Lower Respiratory Tract infections Flashcards
What are the 4 main categories of LRTIs and where do they affect?
1) Tracheitis (trachea)
2) Bronchitis (Bronchi or bronchioles)
3) Pneumonia (lung)
4) Abscesses (lung)
What are the 3 main types of bronchitis?
1) Acute bronchitis
2) Chronic bronchitis
3) Bronchiolitis
What are the 4 main types of pneumonia?
1) Community aquired (CAP)
2) Hospital aquired (HAP)
3) Ventilator aquired (VAP)
4) Aspiration pneumonia
Give the 6 main predisposing factors for LRTIs?
1) Loss or suppression of cough reflex/swallow eg. stroke, coma ventilation
2) Ciliary defects eg. primary ciliary dyskinesia
3) Mucous disorders eg. CF
4) Pulmonary oedema - fluid flooding alveoli, provides good environment for infection eg. congestive HF
5) Immunodeficiency: congenital or aquired
6) Macrophage function inhibition eg. Smoking
What 2 main types of organisms cause LRTIs?
Bacteria and Viruses
Do fungi commonly cause LRTIs?
Not in healthy people
Fungi only tend to cause LRTIs in immunosuppressed patients
Which 8 bacteria commonly cause LRTIs?
1) Strep pneumoniae
2) Haemophilus influenxa
3) Staph aureus
4) Klebsiella pneumoniae
5) Mycoplasma pneumoniae
6) Chlamydophilia pneumoniae
7) Legionella pneumophilia
8) Mycobacterium TB
Which 4 viruses commonly cause LRTIs?
1) Influenza
2) Parainfluenza
3) Respiratory syncitial virus
4) Adenovirus
What 3 fungi can cause LRTIs, normally in immunocomprimised patients?
1) Aspergillus sp.
2) Candida sp.
3) Pneumocystitis jiroveci
What is acute bronchitis?
Inflammation and oedema of trachea and bronchi - mediated by an infective cause
What are the 4 common symptoms of acute bronchitis?
1) Cough (typically dry)
2) Dyspnoea
3) Tachypnoea
4) Cough may be associated with retrosternal pain (due to inflammation)
When does acute bronchitis most commonly occur and in who?
Most frequent in winter, commonly in children
What are the usual cause of acute bronchitis?
Viruses - bacterial causes are less common (h. influenza, m. pneumoniae and B. pertussis)
What procedures are usually involved in the diagnosis of acute bronchitis?
- Diagnostic tests are not indicated in mild presentations
- Vaccination and previous infection history can help determine the organism causing the infection
- If needed can do cultures of respiratory secretions to look for specific cause although this is uncommon
What is the treatment for acute bronchitis?
- Supportive for healthy patients
- People with severe disease or co-morbidities may need O2 therapy or even ventilation
- Abx would only be used if bacterial cause is found
What is the definition of chronic bronchitis?
Cough production of sputum on most days for 3 months if 2 successive years, which cannot be attributed to an alternative cause
In what group is chronic bronchitis most common?
Males >40
What are the main 3 risk factors for chronic bronchitis?
1) Smoking
2) Pollution
3) Antigens
Other than the length of symptoms what is the main difference in pathology between chronic and acute bronchitis?
The inflammation and oedema in chronic bronchitis is mediated by exogenous irritants rather than infective agents
But patients with chronic bronchitis can have exacerbations mediated by the same pathogens which cause acute bronchitis
Bronchiolitis commonly occurs in which group of patients?
Infants 2-10 months
What is bronchiolitis?
Inflammation and oedema of the bronchioles
What is the most common cause of bronchiolitis?
Respiratory syncitial virus (75% of cases) but can also be caused by parainfluenza, adenovirus and influenza
What are the 4 main symptoms of bronchiolitis?
1) Acute onset wheeze
2) Cough
3) Nasal discharge
4) Respiratory distress (grunting, retractions, nasal flaring)
What 3 procedures would be involved in a diagnosis of bronchiolitis?
1) Chest x-ray
2) Full blood count
3) Microbiological diagnosis - Viral PCR of nasopharyngeal aspirate