micro chap 19

  1. -occurs years after an intital measles episode
    -seems to be caused by direct viral invasion of neural tissue
    measles virus: subacute sclerosing panencephalitis (SSPE)
  2. -transmissible spongiform encephalopathies (TSEs): neurodegenerative diseases with long incubation periods but rapid progression once they begin
    -Human TSEs
    *Creutzfeldt-Jakob disease (CJD)
    *Gerstmann-Strussler-Scheinker disease
    *fatal familial insomnia
  3. -slow, progressive zoonotic disease
    -characterized by fatal encephalitis
    -average incubation time: 1-2 months or more
    -prodromal phase begins with fever, nausea, vomiting, headache, fatigue, and other nonspecific symptoms
    -two forms (both forms progress to the coma phase, resulting in death)
  4. -periods of agitation, disorientation, seizures, and twitching
    -spasms in the neck and pharyngeal muscles lead to hydrophobia
    furious rabies
  5. -patient is not hyperactive but is paralyzed, disoriented and stuporous
    dumb rabies
  6. -acute enteroviral infection of the spinal cord
    -can cause neuromuscular paralysis
    -often affects small children
    -most infections are contained as short-term, mild viremia
    -some develop mild nonspecific symptoms of fever, headache, nausea, sore throat, and myalgia
    -then spreads along specific pathways in the spinal cord and brain
  7. poliomyelitis

    -the virus infiltrates the motor neurons of the anterior horn of the spinal cord
  8. poliomyelitis

    -invasion but not destruction of nervous tissue
  9. poliomyelitis

    -various degrees of flaccid paralysis
  10. poliomyelitis

    -bulbar poliomyelitis
    rare cases
  11. -also known as lockjaw
    -Clostridium tetani
    -gram-positive, spore-forming rod
    -releases a powerful neurotoxin, tetanospasmin, that binds to target sites on peripheral motor neurons, spinal cord and brain, and in the sympathetic nervous system
    -toxin blocks the inhibition of muscle contraction
    -results in spastic paralysis
    -first symptoms: clenching of the jaw, followed in succession by extreme arching of the back, flexion of the arms, and extension of the legs
    -Risus sardonicus
  12. -intoxication associated with eating poorly perserved foods
    -can also occur as a true infection
    -three major forms
    -symptoms: double vision, difficulty in swallowing, dizziness; later symptoms include descending muscular paralysis and respiratory compromise
    -Clostridium botulinum (spore forming anaerobe, releases an endotoxin- botox)
  13. ingestion of preformed toxin
    food-borne botulism
  14. entrance of botulinum toxin into the bloodstream
    infant botulism and wound botulism
  15. -Trypanosoma brucei
    -also called trypanpsomiasis
    -affects the lymphatics and areas surrounding blood vessels
    -usually a long asymptomatic period precedes onset of symptoms
    -symptoms include intermittent fever, enlarged spleen, swollen lymph nodes, and joint pain
    -central nervous system is affected with personality and behavioral changes that progress to lassitude and sleep disturbances
    African sleeping sickness
Card Set
micro chap 19
infectious diseases affecting the nervous system