Pneumonia SR

Question 1

Features of pneumonia in the elderly

Answer 1

RR increase
crackles
consolidation
fevers/chills

*lower areas of lung

Question 2

Bacteria with capsules (can’t be phagocytosed)

Answer 2

Streptococcus pneumoniae 
Staphylococcus aureus 
Haemophilus influenzae 
Neisseria meningitidis 
Escherichia coli

Question 3

Common causes of pneumonia

Answer 3

Streptococcus pneumoniae 
Haemophilus influenzae 
Staph aureus
Enterobacteriaceae
Legionella pneumophila 
(rare) Mycoplasma pneumoniae 
Chlamydophilia pneumoniae
Aspiration
Influenza viruses

Question 4

Features of strep pneumoniae

Answer 4

1. alpha-haemolytic streptococcus

2. colonizes nasopharynx of 5-10% of adults, 20-40% of children

Question 5

Pneumococcal virulence

Answer 5

1. pneumococcal surface protein A - binds to epithelial cells and also prevents deposition of C3b
2. PspC prevents activation of complement cascade
3. pili contribute to colonisation and cytokine production (TNFa) during invasion
4. choline binding protein - binds Ig receptor on epithelial cells to allow transport into cell
5. pneumolysin (toxin) lyses neutrophils and epithelial cells
6. polysaccharide capsule prevents phagocytosis and complement deposition

Question 6

Pneumonia investigations

Answer 6

1. PRIMARY CXR
(if none no antibiotics)
2. Sputum culture
(only on admission)
3. Nasopharyngeal swab
(if admitted) - if viral shown on PCR stop antibiotics
4. blood cultures 
5. urine ICT (immunochromatographic test)
6. serology
7. CT chest/ bronchoscopy

Question 7

Treatment

Answer 7

1. Antibiotics! reduce duration of illness and risk of death

• Penicillin resistance is increasing - mediated by altered PBP/transpeptidace which reduces penicillin binding affinity
• *oral dosing inadequate. IV dosing okay - important in treating menigitis caused by s. pn
• **penicillin resistance is associated with resistance to other antibiotics - quinolones, recently developed macrolides, ketolides

Question 8

Ribosome targets

Answer 8

50S transpeptidation -
1. macrolides eg erythromycin A, azithromycin, clarithromycin,

(broad spectrum, limited activity against gram negative bacteria, active against streptococci, staphylococci and other causes of pneumoniae, tratment of chlamydia)

2. lincosamides

50S peptidyl transferase - chloramphenicol

30S initiation - aminoglycosides

30S tRNA binding - tetracyclines

Question 9

Macrolides adverse effects

Answer 9

GIT upset
Sudden death
drug-drug interactions

Question 10

Empiric therapy

Answer 10

A medical term referring to the initiation of treatment prior to determination of a firm diagnosis.

Community acquired
Mild (can stay home) - doxycycline, amoxycillin 500mg tds

Moderate (often in hospital)
amoxycillin 1g oral/IV Q6H AND roxithromycin 300mg daily OR doxycycline 200mg on day 1 then 100mg daily

Very sick (ICU)
amoxycillin/clavulanic acid 1.2gm IV Q8H and erythromycin 1g IV Q6H or moxifloxacin 400mg IV daily

Health care associated pneumonia
cefuroxime 1.5gm IV Q8H +/- gentamicin IV daily

Question 11

Bronchitis

Answer 11

Viral illness
Antibiotics not beneficial
Treatment for cough include NSAIDS, sedating antihistamines, chlorpheniramine

1. Influenza
2. Adenovirus
3. other viruses
4. measles
5. bordetella pertussis
6. chlamydia/mycoplasma