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
What is the pathology of bronchitis?
Long term irritation of bronchial epithelium, causing:
- hyperplasia of goblet cells and mucus hypersecretion
- persistent inflammation and oedema
- replacement of ciliated cells with squamous cells (loss of mucus escalator)
What is the pathology of emphysema?
- elastase released by phagocytes during inflammation
- elastase destroys elastin in alveolar walls
- alveolar walls start to thin
- alveoli become distended and overinflate
- alveoli rupture and are destroyed - Blebs / bullae:
- distended alveoli and air escaping from damaged alveoli can cause blebs/bullae
- can rupture and cause pneumothorax
What is the respiratory ancinus?
All structures arising from the terminal bronchiole (respiratory bronchioles, alveolar ducts, alveolar sacs / alveoli)
What are the serious outcomes associated with COPD?
- pulmonary HTN
- persistent hypoxia stimulates pulmonary vasoconstriction - Cor pulmonale (right sided heart failure)
- because of pulmonary HTN - Acute respiratory failure
Which SSX do both bronchitis and emphysema have in common?
- increasing dyspnoea
- increasing hypoxia causing pulmonary vasoconstriction and pulmonary HTN
What are the distinctive SSX of bronchitis?
- audible breath sounds (wheezing, rhonchi, crepitations)
- productive cough
- tachypnoea
- chest tightness
- cyanosis / hypoxia
- digital clubbing
What are the distinctive SSX of emphysema?
- diminished breath sounds
- ineffective cough
- prolonged expiration and purse lip breathing
- barrel chest
- short jerky sentences
- accessory muscles
What are the different SSX between bronchitis and emphysema?
Cough:
- B: productive
- E: ineffective
Breath sounds:
- B: noisier
- E: diminished
Chest:
- B: chest tightness
- E: barrel chest
Colouring:
- B: cyanosis
- E: flushing
Ventilatory drive:
- B: lowered
- E: heightened
Specific:
- B: digital clubbing, cyanosis
- E: purse lip breathing, speaking in short bursts
