Pathology of Respiratory Tract Infection (Pulmonary Infection) Flashcards
What are the factors that determine the effect an infection will have?
The micro-organism pathogenicity, patient’s ability to resist infection and the population at risk
What is the difference between primary, facultative and opportunistic pathogens?
Primary - would infect anyone
Facultative - need a pre-existing pathology
Opportunistic - need a reduction in the host’s ability to fight infection (immunosuppressed patients)
What effects a patients capacity to resist an infection?
Defence mechanisms. age, health and pathologies
What defence mechanisms does the respiratory tract have?
-Macrophage-mucociliary escalator
-Immune System
-Respiratory Tract Secretions
‘Filter’ of Upper Respiratory Tract
-Alveolar macrophages
-Cough reflex
Is the lower respiratory tract a sterile or non-sterile site?
Sterile
What are the two ways that particles can be cleared from the lungs?
Lymph nodes and the muco-ciliary escalator
What is the leading cause of death in patients with influenza?
Secondary bacterial infection
What is community acquired pneumonia?
The pneumonia is not acquired in a hospital setting
What is nosocomial pneumonia?
Pneumonia acquired in a hospital - micro-organism is much more likely to be resistant to antibiotics
What is atypical pneumonia?
Pneumonia caused by a rare or unusual organism
What is aspiration pneumonia?
Pneumonia secondary to inhaling gastric contents - quite common
What would recurrent pneumonia suggest?
That something is very wrong - especially if it always occurs in the same part of the lung
What is hypostatic pneumonia?
Pneumonia caused by a build up of secretions in the lung - common in the elderly and those who are bedridden etc.
What are the complications that can arise from pneumonia?
Pleurisy, pleural effusion, empyema, organisation, lung abscess and bronchiectasis
What is bronchiectasis?
Pathological dilatation of bronchi due to: severe infection, recurrent infection, proximal bronchial obstruction and lung parenchymal destruction
What are the signs and symptoms of bronchiectasis?
Cough, sputum, haemoptysis, course crackles and clubbing
What is the treatment of bronchiectasis?
Postural drainage, antibiotics and surgery
Name the aetiological classification of pneumonia
- Community acquired
- Hospital acquired
- Pneumonia in the immunocompromised
- Atypical
- Aspiration
- Recurrent
Name the features of bronchopneumonia
- Bilateral
- Patchy basal opacification
- Focal nature of consolidation
What are the potential causes of recurrent lung infection?
- Local bronchial obstruction (tumour, foreign body etc.)
- Local pulmonary damage (bronchiectasis)
- Generalised lung disease (CF, COPD)
- Non-respiratory disease (immunocompromised, aspiration etc.)
Name some of the potential causes of aspiration pneumonia
- Vomiting
- Oesophageal lesion
- Obstetric anaesthesia
- Neuromuscular disorders
- Sedation
Name the potential opportunistic infections
- Low grade bacterial pathogens
- CMV
- Pneumocystis jirovecii
- Other fungi and yeasts
What are the features of Type 1 respiratory failure
- PaO2 < 8 kPa
- PaCO2 normal or low
What are the features of Type 2 respiratory failure?
- PaCO2 > 6.5 kPa
- PaO2 usually low
Name the four abnormal states associated with hypoxaemia
- Ventilation/perfusion imbalance
- Diffusion impairment
- Alveolar hypoventilation
- Shunt
What is shunt?
- Blood passing from the right to the left side of the heart without contacting ventilated alveoli
- Normal is 2-4%
- Pathological in AV malformations, congenital heart disease and pulmonary disease
