lower respiratory tract infection

Question 1

what part of the airway is the lower airway?

Answer 1

from trachea downwards

Question 2

name common LRTIs?

Answer 2

bronchitis, bronchiolitis, pneumonia, influenza

Question 3

what pathogen commonly causes LRTIs?

Answer 3

bacteria or virus

Question 4

in what % of acute bronchitis is the cause identified?

Answer 4

> 30% of cases

Question 5

what % of cases of acute bronchitis are viral and bacterial?

Answer 5

90% of cases = viral, 10% = bacterial

Question 6

how long is acute bronchitis symptomatic for?

Answer 6

up to 2 weeks

Question 7

what viruses can cause acute bronchitis?

Answer 7

adenoviruses, coronavirus, parainfluenza, influenza and rhinovirus

Question 8

what bacteria cause acute bronchitis?

Answer 8

Bordetella pertussis & Mycoplasma pneumonia

Question 9

what causes severe bronchiolitis?

Answer 9

Respiratory Syncytial Virus

Question 10

what are symptoms of acute bronchitis?

Answer 10

sore throat, fatigue, stuff or runny nose, fever, body aches, vomiting, diarrhoea

Question 11

what is the pathophysiology of acute bronchitis?

Answer 11

• RSV infects host cells – activates innate and adaptive response
• Viral RNA is recognised by TLRs and RIG-I-like receptors
• Triggers release of early inflammatory mediators e.g. IFNs , TNF-a and chemokines (CXCL8 and CXCL11)
• NK cells, PMNs, macrophages release cytokines
• Dendritic cells present to T cells  B cells  antibodies
• T cells also activate eosinophils which release cytokines

Question 12

what do IFNs do?

Answer 12

upregulate pro-apoptotic factors in epithelial cells)

Question 13

what does TNF-a and chemokines do?

Answer 13

recruit NK cells and polymorphonuclear leukocytes (PMNs) -kill infected cells and limit viral replication

Question 14

how can you prevent acute bronchitis?

Answer 14

• Avoid contact with viral particles
• Wash hands frequently
• Avoid touching your eyes with contaminated hands
• Use disposable tissues
• Use hand sanitisers to stop spread of germs
• Avoid touching your nose

Question 15

how do you manage acute bronchitis?

Answer 15

• encourage increased fluid intake, humidity

- recommend antipyretics, analgesics and antitussives for symptom relief

Question 16

define pneumonia?

Answer 16

inflammation of the alveoli in either one or both lungs

become inflamed and fill up with fluid

Question 17

what’s the most common causative agent to cause pneumonia?

Answer 17

Strep. Pneumoniae

Question 18

which groups of people are most at risk of pneumonia?

Answer 18

elderly and the very young

Question 19

what % of S. pneumoniae are resistant to penicillin and macrolides?

Answer 19

Penicillin (10%) & Macrolides (15%)

Question 20

how long does it usually take pneumonia symptoms to resolve without complications?

Answer 20

4-7 days

Question 21

what can complicate the duration for which pneumonia symptoms take to resolve?

Answer 21

Primary influenza pneumonia/secondary bacterial pneumonia can complicate this

Question 22

what are the symptoms of pneumonia?

Answer 22

headache, fever, weakness, dry cough, nasal congestion, chills, sore throat, sweating, muscle aches

Question 23

how long do pneumonia symptoms last?

Answer 23

3-4 weeks

Daily activities impaired for a further 3 weeks

Question 24

what is the pathophysiology of pneumonia?

Answer 24

• Pneumonia (direct injury) → Inflammation → Innate immunity →Alveolar injury/dysfunction
• Invasion & overgrowth of a pathogenic microorganism in the lung parenchyma → intra-alveolar exudates → Pneumonia

Question 25

what diagnosis methods are used for pneumonia?

Answer 25

• Physical exam
• Complete blood count
• Sputum culture
• Urine test
• PCR
• CT scan
• Chest x-ray – right lower lobe consolidation with mid-zone changes

Question 26

how is CAP diagnosed in secondary care?

Answer 26

clinical symptoms + signs of a LRTI + CXR (consolidation

Question 27

how is CAP diagnosed in primary care?

Answer 27

Symptoms + New focal chest signs on examination + At least one systemic feature (fevers, sweats, rigors and/or a temperature of ≥38oC)
o CXR not usually available in a primary care setting

Question 28

what is the criteria of the CRB65 severity score?

Answer 28

o Confusion
o Respiratory Rate > 30/min
o Blood pressure (SBP <90 or DBP <60)
o Age > 65 years

Question 29

what treatment should be given for each range of scores of the CRB severity score?

Answer 29

• 0 – low severity. Likely suitable for home treatment. Give antibiotics as per the table.
• 1-2 – moderate severity. Consider hospital referral
• 3-4 – high severity. Urgent hospital admission. Empirical antibiotics if life-threatening

Question 30

what are the main causes of early treatment failure in pneumonia?

Answer 30

• Sepsis and cardiovascular complications

Question 31

how can you prevent pneumonia?

Answer 31

• Routine immunisations, including pertussis, measles and Hib
• Pneumococcal vaccinations
• Exclusive breastfeeding for the first 6 months
• Safe drinking water, good sanitation and frequent hand washing with soap
• Good nutrition esp for children over 6 months of age
• Improve indoor air quality
• Recognising danger signs of pneumonia and seek care quickly

Question 32

what are the clinical parameters for severe pneumonia in a baby less than 2 months of age?

Answer 32

RR >60/min and/or lower chest wall in-drawing

Question 33

what are the clinical parameters for very severe pneumonia in a baby less than 2 months of age?

Answer 33

any of the below;

• central cyanosis
• not able to drink
• head nodding

Question 34

what are the clinical parameters for pneumonia in children 2-60 months?

Answer 34

RR >50/min for 2-11 months

RR > 40/min for 12-60 months

Question 35

what are the clinical parameters for severe pneumonia in children 2-60 months?

Answer 35

lower chest wall in-drawing

Question 36

what are the clinical parameters for very severe pneumonia in children 2-60 months?

Answer 36

central cyanosis
unable to drink
head nodding