Respiratory Diseases Flashcards
Define Asthma?
Asthma is a chronic lung disease that inflames and narrows the airways.
Asthma causes recurring periods of wheezing, chest tightness, shortness of breath and coughing
Airway narrowing is reversible
Describe the differences between a normal airway and an asthmatic airway
Normal airway: Fully patent
During Asthma symptoms: Narrowed airway (limited air flow)
Tightened muscles constrict airwat
Inflamed/thickened airway wall
Mucus
What is the global burden of asthma?
300 million people suffer from asthma worldwide
- 255 000 asthma deaths in 2005
approx 3500 in US
approx 1100 in UK
-over 80% of all asthma deaths occur in LMICs
What are asthma triggers?
- Exercise
- Pollen
- Bugs in the home
- Chemical fumes
- Cold air
- Fungus spores
- Dust
- Smoke
- Strong odors
- Pollutions
- Anger
- Stress
- Pets
What are different species of house dust mites?
Dermatophagoides pteronyssinus
Blomia tropicalis
Mite faeces contain allergens (Der p 1, Blo t 5, etc)
What are risk factors for asthma?
- Parents with asthma (genetics)
- Atopy
- Atopy refers to the genetic tendency to develop allergic diseases such as allergic rhinitis, asthma and atopic dermatitis (eczema).
- Atopy is typically associated with heightened immune responses to common allergens, especially inhaled allergens and food allergens.
- Childhood respiratory infections
- Exposure to allergens or infections while the immune system is developing
How do we measure atopy in epidemiological studies?
Either allergen Skin Prock Tesr reactivity (SPT)
Or allergen-specific IgE (asIgE)
What is a Bronchiodilator response (BDR)?
Bronchiodilator testing is utilised as a diagnostic method in obstructuve airway diseases.
In terms of the ISAAX phase II investigation: the aims of the investigation was to compare different methods for measuring BDR in participants with asthma and COPD & to study to the extent to which BDR was related to symptom burden and phenotypic characteristics
What is spirometry and how is it used as an asthma diagnosis?
Spirometry is one of the most commonly used approaches to test pulmonary function
It measures the vol of exhaled air vs time
Increased bronchial flow rate in a patient with asthma. (reversibility)
- Spirometry can help to assess if inhaled medication or inhalers can open up your airways by bronchodilator responsiveness testing (sometimes known as reversibility testing).
- Usually, medication causes a bigger change in scores if you have asthma than COPD. People with COPD have an FEV1/FVC ratio lower than 70%.
Define FEV1 and FVC
- Forced expiratory volume (FEV1) is a measurement taken from a pulmonary function test. It calculates the amount of air that a person can force out of their lungs in 1 second.
- Working out a person’s FEV1 value can help diagnose chronic lung diseases, such as chronic obstructive pulmonary disease (COPD).
Vital capacity is the maximum amount of air a person can inhale after a maximum exhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume.
What is the FEV1/FVC ratio?
An obstructive defect is a disproportional decrease in maximal airflow from the lung (FEV) in relation to the maximal volume (FVC) that can be displaced from the lung. In practical terms, an FEV/FVC ratio of less than 0.70 defines an obstructive ventilatory defect.
What does fractional inhaled nitric oxide mean?
NICE has recommended FeNO testing to help diagnose asthma in adults and children when diagnosis is unclear.
It has also recommended FeNO testing to help manage asthma in peopel who have symptoms despite using inhaled corticosteroids.
What is the management of asthma?
- Quick relief (rescue) medications
- Short-acting beta agonists
- Ipratropium
- Oral and IV corticosteroids
- Long-term control
- Inhaled corticosteroid
- Leukotriene modifiers
- Long-acting beta agonists
- Combination inhalers
- Avoid triggers
What is the treatment for different levels of asthma?
Step 1 is intermittent Asthma!
- STEP 1: Preferred SABA PRN
After step 1, we move onto persistent Asthma requiring daily medication. You must consult with a specialist after stage 4
- STEP 2: Preferred Low dose ICS. Alternative: Corimolyn LTRA, Nedocromil or theophylline
Goes all the way up to step 6
What are the issues with Asthma in LMICs?
- Increasing burden of disease
- Urbanisation and urban risk factors
- Access to healthcare and drugs
- Underdiagnosis/poor training
- Use of ER for control
- Affordable inhaled drugs
- Low dose ICS/inhaled beta-2 agonists
- Economic costs to family
- Different risk factors and predominance of non-atopic disease
- Ascaris
- Ascaris infections, with a worldwide prevalence above 10%, can cause respiratory pathology. However, long-term effects on lung function in humans are largely unknown.
- Ascaris