Lower Resp tract infections

Question 1

Acute bronchitis is caused by which class of pathogens:
a) 90% of time?
b) 10% of time?

Answer 1

Acute bronchitis is caused by which class of pathogens:
a) 90% of time: Viral
b) 10% of time: bacterial

Question 2

Name 3 viruses that can cause acute bronchitis [3]
Name 2 bacteria that can cause acute bronchitis [2]

Answer 2

Viruses: Adenovirus, coronavirus, parainfluenza, influenza & rhinovirus
Bacteria: Bordetella pertussis & Mycoplasma pneumonia

Question 3

Whats the difference between bronchitis and bronchiolitis?

Answer 3

Severe bronchiolitis (children less than 2 yr): Respiratory Syncytial Virus

Question 4

Describe the pathophysiology behind acute bronchitis (e.g. caused by respiratory synctial virus)

Answer 4

Epithelial cells: 1st line of defence

RSV: binds and invades mucosal lining via epithelial cells

Epithelial cells switch on immune response after recognised through Toll-like receptor (TLR)-3 and retinoic acid-inducible gene (RIG)-I-like receptors

Cellular infection triggers the release of early inflammatory mediators (e.g.interferons (IFNs) and tumour necrosis factor (TNF)-α) and chemokines (e.g.CXCL8 and CXCL11).

A) Innate: Macrophages and Neutrophils, e.g. PMN polymorphonuclear leukocytes cells recruited PMNs)

B) Acquired: Dendritic cell, triggering B and T cells: CD4, CD8 and primed T cells

Question 5

Why is pneumonia a significant disease? [2]

Answer 5

Is responsible for more death in children under 5 than any other infectious disease [1]

Community acquired pneumonia (CAP) is the no. 1 cause of death due to infection in USA and EU [1]

Question 6

How do you distinguish between community acquired pneumonia (CAP) and hospital acquired pneumonia? [1]

Answer 6

Hospital acquired pneumonia is distinguished between CAP by the fact that hospital acquired pneumonia that occurs >48 h after hospital admission & no incubation at time of admission

Question 7

What is the definition of pneumonia? [1]

Which populations are most at risk of pneumonia? [1]

Answer 7

Pneumonia: inflammation of the alveoli in either one or both lungs: Alveoli become inflamed & fill up with sputum.

V. young and elderly are most at risk

Question 8

What is the most frequent causative agent of pneumonia? [1]

What is the second most frequent causative agent of pneumonia? [1]

Answer 8

Streptococcus pneumoniae= 50%

Haemophilus influenzae = 20%

Question 9

Describe the symptoms of pneumonia [4]

How long do pneumonia symptoms normally last? [1]

How long are daily activities normally impaired for? [1]

Answer 9

• headache
• fever
• weakness
• dry cough
• nasal congestion
• chills
• sweating
• muscle aches

Duration: 3-4 weeks

Impairment: Further 3 weeks

Question 10

Name the signs of pneumonia [4]

Name a complication that pneuomonia a risk factor for !!

Answer 10

Signs:
- Tachypnoea
- Tachycardia
- Hypoxia
- Hypotension
- Fever
- Confusion

Can lead to sepsis

Question 11

Explain the pathophysiology of pneumonia xx

Question 12

How can loss of barrier function in pneumonia lead to sepsis?

Answer 12

• Initially localised immune repsone becomes systemic
• Loss of barrier function between alveoli and capillaries may lead to spread of infection (sepsis) and systemic immune response.

Question 13

What does pneumonia appear like on CXR? [1]

Answer 13

Pneuomonia indicated by consolidation

Question 14

What investigations would you undertake to ID if Ptx has pneumonia? 6

Answer 14

• CXR: look for consolidation
• PCR to ID pathogen causing infection
• Urea and electrolytes informs severity
• C reactive protein
• FBC
• Liver functon tests

Question 15

How does CXR compare between acute bronchtits and pneumonia? [1]

Answer 15

Pneumonia: consolidation of the lung parenchyma

Acute bronchitis: appears normal

Question 16

How do you diagnose community acquired pneumonia (CAP) in:

• Primary care
• Secondary care

Answer 16

Primary care:
- symptoms & new focal chest signs on exam (new complaint less that 7 days old) & at least one systemic feature &or temp greature 38

Secondary care:
- Clinical symptoms & signs of a lower respiratory tract infection + chest-X-ray (consolidation)

Question 17

How do you assess severity of pneumonia in:

• community
• hospital

Answer 17

Community:
Use CRB65 severity score:
- Confusion
- Resp. rate greater than 30/min
- Blood pressure (SBP <90 or DBP < 60)
- Age <65

Hospital:
CURB severity score
Use CRB65 severity score:
- Confusion
- Urea
- Resp. rate greater than 30/min
- Blood pressure (SBP <90 or DBP < 60)
- Age <65

Question 18

Label the CRB severity scores xx

Answer 18

A: 0 = Low severity
B: 1-2 = Moderate severity
C: 3-4 = High severity

Question 19

Which drugs would you use to manage pneumonia for:

CRB Score 0
CRB Score 1-2
CRB Score 3-4

Answer 19

Always follow yourlocal area guidelines. These are developed by looking at the bacteria in the local area for theirantibiotic resistanceso are specific to that population.

CRB Score 0: Amoxicillin or Doxycycline or Clathromycin

CRB Score 1-2: Amoxicillin AND Clathromycin
OR
Doxycycline

CRB Score 3-4: Benzylpenicillin

Question 20

Why may doxycycline be preferred to amoxycillin as first line of treatment? [1]

Answer 20

Doxy has greater broad spectrum antibiotic than amoxy

Question 21

What are different methods for O2 delivery systems? [4]

Answer 21

In order of increasing concentrated oxygen therapy:

• Nasal cannuale
• Simple face mask
• Non-rebreather mask
• Venturi mask

Question 22

How do you diagnose acute bronchitis?

Answer 22

Diagnosis by exclusion:

• Cough >3 weeks
• If signs of consolidation (on CXR), airway obstruction, fever, increase RR, increase HR: NOT acute bronchitis
• If no: is there currently an outbreak of influenza pertusis (whooping cough)?
• If no: Acute bronchitis

Question 23

How do you treat acute bronchitis?

Answer 23

Self limiting: establish expectation of cough of 14 days

Encourage fluid intake. Explain lack of antiobiotic evidence

Recommend analgesics like paracetemol