Week 3 Respiratory Disorders ✅ Flashcards
What is the difference between chronic bronchitis and emphysema?
Chronic bronchitis = productive cough
Emphysema = structural changes
How does FVC change in COPD?
FVC is lower
How does FEV1 change in COPD?
FEV1 is lower
What is a normal FEV1:FVC and in COPD?
Normal
FEV1:FVC = 4L:5L = 80%
COPD
FEV1:FVC = 2L:5L = 50%
How does TLC change in COPD?
Higher due to air trapping
How is elastin and collagen broken down in emphysema?
Smoking
Inflammatory reactions in alveoli
Produces IL-8, TNFa, leukotriene B4
Stimulates immune cells
Stimulates proteases (proteases and collagenases)
Breaks down collagen and elastin
Alveoli collapse
How does loss of elastin affect respiration?
Breakdown of septa
Larger spaces created
Reduced surface area
Affects O2 and CO2
What are the 3 different types of emphysema?
Centriacinar/centrilobular
Panacinar
Paraseptal
Where does emphysema usually affect?
Acinus (end of airway)
What is centriacinar/centrilobular emphysema?
Only damages central/proximal alveoli
Affects upper lobes
What is panacinar emphysema?
Entire acinus affected
Affects lower lobes
Which type of emphysema is associated with a1 anti-trypsin deficiency?
Panacinar emphysema
What is paraseptal emphysema?
Distal alveoli most affected
Affects periphery of lobes
Can rupture and cause pneumothorax
Which is the most common type of emphysema?
Centriacinar/centrilobular
What are the symptoms of emphysema?
Dyspnoea
Breathing slowly through pursed lips “pink puffers”
Weight loss due to extra effort breathing
Cough
Barrel chest - air trapping and hyperinflation
How does emphysema affect the heart?
If there is poor gas exchange in a healthy person, vasoconstriction can divert blood to efficient area
However
COPD too many vessels involved so right side of heart works harder –> cor pulmonae –> right sided heart failure
What is the treatment of emphysema?
Stop smoking
O2
Bronchodilators, inhaled steroids, antibiotics for secondary infections
What does the mucosa consist of?
Epithelial cells and lamina proper
What does the submucosa consist of?
Smooth muscle
What is the atopic triad?
Asthma
Atopic dermatitis
Allergic rhinitis
Which immune cells work against allergens?
TH2
What is the role of dendrites in asthma?
Dendritic cells present allergen to TH2
TH2 releases IL-5 which recruits eosinophils –> cytokines and leukotrienes released
TH2 also releases IL-4 which activates IgE which releases histamine, prostaglandins etc
When eosinophils release chemical mediators, what happens?
Damage endothelium
What happens in type 1 asthma?
Smooth muscle spasm
Increased mucus
Airways narrowed
Increased vascular permeability
Increased immune cells
What are the long term complications of asthma?
Oedema
Scarring
Fibrosis
Thickening basement membrane
What are the TRIGGERS for asthma?
Pollution
Allergens
Mould
Cigarettes
What are the symptoms of asthma?
Chest tightness
Dyspnoea
Wheeze
Cough
Sputum (curschmann spirals/charcot-leyden crystals)
How is asthma classified?
Frequency of symptoms
Night time/early morning
FEV1
PEFR
Frequency of medication use
What are the classifications of asthma?
Intermittent
Persistent
Moderate persistent
Severe persistent
What are the treatments of asthma?
Avoid trigger
Medications:
Bronchodilators
Corticosteroids
Long acting B agonists
Leukotriene antagonists
IV steroids, magnesium sulfate, O2
How is chronic bronchitis defined?
Productive cough >3m
What are the risk factors for chronic bronchitis?
Smoking, air pollutants, dust, genetic factors
What happens in the airways in chronic bronchitis?
Lungs do not empty properly, air is stuck, so lower volume of air expired (FVC), especially FEV1
What is a normal FEV1:FVC radio and what is it like in COPD?
Normal FEV1:FVC is 4L/5L = 80%
COPD FEV1:FVC is 2L/4L = 50%
What is the TLC of COPD and why?
Higher because of air trapping
What is Reid Index and what is it in chronic bronchitis compared to normal?
Thickness of glands/thickness of wall
Normal = <40%
Chronic bronchitis = >40%
What can vasoconstriction in the lungs lead to?
Increased pulmonary vascular resistance
Pulmonary hypertension
Right heart hypertrophy
Right heart failure
Cor pulmonale
What is the treatment for chronic bronchitis?
Reduce risk factors (stop smoking)
Supplemental O2
Bronchodilators, inhaled steroids, antibiotics
How is emphysema caused?
Phagocytes release elastase which breaks down elastin in alveolar walls
What happens in emphysema?
Reduced elastic recoil
Alveoli and small airways collapse which leads to air trapping
Scar tissue thickens walls = obstruction
What protects the lungs from elastase?
α-1 antitrypsin (produced in liver)
What is AAT deficiency?
α-1 antitrypsin deficiency
How is chronic bronchitis caused?
Damaged cells release inflammatory mediators which cause capillary dilation, increased capillary wall leakiness, increased goblet cells and attraction of WBC
What does capillary dilation in chronic bronchitis lead to?
Red, hot tissue
What does increased capillary wall leakiness in chronic bronchitis lead to?
Escape of plasma
What does increased number of goblet cells in chronic bronchitis lead to?
Increased mucus production
What does attraction of WBC in chronic bronchitis lead to?
Increased inflammation
What are the triggers of asthma?
Infection, allergens, irritants, exercise
What is the MOA of asthma?
Mediators are released from mast cells and other WBC including histamine and leukotrienes
What does the release of mediators in asthma cause?
Swelling of mucosa, excess production of mucus, smooth muscle bronchoconstriction
What is a blue bloater?
Cyanosis - chronic bronchitis
