Patholophysiology of Respiratory Diseases II

Question 1

What is COPD?

Answer 1

COPD is an umbrella term used to describe patients with varying respiratory disease involving both chronic bronchitis and emphysema.
COPD encompasses a long-term, progressive and accelerated decline in respiratory function

Question 2

What pathological features are observed within the airways of COPD patients? (chronic bronchitis)

Answer 2

• Damage to cilia
• Mucus hypersecretion (↑ goblet cells
  +↑ mucus gland activation)
• Inflamed, swollen airway tissue and oedema
• Weakened airway structure (loss of elastin) and loss of patency (airway collapse)

Question 3

What pathological features are observed within lungs of COPD patients?

Answer 3

Decreases surface area and perfusion resulting in decrease in gas exchange
Loss of elastin fibres resulting in increase in compliance and decrease in recoil.

Question 4

How can chronic alveolar hypoxia lead to right heart failure?

Answer 4

Chronic alveolar hypoxia will lead to:

• hypoxic vasoconstriction
• pulmonary hypertension
• increased right ventricular afterload -> RV hypertrophy
• Right heart failure

Question 5

How can chronic alveolar hypoxia affect quality of life?

Answer 5

It can lead to hypoxaemia, hypercapnia and acidemia which can result in decreased exercise tolerance and fatigue leading to decrease in quality of life.

Question 6

Symptoms of right sided heart failure

Answer 6

fatigue
ascites
enlarged liver and spleen
weight gain
distended jugular veins
anorexia
complaints of GI distress

Question 7

What is pneumonia?

Answer 7

infection of the lung parenchyma resulting in inflammation and oedema

Question 8

What pathological features are associated with pneumonia/

Answer 8

1. Weakening of host defence
2. Infection of the lung parenchyma
3. Alveolar inflammation (activation of macrophages by pathogens, release of cytokines, recruitment of neutrophils, neutrophil degranulation, release of proteases/reactive oxygen species)
4. Alveolar injury (damage to alveolar wall, basement membrane, and capillary
   endothelium, hyaline membrane formation)
5. Oedema within alveoli/interstitial tissue and hyaline membrane formation
6. Impaired gas exchange, reduced oxygenation of blood, hypoxaemia

Question 9

Pathological changes to the airways in COPD

Answer 9

swelling, mucus hypersecretion, impaired mucociliary
transport, recurrent infections and damage to the integrity of airway structure, leading to
coughing and obstruction.

Question 10

Pathological changes to the lungs in COPD

Answer 10

airspace enlargement, decreased alveolar surface
area, and loss of elastin, leading to reduced gas exchange, increased compliance and
reduced recoil.

Question 11

what are the characteristics of the inflammation associated with allergic asthma

Answer 11

Eosinophils,
Th2 cells, 
Mast cells; 
IL-4, IL-5, IL-13; 
ROS, 
LTs, 
PGs

Question 12

what are the characteristics of the inflammation associated with COPD?

Answer 12

Neutrophils + 
Macrophages; 
IL-8, 
TNF-α; 
proteases

Question 13

what are the characteristics of the inflammation associated with viral pneumonia?

Answer 13

Neutrophils + 
Macrophages; 
IL-6, 
IL-8, 
TNF-α; 
proteases, 
ROS

Question 14

Major impact of asthma on tissue function

Answer 14

Airway smooth muscle
contraction, mucus
hypersecretion

Question 15

Major impact of COPD on tissue function

Answer 15

Large airways = mucus 
hypersecretion. 
Small airways = structural 
degradation & loss of patency. 
Alveoli = airspace enlargement/reduced surface area

Question 16

Major impact of viral pneumonia on tissue function

Answer 16

Hyaline membrane 
formation, oedema of 
alveoli and interstitial 
tissue (potential V/Q 
mismatch)

Question 17

what can pneumonia lead if left untreated

Answer 17

Acute lung injury and 
ARDS. 
Reduced gas exchange 
(type 1 Resp Failure); ↓PaO2. 
Potentially normal PaCO2 if 
normal rate of ventilation 
maintained