Pathophysiology of respiratory diseases - Part 2 Flashcards
What is COPD
Chronic obstructive pulmonary disorder
umbrella term used to describe patients with varying respiratory disease involving chronic bronchitis and emphysema
Is COPD progression rapid ?
Long-term, acclerated decline in respiratory function
How does quitting smoking affect lung fucntion?
Does not cause reversal of symptoms/does not improve lung function but the acceleration of the decline is halted
What percentage of COPD is associated with smoking?
90%
What are the causes for the remaining cases?
Largely due to exposure to pollution/chemicals
Genetic disorder like alpha-1-deficiency
What percentage of long term smokers develop COPD?
30% circa
Explain the process that causes tissue damage
Inhalation of chemicals
Causes tissue damage
Creates an inflammatory response
Attracts neutrophils/macrophages due to inflammation
Release proteolytic enzymes to try to clear inflammation +repair damage tissue
Why is the balance of proteases+anti-proteases so important
specific chemicals in tobacco smoke also inactivate antiprotease enzymes
So proteases cause even more damage
Long-term effects is tissue remodelling
mucociliary clearance defemce mechanisms are impaired by the remodelling.
WHY?
Loss of cillia + hypersecretion of mucus
leads respiratory system vulnerable to infections that lead to exacerbations, during which inflammation increases
Symptoms of chronic bronchitis
Excesive sputum production
Coughing + airway obstruction
Is chronic bronchitis reverisble?
No
What is the cause of narrowed lumen in bronchitis vs asthma
Bronchitis- excessive mucus production/tissue swelling, degradation
Asthma- smooth muscle contraction
This is why beta-2-agonists are less effective
What is emphysema?
Pathological enlargement of alveolar airspace due to degradation of lung tissue
Loss of structural fibres such as elastin+reduced surface area
What does reduced elastin mean?
Increased compliance
What is pulmonary heart disease
when respiratory failure places burden on Cardiovascular system
Overall results of COPD
Decreased airflow,ventilation, gas exchange
results in respiratory failure
explain what causes pulmonary heart disease
Hypoventilation of alveoli causes hypoxic vasoconstriction
Leads to vascular resistance, increasing force needed to pump blood
Pulmonary hypertension - right heart hypertrophy
Definition of pnuemonia
infection of lung parancheyma (alveoli and surrounding tissue)
How can pneumonia be classified? (3types)
- type of pathogen responsible
- specific tissue(s) affected
- where the infection was acquired (hospital/community)
Starting from before point of infection explain what happens in pneumonia
Weakening of host defence leads person susceptible
Colonisation of alveoli by pathogens
Activation of macrophages and cytokine release
Recruitment of neutrophils + release of proteases
Injury to alveolus + surrounding tissues
Why is hypercapnia typically avoided during pneumonia
high PaCO2 and low PaO2 inducing an immediate reflex increase in ventilation within any remaining parts of the lung that are still relatively functional, removing the excess carbon dioxide.
Why is hypoxemia not resolved by increased ventilation?
VQ mismatch and shunt effect
Alveolar damage causes deoisition of dead cekks and proteins in alveolar wall what does this cause
“Hyaline membrane” formation
Causes impaired gas exchange
Causes hypoxemia
