Respiratory tract infections

Question 1

Most likely causative organism of pneumonia

Answer 1

Strep pneumonia (30-40% CAP)

Question 2

Ager of prevalence of pneumonia organisms

Answer 2

• 0-1 months  Escherichia coli, Group B Streptococcus, Listeria monocytogenes
• 1-6 months  Staphylococcus aureus, RSV
• 6 months - 5 years  Mycoplasma pneumoniae, Influenza
• 16-30 years  Mycoplasma pneumoniae

Question 3

Cause of atypical CAP

Answer 3

o	Legionella
o	Mycoplasma
o	Coxiella burnetii (Q fever) from exposure to farm animals 
	Hepatitis 
o	Chlamydia psittaci (birds)

Question 4

CURB65 score and management

Answer 4

• Confusion 2 = consider admitting
• Urea > 7 mmol/L 2-5 = manage as severe / consider ITU
• RR > 30
• BP < 90 systolic, < 60 diastolic
• 65+ years

Question 5

Organisms that cause cavitation

Answer 5

o Staphylococcus aureus
o Klebsiella pneumoniae
o Haemophilus influenzae
o TB

Question 6

H. influenza features

Answer 6

o Gram-negative cocco-bacilli (stain on chocolate agar)
o 15-35% of CAP
o More common with pre-existing lung disease
o May produce beta-lactamase

Question 7

Extra features of atypical pneumonia

Answer 7

o Extra-pulmonary features (e.g. hepatitis, hyponatraemia) – characteristic of atypical pneumonias
o Often have a flu-like prodrome before fever and pneumonia

Question 8

ABx for atypical pneumonia

Answer 8

Macrolides

Question 9

How coxiella burnets is spread

Answer 9

o Common in domesticated farm animals

o Transmitted by aerosol or milk

Question 10

Symptoms of Legionella and investigations

Answer 10

 Confusion Abdominal pain Diarrhoea
 Lymphopaenia Hyponatraemia
Ix: urinary antigens

Question 11

Signs of empyema

Answer 11

Continued to spike fevers even on ABx- due to wall around them
Homogenous shadowing with meniscus level of right side on CXR

Question 12

Staining of TB

Answer 12

 An auramine stain and a Ziehl-Neelsen stain will be done

 Red rods are the acid-fast bacilli

Question 13

Aetiology fo HAP

Answer 13

Enterobacteriaciae (e.g. E. coli, K. pneumoniae) – 31%	
Staphylococcus aureus – 19%
Pseudomonas spp – 17%					
Haemophilus influenzae – 5%
Acinetobacter baumanii – 4%				
Fungi (Candida spp) – 7%

Question 14

Clues for TB

Answer 14

o Clues  Ethnicity, Prolonged prodrome, Fevers, Weight loss, Haemoptysis
o CXR  classically upper lobe cavitation (but can vary)

Question 15

Pneumocystis jirovecii Pneumonia CXR

Answer 15

Bilateral ground-glass shadowing (“bat’s wing”)

Question 16

Investigation and treatment of PJP

Answer 16

• Investigations: bronchoalveolar lavage
• Treatment: co-trimoxazole (septrin)
• Prophylaxis: co-trimoxazole

Question 17

Types of aspergillum fumigates infections and features

Answer 17

o Allergic bronchopulmonary aspergillosis
 Chronic wheeze
 Eosinophilia
 Bronchiectasis

o Aspergilloma
 Fungal ball, often in pre-existing cavity
 May cause haemoptysis

o Invasive aspergillosis
 Immunocompromised
 Treatment: amphotericin B

Question 18

Types of immunosuppression and LRTI associations

Answer 18

o HIV  PCP, TB, Atypical mycobacteria
o Neutropoenia  Fungi (e.g. Aspergillus spp)
o Bone Marrow Transplant  CMV
o Splenectomy  Encapsulated organisms (S. pneumoniae, H. influenzae, malaria)

Question 19

CAP AB therapy

Answer 19

 Mild-Moderate: Amoxicillin [OR erythromycin/clarithromycin]

 Moderate-Severe
• Needing hospital admission: Co-amoxiclav (augmentin) AND clarithromycin
• Allergic: Cefuroxime AND clarithromycin

Question 20

HAP AB therapy

Answer 20

 1st Line  Ciprofloxacin ± vancomycin

 2nd Line/ITU  Piptazobactam AND vancomycin
 Specific Therapy:
• MRSA: Vancomycin
• Pseudomonas: Piptazobactam OR ciprofloxacin