Obstructive: Chronic Bronchitis

Question 1

What is the definition of Chronic Bronchitis?

Answer 1

A chronic productive cough lasting at least 3 months over a minimum of two years

Highly associated with smoking

Question 2

Explain the histology of Chronic bronchitis (explain the types of cells involved)

Answer 2

Pseudostratified columnar (tall) ciliated epithelium lines bronchus
So cells touch the basement membrane (BM) sitting on the epithelium
Some nuclei are high and some are low

Under epithelium = Lamina Propria

• With large blood vessels (venules)
• Venules bring warm blood into the region allowing air to be warmed before going to the bottom of the lung to be exchanged

Under the lamina propria = the submucosa
Containing two types of glands
1. Serous – produces watery fluid - humidifies air prevent the lung from drying
2. Mucinous – produces mucous fluid lining epithelial surface - acts as a filter for inhaled particles

Ratio of the glands to whole wall is under 40%

Underneath submucosa = cartilage

Question 3

What is the pathophysiology of Chronic Bronchitis?

What happens to the cells + Reid Index

Answer 3

Smoking brings pollutants into lung
Lung responds by increasing mucus production

Hyperplasia and hypertrophy of bronchial mucinous glands

Reid index –
measures thickness of the mucinous glands relative to entire thickness of wall

Increased thickness of mucinous glands relative to bronchial wall thickness = over 50%

• Reid index of lung = over 50%,
• Normal = below 40%
• CB = over 50%
• Excess mucus goes into lumen
• Some is coughed up – productive cough
• Some goes back and plugs the airways,
• Obstructing getting air out of the lung
• DLCO = Normal

Question 4

What are the clinical signs and symptoms for CB?

Answer 4

Productive cough due to excessive mucus/sputum production

Wheezing

Dyspnoea

Crackles

Cyanosis – Blue Bloaters (hypoxemia due to shunting)

Weight GAIN

Secondary polycythaemia

Increased PACO2/PaCO2 – mucus plug traps CO2

Decreased PAO2/PaO2

Question 5

What are the consequences of CB?

Answer 5

Increased risk of infection (because of blockage)

Cor pulmonale
(BV in lung recognise a lack of O2 and block the particular region
Shunt blood in another direction
Infection spread
Right side of the heart has to pump against all the high pulmonary BP (pulmonary hypertension) –
Initially causes RV hypertrophy
Eventually the R heart fails – called cor pulmonale