27 - Viral infections of the Respiratory Tract II Flashcards
(117 cards)
1
Q
What are the symptoms of influenza?
A
Symptoms
- Myalgia
- Headache
- Fever
- Shaking chills
- Cough peaking between 3 & 5 days of illness.
- Cough, fatigue, and generalized weakness may last 2-6 weeks – longer duration of illness than the common cold
2
Q
When would you see increased severity of symptoms and an increased incidence of complication?
A
Usually seen in pandemic outbreaks (seasonal epidemic or outbreak)
3
Q
What is the definition of a pandemic?
A
A pandemic is a world-wide epidemic when we are talking about influenza - During this time, the pandemic can lead to increased problems and increased complications with the influenza virus
4
Q
During which season do we see a peak in influenza?
A
During the winter months, but ONLY in temperate climates (no “peaks” seen in the tropics)
Peak in Iowa = end Jan., beginning Feb.
5
Q
What is the incubation period of influenza?
A
2 days
6
Q
Which populations are more at risk for complications due to influenza?
A
- Children younger than 2
- Adults older than 65
- Pregnant women (up until 2 weeks postpartum)
- People with certain medical conditions (asthma, endocrine disorders, heart disease, etc.)
7
Q
Influenza will go away on its own… The bigger concern is ___________.
A
Complications that arise from the influenza virus
Can lead to hospitalizations and be fatal
8
Q
What is the biggest complication we worry about with influenza?
A
Pneumonia
9
Q
What is pneumonia?
A
Inflammation of the lung parenchyma leading to abnormal gas exchange
10
Q
What are symptoms of pneumonia?
A
- Fever
- Chills
- Cough
- Pleural chest pain
- Increased respiratory rate
- Wheezes and crackles
- Hypoxia and cyanosis (severe cases – interfere with oxygen exchange)
11
Q
Primary influenza virus pneumonia is usually the result of which influenza strain?
A
Influenza A
12
Q
Primary influenza virus pneumonia occurs most frequently in which age groups?
A
Children and 40+ population
13
Q
What are the symptoms of primary influenza virus pneumonia?
A
- 1-4 days following influenza virus symptoms, patient gets progressively worse
- Increased cough, tachypnea, dyspnea, acute respiratory distress
14
Q
How will a sputum test stain in a gram stain?
A
Abundant PMN cells without a significant number of bacteria
15
Q
What will a chest radiograph show in primary influenza virus pneumonia?
A
Bilateral mid lung and lower lung infiltration
16
Q
What is the fatality rate for primary influenza virus pneumonia?
A
Approx. 50%
17
Q
What accounts for the high fatality rate?
A
We are limited in how we can manage these patients
18
Q
What is bacterial influenza-associated pneumonia?
A
This is “good news” because it is easily treatable - much easier to treat than influenza A pneumonia
19
Q
When will symptoms of bacterial influenza-associated pneumonia begin?
A
About a week after influenza symptoms begin
20
Q
What are the symptoms of bacterial influenza-associated pneumonia?
A
Basic influenza symptoms which lessen, then followed by increased cough, return of fever and respiratory distress
21
Q
How will a gram stain of bacterial influenza-associated pneumonia stain?
A
The stain may contain a bacterial cause
22
Q
Which types of bacteria is typically the cause of bacterial influenza-associated pneumonia?
A
1 - S. pneumoniae – most common
2 - S. aureus & H. influenzae – also common
Others: N. meningitidis, other Streptococcus, and Gram negative Bacillus
23
Q
What is the cause of influenza?
A
The influenza virus - a member of the orthomyxovirus
24
Q
What type of virus is the influenza virus?
A
ssRNA virus genome - Segmented
25
Is the influenza virus enveloped?
Yes!
26
What is the hemagglutinin (H) portion of the influenza virus?
Functions in attachment - it agglutinates to RBCs
27
What is the neuraminidase (N) portion of the influenza virus?
Functions to...
- Cleaves sialic acid (it is an enzyme, cleaves sialic acid which is on the outside of the cell)
- Allows for virion release
- Allows for virion spread
28
What does antigenic DRIFT mean in terms of the influenza virus?
Antigenic Drift
- Small changes in H and N
- Driven by point mutations made by the polymerase during replication
- Epidemiological significant changes every 2-3 years – the antigen “drifts” so much that it is no longer recognized as the parent
- This is why we change the immunization every year
29
What does antigenic SHIFT mean in terms of the influenza virus?
Antigenic Shift
- Large changes in H and N
- Driven by reassortment of two viruses
- Co-infection of the same cell
- Risk for pandemics
30
Where does reassortment occur?
"MIXING VESSELS"
- What we worry about is when a virus reassorts in different animals
- Pigs, for example, are easily infected by both human and bird influenza
- Pigs are therefore considered a dangerous “mixing vessel”
31
What is unique about influenza B viruses?
- ***ONLY humans, not animals
- ***Can undergo antigenic drift, but NOT antigenic shift
- It can occasionally become severe, but not usually
- Causes outbreaks and sometimes epidemics
32
What is unique about influenza A viruses?
***
- Can infect human, swine, avian, mammals, etc.
- ***The ONLY type of influenza virus that can undergo antigenic SHIFT (as well as drift)
- ***Probably why it is the ONLY one we see causing pandemics (and frequent epidemics)
- Often a very severe disease
33
What is unique about influenza C?
- Infects human and swine
- Usually a mild infection
- Limited outbreaks
- Demonstrates antigenic drift, but not shift
34
How do we name influenza strains?
We change the names of H and N... H1N1, H3N2, etc.
35
How did the novel 2009 H1N1 virus pandemic occur?
- Multiple reassortments, meaning there were parts from many different viruses included in the H1N1 strain
- Most cases of influenza worldwide were being caused by the same strain
36
When should we treat a patient with influenza with antivirals?
It depends on whether or not they exhibit risk factors and when they experienced onset
37
How should you treat an influenza patient with no risk factors?
- If you see them within 48 hours of onset, prescribe antivirals
- Treat symptoms
- Infection control
- Return if no improvement in 72 hours
38
How should you treat an influenza patient with risk factors?
- Treat with antiviral regardless of onset
- Treat symptoms
- Infection control
- Return if no improvement in 72 hours
39
What are two ion-channel blocker antivirals?
Amantadine and rimantadine
40
What do ion-channel blocker antivirals do?
They block replication prior to genome release (M2)
41
What is a major concern when prescribing ion-channel blocker antivirals?
The current strains of influenza A virus are RESISTANT to this drug
Not recommended by the CDC at this time
42
What are the names of the 3 neuraminidase inhibitor antiviral drug?
1 - Zanamivir (oral inhalation)
2 - Oseltamivir - Tamiflu (oral administration)
3 - Peramivir (IV administration)
43
Is there any current resistance to tamiflu?
No
44
How do neuraminidase inhibitors work?
They inhibit viron release and spread
45
Which type of influenza are neuraminidase inhibitors effective against?
Influenza A and influenza B
46
What is the "time restriction" on neuraminidase inhibitors?
For uncomplicated influenza, they must be given early (first 48 h) to reduce disease symptoms/duration
47
What is the best way to help with the influenza problem?
VACCINATE
Antivirals typically only shorten symptoms by about a day, so the best way to help with influenza is to VACCINATE
48
There are three types of influenza vaccines. What are they?
1 - Inactivated influenza vaccines (IIV)
2 - Live attenuated influenza vaccines (LAIV)
3 - Recombinant influenza vaccines (RIV)
49
What is the agent in the inactivated influenza vaccine (IIV)?
Formaldehyde-inactivated influenza viruses
50
What is the administration for Inactivated influenza vaccines (IIV)?
IM (intramuscular) or ID (intradermal)
51
Which patients are eligible for inactivated influenza vaccines (IIV) given IM?
- Older than 6 months
- Includes those with chronic medical conditions
Very safe!
52
Are Inactivated influenza vaccines (IIV) that are given IM trivalent or quadralent?
Can be either
53
Which patients are eligible for inactivated influenza vaccines (IIV) given ID?
Adults ages 18-64
54
Are Inactivated influenza vaccines (IIV) that are given ID trivalent or quadralent?
Trivalent
55
What is the agent in Live Attenuated Influenza Vaccines (LAIV)?
Attenuated influenza viruses
56
What is the administration route for Live Attenuated Influenza Vaccines (LAIV)?
Intranasal inhalation
57
What populations are eligible for Live Attenuated Influenza Vaccines (LAIV)?
- Healthy
- Non-pregnant
- Ages 2-49
58
How many strains are included in the Live Attenuated Influenza Vaccines (LAIV)?
Quadrivalent
59
What is the agent in recombinant influenza vaccines (RIV)?
Hemagglutinin protein
60
What is the administration rout for recombinant influenza vaccines (RIV)?
Intramuscular (IM)
61
What patients are eligible for recombinant influenza vaccines (RIV)?
Adults ages 18-49
62
How many influenza strains are included in recombinant influenza vaccines (RIV)?
Trivalent
63
What is the classic method of producing influenza vaccines?
Production in embryonated chicken eggs
Some of the problems could be egg supply, takes time to grow in eggs, etc.
64
What is the new method of producing influenza vaccines?
Production in mammalian cells - Madin Darby Canine Kidney (MDCK) cells
65
What are the advantages of the new mammalian cell method?
1 - rapid scale up of vaccine production
| 2 - reduced likelihood of egg protein carry over - allergies
66
What is the method of making the recombinant influenza vaccine?
Baculovirus expression vector system technology
- Create a recombinant protein
- Infect the cells
- Purify the protein
- Formulate it into a vaccine
67
What are the advantages of the recombinant influenza vaccine type?
- Rapid production
| - Egg-free system
68
What does trivalent include?
2 influenza A
| 1 influenza B
69
What does quadravalent include?
2 influenza A
| 2 influenza B
70
When is the ideal time to vaccinate?
2 - 4 months before flu season
71
Who do you vaccinate first when there is limited availability?
1st - People at highest risk for complications & health care workers
2nd - Anyone who wishes to reduce the likelihood of becoming ill from influenza
72
When would someone require two doses of the vaccine?
2 doses for children younger than 9 years of age being vaccinated for the first time
73
When would you prophylactically treat with anti-virals?
- Those at high risk for complications, which are vaccinated after the flu season has begun.
- Non immune health care workers and family members who care for those at high risk for influenza complications.
- Poor match between vaccine and currently circulating strains.
74
What is the SARS coronavirus?
A virus of the coronavirus family that has caused recent pandemics
75
Is the SARS coronavirus enveloped?
Yes
76
What type of genome does the SARS coronavirus have?
+ ssRNA
77
Is the SARS coronavirus more or less resistant to environmental conditions than the non-SARS form?
MORE resistant - more severe also
78
Describe the course of the SARS coronavirus disease
1 - Fever, malaise, and myalgia
2 - Dry cough & shortness of breath
3 - Most severe cases - adult respiratory distress syndrome (ARDS) & death within weeks
Other - diarrhea, abnormal liver function, and lymphopenia
79
How is the SARS coronavirus transmitted?
- Fecal-oral route
- Close contact
- Aerosol routes
80
What is the incubation period for SARS coronavirus?
2-10 days
81
How many cases have we seen of the SARS coronavirus?
8000 probable cases
82
Are these cases severe?
Yes
- Almost all of required hospitalization
- 20% intensive care
- Fatality rates were 10% overall, approximately 50% in elderly
83
When did we begin to control SARS?
June 2003
84
When was the last case of SARS?
November 2004
***
85
How did we control SARS?
MAIN WAY: Isolation and infectious control measures ***
- Medical workers all suited up
- Screen for fever – sign of when someone was infected
- One reason they think this was successful is because this occurred by having a fever for a day or so before you started having the coughing and sneezing, and that’s when they actually started spreading the virus a lot
- They were able to identify people that may be infected and control them
86
What is bronchiolitis?
Inflammation of the bronchioles
87
What are the symptoms of bronchiolitis?
- Expiratory Wheezing
- Nasal flaring
- Air Trapping
- Subcostal Retractions
- Variable fever
88
Why can bronchiolitis be a severe disease in infants?
Because their structure are so small that inflammation can easily close them
89
What would be on your differential diagnosis list?
- Allergic asthma
| - Foreign body inhalation
90
What is Respiratory Syncytial Virus (RSV)?
A virus from the paramyxovirus family that is the most common cause of bronchiolitis and pneumonia in children less than 1 year old
91
Is the Respiratory Syncytial Virus (RSV) enveloped?
YES
92
What type of genome does the Respiratory Syncytial Virus (RSV) have?
- ssRNA genome
93
Is Respiratory Syncytial Virus (RSV) highly infectious or more challenging to transmit?
Highly infectious – something that can be transmitted quite easily
94
How is Respiratory Syncytial Virus (RSV) transmitted?
- Inhalation of large droplets ***
| - Direct contact with respiratory secretions
95
What is the incubation period of Respiratory Syncytial Virus (RSV)?
4-5 days
96
How common is Respiratory Syncytial Virus (RSV) in children?
Nearly ALL children have been infected by age 4
97
How common is it to develop a secondary infection from Respiratory Syncytial Virus (RSV)?
Between 25-40% of primary infections result in pneumonia or bronchiolitis
98
Do you experience life-long immunity to RSV?
No - You do NOT have life-long immunity but reinfection leads to less severe disease (colds in adults)
99
When would you see severe infections arise from RSV?
In the elderly and immunocompromised populations
100
How do you treat RSV?
Aerosolized ribavarin
101
What is the mechanism of action of the aerosolized ribavarin treatment?
- It is a guanosine analogue
| - Inhibits nucleotide biosynthesis and mRNA capping and promotes hypermutation of the genome
102
When is this treatment indicated for RSV infections?
Indicated for severe lower respiratory tract RSV infections in special populations
- Premature infants
- Patients with chronic lung disease
- Patients with congenital heart disease
- Immunocompromised patients
103
How can you prevent RSV?
Prophylactic treatment for some patient groups
104
When is it indicated to treat a patient prophylactically for RSV?
- Birth before 32 weeks (sometimes before 35)
| - Less than 2 years old when on therapy for chronic lung disease within 5 months of RSV season
105
How do you treat patients prophylactically for RSV?
Two agents
- Palivizumab (pah lih VIH zyou mab)
- RSIG
106
What is Palivizumab?
A chimeric human-mouse monoclonal anti-RSV antibody
107
What is RSIG?
A pooled human immunoglobin, enriched for anti-RSV antibodies ( not quite as specific)
108
What other viruses can cause respiratory illness?
- Avian Influenza
- Cytomegalovirus
- Measles and Varicella-Zoster virus
109
What should you know about the avain influenza?
There is bird-to-human, NOT human-to-human transmission
110
What should you know about cytomegalovirus?
It occurs in immunocompromised individuals
111
What should you know about measles and varicella-zoster virus?
It is usually associated with distinct skin lesions = chicken pox
112
What percentage of measles can lead to pneumonia?
6% - it is the number 1 cause of measles related deaths
113
What percentage of chicken pox (VZV) can lead to pneumonia?
20% - it is the most serious complication of chicken pox
114
A number of your fellow survivors are suffering from rhinitis, pharyngitis, and a hacking cough. You suspect this is caused by a coxsackievirus outbreak. Observing which of the following illnesses in group members would best support your diagnosis?
A. Walt, a 10 year old child presenting with fever and vesicular lesions on his palms, soles of his feet, and around his mouth.
B. Kate, a 31 year old female presenting with pharyngitis, conjunctivitis, and fever.
C. Shannon, a 22 year old female, indicates her asthma attacks have been more severe and frequent in the last few days.
A. Walt, a 10 year old child presenting with fever and vesicular lesions on his palms, soles of his feet, and around his mouth.
Young kids usually get this
115
Aaron, a 2 month old male born on the island presents to your makeshift clinic with fever and a cough that sounds like a seals bark. You can hear a vibrating sound when he tries to take in air. You tell the rest of the survivors that the virus causing these symptoms is transmitted through ____________.
A. The fecal-oral route
B. Being bitten by an infected insect.
C. The respiratory secretions
C. The respiratory secretions
116
An outbreak of influenza-like illness strikes the island. An stockpile of oseltamivir is found in a previously hidden storage cellar. Barring the development of antiviral resistance, this drug would be expected to be effective against ____________ viruses.
A. Influenza type A
B. Influenza type B
C. Influenza type A and B
C. Influenza type A and B
117
Rose, a 62 year old female who received chemotherapy for advanced stage cancer 2 days before Oceanic flight 815 crash landed on the island is suffering from a severe cough, fever, and is having difficulty breathing. You suspect that RSV may be the cause. If this is true, antiviral treatment would be administered through the ____________.
A. Oral route
B. Aerosol route
C. Intramuscular injection
B. Aerosol route
