Pneumonia

Question 1

What flora may normally colonise the lower respiratory tract?

Answer 1

The lower respiratory tract is usually considered sterile

i.e. there should be no flora in the lower respiratory tract

Question 2

What flora may normally colonise the upper respiratory tract?

Answer 2

The upper respiratory tract may be colonised by staphylococci, streptococci, haemophilus, neisseria and anaerobes.

Question 3

What is the pathogenesis of pneumonia?

Answer 3

Organisms colonising the upper respiratory tract descend into the lower respiratory tract (usually sterile) and cause infection.

Question 4

What are the common respiratory pathogens?

Answer 4

Gram +ve cocci:

• Staphylococci
• Streptococci

Gram -ve cocci:
- Moraxella catarrhalis

Gram +ve bacilli
(Not commonly respiratory pathogens)

Gram -ve bacilli:

• Pseudomonas aeruginosa
• E-coli
• Klebsiella

Gram -ve coccobacilli:
- Haemophilus

Spiral bacteria:
(Not commonly respiratory pathogens)

Atypicals:

• Mycoplasma
• Legionella
• Chlamydia

Question 5

Which patients should be have a urinary legionella antigen test?

Answer 5

All patients with severe pneumonia as classified by CURB65 score

Question 6

What is the CURB-65 score and what does the score indicate?

Answer 6

Estimates mortality of community acquired pneumonia to help determine inpatient vs. outpatient treatment.

Each clinical feature earns 1 point:

• Confusion
• Urea >7 mmol/L
• Resp Rate >=30
• BP <90/60
• 65 years or older

0-1 = 1.5% 30 day mortality, low risk; probably outpatient treatment.

2 = 9.2% 30-day mortality, moderate risk; probably admit.

3-5 = 22% 30-day mortality, servere; definitely admit.

Question 7

What is the general treatment for respiratory infections?

Answer 7

1) Empirical treatment should be started per local guidelines while awaiting culture results.
2) Targeted treatment should begin once culture results are available

Question 8

What antibiotic options are available for respiratory infections?

Answer 8

ABx for respiratory tract infections must penetrate into the lungs and cover common respiratory tract pathogens.

PO options: Amoxicillin, doxycycline, co-amoxiclav, clarithromycin, ciprofloxacin, cotrimoxazole.

IV options: Amoxicillin, clarithromycin, co-amoxiclav, cefuroxime, tazocin, temocillin.

Question 9

Mrs Smith is an 80 year old lady with a background of COPD. She was admitted three days earlier with increasing breathlessness and a more productive cough. She is apyrexial and her CRP and WCC are normal. A sputum culture was sent from A&E on admission.

Microbiology results:
Sputum Culture
\+++ coliform isolation
Resistant to amoxicillin
Susceptible to co-amoxiclav

What is the appropriate next step in her management?

Answer 9

This patient has no signs of infection (apyrexia, CRP and WCC normal), therefore a sputum sample was never indicated.

The sputum culture results indicate an upper airway colonisation (probably e-coli) but not an infection. No antibiotics are required.

Treat for exacerbation of COPD (bronchodilators and steroids).

Question 10

What are some key risk factors for aspiration pneumonia?

Answer 10

• Incompetent swallow
• Poor dental hygiene
• Prolonged hospitalisation or surgery
• Impaired consciousness
• Impaired mucociliary clearance

Question 11

Which lobes are most l commonly sites for aspiration pneumonia?

Answer 11

Right middle and lower lung lobes, due to the larger calibre and more vertical orientation of the right main bronchus.

Question 12

Which bacteria are often implicated in aspiration pneumonia?

Answer 12

Streptococcus pneumoniae

Staphylococcus aureus

Haemophilus influenzae

Pseudomonas aeruginosa

Question 13

Which is main causative pathogen of community acquired pneumonia?

Answer 13

Streptococcus pneumoniae (accounts for ~80% of cases)

Question 14

Which causative pathogen of pneumonia is classically found in alcoholics?

Answer 14

Klebsiella pneumoniae