Microbial Diseases Of Nervous System & Eyes Pt. 1 Flashcards
What are the two ways in which bacteria can cause nervous system disease?
Infect cells of the nervous system
Bacteria grow elsewhere and release toxins that affect neurons
In what way do meningitis and leprosy cause nervous system disease?
By directly infecting the cells of the nervous system
In what way do botulism and tetanus cause nervous system disease?
By releasing toxins elsewhere that affect neurons
What are the signs and symptoms of meningitis?
Headache and stiffness associated with fever, confusion, altered consciousness, vomiting, photophobia or phonophobia
When meningitis occurs, what can it lead to?
Encephalitis which could lead to coma and/or death
What are the five species that cause 90% of all bacterial meningitis cases?
Neisseria meningitidis, streptococcus pneumoniae, haemophilus influenzae B, listeria monocytogenes, streptococcus agalactiae
What pathogen is most commonly responsible for meningitis in babies less than three months old (newborns)?
Streptococcus agalactiae
How is haemophilus influenzae B transmitted?
Respiratory droplets
What pathogen most commonly causes meningitis among children under the age of 5?
Haemophilus influenzae B
What pathogen is known as the “pneumococcus”?
Streptococcus pneumoniae
Does haemophilus influenzae B cause the flu?
Noooo; the flu is caused by a virus
How is streptococcus pneumoniae transmitted?
Respiratory droplets or opportunistic
What is the pathogen most likely to cause meningitis in adults?
Streptococcus pneumoniae
How is listeria monocytogenes transmitted?
In contaminated food
Where is streptococcus pneumoniae found normally?
Throat of 75% of humans
Listeria monocytogenes most commonly causes meningitis among what populations?
Elderly, babies, and pregnant women
Meningitis caused by listeria monocytogenes is most dangerous among which population?
Pregnant women
What pathogen is known as the meningococcus?
Neisseria meningitidis
What pathogen is the only one that causes a purple rash developed from meningitis?
Neisseria meningitidis
What is the most common age group for those with meningitis caused by neisseria meningitidis?
Under 20 (college kids)
How is neisseria meningitidis transmitted?
Respiratory droplets
How is meningitis diagnosed?
Based on symptoms and culturing of bacteria from CSF by spinal tap
How is meningitis treated?
IV antibiotics
Which causes of meningitis have vaccines developed against them?
Streptococcus pneumoniae (PCV), haemophilus influenzae B (Hib), neisseria meningitidis (MCV)
What is the other name for leprosy?
Hansen’s disease
What are signs and symptoms of leprosy?
Skin sores, nerve damage, and muscle weakness
What kind of leprosy is more likely to be seen among one with a strong immune system?
Tuberculoid leprosy
What type of leprosy is more likely to be seen with someone with a weaker immune system?
Lepromatous leprosy
Which type of leprosy involves regions of lost sensation of skin as a result of nerve damage?
Tuberculoid leprosy
Which type of leprosy involves progressive, gradual loss of facial features, digits, and other body structures over a long time period?
Lepromatous leprosy
Do most people die who get leprosy?
No
What is the causative agent for leprosy?
Mycobacterium leprae
How is leprosy transmitted?
Person to person contact or breaks in the skin
Leprosy can also be acquired from consuming or handling what animal?
Armadillo
What are the three forms of botulism?
Foodborne, infant, and wound botulism
What is the causative agent for botulism?
Clostridium botulinium
Why is Clostridium botulinum dangerous?
Produces 7 neurotoxins and also endospores
What is the mechanism used by the clostridium botulinum toxins to inflict damage?
They bind irreversibly to normal neuronal cytoplasmic membranes, preventing muscular contractions, resulting in flaccid paralysis
Foodborne botulism usually appears in 1-2 days following the consumption of what foods?
Home-canned foods or preserved fish
Progressive paralysis from botulism eventually affects what organ that can result in death?
Diaphragm
How can death by asphyxiation result from foodborne botulism?
Inability to inhale due to diaphragmatic paralysis
What is the frequency of foodborne botulism?
25 cases per year in the US
Is full recovery possible from foodborne botulism?
Yes but slowly over time to regrow neurons
What is the frequency of infant botulism?
100 cases per year in the US
What food should not be given to infants less than 1 year old due to the possible presence of the endospores of Clostridium botulinium?
Honey
What are the symptoms for infant botulism?
Failure to thrive, crying, constipation, “floppy baby syndrome”
“Floppy baby syndrome” involving flaccid paralysis is a good indicator of what bacterial disease?
Infant botulism
Which type of botulism does NOT involve any GI system involvement?
Wound botulism
How does a person get wound botulism?
Contamination of a wound by endospores
What is the treatment for botulism?
Repeated washing of GI tract to remove Clostridium, antitoxins, microbial drugs used in infant botulism cases
How can botulism be prevented?
Proper canning of food, not giving honey or corn syrup to infants under 1 year old
What is the other name for tetanus?
Lockjaw
What is one of the earliest signs of tetanus?
Tightening of neck and jaw muscles
What sign of tetanus usually follows lockjaw?
Smiling spasm (risus sardonicus)
Which is associated with severe spasms: botulism or tetanus?
Tetanus
Death resulting from the inability to inhale is associated with which condition: botulism or tetanus?
Botulism
Death resulting from the inability to exhale is associated with which condition: tetanus or botulism?
Tetanus
How is the cardiovascular system affected by tetanus?
Heartbeat irregularities, fluctuations in blood pressure
What is the causative agent for tetanus?
Clostridium tetani
What condition inhibits the body’s usual function of reciprocal inhibition of musculature due to recurrent body spasms?
Tetanus
What is the neurotoxin produced by Clostridium tetani?
Tetanospasmin
How is tetanus acquired?
Through break in the skin or mucous membrane
Is tetanus caused by rust?
No
What type of environment does Clostridium tetani particularly like?
Rust
When untreated, what is the mortality rate for tetanus?
50%
What is the frequency for neonatal tetanus mortality?
90%
What is the most common way that neonates acquire tetanus?
Infected umbilical stump (especially when cut when a non-sterile instrument)
What determines the incubation period of Clostridium tetani?
Distance of infection from CNS (example: slow incubation period if infected foot region)
What is the treatment for tetanus?
Thoroughly clean wound to remove endospores, antitoxins, active immunization (tetanus toxoid), antibiotics
How is tetanus prevented?
Tetanus vaccine (booster every ten years)
The highest tetanus mortality rates are among what populations?
Unvaccinated and people over 60 years of age
Can viruses or bacteria more readily cross the blood brain barrier?
Viruses
What occurs more frequently: viral, bacterial, or fungal infections?
Viral
Which form of meningitis is usually the most mild when it comes to symptoms?
Viral meningitis
What kind of meningitis is also known as aseptic meningitis?
Viral meningitis
90% of viral meningitis case are caused by viruses in what genus?
Enterovirus
What other viruses are known to be able to cause viral meningitis?
Mumps, measles, influenza viruses and HHV 1, 2, 3, and 4
What is the most common form of meningitis?
Viral meningitis
How is viral meningitis transmitted?
Via respiratory droplets and feces
How is viral meningitis diagnosed?
Based on symptoms and absence of bacteria in the CSF
What is the treatment for viral meningitis?
There isn’t treatment, but patients resolve within about two weeks
How can pathogens enter the CNS (a normally axenic environment)?
Breaks in the bones/meninges
Medical procedures
Travel by peripheral neurons
Infect and kill meninges (meningitis)
