T4 L8: Respiratory tract infections

Question 1

Which 2 innate immunity features are in the lungs?

Answer 1

cilia and alveolar macrophages

Question 2

Which 3 acquired immunity features are in the lungs?

Answer 2

B cells, T cells, and igA

Question 3

What is empyema?

Answer 3

Puss in the pleural spaces

Question 4

What is pneumonia?

Answer 4

Filled airspaces in the lungs

Question 5

What are pulmonary abscesses?

Answer 5

Puss-filled dead areas

Question 6

What is the most common upper respiratory tract infection?

Answer 6

Rhinovirus

Question 7

How does Bradykinin cause symptoms of the cold?

Answer 7

Causes a sore throat and it may cause nasal congestion due to vasodilatation

Question 8

How is sneezing mediated?

Answer 8

By histamines. Stimulation of the trigeminal sensory nerves

Question 9

What protein causes nasal discharge colour change?

Answer 9

myeloperoxidase

Question 10

What nerve mediates a cough?

Answer 10

The vagus nerve but the inflammation has to spread to the larynx to cause this

Question 11

Which proteins are responsible for systemic symptoms like fever?

Answer 11

Cytokines

Question 12

What are some differences between the cold and the flu?

Answer 12

Cold

• appears gradually
• usually no fever
• able to function

Flu

• quick onset
• high fevers
• unable to function normally

Question 13

Which 4 groups are at risk of complication of the flu?

Answer 13

Immunosuppressed, pregnancy or 2 weeks post partum, age <2 or >65years, or BMI >40

Question 14

What are the H proteins on an influenza virus?

Answer 14

Haemagglutinin proteins which bind to sialic acids on the surface to glycoproteins. They allow the virus to enter the cell

Question 15

What are the N proteins on an influenza virus?

Answer 15

Neuraminidase proteins that allow the virus to escape by cleaving sialic acid bonds otherwise they would all clump up together

Question 16

What is antigenic drift?

Answer 16

Small mutations that occur each time a virus replicates its DNA/RNA

Question 17

What us antigenic shift?

Answer 17

Big mutations that occur in entire sections of the genome. This is special for influenza A

Question 18

When is antigenic shift most likely to occur?

Answer 18

When the host is already infected with another virus

Question 19

Which proteins on a influenza virus under go antigenic shift and drift?

Answer 19

The H and N proteins

Question 20

What is pneumonia?

Answer 20

Infection of lung parenchyma

Question 21

What is the lung parenchyma?

Answer 21

Portion of the lung involved in gas exchange

Question 22

How would you diagnose pneumonia?

Answer 22

Using a CXR with supporting clinical features

Question 23

What is consolidation?

Answer 23

Alveoli and bronchioles are completely filled with inflammatory fluid so they appear solid

Question 24

How would pneumonia appear on a CXR?

Answer 24

White parts all over the lung. The heart and diaphragm borders will be obscured because of loss of clear alveoli

Question 25

Why is community vs hospital acquired pneumonia classified?

Answer 25

Because pathogens involved will differ which alters management

Question 26

What are some community-acquired pneumonia pathogens?

Answer 26

Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Staphylococcus aureus

Question 27

What is the commonest organism behind pneumonia?

Answer 27

Streptococcus pneumoniae

Question 28

What type of bacteria is streptococcus pneumoniae and what is the treatment?

Answer 28

A gram negative cocci treated with penicillin

Question 29

Which part of the body does streptococcus pneumoniae attach to primarily?

Answer 29

In the nasopharynx

Question 30

What are the risk factors for a streptococcus pneumoniae infection?

Answer 30

Alcoholics, respiratory disease, smokers, hypersplenism, chronic heart disease, HIV

Question 31

What is the commonest cause of ambulatory 'atypical pneumonia' and what does that mean?

Answer 31

Mycoplasma pneumoniae meaning it attacks more mildly but is more persistent than typical pneumonia

Question 32

What is the treatment for mycoplasma pneumoniae?

Answer 32

Macrolides and tetracyclines (they attack ribosomes)

Question 33

Why can't mycoplasma pneumoniae be treated with penicillins?

Answer 33

It lacks a cell wall so is resistant to penicillin's. It also cannot be grown on normal lab plates

Question 34

How do Legionella pneumophilia infections occur?

Answer 34

Sporadic infections associated with outbreaks of contaminated water associated with travelling. It's very rare

Question 35

How would you diagnose Mycoplasma pneumoniae?

Answer 35

A PCR of throat swab (VTS)

Question 36

How would you diagnose Legionella pneumiphila?

Answer 36

Urinary legionella antigen

Question 37

What is the treatment for Legionella pneumophila?

Answer 37

Macrolides and quinolones

Question 38

What proportion of the world has latent TB?

Answer 38

A quarter of the worlds population

Question 39

Describe TB as a cell

Answer 39

Aerobic bacillus, often referred to as acid-fast bacillus (AFB). It has a cell wall but lacks the phospholipid outer layer

Question 40

What stains are used for TB?

Answer 40

Zhiel-Neelsen or auramine-rhodamine stains

Question 41

Why is TB referred to as acid fact bacillus?

Answer 41

Because it retains stains after treatment with acids

Question 42

Which infection develops in granulomas and how?

Answer 42

TB. T cells, B cells and activated macrophages establish granulomas which contain TB where the pathogen survives

Question 43

What is meant by latent TB?

Answer 43

The bacilli are dormant and contained within host defences. Its non-infectious and asymptomatic

Question 44

What is meant by active TB?

Answer 44

Actively replicating bacilli, may be infectious and is symptomatic