8. Asthma: clinical features Flashcards
What is the definition of asthma?
Disease characterised by an increased responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread NARROWING of airways that changes severity either spontaneously or as a result of therapy
Why is asthma difficult to diagnose at times?
-There is no diagnostic test or specific symptom
How is asthma diagnosis? (what is used?)
Diagnosis made on patterns in tests and symptoms
Is there an alveolar component to asthma?
No- just the airways (trachea, bronchi)
What is the main difference between COPD and asthma?
- COPD has constantly constricted airways (irreversible)
- Asthma can have better and worse symptoms (comes and goes) which makes narrowing of airways reversible and variable
What is airway inflammation mediated by?
The immune system
What 2 things can airway inflammation lead to?
- widespread narrowing of airways
2. increased airway reactivity (leading to airway narrowing)
In what 2 ways can airway narrowing/constriction happen?
- spontaneously (waking up with closed airways)
2. stimuli (due to allergen like pollen or exposure to a stimulant)
What do inflamed airways produce?
Increased mucus production (for debris) leading to irritability
What is the prevalence of asthma in children? (%)
10-15%
Is asthma more prevalent in males or females in children?
males
What is the prevalence of asthma in adults? (%)
5-10%
Is asthma more prevalent in males or females in adults?
females
How many people are receiving asthma treatment in UK?
~5.4 million (1.1 million children and 4.3 million adults)
How many asthma related deaths are there in UK every year?
~1000 per year (most are >60 years and smokers, usually COPD related)
What are the 3 top activities which are the most limited by asthma?
running, sport and stairs
Roughly how many asthma admissions are there per year?
67,000 admissions (220,000 bed days)
Roughly how many asthma GP consultations are there?
approx. 4.1 million
How much does treating patients with asthma cost the NHS annually?
~£2.3 million (only 2% of NHS budget)
What are 3 top PROVEN factors for asthma?
- genetics (atopy)
- occupation
- smoking
Define atopy.
Inherited tendency to IgE response to allergens (genetic inheritance predisposition towards developing an allergic hypersensitivity)
What 4 common conditions can be caused by atopy risk factor?
- asthma
- eczema
- hayfever
- food allergy
What methods are used to test for atopy related asthma (or other allergies)?
- IgE testing
- skin pick tests
- markers
Out of all 3 risk factors for asthma, what is the strongest risk factor?
personal, familial atopic tendency
Which copy, maternal or paternal is most influential?
Maternal (3x stronger than paternal)
-mother has bigger genetic effect on the child than father
What are 2 groups of genetic associations related to asthma? And what are their examples?
- immune response genes (IL-4, IL-5, IgE)
2. airway genes (ADAM33)
Occupation contributes what percentage towards adult onset asthma?
10-15% (interaction with smoking and atopy)
What are 7 common agents which can lead to asthma in occupation circumstances? (GLEDDIC)
- isocyanates
- colophony
- laboratory animals
- grains
- enzymes
- drugs
- crustaceans
GLEDICC
What is an example of isocyanates that can cause asthma?
twin pack paints
What is an example of colophony that can cause asthma?
welding solder flux (cleaning agent)
What is an example of lab animals features that can cause asthma?
rodent urinary proteins
What are examples of grains that can cause asthma? (2)
- wheat proteins
- grain mites
What are examples of enzymes that cause asthma?
- subtilisin
- amylase
What are examples of drugs that can cause asthma?
- antibiotics
- salbutamol
What are examples of crustaceans that can cause asthma?
-prawns
-crabs
(fish and shellfish proteins due to inhalation)
What does maternal smoking during pregnancy decrease in the unborn child?(1)
Its FEV1
What does maternal smoking during pregnancy increase in the unborn child? (4)
- wheezy illness
- airway responsiveness
- asthma
- severity of disease
Describe the increased risk of the child developing asthma in percentages if;
- mother smoked
- grandmother smoked
- both mother and grandmother smoked during pregnancy
- mother: increased risk of 50%
- grandmother: increased risk of 100%
- mother AND grandmother: increased risk of 150%
“the grandmother effect”
What causes the “grandmother effect”
epigenetic modification in oocytes
What is a patient’s BMI positively associated with in terms of airway conditions? (3)
- asthma
- wheezing
- airway hyperactivity
What dietary diet-related foods are associated with a possible risk factor for developing asthma? (4)
- decrease in antioxidants
- decrease in n-3 polyunsaturated fatty acids
- increase in n-6 polyunsaturated fatty acids
- increase/decrease of vitamin D
What dietary 3 vitamins and a substance decrease are associated with a decrease in FEV1?
Decrease in:
- vitamins E,C,D
- Beta-carotene
What dietary 2 vitamins and 2 other substance decrease are associates with an increased wheeze?
Decrease in:
- vitamins E and C
- fruit
- margarine