Obstructive Airway Diseases Flashcards
what is the inflammatory cascade
1 - genetic predisposition + trigger
2 - airway inflammation
3 - mediators e.g. histamine, leukotrine (D4)
4 - twitch smooth muscle (hyper-reactivity)
what is the FEV1/FVC suggestive of asthma and what other test can be done to confirm diagnosis
FEV1/FVC less than 75%
reversibility to inhaled salbutamol by 15%
what is the process of disease in COPD
1 - smoking
2 - CD8+ lymphocyte + alveolar macrophage
3 - releases mediators, oxygen radicals, neutrophil chemotatic factors
4 - neutrophils
5 - proteases
6 - alveolar wall destruction (emphysema)
7 - mucus hyper-secretion (chronic bronchitis)
8 - progressive airflow limitation
what out of the two conditions of COPD is partially reversible
chronic bronchitis
what does chronic bronchitis cause
Chronic neutrophilic inflammation
Mucus hypersecretion
Smooth muscle spasm and hypertrophy
what is emphysema
Alveolar destruction
Impaired gas exchange
Loss of bronchial support
Irreversible
what do proteases do
breakdown proteins
what ABG are expected in COPD
decreased PaO2
increased PaCO2
what are features of COPD
pulmonary hypertension
RVH
RHF
Cor pulmonale
what are the types of emphysema
centriacinar (centrilobular)
panacinar
what leads to the collapse of alveoli
Loss of elastic recoil and support of small airways
what does decrease pO2 lead to
Dyspnoea and increased respiratory rate Pulmonary vasoconstriction (and pulmonary hypertension)
what genetic condition leads to a high rate of emphysema
α 1 antitrypsin deficiency
what is elastic tissue sensitive to
damage by elastases (enzymes produced by neutrophils and macrophages)
what does alpha 1 antitrypsin do
acts as an anti-elastase
