Respiratory Conditions (Non-infectious) Flashcards
What are the different types of asthma?
Allergic (most common) Infectious Occupational Exercise induced Drug induced Emotional
What are the 3 key features of asthma?
Airway obstruction caused by 3 factors:
- bronchoconstriction
- bronchial oedema
- mucus plugging
What are the SSX of asthma?
- dyspnoea (more marked in expiration)
- wheeze
- nocturnal cough and wheeze
- chest tightness
- recurrent respiratory tract infections
What are the 5 epithelial changes that occur in asthma?
- epithelial thickening and shedding (damaged by inflammation)
- goblet cell hyperplasia and mucus hypersecretion
- smooth muscle cell hyperplasia (hypertrophy of tunica media narrows airway lumen)
- thickening of basement membrane
- angiogenesis (increased number of blood vessels feeding submucosal layer can cause blood to leak into interstitial fluid and cause inflammation and oedema)
What is the pathology of allergic asthma development?
- exposure to initial allergen
- B cells produce plasma cells, which produce allergen-specific IgE antibodies
- IgE antibodies bind to mast cells in respiratory epithelium (these are now sensitized)
- in subsequent exposure, allergen binds to IgE on mast cells
- causes degranulation of mast cells (release of inflammatory mediators)
- inflammatory response
- increased vascular permeability and oedema
- bronchoconstriction
- hypersecretion of mucus
Which 3 inflammatory mediators are released by mast cells in allergic asthma?
- histamine
- leukotrienes
- prostaglandins
What are the most common allergens involved in allergic asthma?
Dust
Pollen
Animal fur / feathers
Eggs, wheat, fish, milk, yeast
What are the main causes of infectious asthma?
Usually viral - RSV in young children, rhinovirus, influenza or parainfluenza in older children
What are the 3 main drug classes that can cause drug induced asthma?
- aspirin
and - NSAIDs
(block COX pathway and cause a compensatory rise in leukotriene production) - beta blockers
(prevent SNS from stimulating B2 receptors in lungs)
What are complications of asthma?
Fatal asthma attack (status asthmaticus)
Spontaneous pneumothorax (air trapping causes formation of bullae that can burst and allow entry of air into pleural space)
Which SSX are associated with status asthmaticus?
tachycardia tachypnoea sweating inability to speak compensatory posture use of accessory muscles
late SSX:
- bradycardia
- confusion
- central cyanosis
- lapse in consciousness
What are the 4 major drug classes used to treat asthma?
- preventers
- inhaled corticosteroids
- leukotriene antagonists - relievers
- B2 receptor agonist
- muscarinic receptor antagonists - symptom controllers
- oral corticosteroids - monoclonal antibody therapy
- for severe allergic asthma
- inhibits activation of IgE
What are the 2 types of COPD?
Bronchitis and emphysema
How are bronchitis and emphysema diagnosed?
Bronchitis is diagnosed by the presence of symptoms (productive cough on most days for 3 consecutive months, in 2 consecutive years)
Emphysema is diagnosed by pathological changes (distention of airways distal to terminal bronchioles)
What is the definition of bronchitis and emphysema?
Bronchitis = chronic irritation of bronchial epithelium resulting in:
- mucus hypersecretion (hyperplasia of goblet cells)
- persistent inflammation
- replacement of ciliated cells with squamous cells
Emphysema = permanent distention and then destruction of air spaces distal to terminal bronchioles