Community Acquired Pneumonia

Question 1

Define pneumonia [1]

Answer 1

Inflammation of the lung caused by bacterial infection, in which the alveoli become filled with inflammatory cells and the lung becomes consolidated

Question 2

What are the 3 pathological causes of pneumonia? [3]

Answer 2

1. Defect in the host defence mechanisms
   
   • Immunosuppressed patients
   • Smokers - destroy their tissue macrophages
2. Large innoculum
   
   • i.e. inhaling a significantly large amount of pathogens which overwhelms the immune system leading to pneumonia
3. Increased virulence

Question 3

What are the 3 typical microbiological causes of pneumonia? [3]

Answer 3

1. Streptococcus pneumoniae
2. Haemophilus influenzae
3. Moraxella catharralis
   
   • (more in people with COPD/defects in lung architecture)

Question 4

What are the atypical microbiological causes of pneumonia? [4]

Answer 4

1. Mycoplasma pneumoniae
2. Legionella pneumoniae
3. Chlamydophila pneumoniae
4. Chlamydophila psittaci

Question 5

What kind of bacteria is streptococcus pneumoniae? [2]

Answer 5

gram positive coccus

Question 6

What are the risk factors for streptococcus pneumoniae? [5]

Answer 6

1. Alcohol
2. Smoking
3. Chronic lung disease (asthma/COPD)
4. Flu virus
5. Immunosuppression (e.g. people with HIV)

Question 7

What are the symptoms of streptococcus pneumoniae? [4]

Answer 7

• Abrupt onset of:
  
  1. Cough
  2. Fever
  3. Pleuritic chest pain

Question 8

What are the signs of streptococcus pneumoniae? [4]

Answer 8

• Typical signs of consolidation:
  
  1. Dull percussion
  2. Coarse crepitations
  3. Increased vocal resonance

Question 9

What are the treatment options for streptococcus pneumoniae? [3]

Answer 9

Amoxicillin (penicillin)

• If patient has allergy to penicillin, use:
  
  • Macrolides (clarithromycin)
  • Tetracyclines (doxycycline)

Question 10

What kind of bacteria is haemophilus influenzae? [2]

Answer 10

gram negative rod

Question 11

Who tends to get haemophilus influenzae pneumonia? [2]

Answer 11

1. Older people
2. Patients with underlying lung disease (COPD/pulmonary fibrosis/cystic fibrosis)

Question 12

What are the complications of non-typeable haemophilus influenzae which normally colonise the upper respiratory tract? [5]

Answer 12

1. Otitis media
2. Conjunctivitis
3. Sinusitis
4. Meningitis (occasionally)
5. Pneumonia

Question 13

What are the symptoms of haemophilus influenzae pneumonia? [4]

Answer 13

• Abrupt onset of:
  
  1. Cough
  2. Fever
  3. Pleuritic chest pain

Question 14

What are the signs of haemophilus influenzae pneumonia? [4]

Answer 14

• Typical signs of consolidation:
  
  1. Dull percussion
  2. Coarse crepitations
  3. Increased vocal resonance

Question 15

What are the treatment options for haemophilus influenzae pneumonia? [5]

Answer 15

• Treatment → oral Amoxicillin
• However risk of beta lactamase (so use…)
  
  1. Co-amoxiclav
  2. Macrolides (clarithromycin)
  3. Tetracyclines (doxycycline)

Question 16

Describe the features of the mycolplasma pneumoniae bacterium [3]

Answer 16

1. Smallest free living bacterium
2. Lack of cell wall
3. Very difficult to grow → tend not to culture it (use other ways to identify it)

Question 17

How is mycolplasma pneumoniae typically spread? [3]

Answer 17

• Spread from person to person
  
  • Sneezing
  • Coughing

Question 18

What are the typical presenting symptoms of mycolplasma pneumoniae? [6]

Answer 18

• Non-specific clinical presentation = flu-like illness
  
  1. Headache
  2. Fever
  3. Myalgia
  4. Arthralgia
  5. Cough (not a prominent symptom)

Question 19

What are the typical signs elicited on examination in a patient with mycolplasma pneumoniae? [4]

Answer 19

• Typical signs of consolidation
  
  1. Dull percussion
  2. Coarse crepitations
  3. Increased vocal resonance

Question 20

What are the manifestations that mycolplasma pneumoniae can cause beyond the lungs? [5]

Answer 20

1. Haemolysis → produce cold agglutinins
2. Guillain-Barre
3. Erythema multiforme → rashes
4. Cardiac → endocarditis
5. Reactive Arthritis

Question 21

What is the typical investigation used to diagnose mycolplasma pneumoniae? [3]

Answer 21

PCR (sputum/throat swab)

Question 22

What are the treatment options for mycolplasma pneumoniae? [3]

Answer 22

• Use intracellular agents:
  
  1. Macrolides (clarithromycin)
     
     • bind to ribosomes and inhibit protein metabolism
  2. Tetracyclines (doxycycline)
     
     • bind to ribosomes (different class) and inhibit protein metabolism
  3. Quinolones (ciprofloxacin)
     
     • inhibit ability to store DNA

Question 23

What is the typical investigation used to diagnose Legionella Pneumophila pneumonia? [1]

Answer 23

urinary antigen test

Question 24

What are the treatment options for Legionella Pneumophila pneumonia? [3]

Answer 24

• Use intracellular agents:
  
  1. Macrolides (clarithromycin)
  2. Tetracyclines (doxycycline)
  3. Quinolones (ciprofloxacin)

Question 25

What things do you want to gather during a history of a patient with suspected pneumonia? [12] hints: 1. symptoms [7] 2. past medical history [2] 3. epidemiology [3]

Answer 25

1. symptoms * cough * sputum * fever * chest pain * insidious * abrupt onset * non-respiratory symptoms 2. past medical history * immunosuppression * underlying lung disease 3. epidemiology * recent travels * ill contacts * water exposure

Question 26

What is sepsis defined as under the qSOFA score? [4]

Answer 26

1. systolic BP \< 100mmHg 2. respiratory rate \> 22 breaths/min 3. altered mental status 4. a score of **2 or more** = sepsis

Question 27

What is the CURB65 score? [5]

Answer 27

1. C = confusion 2. U = urea \>7 3. R = respiratory rate ≥ 30 4. B = BP, diastolic \<60 or systolic \<90 5. 65 = age over 65yrs

Question 28

What is classified as **severe pneumonia**? [2]

Answer 28

1. multilobar consolidation on CXR and/or hypoxia on room air 2. CURB65 score \<2

Question 29

What investigations should be ordered for a patient with suspected pneumonia? [10] hints: 1. blood tests? [4] 2. microbiology? [4] 3. other investigations? [2]

Answer 29

* blood tests 1. FBC 2. U&Es 3. ABGs (arterial blood gas) 4. oxygen saturation * microbiology 1. blood culture 2. sputum sample 3. throat swab 4. urine legionella swab * other investigations * chest x-ray * ECG