Week 210 - Asthma Flashcards
What is Atopy?
A genetic predisposition towards the development of immediate hypersensitivity reactions against common ** environmental antigens**.
How many people are affected by Asthma?
There are 300 million individuals of all ages, ethnic groups and countries that are affected by Asthma worldwide.
What are the two general types of Asthma?
- Extrinsic (otherwise known as Atopic)
- Intrinsic (otherwise known as Non-atopic)
Which sub-type of T-Helper cell is Pro- atopic - Th1 or Th2?
Th 2 - pro atopic; pro asthmatic.
Th 1 is non atopic.
Are Eosinophils “acid loving” or “base loving”?
Eosinophils are “acid loving” white cells. They stain brick red with Eosin staining.
What are the main inflammatory cells in the airway??
- Mast cells: These are the key cell of the innate immune system. They produce a variety of pre-formed and newly-formed inflamatory mediators.
- B lymphocytes: These produce antigen specific IgE (immunoglobulin E), in response to stimulation by interleukin-4 and interleukin-13 cytokines.
Of less importance….
- Dendritic cells - Antigen presenting cells.
- Epithelial cells - Secrete pro-inflammatory mediators (Thymic stromal lymphopoietin)
- Macrophages - Also express receptors which bind IgE and IgG
Antigen specific IgE (immunoglobulin E) is produced by what?
B lymphocytes.
What are the typical early phase clinical signs of Asthma?
Patient develops:
- wheeze
- cough
- SOB
- mucus production.
What are the typical late stage signs of Asthma?
Patient presents with:
- Initial response, but later symptom recurrence.
- Chest tightness
- Worsening SOB
- Bronchodilators do not fully reverse the airway obstruction.
What is the hygiene hypothesis?
It is hypothesized that exposure to certain microbes by early infection or from the environment may drive T cell production** towards the non atopic (Th 1)** phenotype, thereby reducing the occurence of Asthma.
What is Sodium cromoglycate used for?
Sodium Cromoglycate is:
- A mast cell stabiliser
- Used in the treatment of Asthma (usually in children).
Which drug should an Asthmatic taking Salbutamol not be taking, and why?
- What: Beta-Blockers (i.e. Atenolol)
- Why: Salbutamol is a Beta-Agonist. Beta-blockers are Beta-Antagonists. These drugs will be acting in opposition, rendering them both ineffective.
What is Omalizumab used for?
- This is a recombinant DNA- derived humanised monoclonal antibody
- Specifically binds to free human IgE (immunoglobulin E)
- ** AKA: Anti IgE antibody that aids atopic (not non-atopic) asthmatics.**
Why does Omalizumab not help obese asthmatics?
- IgE (immunoglobulin E) is an inflammatory mediator released in atopic asthma.
- Omalizumab blocks production of IgE.
- Asthma caused by obesity does not trigger IgE release as part of an immune cascade.
- This monoclonal antibody anti-IgE treatment will therefore be ineffective.
How does Omalizumab work?
- Binds to free Ige (Immunoglobulin E), decreasing the amount of cell bound IgE
- Decreases expression of receptors that have a high affinity for IgE (i.e. FceRI receptors)
- Decreases the amount of inflammatory mediators released by cells such as mast cells, Basophils, or Eosinophils.
- These collectively decrease allergic inflammation, and prevent exacerbation of asthma.
What is Mepoluzimab?
Mepoluzimab is a…
- Humanised monoclonal antibody
- Recognises IL 5 (Interleukin 5 - this is a cytokine of the innate immune response).
- Reduces Eosinophil production and proliferation.
For which respiratory conditions are leukotrine receptor antagonists used in treatment?
Leukotrine antagonists are Helpful in:
- Cold air induced asthma
- Exercise induced asthma
- Aspirin induced asthma
How is** aspirin** thought to induce Asthma?
- A very complex question that is still being researched
- One theory suggests pharmacological effect on COX enzymes.
- Inhibition of COX enzymes inhibits synthesis of bronchodilatory prostaglandins
What spirometry result is diagnostic of COPD?
- Ratio of FEV (Forced expiratory volume)/FVC (forced vital capaciity) = less than 0.7
- This question is covered in MI WEEK in my year 2 library.
In which age group do most asthmatics first present to the GP?
0-4 years (67.7%).
When taking a focussed history from a patient you suspect to have asthma, what are the key points to cover?
- Exercise induced?
- Wheeze?
- SOB (shortness of breath) and/or tight chest?
- Nocturnal cough
- “Tummy ache” (Paeds)
- History of URTIs (Upper Respiratory Tract infections)?
- Are there any nasal symptoms?
- Is this Atopic? (i.e., any eczema, hayfever, allergies, smoking history, Family history)
What are the (important to remember) differential diagnosis for a presenting wheeze in a child under 1 year?
- Viral - Recurrent URTIs - Bronchiolitis - see slide for others (lecture 2 wednesday)
What is the commonest Acute lower respiratory tract infection (LRTI) in infancy?
Bronchiolitis.
What are the clinical signs of Bronchiolitis?
- Respiratory distress:
- Tachynopea
- Grunting
- Subcostal and Intercostal recession -
Also:
- Tracheal tug
- Nasal flaring
- Hyperinflation with palpable liver edge.
- Widespread fine crepitations throughout respiratory cycle.
- Hypoxia
- Fever in most (<38.5C)










