Asthma Flashcards
What is asthma?
It is an inflammatory disorder of the airways
Describe the symptoms of asthmas?
Dyspnoea
Cough
Wheeze
Chest tightness
Describe diurnal variation?
This is when asthma is worse in the morning and worse at night
What are the two classes of asthmas?
Extrinisc
Intrinsic
Describe Extrinsic Asthma
There is a definite external cause
Describe intrinsic asthma
There is no definite external cause
Describe the development of Extrinsic asthma?
The production of IgE antibodies to an external antigen Eg: Pollen Smoke Dust Environmental Pollution Respiratory Infection
Describe the acute response of asthma?
This is reversible
- Bronchoconstriction (Wheeze)
- Mucosal Inflammation and inflammatory cell recruitment
- Excess Mucous Production
Describe the signs of Asthma?
Tachypnoea
Audible Wheeze
Hyper inflated chest
Diminished air entry
Describe the immunology of asthma?
An external antigen presents and IgE antibodies are made. Once the antigen has been the cleared, the spare IgE antibodies bind to mast cells via Fc receptors. When the antigen is re-encountered, it causes mast cell degranulation, release of inflammatory mediators
Describe the chronic response of asthma?
- Increased smooth muscle mass
- Accumulation of interstitial fluid
- Increased mucous secretion
- Epithelial Damage
Describe airway hyperresponsiveness?
Chronic inflammation and epithelial damage causes the nerve endings to become exposed. This means smaller quantities of bronchoconstrictor are required to cause a change in FEV1
Describe drug associated asthma?
Aspirin and other NSAIDs can induce asthma
This is by the process of spontaneous mast cell degranulation
Occurs in 20% of asthmatics
Describe the most common presentation of drug associated asthma?
Asthmatic takes Aspirin
1-3 hours later has an asthma attack
Describe the treatment of Drug associated asthma?
Anti-Leukotriene therapy
Describe the inflammatory mediators released from Mast cells in asthma?
The mast cells release Histamine, Leukotriene C4 and Prostaglandin D2
What do the inflammatory mediators stimulate?
They stimulate Eosinophils to release Leukotrienes and epithelial damaging proteins This causes bronchial constriction and epithelial damage.
What is Samter’s Triad?
Nasal Polyps
Salicylate Sensitivity (Aspirin/NSAIDs)
Asthma
Investigations in asthma?
Peak Flow
Spirometry
Describe the findings of Spirometry in asthma?
The FEV1 is decreased
The FVC is the same
What kind of disease is asthma?
Obstructive
What is obstructive disease?
This is difficulty exhaling all the air from the lungs due to damage to the lungs or narrowed airway
Causes an abnormal amount of air to remain in the lungs after expiration
If the FEV1 is ≥ 80% of the expected value, what class of asthma is this?
Mild
If the FEV1 is ≥ 50%-60% of the expected value, what class of asthma is this?
Severe
