Pneumonia I Flashcards
Intro into Pneumonia
What is pneumonia?
It is the collection of fluid/exudate in the airways and alveoli, due to inflammation caused by infection.
The result is impaired breathing
Classification of pneumonia
Lobar pneumonia, bronchopneumonia, interstitial pneumonia, Lung abscess/necrotising pneumonia
Distinguish between lobar pneumonia and bronchoneumonia
Bronchopneumonia is often bilateral and it is focal inflammation that is centred on the airways
Lobar pneumonia - diffuse inflammation affecting the entire lobe. Characterised by pleural exudate
Explain the pathogenesis of pneumonia
It first starts by the infection of the lower respiratory tract by bacteria, virus, or other pathogen.
This leads to the activation of the immune system and triggers inflammation.
As a result, the airways (esp. alveoli) start to fill with fluid, white blood cells as well as cellular debris
What are the effects of pneumonia on lung function? (5)
Reduced lung compliance
Increased resistance.
Obstruction of airways, which results in collapse of distal airspaces(alveoli), and air-trapping
Altered ventilation-perfusion ratios/relationships
MAY LEAD TO RESPIRATORY FAILURE
What is pneumonia associated with?
necrosis of bronchial or bronchiolar epithelium or lung parenchyma
How do pathogens reach the lungs?
- Inhalation: infective agents can be inhaled if they are small enough to reach the lower airways and not blocked by host defences
Aspiration: Infected agents from the upper airways can be aspirated into the lungs (e.g vomitus) due to the cough reflex not working properly. Can be macro aspiration or micro-aspiration.
- Via bloodstream (rare)
Signs and symptoms of pneumonia
Signs of infection: fever, chills or rigors
Dyspnoea (SOB)
Productive cough
Signs of poor oxygenation: confusion, cyanosis
What will your findings be upon examination of the chest?
Consolidation of the lung due to exudate in the alveoli
Crackles or other abnormal breath sounds on auscultation
Complications of pneumonia (5)
Pleural effusion
Pleural empyema
lung abscess
Permanent lung damage
Death
How is pneumonia diagnosed? (3)
History taking and examination
Radiology (CXR or other radiological tests if required)
Microbiology
In microbiological tests, what can tests can be done?
Aim to determine the aetiology or causative organism(s) if possible
* Microscopy, culture and susceptibility testing (MC+S)
* Sputum
* (Blood occasionally in sicker hospitalised patients)
* Antigen tests
* Look for particular antigens e.g. legionella urinary antigen
* Molecular tests
* Detect nucleic acids of pathogens
* E.g. by Polymerase chain reaction (PCR)
* Serology
* From serum
* Look for antibodies produced by host against a pathogen
* Typically takes 1-2 weeks for immune system to respond so not so useful
Treatment of pneumonia
Antibiotics
Supportive treatment: Hydration, Oxygen supply, antipyretics, analgesics
