LRTI I Flashcards
Bronchitis epidemiology
Characterised by emporary (self-limited) inflammation of the large and mid-sized bronchial tubes.
There is season variation with the peak incidence in winter, and where influenza (outbreak?) is present in the community.
Risk factors for bronchitis
- Age (children <5 years of age; and the elderly)
- Underlying disease (ie. chronic obstructive pulmonary disease [COPD], asthma(
- Exposure to second hand smoke
Bronchitis microbiology
Viral
- Influenza virus
- Rhinovirus
- Adenovirus
- Respiratory synctial virus (RSV)
- Parainfluenza virus
- Human metapneumovirus
Bacterial (10% of cases)
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- *Bordatella pertussis *(rare cases)
Pathophysiology of bronchitis
A virus(es) replicating in the epithelial cells of the upper respiratory tract can spread to the lower airways resulting in:
- Inflammation of the bronchial/bronchiolar epithelia (ie. infiltartion of mononuclear cells)
Necrotic epithelia sloughed off into the lumina of the airways, together with inflammation and increase mucus production and oedema, can cause obstruction characterised by ‘wheezing’
Clinical manifestations of bronchitis
Symptoms usually begin with common cold syndrome:
- Nasal congestion, rhinitis, sore throat and general malaise
- Low grade fever (37.5-38)
- Cough (dry at first/becomes productive [white; green; yellow sputum])
- Wheezing
- Symptoms and signs usually resolve over 7-10 days for otherwise healthy person
Bronchitis diagnosis
Made on clinical presentation; suspected in any person with acute respiratory illness where cough is the dominant symptom.
Bronchitis differential diagnosis
Pertussis (whooping cough)
Pneumonia (ie CXR with signs of infiltrates/consolidation)
Chronic obstructive pulmonary disease (COPD); asthma
Bronchitis treatment
Supportive therapy: adequate hydration; cough suppressants; decongestants; antihistamines
Bronchiolitis epidemiology
Described inflammation of the smaller air passages, bronchioles of the lung.
Season occurence: peak incidence is during winter to early spring; usually correlates with the prevalence of RSV in the community.
More common during the first year of life
- Each year 1-3% of infants <12 months are hospitalised with bronchiolitis, in 80% of these cases the infants are <6 months of age
- More common in boys
- Children with chronic underlying conditions (i.e. cardiopulmonary function decline)
Bronchiolitis risk factors
- Young maternal age
- Lower cord blood antibody titres to RSV
- Lower socioeconomic status
- Crowded living conditions
- Bottle feeding
- Tobacco-smoke exposure
Bronchiolitis microbiology
Virus
- RSV
- Rhinovirus
- Influenza
- Parainfluenza
- Adenovirus
- Bocavirus
- Non-SARS coronaviruses
Bronchiolitis clinical manifestations
Prodrome (range 2-7 days) of signs of URTI
- Coryza
- Cough
- Fever (usually mild)
Followed by:
- Wheezing
- Dyspnoea
- Dehydration (due to coughing spasm associated vomiting/poor oral intake)
- Recovery usually over a period of 1-2 weeks
Diagnosis of bronchiolitis
Based on child’s history and physical examination
Usually suspected in children <2 years of age with:
- Cough
- Wheezing
- Increased respiratory effort
Differential dianosis of bronchiolitis
Usually broad and includes:
- obstruction of airways by foreign bodies
- Retropharyngeal abscess
- Cystic fibrosis
- Congestive heart failure
Treatment of bronchiolitis
- Supportive care for outpatient and inpatient
- Maintain comfort and hydration
- Treat for fever where necessary
