meningitis?
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-fever, severe headache, stiff neck, drowsiness, nausea
-milder disease than bacterial or fungal meningitis
-symptoms occur, but no bacteria found in CSF - Describe the etiological agent for viral meningitis
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-90% caused by Enteroviruses (+ssRNA, coxaskie viruses)
-attack cells in intestinal tract (no GI illness)
-spread through bloodstream to meniniges; also in respiratorty droplets and in feces - How do you treat Viral meningitis?
- -no specific treatment exists
- What are the different types of Polio?
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-Asymptomatic infections (90% of all infections)
-minor polio
-nonparalytic (muscle spasms and back pain)
-paralytic - Describe the etiological agent that causes Poliomyelitis.
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-another Enterovirus
-transmitted most often by drinking contaminated water
*only exists in Africa and Asia today - How to you treat Polio?
- -Two effective vaccines available
- How do you treat Rabies?
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-postexposure prophlaxis
-human rabies immune globulin
-rabies vaccine
*always fatal due to respiratory paralysis - What are the signs and symptoms of Encephalitis?
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-mild, cold-like symptoms and rashes
-when crossing the blood brain barrier, causes symptoms similar to meningitis - What is the most common encephalitis?
- -West Nile encephalitis
- How does one get Encephalitis?
- -transmitted between hosts by lood-sucking arthropods (mosquitoes)
- How do you treat Enceph?
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-can't, supportive care only
*vax for horses available (EEE, WEE, VEE, WNV) - What fungal infections occur in the CNS?
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-mushroom toxin poisoning can produce neurological problems and hallucinations
-Cryptococcal meningitis - What are the signs and symptoms of Cryptococal meningitis?
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-prolonged cough, others similar to bacterial meningitis
-unknown incubation (likely 2-9 months)
-can be found in bird droppings - Describe the Etiological agent for CNS fungal infections.
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-Cryptococcus neoformans
-polysaccharide capsule
-enters through spore inhalation or dried yeast cells from bird guano (then spread to CNS) - How do you treat CNS fungal infections?
- -cryptococcal meningitis patients on anti-fungals for life!
- What are the signs and symptoms of African Sleeping Sickness?
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-bite becomes lesion with necrotic tissue
-parasites in blood create fever, lumph node swelling, and headache
-meningoenxephalitis upon invasion of CNS - Describe the Etiological agent in African Sleeping Sickness.
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-Trypanosoma brucei
*cyclic episodes of parasitemia are characteristic - How do you treat African Sleeping Sickness?
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-various drugs based on how disease has progressed
-new drug: eflornithine
*patient never clears infection due to its ability to evade immune system