Respiratory Diseases Flashcards
What is asthma?
Reversible airflow obstruction, caused by bronchial hypersensitivity to innocuous stimuli.
What is the asthma triad?
Bronchial smooth muscle constriction
Bronchial mucosal oedema
Excessive mucous secretion into the airway
Describe the asthma cellular responses.
Allergen triggers age production.
Causes a B cell/T cell interaction, which causes degranulation of mast cells.
Leads to the asthma triad- oedema of bronchial wall, narrowing of the airway, mucous secretion.
What are the signs and symptoms of asthma?
Cough
Wheeze
Shortness of breath
Diurnal variation- worse overnight and early in the morning
Difficulty breathing out and lungs fill with air.
What does peak expiratory flow rate measure?
Airway resistance.
Describe some common asthma triggers.
Cold air
Infections- i.e. Chest infections
Dust
Smoke
Chemicals at work
Atopy- allergy to a range of different environmental stimuli.
What investigations might you wish to do if you suspect someone has asthma?
PEFR- morning and night
Skin prick test
Describe the biphasic response of asthma.
Acute asthma attack occurs- there is an early response caused by mast cell degranulation and with the action of Beta2 agonists, the patient recovers.
But they then develop a more significant attack later on- caused by activation of T cells, interleukin 4 and interleukin 5.
Leads to increased bronchial hyper-responsiveness.
Describe the drugs that may be used in an asthma patient?
Intermittent short acting beta-adrenergic agonists
Inhaled corticosteroids- low dose
Inhaled corticosteroids- high does
Regular long acting beta adrenergic agonist
Compound preparations- inhaled steroid with long acting beta agonist.
Adjuvant therapy- regular montelukast, prednisolone, biologic therapy.
What is the action of beta-adrenergic agonists?
Relax bronchial smooth muscle
Reduce bronchoconstriction
Reduce resting bronchial tone
What is the difference between a short acting and a long acting beta-adrenergic drug?
Short acting is taken as a reliever drug
Long acting is taken as a preventer drug.
Why might someone need a corticosteroid treatment for asthma?
If they have to take a short acting beta-adrenergic agonist more than 3 times per week.
What are the possible consequences of inhaled corticosteroid treatment?
Candida infections
Adrenal suppression
Osteoporosis
No evidence for adrenal suppression or osteoporosis if the daily dose is less than 1500 micrograms per day.
What drugs impair ventilation and shouldn’t be taken in patients with asthma?
Beta-blockers
Opioids
Benxodiazepines.
What drugs improve ventilation?
Bronchodilators- beta-adrenergic agonists and anticholinergic drugs.
Anti-inflammatory- corticosteroid
Prevent mast cell degranulation- chromglycate, leukotriene receptor antagonists.
What drug improves gas exchange?
Oxygen.
How might some of these asthma drugs be administered?
Metred dose inhaler
Nebuliser
Oral tablet
Why might you wish to use a spacer if you have a corticosteroid inhaler?
Improves drug delivery, makes it easier to get the full volume of drug into the airway.
Reduces the risk of candida.
Give examples of short acting beta2 agonists.
Salbutamol
Terbutaline.
Give examples of long acting beta2 agonists.
Salmeterol
What is the onset time, lasting time and purpose of a short acting beta agonist?
Onset is 2-3 minutes
Lasts 4-6 hours
Used to treat acute bronchial constriction