Fever and Cough: Pneumonia

Question 1

Bronchitis vs pneumonia

Answer 1

Bronchitis: Viral infection of bronchi. Can cause V/Q mismatch, will not really cause breathlessness and hypoxia. No antibiotics
Pneumonia: Infection of terminal bronchioles and lower, most commonly caused by strep pneumoniae

Question 2

Clinically differentiate bronchitis and pneumonia

note that pneumonia is a systemic illness in the elderly

Answer 2

In children with pneumonia, effected side will not rise.
Listen to lungs, percuss the chest
History of respiratory distress/ shortness of breath
can chest x ray

Question 3

Pneumonia risk factors

Answer 3

Age <2 or >65
Chronic lung disease
Smoking
Immune dysfunction (innate immnity in lungs includes cilia, nasal secretions, goblet ells, macrophages, neutrophils etc)

Question 4

Common respiratory infections and viral vs bacterial aetiologies

Answer 4

otitis media 1/3 bacterial
Mastoiditis bacterial
sinusitis 1/2 bacterial
pharyngitis 2/3 viral 1/3 bacterial
epiglottitis bacterial
croup viral
bronchitis viral
pneumonia bacterial

Question 5

Microbial causes and percentages of pneumonia

Answer 5

Streptococcus pneumoniae: 60-75%
Hameophilus influenzae: 5-10%
Staphylococcus aureus: 1-5%
Gram -ve bacilli, such as enterococcus: rare, <1%?
Legionella: 2-5%
Mycoplasma pneumoniae: 5-18% (meta analysis 1%)
Chlamydophila pneumonia: about 1%?
Viral: 8-16% (meta analyses 3%)

Question 6

Streptococcus pneumoniae features

Answer 6

Alpha haemolytic
viridans group colonising 10% of adults, more in children (20-40%).
Prevalence of colonisation increases in winter in nasopharynx

Question 7

Pneumococcal virulence features

Answer 7

• Capsule: prevents phagocytosis and complement
• Pneumococcal surface protein A binds to epithelial cells and prevents C3b binding (opsonisation)
• PspC prevents no complement activation
• Choline binding protein binds to Ig receptor on epithelial cell, allowing transport into
• Pneumolysin: lyses neutrophils and epithelial cells
• pilli contribute to colonisation and cytokine (TNF a) production

Question 8

Investigations and management of pneumonia

kidney function?

Answer 8

• CXR first line, if negative no antibiotics
• Sputum culture: yield dependent on sample
• Nasopharyngeal swab: if admitted- viral PCR, if positive stop antibiotics
• if admitted, yield low
• Urine ICT- if admitted moderate yield for Strep pneumoniae, lower for legionella
• serology
• CT chest/bronchoscopy

Question 9

Treatment of pneumonia

Answer 9

Antibiotics required, reduces duration of illness and risk of death

Question 10

Antibiotics and strep pneumoniae

Answer 10

• Penicillin resistance is increasing due to altered traspeptidase, less penicillin binds
• Oral dosing may be inadequate, IV dosing okay. Important consideration when treating meningitis by s. pneumoniae would IV
• penicillin resistance associated with resistance to other antibiotics.

Question 11

Macrolides

Answer 11

Ribosome targets
Are broad spectrum
Limited activity against gram -ve bacteria
Active against streptococci, staphylococci and other pneumonia causes (used in skin infection when allergic to penicillin)
Treatment of chlamydia

e.g erythromycin, azithromycin and clarithromycin

Question 12

Adverse effects of macrolides

Answer 12

GIT upset, erythromycin agonist of motilin receptor
Sudden death
drug interactions

Question 13

If very sick in ICU treat pneumonia with what?

Answer 13

Augmentin(amoxycillin + clavulanic acid) IV plus erythromycin IV

for healthcare associated pneumonia, IV cefuroxime + IV gentamicin