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Chapter 22
Microbial Disease of the Nervous System
28
Microbiology
11/18/2010

Additional Microbiology Flashcards

 


 

Cards

Term

Meninges

Definition
  • layers that protect the brain and spinal cord
Term

Blood-brain barrier

Definition
  • infections compromise this
Term

Meningitis

Definition
  • inflammation of meninges
Term

Encephalitis

Definition
  • inflammation of the brain
Term

Meningoencephalitis

Definition
  • inflammation of both meninges and brain
Term

Bacterial Meningitis

Definition
  • Initial symptoms of fever, headache, and stiff neck
  • Followed by nausea and vomiting
  • May progress to convulsions and coma
  • Diagnosis by Gram stain and latex agglutination of CSF
  • Treatment: Cephalosporins, vancomycin
  • Most common causes in US:
  • Haemophilus influenzae
  • Neisseria meningitidis
  • Streptococcus pneumoniae
Term

Haemophilus influenzae Meningitis

Definition
  •  Occurs mostly in children (6 months to 4 years)
  • Gram-negative aerobic bacteria, normal throat microbiota
  • 80% of people are healthy nasopharyngeal carriers
  • Prevented by Hib vaccine
Term

Neisseria Meningitis

Definition
  • Also called meningococcal meningitis
  • Caused by N. meningitidis
  • Gram-negative, aerobic cocci with a capsule
  • 10% of people are healthy nasopharyngeal carriers
  • Begins as throat infection, rash
  • Vaccination recommended for college students
Term

Streptococcus pneumoniae Meningitis

Definition
  •  Also called pneumococcal meningitis
  • Caused by S. pneumoniae (a gram-positive diplococcus)
  • 70% of people are healthy nasopharyngeal carriers
  • Most common in children (1 month to 4 years)
  • Mortality: 30% in children, 80% in elderly
  • Prevented by vaccination
Term

Tetanus

Definition
  • Caused by Clostridium tetani
  • Gram-positive, endospore-forming, obligate anaerobe
  • Grows in deep wounds
  • Tetanospasmin (neurotoxin) released from dead cells blocks relaxation pathway in muscles
  • Lockjaw presents first
  • Prevention by vaccination with tetanus toxoid (DTP) and booster (dT) required every 10 years
  • Treatment with tetanus immune globulin
Term

Botulism

Definition
  • Caused by Clostridium botulinum
  • Gram-positive, endospore-forming, obligate anaerobe
  • Intoxication comes from ingesting botulinal toxin
  • Botulinal toxin blocks release of neurotransmitter, causing flaccid paralysis; die from respiratory and cardiac failure
  • Prevention
  • Proper canning
  • Nitrites prevent endospore germination in sausages
  • Botox
  • Chronic headaches, muscle contractions, Parkinson’s, MS
  • Treatment: Supportive care and antitoxin

     

     

Term

Infant Botulism

Definition
  • results from C. botulinum growing in intestines
Term

Wound Botulism

Definition
  • results from growth of C. botulinum in wounds
Term

Leprosy

Definition
  • Also called Hansen’s disease
  • Historical and biblical disease
  • Isolation could have led to its near disappearance
  • Caused by Mycobacterium leprae
  • Acid-fast rod that grows best at 30°C.
  • Grows in peripheral nerves and skin cells
  • Transmission (via secretions) requires prolonged contact with an infected person
  • Disfiguring nodules over body
  • Immunocompromised individuals
Term

Poliomyelitis (Polio)

Definition
  • Poliovirus
  • Fecal-oral transmission
  • Outbreak in Vermont in summer of 1894
  • Initial symptoms: Sore throat and nausea
  • Viremia may occur; if persistent, virus can enter the CNS and cause respiratory failure
  • Destruction of motor cells and paralysis occurs in <1% of cases
  • Prevention: vaccination
  • Sabin vaccine: oral; live virus that is shed in feces
  • Vaccine derived cases
  • Salk vaccine: inactivated virus; series of 3 shots
  • Eradication of polio targeted by CDC
Term

Rabies

Definition

 

  • Caused by the rabies virus
  • Untreated- fatal
  • Transmitted by animal bite
Term

Furious rabies

Definition
  • animals are restless then highly excitable
Term

Paralytic rabies

Definition
  • animals seem unaware of surroundings
Term

Preexposure prophylaxis

Definition
  • injection of human diploid cells vaccine (HDCV)
Term

Postexposure treatment

Definition
  • vaccine plus rabies immune globulin (RIG)
Term

Arboviral Encephalitis

Definition
  • Arboviruses
  • Arthropod-borne viruses that belong to several families
  • Symptoms range from chills, headache, fever to death
  • Prevention: controlling mosquitoes
  • Diseases associated: Western equine encephalitis, Eastern equine encephalitis, St. Louis encephalitis, California encephalitis, and West Nile encephalitis
Term

Cryptococcus neoformans Meningitis

Definition
  • Also called cryptococcosis
  • Soil fungus associated with pigeon and chicken droppings
  • Transmitted by the respiratory route; spreads through blood to the CNS
  • Mortality up to 30% in immunocompromised patients
Term

African Trypanosomiasis

Definition
  • African sleeping sickness
  • Trypanosoma brucei
  • Chronic (2 to 4 years); fever, deterioration of CNS
  • Fatal without treatment
  • Transmitted from animals to humans by tsetse fly
  • Prevention: Elimination of the vector
Term

Naegleria fowleri

Definition
  • Protozoan infects nasal mucosa from swimming water
  • Lakes in summertime
  • Proliferates in brain, feeds on brain tissue
  • 100% fatal
Term

Transmissible Spongiform Encephalopathies

Definition
  • Caused by prions
  • Normal protein in brain encounters the abnormally folded form of the same protein (prion)
  • Causes sponginess in brain
  • Typical diseases
  • Sheep scrapie
  • Creutzfeldt-Jakob disease
  • Bovine spongiform encephalopathy (Mad Cow Disease)
  • Chronic and fatal
Term

Creutzfeldt-Jakob disease

Definition

 

  • Unknown source
  • Transmissible via transplants
  • Human growth hormone
  • prion disease of nervous system
Term

Bovine spongiform encephalopathy

Definition
  •  Outbreak in cattle 1986 in Great Britain
  • Cattle feed from sheep infected with scrapie
  • FDA banned parts of cattle carcass likely to contain prions or meat from “fallen” cattle
  • Percentage of cattle tested in US; all are tested in Europe and Japan
  • prion disease of nervous system
Term

Preventing prion diseases

Definition
  • Difficult to destroy
  • Surgical instruments sterilized by
  • NaOH
  • + extended autoclaving at 134°C