Diseases of the Nervous System Flashcards
Chapter 22
What makes up the human nervous system? (2)
- Central Nervous System
- Peripheral Nervous System
What makes up the Central Nervous System? (2)
- Brain
- Spinal Cord
What is meningitis?
Inflammation of the meninges
What are meninges?
Protective covering of brain and spinal cord
What is encephalitis?
Infection of the brain
What are the symptoms of meningitis? (6)
- headache
- nausea
- vomiting
- stiff neck
- convulsions
- coma
(T/F) Meningitis has a low mortality rate
False
What causes meningitis? (4)
- bacteria
- viruses
- fungi
- protozoa
Which type of meningitis infection is nonfatal?
Virus Cases
How are bacterial meningitis infections transmitted?
Via respiratory route
What Bacteria cause a Meningitis infection? (4)
- Streptococcus agalactiae
- Hemophilus influenzae type B
- Streptococcus pneumoniae
- Neisseria meningitidis
Describe Streptococcus agalactiae (4):
- beta hemolytic group b
- gram (+) coccus
- most common causes of neonatal meningitis
- acquired from mother’s birth canal
What Bacteria is the most common cause of neonatal meningitis?
Streptococcus agalactiae
How is neonatal meningitis acquired?
From mother’s birth canal
Describe Hemophilus influenzae (3):
- encapsulated (6 types)
- gram (-) rod
- leading cause of mental retardation
Which capsule type of Hemophilus influenzae is the most virulent?
Type B. Hib
Before the vaccine, how virulent was Meningitis caused by Hemophilus influenzae?
45-66% cases in children 6 months - 5 years of age
How fatal is Hemophilus influenzae Meningitis?
~1/3 of treated cases
What Bacterial Meningitis causes mental retardation?
Hemophilus influenzae
What vaccine is there for Hemophilus influenzae Meningitis?
Hib vaccine
Describe the Hib Vaccine (3):
- H. influenzae type b
- subunit vaccine
- reduces infection drastically
What is the DOC for Hemophilus influenzae Meningitis?
Third generation cephalosporins
Describe Streptococcus pneumoniae (4):
- encapsulated
- alpha hemolytic
- gram (+)
- diplococcus
What % of all pneumonias is caused by Streptococci pneumoniae?
80% (6 months - 6 years of age)
What is the mortality rate of Streptococci pneumoniae Meningitis in elderly?
80%
What is the mortality rate of Streptococci pneumoniae Meningitis in children?
30%
What vaccine is there for Streptococci pneumoniae?
- capsule conjugated vaccine (subunit conjugated)
What 2 groups should get the vaccine for Streptococcus pneumoniae?
- children under 2
- elderly
What is the DOC of Streptococcus pneumoniae? (2)
- penicillin
- 3rd generation cephalosporins
Describe Neisseria Meningitis (3):
- gram (-)
- diplococcus
- aka meningococcal meningitis
Where is Hemophilus influenzae found?
Normal nasopharynx flora
Where does Hemophilus influenzae travel to cause Meningitis?
Normal Nasopharynx Flora -> Blood -> Meninges
Where is Streptococcus pneumonia found?
Normal nasopharynx flora
Where does Streptococcus travel to cause Meningitis?
Normal nasopharynx flora -> Blood -> Meninges
Where is Neisseria meningitidis found?
Nasopharynx
Where does Neisseria meningitidis travel to cause meningitis?
Nasopharynx -> Blood -> CSF (cerebrospinal fluid)
What symptoms do Neisseria meningitidis cause? (6)
- fever
- weakness
- headache
- stiff neck
- convulsions
- rash on abdomen
What causes the symptoms of Neisseria meningitidis?
Endotoxins
What is the mortality rate of Neisseria meningitidis?
~80% (untreated cases)
What locations are prone to having Neisseria meningitidis cases? (3)
- crowded enclosed spaces
- dorms
- military barracks
What are the virulence factors of Neisseria meningitidis? (4)
- endotoxins
- fimbriae
- IgA protease
- capsules (6 types)
What do endotoxins do?
Cause fever and shock (death)
What does Fimbriae aid with?
Adherence
What does IgA protease do?
Degrades IgA
What do the capsules of Neisseria meningitidis help with?
Resisting phagocytosis (antiphagocytic)
What vaccines are there for Neisseria meningitidis? (3)
- subunit
- conjugated
- capsular polysaccharides
What bacteria causes Tetanus?
Clostridium tetani
What is another name for Tetanus?
Lockjaw
Describe Clostridium tetani (4):
- gram (+)
- spore forming
- anaerobic
- rod
Where is Clostridium tetani found? (3)
- soil
- animal GI tracts
- old, dirty, rusting objects
How does Clostridium tetani spore enter the body?
Through cuts/deep puncture wounds
What needs to happen for Clostridium tetani spores to germinate in a wound?
No oxygen can be present
What is Tetanus neonatorum?
Tetanus in newborns
What causes Tetanus neonatorum?
- nonsterile instruments being used to cut the umbilical cord
How does Tetanus neonatorum enter a newborn baby?
Through the cut stump of umbilical cord
What virulence factor does Clostridium tetani have?
A plasmid that makes tetanospasmin
What is tetanospasmin?
Neurotoxin that causes muscles spasms (Spastic Paralysis)
What causes the symptoms of Clostridium tetani?
The neurotoxin (bacteria cannot spread in body)
What does tetanospasmin do?
Stops nerve impulses at nerve-nerve junctions
What vaccine is available for Clostridium tetani?
DTaP (tetanus toxoid)
How often does someone need to get their DTaP booster?
Every 10 years
What treatments are there for Clostridium tetani?
Administering tetanus immunoglobin
What are the Viral Diseases of the Nervous System? (3)
- Poliomyelitis
- Rabies
- Arthropod-Borne Encephalitis
What is poliomyelitis also called?
Polio
Describe Poliomyelitis (5):
- member of picornaviridae
- small, naked
- icosahedral
- single stranded
- (+) RNA
What does the polio virus tend to attack? (3)
- motor neurons
- spinal cord
- brain
What is the polio virus resistant against? (1)
- drying (viable for long periods of time in food and water)
What are the reservoirs for polio?
Only humans
Are there different types of polio?
Yes, 3 serotypes (all antigenic)
How is polio transmitted to others? (2)
- oral-fecal route
- pharyngeal secretions
Where is polio virus acquired?
Through GI tract
Where does polio multiply in the body? (2)
- small intestines
- throat
Where are viral particles of polio shed?
Feces
What does the polio virus invade? (2)
- blood
- lymph nodes
Symptoms of polio (4):
- MOST asymptomatic
- headache
- sore throat
- high fever
What type of infection can polio cause?
CNS infection (less than 1%)
What happens in a CNS infection? (2)
- flaccid paralysis (asymmetric)
- death to respiratory system paralysis
What vaccines are available for Polio? (2)
- Salk Vaccine
- Sabin Vaccine
Describe the Salk Vaccine (3):
- inactivated polio vaccine (IPV)
- injection + booster required
- no IgA immunity
Describe the Sabin Vaccine (3):
- oral polio vaccine (OPV)
- attenuated virus vaccine
- IgA immunity produced
Where are the remaining reservoirs of polio currently located in? (2)
- Parts of Africa
- Parts of Asia
What virus causes Rabies?
Rhabdoviridae
Describe Rhabdoviridae (5):
- enveloped
- helical
- (-) RNA
- single stranded
- bullet shaped
How is rabies spread?
Exposure to infected animals (biting/handling)
Which animals are prone to rabies? (6)
- dogs
- foxes
- raccoons
- skunks
- cats
- bats
Where does the rabies virus replicate?
In the skin/muscle -> peripheral nerves to CNS
What happens when rabies infects the CNS?
Leads to fatal encephalitis
How long is the incubation time for rabies?
13 days - 2 years (usually 30-50 days)
What are the symptoms of rabies? (6)
- agitation
- mouth spasms
- salivation
- hydrophobia
- convulsions
- coma
Is rabies always treatable?
No! Must be treated before symptoms appear
How is rabies diagnosed? (2)
- presence of viral Ag (saliva, serum, CSF)
- presence of virus in brain slices (negri bodies)
How is rabies treated? (2)
- HRIG (human rabies immunoglobulin)
- rabies vaccine
What is the rabies vaccine?
HDCV = human diploid cell vaccine
Describe HDCV (1):
- inactivated viral vaccine (days 0, 3,, 7, 14)
Which groups of people are given the rabies vaccine frequently? (2)
- laboratory workers
- animal handlers
What is one of the unique vaccination traits about rabies?
You can vaccinate post exposure
How is rabies prevented? (1)
Vaccinating domestic + wild animals
What causes Arthropod-borne viral diseases?
Togaviruses
What is Arthropod-borne encephalitis?
Brain infection
Describe Togaviruses (4):
- enveloped
- icosahedral
- (+) RNA
- single stranded
How are togaviruses transmitted?
Via arthropod vectors
What are examples of arthropod vector? (4)
- mosquitoes
- ticks
- flies
- gnats
Where in the world are Arthropod-borne Viral Diseases common in? (2)
- tropics
- subtropics
Symptoms of a togavirus (6):
- mild chills
- headache
- fever
- mental confusion
- coma
- death
What are 3 types of arthropod viruses?
- Eastern Equine Encephalitis (EEE)
- Western Equine Encephalitis (WEE)
- West Nile Encephalitis (mosquitoes)
Describe the West Nile Virus ():
- flavivirdae family
- RNA (+)
- single stranded
What are the carriers of the West Nile Virus? (4)
- birds
- horses
- humans
- other vertebrates
What cycle maintains the West Nile Virus?
bird-mosquito-bird cycle
How is the West Nile Virus transmitted? (2)
- bite of mosquito
- (implications) breast milk + blood transfusions
What are the symptoms of the West Nile Virus?
Mild Flu-Like symptoms
What happens to immunocompromised people with the West Nile Virus?
Causes encephalitis
Describe the Zika Virus Disease (3):
- flaviviridae family
- single stranded
- RNA
How is the Zika Virus spread? (4)
- bite of infected mosquitoes (primary)
- sexual
- mother to child
- blood transfusions
What occurs if pregnant mother gets the Zika virus?
Increases risk of microcephaly in infant
What is microcephaly?
Small head
What percent of people infected with the Zika Virus display mild symptoms?
20%
How is the Zika Virus diagnosed?
Reverse Transcriptase PCR
How is the Zika Virus Prevented?
Controlling mosquitoes
