Diebel: Causative Microorganisms of the URT Flashcards
1
Q
What is the most common cause of colds?
A
Rhinovirus
2
Q
What family does rhinovirus belong to?
A
Picornaviridae (small RNA viruses)
3
Q
What is the clinical presentation of rhinovirus?
A
common cold
4
Q
How does rhinovirus spread?
A
Contact or aerosol formation
5
Q
How does rhinovirus initiate infection?
A
Binds to ICAM-1 on URT EPITHELIAL cells>
replicates inside cells and spreads to surrounding tissue w/out killing infected host cells
6
Q
What causes “disease” w/ rhinovirus?
A
immune response to infection
LOCAL INFLAMMATION>
Exudate and increased ICAM-1 expression>
enhances ability of virus to spread and cause further infection
7
Q
What can the exudate produced by rhinovirus lead to?
A
It can block airways which can lead to bacterial sinusitis or otitis media.
8
Q
What type of immunity does an individual w/ rhinovirus acquire?
A
IgA immunity to rhinovirus serotype of the infection
9
Q
How do you diagnose rhinovirus?
A
pt’s symptoms
10
Q
How do you treat rhinovirus?
A
supportive care
NO vaccine available
11
Q
What family do the parainfluenza viruses belong to?
A
Paramyxoviridae
12
Q
What surface proteins are common to ALL paramyxoviridae viruses and what do they do?
A
VIRAL FUSION (F) surface proteins> cause infected cells to form multinucleate giant cells
13
Q
How does parainfluenza virus cause tissue damage?
A
Cytopathic effects of the virus and immune response to the infection
14
Q
How does parainfluenza virus present in children?
A
croup (laryngotracheobronchitis)
pneumonia
15
Q
How does parainfluenza virus present in adults?
A
Common cold (moderately severe)
16
Q
How is parainfluenza virus passed?
A
Inhaled through aerosols
17
Q
How does parinfluenza virus infect?
A
Infects the larynx mucosa via contact of the viral hemagglutinin (HA) envelope protein w/ sialic acid on cell surfaces (leads to endocytosis).
18
Q
What envelope protein is important for cleaving HA bound to sialic acid and permits viral spread?
A
Viral neurominidase (NA)
19
Q
How does parainfluenza infection lead to narrowing of the lumen and obstruction of inspiration?
A
As the virus spreads downward to the TRACHEAL AND BRONCHIAL epithelium it causes inflammation and swelling of mucous membranes.
20
Q
Obstruction of inspiration leads to what?
A
Inspiratory stridor
21
Q
Obstruction of expiration leads to what?
A
barking cough–> croup
22
Q
How can parainfluenza cause pneumoniae?
A
It can also invade the lower RT
23
Q
How do you diagnose parainfluenza? What laboratory findings can confirm it?
A
Pts symptoms
Labratory confirmation through hemaglutination activity in respiratory secretions and serology (anti-HA antibodies)
24
Q
How do you treat parainfluenza?
A
Supportive care (cool mist; oxygen in severe cases)
Corticosteroids
25
Why is Coronarvirus called coronavirus?
Club-shaped viral proteins projecting out of the viral envelope that look like the corona surrounding the sun
26
What is the second most common causative agent of the common cold?
Coronavirus (10-20%)
27
Is coronavirus indistinguishable from a rhinovirus infection?
NO
28
What is SARS coronavirus?
Severe Acute Respiratory Syndrome
Causes a rapidly progressive VIRAL PNEUMONIA
29
How does a pt w/ SARS present?
Fever, dyspnea, cough
can progress to respiratory failure and DEATH
30
What is the clinical presentation for corona virus?
Common cold
31
How is coronavirus passed?
Inhaled through respiratory aerosols that leads to infection of URT cells
32
What is the incubation period of coronavirus?
Asymptomatic 3-day incubation period
33
Cold symptoms caused by coronavirus last for how many days?
6-7 days
34
How do you diagnose cornoavirus?
Pt symptoms
Serological identificaiton possible but lab diganosis rarely perfromed
35
How do you treat coronoavirus?
Supportive care
NO vaccines available
36
How many RNA segments does Influenza C have and how does this compare to Influenza A and B?
7 RNA segments
A and B have 8
37
How does the virulence of influenza C compare to A?
MUCH less virulent, many infections are ASYMPTOMATIC
38
Is there an animal reservoir for influenza B and C? What does htis mean?
NO
NO antigenic shifts
39
Is influenza C responsive to amantadine or rimatadine?
NO
40
How does influenza C present clinically?
common cold
41
How is influenza C passed?
inhaled through aerosols
42
How does influenza C cause infection?
Infects the larynx mucosa via contact of HA envvelope protein w/ sialic acid on cell surface--> endocytosis.
43
What permits the viral spread of influenza C virus?
NA envelope protein>
cleaves HA bound to sialic acid>
viral spread
44
Viral replication of influenza C in host cells has what consequences?
DEATH of host cells>
| tissue damage and disease
45
How does the immune response to influenza C contribute to the disease?
IR contributes through production of IL-1 and IFN-y
46
How do you diagnose influenza C?
Pt's sxs
47
How do you get laboratory confirmation of influenza C?
Rapid antigen test on a nasophryngeal swab>
| culture swab and detect HA type via a RBC agglutination test
48
What is the tx for influenza C?
Supportive (acetaminophen, hydration, rest)
No vaccine available for influenza C
49
What causes hand foot and mouth disease?
Cox A and B
50
What does hand foot and mouth usually present as?
Vesicles on HAND, FEET, MOUTH
USUALLY IN YOUNG CHILDREN
51
What is associated w/ 50% of cases of viral myocardidits?
Cox B
52
How does Cox A more commonly present?
Herpangia
and hand foot and mouth disease
53
How does Cox B more commonly present?
Pleurodynia
myocarditis
pericarditis
54
What sxs are common to both Cox A and B?
Aseptic meningitis
paralysis
URI
55
What does Cox virus typically occur?
Summer to fall
56
How is Cox transmitted?
Fecal oral
| aerosal
57
What is the pathogenesis of Cox?
GI tract>
infects mucosal epithelial cells>
Replicates and spreads to cause viremia>
infects/destroys other cell types
58
What is the pathogenesis of Cox A?
Infects skin and mucosal epithelium>
forms vesicles>
herpangina (red oropharynx vesicles, fever, sore throat)>
hand foot and mouth
59
What is the pathogenesis of Cox B?
Infects heart and pleural surfaces>
| Pleurodynia, myocarditis, pericarditis
60
What is the pathogenesis for how Cox A and B cause aseptic meningitis and paralysis?
Infect MENINGES and ANTERIOR HORN motor neurons>
| aseptic meningitis and paryalysis
61
How do you diagnose Cox virus?
Isolate virus
| serology
62
What is the treatment for Cox virus?
Supportive
Symptomatic- anti-inflammatory agents
63
What type of virus is adenovirus and where is it found following infection?
Latent virus found in the TONSILLAR ADENOIDS after infection
64
How many serotypes of adenovirus are there?
40
65
Are there vaccines for adenovirus?
Yes
administered AWAY from the primary site of infection
66
A pt presents with RTI (common cold), conjuntivitis, hemorrhagic cystitis and gastroenteritis. What is causing these symptoms?
Adenovirus
67
How does Adenovirus spread?
Aerosol
Fecal oral
Direct contact
68
What is the pathogenesis of adenovirus?
Binds via HEMMAGGLUTININ>
| enters and LYSES MUCOSAL CELLS
69
How does the pathogenesis of adenovirus differ in upper and lower RT?
Upper- RHINITIS and sore throat
Lower- Atypical PNEUMONIA
70
How do you diagnose adenovirus?
Isolate virus in cell culture
| Serology
71
How do you treat adenovirus?
Vaccine of live viruses of specific serotypes (Only used in military)
72
Why is treatment mandatory for s. pyognes?
Usually SELF LIMITING
but it can cause Rheumatic and glomerulonephritis
73
What VF promote the spread of infection of s. pyogenes and lead to inflammation?
```
Streptokinase (converts plasminogen to plasmin> fibrinolysis)
M protein (resists phagocytosis)
Hyaluronidase (breaks down CT)
DNase (breaks down DNA)
```
74
A pt presents w/ PHARYNGITIS, impetigo, ersipelas and cellulitis. What is the causative organism?
STREPTOCOCCUS pygoenes
75
How is s. pyogenes transmitted?
Part of the normal flora of skin/oropharynx
Transmitted through respiratory droplets
76
How does s. pyogenes cause pharyngitis?
Transmitted through respiratory droplets>
bacteria adhere and colonize pharyngeal epithelial cells via PILI on surface of bacteria>
Localized inflammation and SORE THROAT and ENLARGED LYMPH NODES
77
How do you diagnose s. pyogenes?
```
Throat/skin culture
Gram + cocci
Beta hemolytic
Bacitracin sensitive
ASO +
anti-stretolysin O abs present
```
78
How do you treat s. pyogenes?
Penicillin G
79
What is the second MCC of bacterial pneumonia inpts w/ COPD and nontypeable H influenzae?
Moraxella catarrhalis
80
What VFs does Moraxella have?
SPECIALIZED PILI allows for attachment of microorganism to mucosal surface
ANTIGENIC VARIATION to evade host IR
ENDOTOXIN
CAPSULE
81
What are the three types of infection that moraxella can cause?
otitis media
sinusitis
pneumonia
82
How does moraxella normally colonize?
Colonizes the NASOPHARYNX and spreads to the MUCOSAL SURFACES>
Releases ENDOTOXIN>
Inflammatory response
83
How can you diagnose moraxella?
Hydrolyzes tributyrin
Produces DNase
Reduces nitrite/nitrate
Dones't ferment sugars
84
How do you treat moraxella?
Amoxicillin-clavulanate
Cephalosporins
TMP-SMX
85
When are DTaP vaccines given?
2,4,6 and 18 mos, before starting school and every ten years after that
86
What carries diptheria toxin?
PHAGE--> only lysogenic orgs can cause systemic disease
87
How does diptheriae present locally and systemically?
Locally- pseudomembrane and AIRWAY OBSTRUCTION
Systemically- myocarditis and polyneuritis
88
How does diptheriae cause airway obstruction?
Enters nasopharynx via RESPIRATORY DROPLETS>
creaets gray fibrinous exudate (bacterial cells, WBC, necrotic mucosa)>
Block airways
89
What does the diptheriae secrete? What does this do in the cell?
AB toxin that ribosylates EF2 and prevents PROTEIN SYNTEHSIS
90
What is the ultimate toxic affect of diptheria toxin?
cardiac issues
| NS issues
91
How do you diagnose diptheriae?
Gram + rod
aerobic
Black colonies on Potassium tellurite
92
How do you treat diptheriae?
Antitoxin
penicillin
erythromyacin
93
What is prophylaxis for diptheriae?
DTaP w/ boosters every 10 years
94
What is the major cause of community acquired pneuomonia?
s. pneumonaiae
95
What serves as the ags for the pneumovax vaccine?
Capsule sugars
96
How does s. pneumoniae present locally?
Otits media
| LOBAR pneumonia
97
What is the pathogenesis of s. pneumoniae? How do they evade host defenses?
```
Respiratory droplets>
nasopharynx epitheluim>
evade host defenses by CAPSULE FORMATION and IgA PROTEASES>
spread to middle ear and SINUSES>
Alveoli> Lobar pneumoniae
```
98
How do you diagnose s. pneumoniae?
```
Gram + diplococcic
alpha hemolytic
catalase -
susceptible to optochin
Quelling rxn
```
99
How do you treat S. pneumoniae?
Penicillin/cephalosporins
Preventative- pneumovax vaccine
100
What is the difference between H influenze type B and non-typeable H influenza?
H influenza type B- encapsulated and INVASIVE
non-typeable- colonize locally
101
To whom does non-typeable H influenzae pneumonia occur most often?
Adults w/ COPD
| Recent viral infection
102
How does Haemophilius influenza type B spread?
```
Infects humans via respiratory droplets>
URT>
local inflammation and EPIGLOTTITIS AND OTITS MEDIA>
invades submucosa and blood stream>
PNEUMONIA
```
103
How does Haemophilius influenza type B evade host defenses?
IgA protease
| Capsule
104
```
What is the microorganism?
Gram -
Requires hemin and NAD on chocolate agar
Immunofluorescence
+ Quelling Test
```
Haemophilus Influenza type B
105
How do you brevent haemophilus influenza and treat it?
Hib vacccine
Rifampin for close contacts
Third generation cephalosporin (ceftriaxone)
106
What proteins does RSV use to attach to cells and to fuse infected cells?
G proteins- attachment
| F protein- fuse cells
107
What is the major respiratory pathogen in young children?
RSV--infects everyone by age 3
108
What to conditions present w/ wheezing?
Asthma and RSV
109
What is the pathogenesis of RSV?
Attaches to bronchiolar/alveolar epitheilum via G protein>
necrosis and iflammation of bronchioles>
mucous obstruction of airway>
bronchiolitis and wheezing
alveoli>
pneumonia
110
What can prevent RSV?
Recurrent infectoin builds IgA immunity against futher infection
111
How do you treat RSV?
Supportive
Albuterol
Preventative- Synagis
