Week 3 - Pathology of Respiratory Tract Infections Flashcards
What are some common URTI’s? (6)
coryza, sore throat syndrome, croup, laryngitis, sinusitis and acute epiglottitis
What are 3 common LRTI’s?
Bronchitis, bronchiolitis, pneumonia
What are 6 types of pneumonia?
CHIARA
- community acquired pneumonia
- hospital acquired pneumonia
- pneumonia in immunocompromised
- aspiration pneumonia
- recurrent pneumonia
- atypical pneumonia
What 3 aspects does that macrophage-mucociliary escalator system include?
alveolar macrophages, mucociliary escalator and cough reflex
What is bronchopneumonia vs lobar pneumonia?
bronchopneumonia affects patches throughout both lungs. Lobar pneumonia affects one or more lobes of the lungs
What is characteristic of bronchopneumonia?
pus accumulates in the lungs and alveoli in patchy/spotty pattern throughout the lung
How does pneumonia occur?
Microbe makes it past the resp. systems defence mechanisms and colonises the bronchioles or alveoli. This can infect lung tissue and cause an inflammatory response, causing an accumulation of neutrophils, exudate etc
What can cause pneumonia?
Bacteria, viruses, fungi
What are 3 common bacteria that cause pneumonia?
Staphylococcus aureus, streptococcus pneumoniae and haemophilus influenzae
What is a common virus that causes pneumonia?
influenza
What causes atypical pneumonia? why is it atypical?
bacteria with no cell wall. often cause vague symptoms like fatigue
What bacteria causes the vast majority of lobar pneumonia?
streptococcus pneumoniae
What is the pathogenesis of lobar pneumonia?
- bacteria invades lung.
- blood vessels and alveoli fill with fluid, causing pulmonary oedema.
- exudate of RBC’s, neutrophils and fibrin then fills alveoli and bronchi and make them more solid, like the liver.
- Then RBC’s disappear but neutrophils and fibrin persist and form grey solid lung.
What is the process of resolution of pneumonia?
enzymes digest and macrophages ingest exudate, and waste is coughed up or drained via lymph
What are 3 negative outcomes of pneumonia?
- Pleura becomes infected
- Organisation occurs leaving mass in lung
- Lung abscess occurs - necrosis
What is empyema?
accumulation of pus in pleural space due to bacteria getting in. occurs after lobar pneumonia - not bronchopneumonia
What is acute bronchitis caused by and features?
usually viral, 3 weeks or less. Bronchi becomes inflamed and swell and produce mucus, causing cough
What is bronchiectasis?
abnormal dilatation of bronchi caused by severe infection. bronchi has abnormal cilia and a lot of mucus
What causes bronchiectasis?
can be tuberculosis, cystic fibrosis
What are 3 causes of aspiration pneumonia?
- Vomiting while laying down
- Lesion in oesophagus
- Neuromuscular disorder leading to uncoordinated movement between epiglottis and swallow - food inhaled
What is the normal PaO2 and PaCO2?
PaO2 - 10.5-13.5kPa
PaCO2 - 4.8-6.0 kPa
Why could an individual have reccuring lung infections? (4)
Immunocompromised, general lung disease, pulmonary damage, bronchial obstruction
What is the PaO2 and PaCO2 in type 1 resp. failure??
PaO2 below 8.0kPa and PaCO2 normal or low
What is the PaO2 and PaCO2 in type 2 resp. failure??
PaO2 low and PaCO2 above 6.5kPa - high
What are the 2 main causes of type 1 respiratory failure?
ventilation perfusion mismatch and shunt
In which patients does shunt mostly occur?
severe bronchopneumonia or lobar pneumonia
What is shunt and why does it occur?
perfusion is greater than ventilation. Lobes or areas of lung are poorly ventilated due to “solid lung” or narrowing of airways. Deoxygenated blood returns to the heart
What 2 diseases are large causes of ventilation perfusion mismatch?
bronchopneumonia and bronchitis
Which bacteria (1) and viruses (4) commonly cause URTI?
bacteria - strep. pyogenes
viruses - influenza, parainfluenza, rhinovirus and Epstein-Barr virus
