Respiratory: Asthma Flashcards
What is asthma?
A reversible airflow obstruction
How do you characterise if someone has the inflammatory disease of the airways called asthma?
- Hypersecretion of mucus by bronchial epithelial cells
- Eosinophil infiltration
- Bronchial smooth muscle cells hyperplasia causing airway hyperresponsiveness and bronchospasm
What factors increase the chance of developing asthma?
- Family history of asthma and allergic conditions
- Bronchiolitis as a child
- Exposure to tobacco smoke
- Being born prematurely
- Type of job- occupational exposure
What are the ways asthma is triggered?
- Cigarettes
- Headlice treatment: vapour can irritate airways
- Insecticides and cleaning products
- NSAIDS
- Allergies such as nuts or dairy products
What are the symptoms of an asthma exacerbation (attack)?
Acute or progressive
- Dyspnoea: shortness of breath
- Wheezing: whistling sound during breathing
- Chest tightness
- Cough (occasionally)
- Symptoms WORST at NIGHT and EARLY in the MORNING
What are the airways like when someone experiences an asthma attack?
- Constricted airway
2. Contacted airway of smooth muscle
What is the physiopathology of asthma? (What is the condition of the disease in the lungs like)
- Inflammation
- Hyperplasia (enlargement of organ caused by reproduction rate) of goblet cells
- Hyperplasia and hypertrophy of smooth muscle
- Subendothelial fibrosis (thickening of basal membrane)
- Collagen deposits
How does a severe asthma bronchus compare to a normal bronchus?
- Severe asthma bronchus has a smaller lumen compared to the normal bronchus (restricting airways)
- There’s a lot more production of mucus compared in severe asthma bronchus
How is the asthma mechanism triggered by an allergic reaction (immediate phase)?
- Mast cells are activated by the antigen binding to the mast cell
- Mast cells releases Histamine, Tryptase, Leukotrienes and Prostaglandins
- Leads to Bronchospasms
How does the late phase allergic reaction occur?
- Mast cells are activated by the antigen binding to the mast cell
- Proinflammatory cytokines, chemotactic mediators and chemokines are released which activate the late phase
What is the late phase in an allergic asthma reaction?
- Inflammatory response (airway inflammation and hyperreactivity) occurs
- Factors which do this:
- eosinophil activation
- infiltration of cytokine releasing Th2 cells - Leads to bronchospasm, wheezing, coughing
How can you manage the intermediate and late phase of asthma?
- Intermediate phase:
- Beta 2 agonists
- Theophylline
- Leukotriene Receptors
- Antagonists - Intermediate and Late phase: Glucocorticoids
What does the spirometry test measure? And how can you use the results?
- Forced vital capacity (FVC): Maximal amount of air that can be exhaled after a maximal breath
- Forced expiratory volume (FEV1): volume of air exhaled during the first second of the FVC
- FEV1/FVC at least 70% = normal
When is the spirometry test used?
- Screen for COPD and monitor disease progression
- Differentiating between asthma and COPD
- Diagnosing, evaluating progression and seriousness of lung diseases
- Distinguishing between obstructive and restrictive disorders
- Assessing the extent of abnormalities
- Judging responses to therapy
What does it mean if the results of the spirometry ratio is under 70%?
- Obstructive dis
What are some non pharmacological treatments of asthma?
Avoid environmental, dietary and other triggers of asthma
In terms of asthma management, what is achieving early control?
- Controlling symptoms
- Prevent exacerbations
- Achieve the best possible lung function
How do you remain control in terms of treatment of asthma?
Stepping treatment up and down when necessary
Describe what complete control of asthma is?
- No daytime symptoms
- No night time awakening due to asthma
- No need for rescue medication
- No exacerbations
- No limitations on activity including exercise
- Normal lung function 80% or more
- Minimal side effects on medication
What are the pharmacological treatments of asthma?
- Short acting bronchodilators (reliever)
2. Long acting bronchodilators and anti-inflammatory drugs known as Controllers (preventer)
Describe what options are available to use for a asthma reliever?
- Inhaled short acting beta 2
- Inhaled ipratropium bromide
- Beta 2 agonist tablets or syrup
- Theophyllines
When do you use short acting bronchodilator relievers?
Administer during asthma symptoms
When do you use long acting bronchodilators and anti-inflammatory drugs?
Regular preventer therapy to improve symptoms, lung function and prevent asthma attack
Describe what options are available to use for a asthma preventer?
- Inhaled corticosteroids
- Inhaled long acting beta 2 agonists in combination with inhaled corticosteroids
- Leukotriene receptor antagonists
- Systemic corticosteroids
- Theophylline
- Cromones
- Anti-IgE
What is step 1 that’s used in asthma patients? (mild asthma)
- Reliever inhaler when needed
What is step 2 that’s used in asthma patients?
Regular preventer therapy
Preventer inhaler containing steroids: taken everyday. Reliever when necessary
What is step 3 that’s used in asthma patients?
Initial add on spray
Preventer inhaler containing steroids: taken everyday. Reliever when necessary.
and long acting reliever inhaler when needed.
- Increased dose of long acting reliever if doesn’t help much
- If no help, stop medication
What is step 4 that’s used in asthma patients?
persistent poor control
Increase dose of inhaled steroid or adding fourth medicine:
- Leukotriene receptor antagonists
- Theophylline reliever tablets
What is step 5 that’s used in asthma patients?
Continuous or frequent use of oral steroids
Take steroid tablets in lowest dose (best control)
Keep taking inhaled high dose of steroid
Consider other medications
Referred for specialist care
Explain the mechanism of action of Beta adrenergic agonists such as salbutamol?
- Activation of beta 2 adrenoceptor in smooth muscle
G alpha S subunit:
- Relaxes the cAMP dependent and cAMP indecent mechanisms
- Causes activation of K+ channels which lead to hyper polarisation
- Inhibits L-type Ca2+ channels
List 2 short acting beta 2 adrengeric agonist and how to use them for acute asthma attacks?
- Salbutamol (occasional reliever) and terbutaline (prevention)
- Monitor and repeat treatment if needed
List 2 long acting beta 2 adrengeric agonist and how to use them for chronic asthma?
- Salmeterol and Formoterol
2. Use only in combination of corticosteroids
What are the advantages of long acting Beta 2 adrenergic agonists?
- Allow reduction of corticosteroid dose
2. Reduction of symptoms and improvement of lung function
What are the disadvantages of long acting Beta 2 adrenergic agonists?
- Delayed onset of action
2. Risk of asthma exacerbation, hospitalisation and death
What are the side effects of beta 2 adrenergic agonists
- Fine tremor (particularly in hands)
- Headache
- Palpitiation, tachycardia and arrythymias
- Peripheral vasodilation
What are the contraindications and use with caution?
Cardiovascular disease and interaction with other drugs
Explain how corticosteroids work in the anti-inflammatory therapy for asthma?
- Switch off multiple activated inflammatory genes and decrease transcription:
- cytokines (IL1 and TNFalpha)
- chemokines (IL8)
- Inflammatory enzymes (COX2 and iNOS)
- Inflammatory receptors - Activate anti-inflammatoy gene expression and transcription of:
- Beta adrenergic receptor
- IL-1 receptor antagonist
- Others
Give examples of inhaled (preventers) and their use?
- Beclometasone dipropionate
- Budesonide
- Fluticasone propionate
- Mometasone fluroate
- ciclesonide (prodrug)
Use: recommended preventer drug for adults and children for overall treatment goals
What’s an oral corticosteroid example and its use?
Prednisoline
Use: acute and severe asthma
What’s the parenteral corticosteroid example and its use?
Hydrocortisone
use: life threatening acute asthma
What is the mechanism of action of Theophylline and use?
MoA:
1. Inhibits phosphodiesterase
- Antagonist at adenosine receptors
- Inhibits release of inflammatory mediators by unknown mechanism
- Activate histone deacetylases (HDACS)
Use:
Oral or parenteral for acute and chronic asthma (reliever or preventer)
What should you watch out for in Theophylline?
- Small therapeutic window
- Metabolised by liver
- Serum levels must be monitored to avoid toxicity
What is the mechanism of action of Leukotriene receptor antagonists and use?
MoA:
1. block cysteinyl leukotriene receptors on bronchial tissue (and other cells)
- Therefore reduces bronchoconstriction, mucus secretion, oedema, eosinophil migration
Use:
Oral asthma preventer not as reliever or rescue remedy
What are the overall effects of mast cell stabilisers and its use?
- Inhibit the bronchoconstrictive reactions to inhaled allergens
- Reduces bronchospasm caused by exercise, cold air, environmental pollutant in some patients
- Use: Inhaled asthma preventer (and allergies)
Give some examples of mast cell stabilisers?
- Sodium Cromoglicate
2. Nedocromil Sodium
What are anti-cholinergic agents used for?
COPD
Describe the mechanism of action of Anti IgE? Give an use?
- Antibody binds to circulating IgE
- Decreases binding of IgE to the high affinity IgE receptor in mast cells
- Subcutaneous Injections every 4 weeks
