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MMG Nervous System Diseases


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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?
*no normal flora
How can pathogens enter the CNS?
-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?
-infect NS cells (meningitis and leprosy)
-release toxins that affect neurons (botulism, tetanus)
What are the signs and symptoms of Meningitis?
-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?
-S. pneumoniae
-N. meningitidis
-H. influenzae
Describe S. pneumoniae in terms of bacterial meningitis.
-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.
-causes meningococcal meningitis
-fimbria, capsule, and lipooligosaccharide required for virulence
Describe Haemophilus influenzae in terms of meningitis.
-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.
-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.
-"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)?
-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.
-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?
-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?
-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?
-Clostridium botulinum
-Gram + bacillus that forms endospores
-different strains produce one of seven neurotoxins
*deadliest toxins known
How can you treat botulism?
-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?
-rigid paralysis in face
-then fever, muscle spasms, and respiratroy failure
Describe the etiological agent that cuases tetanus.
-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?
-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
-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?
-Asymptomatic infections (90% of all infections)
-minor polio
-nonparalytic (muscle spasms and back pain)
Describe the etiological agent that causes Poliomyelitis.
-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?
-postexposure prophlaxis
-human rabies immune globulin
-rabies vaccine
*always fatal due to respiratory paralysis
What are the signs and symptoms of Encephalitis?
-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?
-can't, supportive care only
*vax for horses available (EEE, WEE, VEE, WNV)
What fungal infections occur in the CNS?
-mushroom toxin poisoning can produce neurological problems and hallucinations
-Cryptococcal meningitis
What are the signs and symptoms of Cryptococal meningitis?
-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.
-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?
-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.
-Trypanosoma brucei
*cyclic episodes of parasitemia are characteristic
How do you treat African Sleeping Sickness?
-various drugs based on how disease has progressed
-new drug: eflornithine
*patient never clears infection due to its ability to evade immune system

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