Chapter 22: Diseases of the Nervous System Flashcards
List the normal microbiota of the nervous system
none
Explain the progression and treatment for encephalitis and meningitis.
a. initial symptom of fever, headache, and stiff neck
b. followed by nausea and vomiting
c. may progress to convulsions and coma
d. diagnosis by Gram stain and latex agglutination of CSF
e. treatment: Cephalosporins, vancomycin
f. treatment must be lipid soluble so it is able to cross the blood-brain barrier
Give the general characteristics of Neisseria meningitidis
a. associated with meningococcal meningitis
b. Gram-negative, aerobic diplococci with a capsule
c. fastidious
Give the general characteristics of Haemophilus influenzae
a. associated with meningitis - occurs mostly in children ( 6 months to 4 yrs)
b. gram- negative aerobic bacteria, normal throat microbiota
c. capsule antigen type b
d. prevented by Hib vaccine
Give the general characteristic of Mycobacterium leprae
a. acid fast rod that grows best at 30 C
b. grows in peripheral nerves and skin cells
c. transmission requires prolonged contacted with an infected person
d. causes leprosy or Hansen’s disease
Give the general characteristics of Cryptococcus neoformans
a. causes cryptococcosis
b. encapsulated soil fungus associated with pigeon and chicken droppings
c. transmitted thru respiratory route; spreads thru blood to CNS
d. mortality up to 30%
Give the general characteristics of Naegleria fowleri
protozoan that can infect nasal mucosa and is found in swimming water
Describe rabies including mode of transmission, agent, reservoir, signs and diagnosis.
a. Caused by the rabies virus
b. Transmitted by animal bite
i. Furious rabies: Animals are restless then highly excitable
ii. Paralytic rabies: Animals seem unaware of surroundings
c. Initial symptoms may include muscle spasms of the mouth and pharynx, hydrophobia, and brain and spinal cord damage
d. Contracted by bite of rabid animal, inhalation of aerosols, skin abrasions, transplants
e. Virus multiplies in the skeletal muscle and in connective tissue
f. Virus moves along peripheral nerves to the CNS and causes encephalitis
g. Diagnosis by immunofluorescent test of saliva, serum or CSF
h. Brain smears
i. Reservoirs include skunks, foxes, and raccoons
j. Animals likely to contract the disease include domestic cattle, dogs, and cats
k. Rodents and rabbits seldom get rabies
l. Bats are the only animal that can harbor the rabies virus without getting the disease
Explain how the invasion of pathogens into the CNS occurs
thru the blood
Describe leprosy, including mode of transmission
a. Caused by Mycobacterium leprae
b. Slow growing bacteria, cannot be cultured on artificial media, armadillos are used
c. Causes Tuberculoid form (neural)
i. Loss of skin sensation surrounding nodules
ii. Lepromin test positive
d. Lepromatous form (progressive)
i. Disseminated nodules and tissue necrosis
ii. Lepromin test negative
e. Leprosy is not very contagious
f. Bacterium can be transmitted via nasal secretions and oozing exudates from the lesions.
g. Patients with leprosy are no longer kept in isolation.
Describe poliomyelitis and mode of transmission.
a. Caused by Poliovirus
b. Transmitted by ingestion of fecally contaminated water or foods
c. Initial symptoms: Sore throat and nausea
d. Viremia may occur; if persistent, virus can enter the CNS
e. Destruction of motor cells and paralysis occurs in <1% of cases
f. Prevention: vaccination
g. Death may occur by respiratory failure
h. Most cases are mild or asymptomatic
- Describe tetanus’ cause, progression, and treatment.
a. Caused by Clostridium tetani= Gram positive, endospore former, anaerobic rod that can grow in unclean wounds and in deep wounds
b. Can start as a local infection
c. Produces neurotoxin, tetanospasmin which causes spasms, muscle contraction in the jaw, death from paralysis of the respiratory muscles
d. Prevention by vaccination with tetanus toxoid (DTP) and booster (dT)
e. Treatment with tetanus immune globulin
Explain the control of vector borne diseases
.- control of the vectors, such as mosquito, is the most effective way
List the vectors for Dengue fever Rocky Mountain Spotted Fever Encephalitis Endemic Typhus Malaria
a. Dengue- mosquito
b. Rocky Mountain Spotted Fever- tick
c. Encephalitis- mosquito
d. Epidemic Typhus- lice
e. Malaria- mosquito
List the symptoms of meningitis in order of occurrence.
a. Initial symptoms are like a mild cold, fever, headache, and stiff neck
b. Followed by nausea and vomiting
c. May progress to convulsions and coma
