Respiratory Tract Infections Flashcards
What is pneumonia?
Infection involving the distal airspaces (gas exchange region) of the lungs usually with inflammatory exudation and cellular infiltration.
These fluid filled spaces lead to consolidation.
What is an exudate?
Any fluid that filters from the circulatory system into lesions or areas of inflammation
What are the physical signs of consolidation within the lungs?
Changes in percussion
Changes in oscillation
What are the classifications of a pneumonia?
- By clinical setting
- By organism
- By morphology
What are the clinical settings that can define a pneumonia?
Hospital acquired pneumonia
Community acquired pneumonia
Which organisms can cause pneumonia?
Viruses - influenza, measles, COVID, RSV
Bacteria
Chlamydia, mycoplasma
Fungi
What can COVID cause in patients?
Adult Respiratory Distress Syndrome (ARDS) - acute lung injury with epithelial damage.
It can also affect non-respiratory related organs, especially the heart.
What is lobar pneumonia?
This is confluent consolidation involving a complete lung lobe.
What is the most common pathogen causing lobar pneumonia?
Streptococcus Pneumoniae. Other organisms include Klebsiella and Legionella.
Who is most likely to get community aquired pneumonia?
It is classically seen in otherwise healthy young adults
What is the classic acute inflammatory response seen in pneumonia?
Exudation of fibrin rich fluid
Neutrophil infiltration
Macrophage infiltration
Resolution
What is the ideal role of the immune system in pneumonia?
Antibodies lead to opsonisation and further phagocytosis of bacteria.
What are some complications associated with pulmonary fibrosis?
Fibrosis
Abscess formation
Bronchiectasis
Empyema
What is bronchopneumonia?
This is when an infection starting in the airways (bronchi/bronchioles) spreads to adjacent alveolar lung (lobules).
This is most often seen in patients with pre-existing disease.
What are the most common causes of bronchopneumonia?
Patients with - COPD Cardiac Failure Complications of Viral Infaction Aspiration of gastric contents
What is the most common pathogen causing bronchopneumonia?
The pathogens are more varied. Strep. Pneumoniae Haemophilus influenza Staphylococcus anaerobes Coliforms
What is a lung abscess?
This is a tumour-like collection of pus. (severe localised suppuration). This can be viewed on a CXR or CT to show a fluid level
What are the symptoms of a lung abscess?
Swinging fever
Malaise
Weightloss
What are the causes of a lung abscess?
Aspiration pneumonia
TB
Klebsiella pneumoniae
Staphylococcus aureus
What is bronchiectasis?
This is an irreversible widening of the the bronchi
What are some of the causes of bronchiectasis?
This is usually due to fibrous scarring following infection. Tumours Pneumonia Cystic fibrosis tuberculosis sarcoidosis Immune deficiency etc.
What are some of the symptoms of bronchiectasis?
Recurrent infection Airway damage Chronic suppuration Persistent cough sputum production breathlessness pleuritic chest pain coarse crackles clubbing haemoptysis
What is tuberculosis?
This is a myobacterial infection where there is chronic infection in many sites including the lungs, gut, kidneys, lymph nodes and skin.
Which pathogen causes TB?
Mycobacterium tuberculosis- This is an aerobic, intracellular pathogen. It is airborne and spread by respiratory droplets.