Respiratory Infections Flashcards
How common are respiratory tract infections?
They are the most common source of childhood infections
Give 6 examples of respiratory tract infections?
- Otitis media
- Nasopharyngitis
- Tonsillitis
- Sinusitis
- Bronchiolitis
- Pneumonia
What is the most common virus causing respiratory tract infections?
Rhinovirus
What kind of virus is rhinovirus?
Small RNA virus (picornavirus)
What is the most common cause of bronchiolitis?
RSV
Is pneumonia bacterial or viral?
Can be either, can can involve multiple viruses or viral/bacterial co-infection
Give 2 examples of seasonal pathogens
- RSV
- Influenza
When was routine seasonal influenza vaccination for younger children introduced?
In 2013
How do respiratory infections usually begin?
With invasion of the pathogen in the nasopharynx
What does the initial local immune response to a pathogen invading the nasopharynx involve?
An influx of neutrophils and cytokine secretion, in particular IL-8, IL-1ß, and IL-6
What does an influx of neutrophils and cytokine secretion in the nasopharynx lead to?
Coryzal symptoms
When might a pathogen invading the nasopharynx spread?
- If organism is particularly virulent
- If organism expresses appropriate surface molecules for receptors found elsewhere in the respiratory tract
- If there is an absence of systemic or mucosal immunity to the organism
What are the categories of pulmonary defences?
- Physical
- Immune
What are the physical respiratory defences?
- Nasal hairs
- Humidification
- Mucus
- Cilia
How does the alveolar fluid aid in the immune response?
It contains antimicrobial compounds such as surfactant, complement, and lysozyme
What immunoglobulin plays a major role in protection of the upper airway?
IgA
What is the result of IgA having a major role in the protection of the upper airway?
Children with IgA deficiency have increased respiratory infections
How long does a common cold usually take to resolve?
10-14 days
How are most viral respiratory tract infections managed?
Only supportive therapy
What can bacterial otitis media rarely progress to?
Mastoiditis and possibly meningitis
What can sinusitis develop into?
Periorbital or orbital cellulitis, and then intra-cranial infection if untreated
What can bacterial pneumonia be complicated by?
- Bacteraemia
- Empyema
- Necrotising pneumonia
- Lung abscesses
What is the result of the potentially severe consequences of bacterial infections?
It is important to differentiate between bacterial and viral infections
Why is it difficult to differentiate bacterial respiratory infections from viral?
- Difficulty of obtaining sterile samples from the respiratory tract
- Presence of potential pathogens in the nasopharynx of healthy children
