Influenza

Question 1

What kind of virus in influenza?

Answer 1

RNA virus

Question 2

What are the 3 main groups of influenza virus?

Answer 2

A
B
C

Question 3

What are the surface proteins of the influenza virus?

Answer 3

18 different H antigens

11 different N antigens

Question 4

What is the purpose of H antigens?

Answer 4

Facilitate viral attachment and entry to host

Question 5

What is the purpose of N antigens?

Answer 5

Enables new virus to be released from host cell

Question 6

What is antigenic drift?

Answer 6

Continual change in antigenic properties and genetic variation

Question 7

What is antigenic shift?

Answer 7

Abrupt major change in virus, resulting in new combinations due to reassortment of gene segments

Question 8

What does antigenic shift allow for?

Answer 8

Flu strain can jump from one species to another

Question 9

What are the methods of transmission of influenza?

Answer 9

Airborne via large droplets

Direct or indirect contact

Question 10

When does virus shedding occur?

Answer 10

First 1-7 days

Longer in young and immunocompromised

Question 11

What is the viral survival on porous and non porous surfaces?

Answer 11

Porous= 8-12 hours

Non porous= 24-48 hours

Question 12

What is the seasonal flu?

Answer 12

Occurs every winter

Unplesant but not life threatening to healthy individuals

Question 13

What is pandemic flu?

Answer 13

Occurs sporadically

Affects 25%+ of population, more serious and more complications

Question 14

What are the requirements for a pandemic flu?

Answer 14

Human pathogenicity
Antigenic shift
Efficient transmission

Question 15

How is avian flu spread?

Answer 15

Direct contact with birds or occasionally through close human contact

Question 16

What are the risk factors for flu?

Answer 16

Neuro, hepatic, renall, pulmonary or chronic cardiac disease
Diabetes
Severe immunosuppression
>65
Pregnancy
Children <6months
Morbid obesity

Question 17

What is the incubation period of influenza?

Answer 17

1-7 days, usually 2-4

Question 18

What can the fever be in influenza?

Answer 18

Up to 41, normally 38-40

Question 19

How long does the fever last in influenza?

Answer 19

1-5 days

Question 20

What is the clinical definition of influenza?

Answer 20

Abrupt fever of up to 41 plus 2 of

• cough
• myalgia
• headache
• malaise

Question 21

What are the less common symptoms of flu?

Answer 21

N&V

Diahorrea

Question 22

What investigations are dome for flu?

Answer 22

Viral nose and throat swabs
FBC, U+E, CRP
Blood culture
Pulse ox
CXR- if pneumonitis, pneumonia or ARDS

Question 23

What is the treatment of flu?

Answer 23

Antivirals not always given

Question 24

What are the common antivirals given for the flu?

Answer 24

Oseltamivir (Tamiflu)

Zanamivir

Question 25

What is the treatment of flu in pregnancy?

Answer 25

Antivirals recommended, Tamiflu 1st line

Question 26

What are the possible adverse effects of Tamiflu?

Answer 26

N&V, abdo pain, diarrhoea | Headache, hallucinations, insomnia, rash

Question 27

What are the possible adverse effects of Zanamivir?

Answer 27

Rarely bronchospasm

Question 28

What are the common respiratory complications of the flu?

Answer 28

Acute bronchitis | Secondary bacterial pneumonia

Question 29

When does secondary bacterial pneumonia occur in flu?

Answer 29

4-5 days after flu onset

Question 30

What is the CXR protocol in the flu?

Answer 30

Flu like symptoms and fever >4 days= urgent CXR

Question 31

What are the less common respiratory complications in the flu?

Answer 31

Primary viral pneumonia

Question 32

What are the cardiac complications of the flu?

Answer 32

Myocarditis | Pericarditis

Question 33

What are the CNS complications of the flu?

Answer 33

Transverse myelitis Guillain Barre Myositis and myoglobinuria

Question 34

When does flu become non infectious in immunocompetent adults?

Answer 34

24 hours after last flu symptoms or antiviral therapy completed, whatever is later

Question 35

When does the flu become non infectious in immunocompromised adult and children?

Answer 35

Separate for each case

Question 36

What is the flu vaccine?

Answer 36

Viruses grown in allantoic cavity of chick embryos, then clinically inactivated and purified