Asthma And Respiratory Immunology Flashcards
What are the cardinal features of asthma?
Wheezing
Dyspnoea
Dry cough
Allergen sensitisation
Airway inflammation
What is the pathophysiology of asthma? What causes the wheezing?
Inflammed airways due to eosinophilia
Narrow airways due to thickened wall
Wheezing due to turbulent airflow via airway
What does a flow volume loop look like in a patient with asthma? What figures would show an obstruction?
Reversible airflow obstruction
FEV1/FVC
<0.7 in adults
<0.8 in children
What happens physiologically to the bronchial epithelium if someone with allergic asthma is exposed to allergen?
Bronchial epithelium becomes inflamed and it undergoes airway remodelling (higher and fatter)
What kind of immunity is allergic asthma?
What is its physiology?
What is the best diagnostic test for this type of asthma?
Type 2
Allergen presents to dendritic cells and with its MHC II presents as an antigen presenting cell
Naive t helper cells reacts to this and differentiates into T2 helper T cell
This produces: IL-5,IL-13,IL-4
Airways start producing NO
IL-5 = EOSINOPHILIA
IL-13 = MUCUS
IL-4 = B CELLS- make IgE antibodies which bind to mast cells = histamines, chemokines = ALLERGIC asthma
Exhaled nitric oxide
What are the different tests for allergies
What are the different tests for and eosinophilia?
Eosinophilia: exhaled nitric oxide, sputum eosinophilia level, eosinophil blood count
Allergies: wheel and flare test, Ige blood tests
How do you diagnose asthma?
History and examination
Confirm wheeze
Spirometry
BDR- bronchodilator reversibility test
Exhaled nitric oxide
How do you manage asthma?
What does the preventative drug do?
Beta-2 agonists/bronchodilator- smooth muscle relaxation (RELIEVER)
Inhaled corticosteroids- decreases eosinophils and mucus secretion (MOST IMPORTANT, PREVENTATIVE)
Triggers apoptosis of eosinophils and reduces cytokines. Inhibits mucus secretion
What is anti-igE antibody therapy?
Who can access it?
What is the name of this drug?
What is Anti-IL5 therapy called?
Humanised anti-igE is given, this traps igE antibodies in patients with asthma and prevents them from binding to mast cells and basophils
Only people with severe asthma are offered this treatment and high levels of IgE antibodies
Omalizumab
Mepolizumab- given to high eosinophil count
What are the environmental exposures for asthma?
What is the difference between having an allergy and an allergic disease?
Exposures: pollution, infection, allergen
Allergy is an overreacting to house dust whereas an allergic disease is an extreme reaction eg asthma
How long do inhaled corticosteroids take to work?
6 months
