Respiratory Systems 10 - Lung Infections

Question 1

Why is it good to measure acute lung infection in DALYs?

Answer 1

• Dalys - Disability Adjusted Life Years
• Used as the people infected with acute lung infection are often children
• Therefore this shows a greater effect

Question 2

List the main bacterium commonly associated with community acquired pneumonia

Answer 2

• Staphylocoocus aureus
• Pseudomonas aeruginosa
• Klebsiella
• E. Coli
• Acinetobacter
• Enterobacter

Question 3

What is the leading infectious cause of hospitalisation and death among adults in the US?

Answer 3

Community aquired pneumonia

Question 4

Define pneumonia

Answer 4

• Lung inflammation caused by bacterial or viral infection
• The air sacs fill with pus and may become solid.
• Inflammation may affect both lungs (double pneumonia) or only one (single pneumonia).

Question 5

What are the annual medical costs of community acquired pneumonia?

Answer 5

Over $10 billion annually

Question 6

What are typical and atypical pathogens in community acquired pneumonia?

Answer 6

• Typical pathogens are covered by penicillins (S. pneumoniae, haemophilus influenzae, Moraxella catarrhalis)
• Atypical pathogens must be targeted with additional agents such as macrolides. (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophilia)

Question 7

List the risk factors for pneumonia

Answer 7

• Age
• Smoking
• Contact with children age <15
• Medical history (COPD, asthma, heart disease, diabetes)
• Poverty/overcrouding
• Animal contact
• Healthcare workers

Question 8

How can pneumonia and bronchitis be distinguished?

Answer 8

• Pneumonia shows new signs or symptoms, patients are hypoxic and confused, and severe enough to be admitted to hospital
• Acute bronchitis, patients have a very bad cough as well as tracheal pain, rather than pleuritic pain. No new x-ray changes

Question 9

List the BTS guidelines for diagnosis pneumonia

Answer 9

• Acute lower respiratory tract symptoms
• New focal chest signs and, if in hospital, new CXR changes
  >1 systemic feature (fever, shivers, aches and pains, temperature >380C)
• No other explanation for illness

Question 10

How is it determined whether patients need to be admitted to hospital?

Answer 10

• CRB65 severity score (includes confusion, high respiratory rate, low blood pressure, age over 65)
• Treated according to clinical judgement as well as the CRB65 score

Question 11

List the supportive therapies for pneumonia

Answer 11

• Oxygen to treat hypoxia
• Fluids to treat dehydration
• Analgesia for pain
• Nebulised saline
• Chest physiotherapy
• Antibiotic therapy

Question 12

List the effects of viruses on the lung

Answer 12

• Inflammation
• Release of mediators, and local immune memory formation
• Damage to epithelium (loss of cilia, bacterial growth, poor barrier to antigen)

Question 13

List the common cold agents

Answer 13

• Rhinovirus
• Corona virus
• Influenza virus
• Parainfluenza virus
• Respiratory syncytial virus

Question 14

List the factors that could result in severe flu

Answer 14

• Highly pathogenic strains
• Absense of prior immunity (innate immunodeficiency/ B cells/T cells)
• Predisposing illnesses - Frail elderly, COPD, obesity, pregnancy

Question 15

Compare influenza and respiratory syncytial virus

Answer 15

• Influenza causes no reinfection by the same strain. Vaccines are imperfect (annual vaccines required, and immunity does not last long)
• RSV causes reccurent reinfections with similar strains. There is no vaccine.

Question 16

List the clinical features of RSV bronchitis

Answer 16

• Chest wall retractions
• Nasal flaring
• Hypoxemia
• Cough
• Weezing
• Tachypnea

Question 17

How is RSV disease age dependent?

Answer 17

• Often it is caught by children, who then pass it on to siblings. Siblings tend to pass it on to grandparents.
• While children recover easily, elderly people cannot recover and soon get pneumonia and die
• Once illness occurs, it is unlikely RSV will still be in the body

Question 18

Compare the symptoms and viral load of influenza and RSV

Answer 18

• Influenza causes symptoms earlier on, and viral load peaks earlier on
• RSV is tackled by the immune system in the early stages, and once it persists viral load peaks later on and remains high for a long period of time. Symptoms last a long time.

Question 19

Where to most bacterial pneumonias arise?

Answer 19

They arise from preexisting bacteria in the nose/lungs which become pathogenic in the wrong location.