Infectious causes of Pneumonia Flashcards
What would a patient with a typical pathogen pneumonia present like?
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
What are the typical pathogens of pneumonia?
Streptococcus penumoniae (Pneumococcus) - gram +ve (>50%)
Haemophilus influenza
- gram -ve (5%)
What type of bacteria is Streptococcus pneumoniae (pneumococcus)?
Gram +ve
Describe the distinct characteristics of Haemophilus influenza?
Gram -ve bacillus
Common cause of bronchiectasis exacerbations
Can be diffuse or contained to one lobe
What would a patient with an atypical pathogen pneumonia present like?
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
What are the atypical pathogens of pneumonia?
Mycoplasma pneumoniae
Chlamydia pneumoniae
Legionella Pneumophila
Coxiella burnetti
Chlamydia psitacci
What type of bacteria is Mycoplasma pneumoniae?
Atypical bacterial with no cell wall
What type of bacteria is Chlamydia pneumoniae?
Obligate intracellular bacterium
What type of bacteria is Legionella pneumophila?
Gram -ve bacteria
What type of bacteria is Coxiella burnetti?
Gram -ve bacteria (small)
What type of bacteria is Chlamidiya psittaci?
Obligate intracellular bacterium
Describe the distinct characteristics Chalmydia psitacci
An obligate intracellular bacterium
Often transmitted from birds
Prefers lower lobes
Describe what is meant by a hospital acquired pneumonia (HAP)?
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
What three things can increase the risk of aquiring a HAP?
Immunocompromised
Previous viral infection
Ventilated
What are the most common HAP organisms?
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)
Describe the distinct characteristics Staphylococcus aureus
Usually a HAP
Often follows influenza infection
- presents with pneumonia, pleuritic chest pain +/- haemoptysis
Produces cavitation - empyema and abcess develop
Describe the distinct characteristics klebsiella
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
Describe the distinct characteristics E-coli
Usually affects immunocompromised
- often develops from aspiration or UTI
Lower lobes usually
Describe the distinct characteristics Pseudomonas aeriginosa
Usually affects hospitalised or immunocompromised
Gradual onset with copious green sputum
Describe who pneumocystis normally affects?
Immunocompromised
- AIDS sufferers
- rare infection
Where does streptococcus pneumoniae live?
Respiratory tract and multiplies rapidly
Is streptococcus a lobar or diffuse pneumonia?
Lobar pneumoniae
Describe the sputum of a Streptococcus pneumoniae?
Rusty coloured sputum - classically
What virus is associated with Streptococcus pneumoniae?
Herpes Labialis - cold sores
How sudden and severe can Mycoplasma pneumoniae present?
Slow progressiong
Mild-moderate pneumonia
Flu-like symptoms followed by a dry cough
What can Mycoplasma pneumoniae also cause?
Haemolytic anaemia
Eyrthema multiforme
Which pneumonia initiates as Q fever (flu-like fever)?
Coxiella burnetti
Which pneumonia is often transmitter from birds?
Chlamydia psitacci
How is Legionella pneumophila normally acquired?
Those who are immunocompromised
Due to air conditioning/stagnant water in health patients
What are the symptoms and effects of Legionella pneumophilla?
Produce flu like symptoms, i.e. dry cough, fever, diarrhoea
May cause:
- lymphopaenia
- derranged LFT
- hyponatraemia
Where is Coxiella burnetti normally acquired from?
Animals
What are the symptoms of Q fever?
A flu like fever
- malaise
- headache
- joint pain
- GI symptoms
What can Coxiella burnetti progress to?
Atypical pneumonia
Hepatitis
Chronic endocarditis
What can result from a pneumonia that causes cavitation?
Empyema
Abcess
What organism is likely for a pneumonia following infleunzae infection?
Staphylococcus aureus
Which pneumonia organism presents with a currant jelly like sputum?
Klebsiella
Which pneumonia organism presents with a copious green sputum?
Pseudomonas aeriginosa
Which lobes is Chalmydia psitacci normally associated with?
Lower lobes
Which lobes is E.coli normally associated with?
Lower lobes
