RESP- Pathophysiology of Respiratory Diseases II

Question 1

what is COPD

Answer 1

an umbrella term used to describe a mixture of long-term progressive and accelerated decline in respiratory function

Question 2

outline how tobacco smoke causes decreased respiratory function

Answer 2

tobacco smoke increases the inhalation of noxious chemicals and reactive oxygen species - this causes tissue damage - this causes tissue remodelling - leading to decreased respiratory function

Question 3

outline some pathological features observed within airways of COPD patients

Answer 3

damage to cilia
mucus hypersecretion 
inflamed, swollen airway and tissue oedema
weakened airway structure 
impaired mucocillary clearance
irritation of sensory neurones
decreased luminal area

Question 4

what are some pathological features observed in the lungs of people with COPD

Answer 4

decreased alveolar surface area + perfusion = decreased gas exchange
loss of elastin fibres = increased compliance, decreased recoil

Question 5

what are the effects of chronic respiratory failure on the body

Answer 5

hypoxaemia, hypercapnia, acidaemia, decreased excercise tolerance, fatigue, decreased quality of life, hypoxic vasoconstriction = increased pulmonary vascular resistance
pulmonary hypertension
increased right ventricular afterload
right side heart failure

Question 6

what is pneumonia

Answer 6

infection of the lung parenchyma, resulting in inflammation and oedema

Question 7

what is the pathophysiology of pneumonia

Answer 7

weakening of host defence (following infection, damage to epithelium, immune suppression)
colonisation of alveoli by pathogens
activation of macrophages and cytokine release
recruitment of neutrophils into alveolar space = release of ROS
injury to alveolus and surrounding structures

Question 8

how does alveolar injury lead to impaired gas exchange

Answer 8

deposition of dead cells and proteins in the alveolar wall / disruption of the endothelium and basement membrane
fluid accumulates in the alveoli / interstitium / lung crepitations
impaired gas exchange
hypoxaemia

Question 9

compare and contrast how respiratory function is differentially impacted by asthma, COPD and Pneumonia

Answer 9

asthma:
inflammation - eosinophils, TH2 cells, mast cells IL-4,5,13
affects: airways
impact on tissue: airway smooth muscle contraction
impact on respiratory function: dyspnoea, obstruction, impaired ventilation

COPD
inflammation: neutrophils, macrophages, IL-9, TNFa
affected: airways and lungs
impact on tissue - mucus secretion, degradation of alveoli
impact on resp function - impaired ventilation

Pneumonia:
inflammation- macrophages, neutrophils, IL-6,8, TNFa
affected: lungs
tissue impact: hyaline membrane formation, oedema of alveoli
resp impact: acute lung injury, reduced gas exchanged