Chronic respiratory disease

COPD definition

1) Chronic bronchitis ± emphysema ± chronic asthma

Causes of COPD ( environmental )

SMOKING - single most important cause, accounts for 80-90% of cases.
• Direct correlation between number of cigarettes and
development of COPD
• Smoking cessation slows
the average rate of
decline [diagram below]
• Occupational exposure to
dusts and/or chemicals
• Air pollution

Causes of COPD ( personal )

*History of recurrent severe
childhood respiratory
infections

• Airway hyper-responsiveness
Alpha 1 antitrypsin deficiency
(genetic abnormality)

Pathophysiology of chronic bronchitis

1) mucous gland hyperplasia + mucus hypersecretion —> inflammation

2) Smooth muscle hypertrophy + hyperplasia

3) Reduction in mucociliary function —> mucus retention

—> airway obstruction

Pathophysiology of emphysema

1) Alveolar septa destroyed

2) Terminal air spaces enlarged

—> impaired gas exchange

Physical exam findings for COPD

1) SOB

2) Barrel shaped chest

3) Accessory use of muscles

4) Paradoxical breathing pattern: diaphragm maintains horizontal/ flattened position from hyperinflation

5)Ausc: wheeze/ reduced BS/ coarse crackles

6) digital clubbing

Patient interview for COPD

1) Cough: most days for 3 months + > 2 consecutive years w/o other causes

2) Increase in severity + duration of cough

3) Sputum

4) Wheeze: on both inspiration + expiration —> airway narrowing ( moderate stage of disease )

5) Dyspnoea

6) Decrease in exercise tolerance

Oxygen therapy precautions

Need to monitor PaCO2 and PaO2 ( ABGs )

—> COPD rely on hypoxic drive to maintain ventilation

—> stop breathing completely when there is high O2 but also high CO2

Bronchiectasis definition

1) Abnormal + permanent dilation of bronchi

Bronchiectasis pathophysiology

1) Muscular + elastic components of bronchial walls damaged

2) Undamaged lung —> contractile force —> hypertrophy + hyperplasia of tissue in area —> elasticity loss

3) Fibrosis of distal bronchi from inflammation

4) Airway anatomy altered + mucociliary clearance impaired

Congential causes of bronchiectasis

1) Cystic fibrosis

2) Kartogener’s syndrome

Acquired causes of bronchiectasis

1) Post infection

2) Pertusis

3) TB

4) Measles

4) Immune difficiency

Clinical features of bronchiectasis

1) Recurrent infections

2) SOB

3) Cough + sputum —> can be productive/ X productive

4) Haemoptysis

3) Sinusitis

5) Wheeze

Cystic fibrosis pathophysiology

1) Reduced chloride secretion

2) Net increase in mvmt of water from airways to cells —> mucus layer is more viscous

3) Excess bronchial secretions due to impaired airway clearance

4_ Recurrent infections —> areas of consolidation/ collapse

—> bronchiectasis/ fibrosis —> lung damage

—> SOB —> resp failure

Clinical features of cystic fibrosis

1) Recurrent infections

2) Suppurative lung disease

3) Bronchiectasis

4) Haemoptysis

5) Chest pain —> MSK/ pleuritic

6) Pneumothorax —> sudden increase in SOB + shoulder tip pain