Viral Respiratory Tract Infections Flashcards
(86 cards)
1
Q
What are the types of respiratory tract infections?
A
- Upper
- Middle
- Lower
2
Q
What are the upper respiratory tract infections?
A
- Rhinitis
- Pharyngitis
- Tonsillitis
- Otitis Media
- Sinusitis
3
Q
What is rhinitis commonly caused by?
A
Rhinovirus
4
Q
What are the symptoms of rhinitis?
A
Runny nose’ and sneezing
5
Q
What is pharyngitis caused by?
A
Adenoviruses or coxsackie virus
6
Q
What does pharyngitis result in?
A
Fever and painful infected throat producing pus or exudates
7
Q
What happens in tonsillitis?
A
The tonsils become red and swollen, and exudates produced
8
Q
What is a common cause of tonsillitis?
A
EBV
9
Q
What is a potential complication of tonsillitis?
A
Quincy
10
Q
When do otitis media and sinusitis usually occur?
A
When sinuses or the middle ear (Eustachian tube) become occluded from inflammation
11
Q
What does otitis media and sinusitis produce?
A
Fever and pain
12
Q
What is otitis media and sinusitis caused by?
A
- S. Pyogenes
- S. Pneumonia
- H. Influenzae
13
Q
What are the middle respiratory tract infections?
A
- Laryngitis
- Tracheitis
- Laryngo-tracheo-bronchitis
14
Q
What does laryngitis produce?
A
A hoarseness and loss of voice
15
Q
What does tracheitis produce?
A
- Tracheal tiredness
- Retrosternal pain on breathing
16
Q
What is laryngo-tracheo-bronchitis known as?
A
Croup
17
Q
How common is croup?
A
Relatively
18
Q
What are the symptoms of croup?
A
- Barking cough
- Hoarseness
- Stridor
19
Q
What is stridor?
A
High-pitched wheezing
20
Q
What causes stridor in croup?
A
Occlusion from inflammation, as cartilage rings make trachea non-expandable
21
Q
What are the lower respiratory tract infections?
A
- Acute bronchitis
- Bronchiolitis
- Pneumonia
22
Q
What is acute bronchitis?
A
Cough associated with whitish sputum
23
Q
What change is seen on chest X-ray with acute bronchitis?
A
None
24
Q
In whom does bronchiolitis mainly occur?
A
Infants
25
What are the symptoms of bronchiolitis?
* Wheeze
* Cough
* Dyspnoea
26
How long does bronchiolitis last?
Several days
27
What is the most common cause of bronchiolitis?
RSV
28
What can viruses act as triggers to?
Underlying chronic conditions
29
What underlying chronic conditions can viruses act as triggers to?
* Asthma
* Cystic Fibrosis
* COPD exacerbations
30
What adversaries for viral RTIs are there?
* Influenza types A, B, and C
* Adenoviruses
* Respiratory syncytical virus (RSV)
* Parainfluenza virus types 1, 2, and 3
* Rhinovirus
* Coxsackie virus
* Coronaviruses
31
How can influenza A be further classified?
Depending on the antigens on their surface
32
What happens to the antigens on the surface of influenza A?
Point mutations occur
33
What do point mutations in the antigens on the surface of influenza A produce?
Antigenic drift
34
What are adenoviruses?
DNA viruses
35
How many serotypes are there of adenoviruses?
More than 50
36
How many of the serotypes of adenoviruses cause disease?
9
37
What is RSV?
A paramyxovirus
38
How many major serotypes of RSV are there?
2
39
How do the major serotypes of RSV differ?
In their antigenic properties
40
Who does RSV infect?
Children in their first 3 years of life
41
What does RSV cause?
Bronchitis, bronchiolitis, and pneumonia in infants
42
Is there a vaccine to RSV?
No
43
What is parainfluenza virus the major cause of?
Croup in children
44
How does parainfluenza virus cause croup?
By infecting the tracheobronchial tree
45
Where can parainfluenza virus be found in adults?
In the upper respiratory tract
46
What does rhinovirus cause?
Rhinitis
47
How many serotypes of rhinovirus are there?
More than 100
48
What type of viruses are rhinoviruses?
Picornaviruses
49
What kind of viruses are coxsackie?
Echoviruses
50
What do coronaviruses cause?
Coryza-like illness, *similar to rhinitis*
51
Can a virus be identified by the symptoms and syndromes caused?
No
52
Why can a virus not be identified simply by the symptoms and syndromes caused?
As there is so much overlap between viruses and conditions caused
53
What do acute viral respiratory illnesses cause?
High rates of illness in children
54
What is the result of acute viral respiratory illnesses caused high rates of illness in children?
They are a large proportion of GP consultations
55
In whom do acute viral respiratory illnesses cause a large proportion of deaths?
The elderly
56
What are influenza viruses made up of?
3 different subtypes, A, B, and C
57
What does type A influenza undergo?
Genetic shift
58
What do the influenza viruses contain?
A lipid protein coat
59
What does the lipid protein coat of influenza viruses have?
Two main antigens expressed within it
60
What are the main antigens expressed within the lipid protein coat of influenza viruses?
* Haemagglutin
* Neuraminidase
61
What are haemagglutin and neuraminidase used to do?
Classify the virus into sub-classification
62
How does the virus use haemagglutin?
* To adhere to the host cell
* Facilitates the entry of the viral genome into the target cells
63
How does the virus use neuraminidase?
To facilitate its release from the host cell
64
What is the clinical significance of the influenza viruses use of neuraminidase?
It can be used to some effect against influenza viruses for antiviral therapy
65
Give two examples of influenza viral classifications based on haemagglutin and neuraminidase?
* H1N1
* H3N2
66
What part of influenza viruses undergo antigenic changes?
* Haemagglutin
* Neuraminidase
67
What is antigenic drift?
Point mutations that occur in the virus genome that allow slightly new variants of the haemagglutin and neuraminidase to be altered slighlty.
## Footnote
*The introduction of a new influenza subtype into the population*
68
What does antigenic drift allow haemagglutin and neuraminidase to do?
Evade the immune system
69
What is antigenic drift responsible for?
Seasonal changes in the influenza virus
70
What is the result in the seasonal change in the influenza virus?
Vaccination against it needs to be renewed annually
71
What is the purpose of the antigenic drift process?
It is a process of continual evolution such that antibodies intended for its predecessor are ineffective against it
72
Currently, what are the stable lineages of influenza?
* H1N1
* H2N2
* H3N2
73
How are new strains of influenza produced?
A new subtype evolves as a result of genetic reassortment between human and animal influenza viruses
74
What do genetic reassortments between human and animal influenza viruses occur as a result of?
Direct reassortment, or via an intermediate host
75
In what species has genetic rearrangement occurred with human viruses?
* Avian flu
* Swine flu
76
Evaluate the use of current vaccines for influenza?
They are a good means of prevention, yet constantly have to be altered each year for that specific antigenic drift sequence
77
What does the influenza vaccine contain?
Attenuated viruses or purified surface antigens
78
What purified surface antigens may the influenza virus contain?
* HA
* NA
79
Who is given the vaccine for influenza?
Those at most risk of complications if infected with the virus
80
Who is at most risk of complications if infected with influenza?
* Over 65
* Diabetes
* Heart failure
* Renal failure
81
What is the purpose of the influenza vaccine?
Prevent morbidity or mortality
82
What are the main influenza antivirals that can be used?
Neuraminidase inhibitors
83
Give an example of a neurominidase inhibitor?
Zanaminvir
84
How do neurominidase inhibitors work?
As NA is essential for the release of viruses from virally infected cells, inhibiting the NA prevents further infection of other uninfected cells
85
What are the main problems with NA inhibitors?
* The rapid development of resistance
* The cost of treatment
* Only beneficial if given within 48 hours of onset of symptoms
86
How is diagnosis of influenza viruses made?
By direct immunoflouresence and NAAT
