Pneumonia

Question 1

What is pneumonia?

Answer 1

When bacteria reach the alveoli, replicating and destroying alveolar tissue resulting in an immune response and fluid buildup in the lungs.

Question 2

What are the 3 ways bacteria can enter the alveoli?

Answer 2

Aspiration (Most common)
- Microaspiration: Bacteria colonise oropharynx and trickle down into lungs
- Macroaspiration: Food or vomitus is inhaled into lungs

Direct inhalation (Less common)

Bloodborne (Very rare)
- Enter through alveolar capillaries in bacteraemic patient
- Can be caused by staphylococcus aureus

Question 3

What is the most common cause of pneumonia?

Answer 3

Streptoccocus pneumoniae

Question 4

What virulence factors does streptococcus pneumoniae have to aid in its infection?

Answer 4

Pneumolysin (A cytolysin)
- Attacks and lyses alveolar cells and alveolar macrophages

Capsule
- Allows evasion from phagocytes in the absence of antibodies that bind to the capsule

Question 5

What is the fluid buildup in the lungs of a pneumonia patient?

Answer 5

Cytoplasmic contents and debris of dying cells/bacteria plus fluid from alveolar capillaries containing complement and antibodies

Question 6

What are the symptoms of pneumonia?

What can untreated pneumonia progress to?

Answer 6

• Coughing with sputum
• Shortness of breath

Untreated pneumonia can progress to bacteraemia and infection of other areas (e.g. causing bacterial meningitis)

Question 7

What tests can diagnose pneumonia?

Answer 7

• X-rays will show fluid pooling at the bottom of the lungs
• Crackling will be heard when auscultating the lower lobes
• Dullness will be heard while percussing the lower lobes
• +ve gram stain from sputum sample

Question 8

What is the treatment for pneumonia?

Answer 8

• Oxygen therapy
• Anti-streptococcal antibiotics (Amoxicillin, clindamycin, erythromycin)