Obstructive Lung Diseases Flashcards
What three examples of major obstructive lung disease are there?
Asthma
Chronic bronchitis
Emphysema
(COPD being a combination of the last two)
What is the definition of asthma?
Words to the effect of:
Disease characterised by an increased responsiveness of the airways to various stimuli and manifested by a widespread narrowing of airways - pharmacologically reversible
What is the definition of chronic bronchitis?
Chronic cough productive of sputum most days in at least three consecutive months for more than two consecutive years
Why are there complex time restraints on qualification of chronic asthma?
To rule out other diseases such as tuberculosis
What is chronic bronchitis often confused with diagnostically?
Chronic bronchial asthma
What is the definition of emphysema?
Increase beyond normal size of airspaces distal to the terminal bronchiole arising either from loss of elastic network of lungs without obvious fibrosis
What is a terminal bronchiole?
Last conducting vessel before the alveolar sac
What are respiratory bronchioles?
Attach alveoli to terminal bronchiole
What heart condition can all obstructive lung diseases can cause as a result of right sided ventricular hypertrophy?
Cor pulmonale
What is the pathophysiology of cor pulmonale?
Pulmonary hypertension (>25mmHg) causes right ventricular hypertrophy which causes cor pulmonale
Describe the prevalence of asthma in children
10-15% have it, most common in males
Describe the prevalence of asthma in adults
5-10% have it, more common in females
How many deaths per year does asthma cause on average in the UK?
1000
What is the key feature of asthma? If it don’t ____ then it ain’t asthma!
Wheeze
What are the proven aetiologies of asthma?
Genetic atopy, occupational exposure and lifestyle (smoking e.g.)
What are a few possible aetiologies?
Diet, weight and exposure to microbes
What is a wheeze? What causes it?
Polyphonic breath sound caused by narrowing of airway
Can be caused b a tumour, inflammation, asthma, infection or aspiration of foreign body
What are the symptoms of asthma?
Wheeze
Dyspnoea
Chest tightness
Cough (usually dry but can be productive)
List some common triggers of asthma
Exercise Cold air Smoke Perfume Pets Grass pollen Aspirin
Not all are mentioned theres lots more
What can the varied presentation of asthma indicate daily, weekly and annually?
Daily - potentially worse at night
Weekly - better at weekends indicating an occupational factor
Annually - environmental
What is shunt?
Blood moving from one side of the heart to the other through the lungs without being oxygenated
What is the normal physiological percentage of shunt?
2-4%
What are the key features of past medical history in asthmatics?
Childhood asthma
Eczema
Hay fever
Drugs including inhalers, aspirin and NSAIDs
What important features of a social history are there in regard to asthma?
Smoking
Pets
Occupation
Psychological aspects
What do FEV1 and FVC represent in vivo?
FEV1 - airway diameter
FVC - lung capacity
What tests are used to confirm an obstructive disease profile?
Lung function:
Helium dilution - test for gas trapping
CO gas transfer - to test for adequate gas transfer
What investigations are required before beginning treatment of asthma?
Test reversibility to bronchodilators and corticosteroids
What is alveolar dead space?
Air in poorly perfused alveoli that doesn’t take part in gas transfer
What is anatomical dead space?
Air in conducting airways that doesn’t take part in gas transfer
What is the distinguishing feature of COPD from asthma?
COPD is non-reversible
What pharmacological agents are available for the treatment of asthma?
- Bronchodilators (SABA, LTRA, Theophylline)
- Corticosteroids (inhaled or oral)
What two types of inhalers are there?
Pressurised metered dose and dry powder
Outline the stepwise approach to asthma treatment§
- Add SABA
- Add inhaled corticosteroid
- Add LTRA and refer to specialist
- Oral steroid
