Infectious causes of Pneumonia

Question 1

What would a patient with a typical pathogen pneumonia present like?

Answer 1

Increased fever, usually:
- high with rigors (cold, shivering, hot, copious sweating)

Productive cough
- sputum / sputum change
[] volume, freq, colour, consistency, blood, smell

Dyspnoea

Pleuritic pain - localised

Focal chest signs

Question 2

What are the typical pathogens of pneumonia?

Answer 2

Streptococcus penumoniae (Pneumococcus)
 - gram +ve (>50%)

Haemophilus influenza
- gram -ve (5%)

Question 3

What type of bacteria is Streptococcus pneumoniae (pneumococcus)?

Answer 3

Gram +ve

Question 4

Describe the distinct characteristics of Haemophilus influenza?

Answer 4

Gram -ve bacillus

Common cause of bronchiectasis exacerbations

Can be diffuse or contained to one lobe

Question 5

What would a patient with an atypical pathogen pneumonia present like?

Answer 5

More systemic symptoms

Often less focal chest signs

Associated with milder pneumonias in immunocompetent, except for Legionella (severe atypical pneumonia)

Hard to detect since difficult to culture
- but may cause ~30% of CAP

Question 6

What are the atypical pathogens of pneumonia?

Answer 6

Mycoplasma pneumoniae

Chlamydia pneumoniae

Legionella Pneumophila

Coxiella burnetti

Chlamydia psitacci

Question 7

What type of bacteria is Mycoplasma pneumoniae?

Answer 7

Atypical bacterial with no cell wall

Question 8

What type of bacteria is Chlamydia pneumoniae?

Answer 8

Obligate intracellular bacterium

Question 9

What type of bacteria is Legionella pneumophila?

Answer 9

Gram -ve bacteria

Question 10

What type of bacteria is Coxiella burnetti?

Answer 10

Gram -ve bacteria (small)

Question 11

What type of bacteria is Chlamidiya psittaci?

Answer 11

Obligate intracellular bacterium

Question 12

Describe the distinct characteristics Chalmydia psitacci

Answer 12

An obligate intracellular bacterium

Often transmitted from birds

Prefers lower lobes

Question 13

Describe what is meant by a hospital acquired pneumonia (HAP)?

Answer 13

Pneumonias that occur after >=2 days of admission, or in patients who have been in healthcare environment in last 3 months (e.g. nursing home)

However, may be caused by typical pathogens also

Question 14

What three things can increase the risk of aquiring a HAP?

Answer 14

Immunocompromised

Previous viral infection

Ventilated

Question 15

What are the most common HAP organisms?

Answer 15

Bacteria

• Stapylococcus aureus (Gram +ve)
• Klebsiella (Gram -ve enterobacteria)
• E-coli (Gram -ve enterobacteria)
• Pseudomonas aeriginosa (Gram -ve enterobacteria)

Viruses
- Influenza virus ~ 8%

Fungi
- Pneumocystis (rare)

Question 16

Describe the distinct characteristics Staphylococcus aureus

Answer 16

Usually a HAP

Often follows influenza infection
- presents with pneumonia, pleuritic chest pain +/- haemoptysis

Produces cavitation - empyema and abcess develop

Question 17

Describe the distinct characteristics klebsiella

Answer 17

Usually affects hospitalised or immunocompromised
- e.g. alcoholics - may follow aspiration

Prefers upper lobes

Causes cavitation/abcess
- haemoptysis with a currant jelly sputum is classical

Question 18

Describe the distinct characteristics E-coli

Answer 18

Usually affects immunocompromised
- often develops from aspiration or UTI

Lower lobes usually

Question 19

Describe the distinct characteristics Pseudomonas aeriginosa

Answer 19

Usually affects hospitalised or immunocompromised

Gradual onset with copious green sputum

Question 20

Describe who pneumocystis normally affects?

Answer 20

Immunocompromised

• AIDS sufferers
• rare infection

Question 21

Where does streptococcus pneumoniae live?

Answer 21

Respiratory tract and multiplies rapidly

Question 22

Is streptococcus a lobar or diffuse pneumonia?

Answer 22

Lobar pneumoniae

Question 23

Describe the sputum of a Streptococcus pneumoniae?

Answer 23

Rusty coloured sputum - classically

Question 24

What virus is associated with Streptococcus pneumoniae?

Answer 24

Herpes Labialis - cold sores

Question 25

How sudden and severe can Mycoplasma pneumoniae present?

Answer 25

Slow progressiong Mild-moderate pneumonia Flu-like symptoms followed by a dry cough

Question 26

What can Mycoplasma pneumoniae also cause?

Answer 26

Haemolytic anaemia Eyrthema multiforme

Question 27

Which pneumonia initiates as Q fever (flu-like fever)?

Answer 27

Coxiella burnetti

Question 28

Which pneumonia is often transmitter from birds?

Answer 28

Chlamydia psitacci

Question 29

How is Legionella pneumophila normally acquired?

Answer 29

Those who are immunocompromised Due to air conditioning/stagnant water in health patients

Question 30

What are the symptoms and effects of Legionella pneumophilla?

Answer 30

Produce flu like symptoms, i.e. dry cough, fever, diarrhoea May cause: - lymphopaenia - derranged LFT - hyponatraemia

Question 31

Where is Coxiella burnetti normally acquired from?

Answer 31

Animals

Question 32

What are the symptoms of Q fever?

Answer 32

A flu like fever - malaise - headache - joint pain - GI symptoms

Question 33

What can Coxiella burnetti progress to?

Answer 33

Atypical pneumonia Hepatitis Chronic endocarditis

Question 34

What can result from a pneumonia that causes cavitation?

Answer 34

Empyema Abcess

Question 35

What organism is likely for a pneumonia following infleunzae infection?

Answer 35

Staphylococcus aureus

Question 36

Which pneumonia organism presents with a currant jelly like sputum?

Answer 36

Klebsiella

Question 37

Which pneumonia organism presents with a copious green sputum?

Answer 37

Pseudomonas aeriginosa

Question 38

Which lobes is Chalmydia psitacci normally associated with?

Answer 38

Lower lobes

Question 39

Which lobes is E.coli normally associated with?

Answer 39

Lower lobes