Respiratory Diseases Flashcards
What 3 types of Airway diseases?
Obstructive
Restrictive
Mixed Defect
Summarise Obstructive diseases:
- Characterised by reduced airway diameter
- Have increased airway resistance
- Examples: Asthma, COPD, Bronchiectasis
Summarise Restrictive diseases:
- Reduced lung compliance
- Decreased lung volume
What is Chronic Obstructive Pulmonary Disease (COPD)?
Progressive airflow obstruction, It not only affects the airways but the lung parenchyma and pulmonary vasculature
What are the 2 sub-types of COPD:
Emphysema
Chronic Bronchitis
What is Emphysema?
- Abnormal and permanent enlargement of airspaces distal to the terminal bronchioles
- It is destruction of the airways without fibrosis
Emphysema affects:
- Respiratory bronchioles
- Alveolar Ducts
- Alveolar Sacs
- Alveoli
What are the 2 patterns of Emphysema:
Centriacinar
Panacinar
Describe Centriacinar Emphysema:
- Primarily Upper lobes affected
- Loss of respiratory bronchioles in the proximal acinus - spares the alveoli
- Typical in smokers
Describe Panacinar Emphysema:
- Affects all lobes
- Loss of all parts of acinus
- Typical for α-1 antitrypsin deficiency
Describe the pathogenesis of COPD:
- Exposure to tobacco or noxious substance
- Airway epithelial cells and macrophages release cytokines to attract inflammatory cells
- CD8 T-cells, Mast cells and Neutrophils begin to attack airway tissue via proteolytic enzymes and activates fibroblasts that cause scarring
- Antiprotease α-1 antitrypsin is supposed to inhibit proteolytic enzyme activity but smoking can decrease its effect
- Mucus secretion increases and airways narrow (due to scarring)
COPD leads to chronic ________ due to the destruction of the __________ and loss of the ___________.
Hypoxia
Lung Parenchyma
Vascular Bed
COPD causes thickening of the ___________ which increases _________ and decreases ________. This leads to ___________________.
Blood vessels
Increases resistance and decreases blood flow
Pulmonary Hypertension
What is asthma?
Airway hyper-responsiveness to certain triggers which causes inflammation of the conducting regions
What are the 2 types of asthma?
Intrinsic
Extrinsic
Inflammation in asthma is ______ and mediated by _________ and ________
Chronic
Helper T-cells
Cytokines
What is Intrinsic Asthma?
Asthma is non-immune mediated
Usually to do with viral infection, Aspirin and stress
What is Extrinsic Asthma?
- Asthma caused by a Type 1 hypersensitivity immune response
- It is associated with atopy (e.g. hayfever is associated with eczema
- Triggered by allergens
Describe the pathogenesis of Asthma:
- Th2 helper cell overexpression stimulates plasma cells to synthesise and secrete IgE antibodies to allergens
- IgE binds to high affinity receptors on mast cells and basophils
- These cells release cytokines and histamine which causes bronchoconstriction
- Re-exposure to allergen leads to early and late phase reactions
What are the symptoms of Asthma?
Coughing Wheezing Chest tightness Shortness of breath Triggered by environmental allergens Diurnal variation in symptoms Relapsing and remitting course
What is Bronchiectasis?
A disease characterised by chronically dilated airways that are filled with mucous
What are the clinical features of Bronchiectasis?
- Chronic Cough
- Increased sputum volume
- Recurrent worsening respiratory symptoms
- Bronchial wall thickening and airway dilation seen on x-ray and CT
Explain the pathophysiology of Bronchiectasis:
- Airway infection
- Airway Inflammation occurs
- Airway damage = Bronchiectasis
- Impaired mucocillary clearance, airflow is obstructed and we get an impaired immune response
- Rinse and Repeat
What is Cystic Fibrosis?
An autosomal recessive disorder caused by Cystic Fibrosis Transmembrane Regulator (CFTR) gene mutations that cause an increase in mucous production and secretion
