lower respiratory tract infection Flashcards
what part of the airway is the lower airway?
from trachea downwards
name common LRTIs?
bronchitis, bronchiolitis, pneumonia, influenza
what pathogen commonly causes LRTIs?
bacteria or virus
in what % of acute bronchitis is the cause identified?
> 30% of cases
what % of cases of acute bronchitis are viral and bacterial?
90% of cases = viral, 10% = bacterial
how long is acute bronchitis symptomatic for?
up to 2 weeks
what viruses can cause acute bronchitis?
adenoviruses, coronavirus, parainfluenza, influenza and rhinovirus
what bacteria cause acute bronchitis?
Bordetella pertussis & Mycoplasma pneumonia
what causes severe bronchiolitis?
Respiratory Syncytial Virus
what are symptoms of acute bronchitis?
sore throat, fatigue, stuff or runny nose, fever, body aches, vomiting, diarrhoea
what is the pathophysiology of acute bronchitis?
- 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
what do IFNs do?
upregulate pro-apoptotic factors in epithelial cells)
what does TNF-a and chemokines do?
recruit NK cells and polymorphonuclear leukocytes (PMNs) -kill infected cells and limit viral replication
how can you prevent acute bronchitis?
- 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
how do you manage acute bronchitis?
- encourage increased fluid intake, humidity
- recommend antipyretics, analgesics and antitussives for symptom relief
define pneumonia?
inflammation of the alveoli in either one or both lungs
become inflamed and fill up with fluid
what’s the most common causative agent to cause pneumonia?
Strep. Pneumoniae
which groups of people are most at risk of pneumonia?
elderly and the very young
what % of S. pneumoniae are resistant to penicillin and macrolides?
Penicillin (10%) & Macrolides (15%)
how long does it usually take pneumonia symptoms to resolve without complications?
4-7 days
what can complicate the duration for which pneumonia symptoms take to resolve?
Primary influenza pneumonia/secondary bacterial pneumonia can complicate this
what are the symptoms of pneumonia?
headache, fever, weakness, dry cough, nasal congestion, chills, sore throat, sweating, muscle aches
how long do pneumonia symptoms last?
3-4 weeks
Daily activities impaired for a further 3 weeks
what is the pathophysiology of pneumonia?
- Pneumonia (direct injury) → Inflammation → Innate immunity →Alveolar injury/dysfunction
- Invasion & overgrowth of a pathogenic microorganism in the lung parenchyma → intra-alveolar exudates → Pneumonia
what diagnosis methods are used for pneumonia?
- Physical exam
- Complete blood count
- Sputum culture
- Urine test
- PCR
- CT scan
- Chest x-ray – right lower lobe consolidation with mid-zone changes
how is CAP diagnosed in secondary care?
clinical symptoms + signs of a LRTI + CXR (consolidation
how is CAP diagnosed in primary care?
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
what is the criteria of the CRB65 severity score?
o Confusion
o Respiratory Rate > 30/min
o Blood pressure (SBP <90 or DBP <60)
o Age > 65 years
what treatment should be given for each range of scores of the CRB severity score?
- 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
what are the main causes of early treatment failure in pneumonia?
• Sepsis and cardiovascular complications
how can you prevent pneumonia?
- 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
what are the clinical parameters for severe pneumonia in a baby less than 2 months of age?
RR >60/min and/or lower chest wall in-drawing
what are the clinical parameters for very severe pneumonia in a baby less than 2 months of age?
any of the below;
- central cyanosis
- not able to drink
- head nodding
what are the clinical parameters for pneumonia in children 2-60 months?
RR >50/min for 2-11 months
RR > 40/min for 12-60 months
what are the clinical parameters for severe pneumonia in children 2-60 months?
lower chest wall in-drawing
what are the clinical parameters for very severe pneumonia in children 2-60 months?
central cyanosis
unable to drink
head nodding
