Asthma Flashcards
What is the pathophysiology of asthma?
It is type I hypersensitivity reaction, increased irritability and responsiveness of bronchi and trachea to various stimuli, specific IgE and mast cell degranulation causes smooth muscle contraction and inflammation of the aways mediated by immune response and oedema. The result is airway narrowing and blockage.
What type of respiratory condition is asthma?
It is obstructive condition with widespread narrowing of the airways.
Which part of respiratory tract is affected?
Trachea and bronchi, no alveolar component.
What is characteristic for asthma?
It has variable narrowing and therefore severity, it is reversible.
What is the result of increased irritability?
Inflammation, increased production of mucus.
What causes narrowing of the airways?
It can be spontaneous or with stimuli such as allergen
What immune cells can be found in asthma?
Eosinophils and lymphocytes
Describe prevalence in adults and kids
More prevalent in kids, more boys, less prevalent in adults more females
What are the proven risk factors ?
Genetics -the tendency to IgE response to allergens, occupation and smoking
Describe genetic component of risk factors
Inherited tendency of IgE response to allergens, atopy in facility such as hay fever, food allergy, eczema. Mothers have 3times bigger influence than father
Genes associated with genetic component
1st group are immune response genes IL4, IL5 IGe and ins group are always gene ADAM33
Describe how smoking increases risk
Maternal smoking increases the risk by 1.5 mother and grandmother 2.6due to epigenetic modifications of oocyte
Name the speculative factors
Obesity, diet, reduced exposure to microbia, indoor and outdoor solution, environmental pathogens
What is the effect of obesity ?
Pro-inflammatory, increased irritability
What is the effect of diet?
Reduced antioxidants, n3 polyunsaturated FA, decreased n6 polyunsaturated FA and vitamin D
What are the symptoms of asthma? WTDCS
Wheeze, dyspnoea, chest tightness, paroxysmal cough and dry, sputum occasionally
What are some common triggers?
Cold air, exercise, perfume, smoke, pets, trees, grass, pollen, food etc
Describe the characteristic variation
Worst in early morning, might wake up during the night, weekly variation due to occupation, annual variation due to environmental allergens
What are signs of asthma?
dyspnoea on exertion, hyperexpanded chest, polyphonic wheeze
When it can’t be asthma?
If patient has finger clubbing, asymmetrical chest expansion, dull precision note, crepitations, stridor
Spirometry test for diagnosis
FEV1 less than 80% of expected value and FEV1/FVC ratio less than 70%
If spirometry shows obstruction what other tests should be done?
Full pulmonary function, CO transfer test, reversibility with beta 2 agonist and oral corticosteroids
What should full pulmonary test show?
Increased lung volume (bigger residual volume as problems with exhalation, also increased total lung capacity, RV/TLC >30%
What should be the result of CO gas transfer test?
Shows transfer of CO to Hb across alveoli, it should be normal as asthma has no effect on alveoli, it excludes COPD
