Respiratory Medicine Flashcards
What is the hierarchy of lung structure?
Trachea - bronchus - bronchioles - alveoli
Which part of the lung is distal?
Bronchus through to capillaries
How many British people have asthma? How much does it cost the NHS per annum?
5.4 million.
Costs £1 billion
Pathophysiology of bronchoconstriction, mucous plugs, mucosal oedema, increased vascularity, increased smooth muscle mass and inflammatory cell activation describes what condition?
Asthma
What is the difference between a brief vs longer asthma attack?
Brief = Last minutes, caused by tightening of muscles. Longer = Increased mass decreasing lumen of bronchioles
What is COPD?
Resp disease where airflow is limited - not fully reversible. Usually progressive and associated with abnormal inflammatory response due to noxious particles/gases.
How many British people have COPD? How much does COPD cost NHS per annum?
1.2 million people.
£3 billion per year.
What is the pathophysiology of COPD?
Narrowing of airways by:
- Collagen disposition
- Mucosal thickening
- Inflammatory exudate in airway lumen
What happens in emphysema?
Alveolar membrane breakdown
Signs and symptoms of COPD?
- SOB
- Chronic cough
- Phlegm
- Wheezing
- Chest tightness
- Resp infection
What is main route of drug admin for resp diseases?
Inhalation
What percent of inhaled medication is deposited in lung and swallowed?
Lung = 5% Swallowed = 95%
What kind of metabolism do inhaled drugs take?
First-pass metabolism
What are two main types of inhalers?
1) Breath actuated metered dose (i.e. mine)
2) Dry powder inhalers
What are two main drug classes of resp drugs?
- Bronchodilators
- Anti-inflammatory
Mechanism of action of beta-2-agonists?
- Treat asthma/COPD
- Targets ANS - sympathetic innervation
- Bronchial smooth muscle relaxation, mucocilary clearance => breathe easier
Example of short acting beta-2-agonist, with onset/duration?
Salbutamol
Onset 5 mins, lasts 4-6 hours.
Example of long acting beta-2-agonist, with onset/duration?
Salmeterol
Onset 10-20 mins, lasts 12 hours.
How do beta-1 and beta-2 blockers differ in location of effect?
B1= Heart B2= Lungs
Antimuscarinic/anticholinergic MoA?
Blocks muscarinic receptors on bronchial smooth muscle, preventing bronchoconstriction mediated by parasympathetic NS
Antimuscarinic/anticholinergic side effects?
- Dry mouth
- Headache
- Dizziness
- Cough
- Dry throat
Example of short-acting antimuscarinic with onset/duration?
Ipratopium - onset 15-30 mins, lasts 6-8 hours.
Example of long-acting antimuscarinic with onset/duration?
Tiotropium - onset 3-7 days, lasts 24 hours
Methylxanthines MoA?
Direct effect on bronchial smooth muscle, affecting contraction. Inhibits phosphodiesterase, increasing cAMP
Methylxanthines side effects?
GI effects (nausea, vomiting etc)
CVS (hypotension, tachycardia, arrhythmias)
CNS (irritability, headaches, insomnia, seizures)
Hypokalaemia
Why do we need to be cautious about Theophylline?
It has a narrow therapeutic index.
Factors affecting Theophylline levels?
Increase: - Congestive HF - Liver disease - Concurrent enzyme inhibitors Decrease: - Smoking - Use of enzyme inducing drugs
MoA of corticosteroids?
Inhibit synthesis/release of mast cells. Inhibits migration of inflammatory cells and decreases capillary permeability, decreasing oedema.
Side effects of inhaled steroids?
- Oropharyngeal candidiasis
- Hoarseness/dysphonia
- Suppress adrenal function?
Side effects of oral steroids?
- Hyperglycaemia
- Hypokalaemia
- Fluid retention
- Infection risk
- Suppress hypothalamic-pituatary axis
Why is it important for resp medications to targets leukotrienes?
They are linked to increases mucus production, airway wall oedema and bronchoconstriction
MoA of leukotriene receptor antagonists?
Blocks effect of leukotriene by binding to receptors i.e. antagonist
Side effects of leukotrienes?
- Headache
- Nausea
- Dyspepsia
- Diarrhoea
- Dizziness
