Asthma Flashcards
Who discovered oxygen and in what year?
Joseph Priestly in 1772
He referred to it as dephlogisticated air.
What is hypoxia?
Oxygen deprivation
What is hypoxaemia?
Low levels of oxygen in the blood
What are some causes of hypoxaemia?
- Cardiac issues
- Local/regional blood supply compromise
- Shunt or venous admixture
- Hypoventilation
- Ventilation-perfusion mismatch
What does the oxygen dissociation curve represent?
The relationship between oxygen saturation and partial pressure of oxygen
What is the primary use of oxygen therapy?
To prevent hypoxia
What are the effects of high-pressure oxygen on respiration?
- Causes respiratory depression
- Reduces ability to exchange CO2
What maintains hypoxic drive in the body?
Carotid and aortic sinus receptors
What is respiratory failure?
A syndrome where gas exchange fails in one or both means
What are the two types of respiratory failure?
- Hypoxemic (Type I)
- Hypercapnic (Type II)
What characterizes Type I respiratory failure?
Arterial PaCO2 < 60 mm Hg
What are common causes of Type I respiratory failure?
- COPD
- Pneumonia
- Asthma
- Pulmonary oedema
- Pulmonary fibrosis
- Pneumothorax
- Pulmonary embolism
- Bronchiectasis
- Obesity
What characterizes Type II respiratory failure?
Arterial PaCO2 > 50 mm Hg
What are common causes of Type II respiratory failure?
- COPD
- Severe Asthma
- Drug overdose
- Poisoning
- Myasthenia gravis
- Polyneuropathy
- Poliomyelitis
- Primary muscle disorders
- Obesity-hypoventilation syndrome
- Pulmonary oedema
- Tetanus
What is the recommended fractional oxygen concentration?
About 0.6
What are the risks associated with oxygen therapy?
- Oxygen toxicity
- Carbon dioxide narcosis
What are key characteristics of asthma?
- Recurrent
- Exaggerated bronchoconstrictor responses
- Inflammation of the airway
What is the genetic component associated with asthma?
Chromosome 17q21
What causes the immediate contraction of airway muscle in asthma?
Release of mediators from mast cells after allergen re-exposure
What are the mediators released during an asthma attack?
- Histamine
- Tryptase
- Prostaglandin D2
- Leukotrienes
- Platelet activating factor
What physiological changes occur in asthma?
- Increased airway resistance
- Rapid respiratory rate
- Low arterial Pco2
What is the purpose of the GINA 2014 asthma treatment algorithm?
To determine the patient’s asthma treatment regimen and level of control
What are common drugs used in asthma treatment?
- Anti-IgE antibodies
- Cromolyn
- Adrenaline and salbutamol
- Calcium channel blockers
- Antihistamines
- Leukotriene receptor antagonists
- Theophylline
What do adrenoceptor agonists do in asthma treatment?
- Relax bronchial smooth muscle
- Prevent secretion of mediator compounds
What are methylxanthines and their effects?
- Theophylline
- Theobromine
- Caffeine
They inhibit phosphodiesterase, increasing cAMP levels.
What is the role of corticosteroids in asthma treatment?
- Inhibit production of inflammatory cytokines
- Reduce bronchial hyperactivity
- Potentiate the action of β agonists
What do leukotriene pathway inhibitors do?
Block the action of leukotrienes, which are involved in the inflammatory response
What is the effect of disodium cromoglycate on mast cells?
Inhibits mast cell degranulation
Disodium cromoglycate alters the functions of delayed sodium channels and inhibits cell activation.
What are leukotrienes elaborated from?
The action of 5-lipoxygenase on arachidonic acid
What is LTB4 known for?
It is a powerful neutrophil chemoattractant involved in asthma
Name two LTD4 receptor antagonists.
- Zafirlukast
- Montelukast
What is the role of omalizumab?
Targets the portion of IgE that binds to its receptor without provoking IgE to action
True or False: Omalizumab can be used in all patients.
False
Its use is restricted to patients with allergic sensitization.
What is the main rescue treatment for acute asthma?
Rapid-acting β-agonist via a rescue inhaler
What are the side effects of inhaled corticosteroids?
Thrush
Fill in the blank: Zileuton acts at the _______ receptor.
CysLT1
What is the primary action of long-acting β-agonists?
Act for up to 12 hours
What are the potential toxicities of β-agonists?
- Lactic acidosis
- Hypokalaemia
What is theophylline classified as?
A methylxanthine
What is the mechanism of action of methylxanthines?
- Inhibit phosphodiesterase (PDE)
- Inhibit cell surface receptors for adenosine
- Enhance histone deacetylation
What kind of agents are antimuscarinic agents?
Competitive antagonists of Ach at its receptor site
Name two examples of antimuscarinic agents.
- Ipratropium
- Tiotropium
What do glucocorticoids mediate?
Inhibition of inflammatory cytokines
What are the effects of corticosteroids on the bronchial tree?
Inhibit infiltration by lymphocytes, mast cells, and eosinophils
What are the two classifications of antitussives?
- Opioids
- Non-opioids
What is the primary function of expectorants?
Enhances the secretion of sputum
What are mucokinetics?
Bronchial secretion enhancers
Name a contraindication for the use of antitussives.
Asthma
What is the cough center located in?
The medulla
What type of cough lasts more than 8 weeks?
Chronic
What is the definition of an antitussive?
Cough suppressant
What is the role of cough expectorants?
Enhances the secretion of sputum
