Chronic Asthma in Adults Flashcards
What is asthma?
Disease characterised by increased responsiveness of the trachea and bronchi to various stimuli, changes in severity spontaneously or as a response to therapy.
Causes inflammation and smooth muscle contraction causing narrowing of airways that makes expiration difficult
Describe the genetic proven risk factor for asthma
Atopy - inherited tendency to IgE response to allergens, maternal atopy most influential
Immune response genes - IL-4, IL-5, IgE
Airway genes - ADAM33
Describe proven occupational risk factors for asthma
Responsible for 10-15% of adult onset asthma
If working with
- grains
- enzymes
- drugs
- lab animals
If low molecular weight - non IgE
If high molecular weight - IgE
Describe the proven risk factor of smoking for asthma
Maternal smoking during pregnancy increases chances of child developing asthma
Describe how obesity may be a possible risk factor for asthma
High BMI associated with asthma, obesity pro-inflammatory (adipose tissue releases cytokines)
Diet, fruit and veg = protective antioxidants. Doesn’t help once you have asthma
Describe possible environmental risk factors for asthma
- house dust mite
- cats
- grass pollen
Describe the aetiology of asthma
- atopy (hypersensitivity reaction) IgE response to allergens
- airway hyper responsiveness
Describe important features of a history taking for asthma
- onset
- variation (indicative or chronic, occupational, seasonal allergies)
- exercise tolerance
- disturbed sleep
- history of atopic disease
- pets, new pillow, carpets
- if already on inhalers
- if used other drugs such as NSAIDs or B-blockers
Describe the aspects of past medical history relevant to asthma
- childhood asthma or bronchitis
- Eczema
- hay fever
Describe the drug history associated with asthma
- current inhalers, check technique
- B-blockers
- aspirin
- non-steroidal anti-inflammatory drugs
- note effects of previous drugs/inhalers
Describe the social history associated with asthma
- smoking
- pets
- occupations past/present
- psychosocial aspects (especially with difficult asthma)
Describe the pathology of asthma
- inflammation of bronchi
- airflow limitation
Describe the symptoms associated with asthma
- intermittent dyspneoa
- wheeze
- cough
- sputum
- increased respiratory rate
- increased heart rate
Describe the signs associated with asthma
- tachypneoa
- wheeze (expiratory wheeze not inspiratory stridor)
Describe the features of asthma likely to be discovered upon examination
- breathless on exertion
- hyperexpanded chest
- polyphonic wheezes
What clinical signs indicates that asthma would not be the correct diagnosis?
- clubbing
- cervical lymphadenopathy
- stridor
- assymmetrical expansion
- dull percussion note
- crepitations ie crackling or rattling sound
What causes exercise drive asthma?
Likely by a release of prostoglandins, leukotrines and histamine from mast cells.
Wheeze usually happens after exercise or inhalation of cold air
Describe the first investigation to be carried out and the levels that show abnormality
Spirometry
Abnormal if:
- FEV1/FVC <70%
- FEV1 <80%
Describe the purpose of full pulmonary function testing
- done if spirometry is abnormal
- trying to exclude COPD/emphysema
- done by performing lung volume (gas trapping) tests and gas transfer tests
Describe reversibility testing
Done when abnormal results from pulmonary function tests shown.
Check response to bronchodilator
- baseline, 15 minutes post 400microg inhaled salbutamol
- baseline, 15 minutes post neb 2.5-5mg salbutamol
Further assess by checking reversibility to oral corticosteroids
Describe the tests that should be carried out to aid the diagnosis of asthma
- Peak expiratory flow rate (PEF)
- spirometry
- sputum culture
- full blood count
- U+Es (urea and electrolytes)
Describe different methods of management for asthma
- inhaled Short Acting B-agonist
- inhaled steroid
- inhaled Long acting B-agonist
- leukotriene (long acting)
- theophylline (severe and acute asthma)
Describe a further test that could be carried out if spirometry is normal
peak flow meter and chart, twice daily for 2 weeks
State 2 specialist investigations for asthma
- airway responsiveness to methacholine/histamine
- exhaled nitric oxide
Describe other useful investigations for asthma
- CXR
- skin prick testing
- total and specific IgE
- full blood count
