Chronic Bronchitis
Air pollution and smoking are key causes for chronic bronchitis.
Chronic bronchitis
- Cause: long-term exposure to irritants : tobacco smoke (commonest) , biomass fuel smoke (wood, charcoal: very important in Kenya) , occupational dusts and fumes, air pollution; recurrent infection.
- Pathology: mucous gland hypertrophy and goblet cell hyperplasia (increased Reid index above 0.5), mucus hypersecretion, chronic inflammation, ciliary dysfunction , bronchial wall thickening and airway narrowing.
- Chronic productive cough , worse in the morning ; recurrent exacerbations with purulent sputum, wheeze and breathlessness .
- Signs: coarse crackles and rhonchi, wheeze, cyanosis and fluid retention (cor pulmonale) in advanced disease (" blue bloater ": overweight, cyanosed, hypoxic, oedematous, CO2 retention).
- Spirometry ( post-bronchodilator FEV1/FVC below 0.7 = COPD); chest X-ray (increased bronchovascular markings, to exclude other causes); sputum culture in exacerbations; FBC (polycythaemia), ABG .
Read this in Bronchitis (Acute and Chronic)
Chronic Bronchitis
- Defined clinically : Persistent productive cough for at least 3 consecutive months in at least 2 consecutive years .
- Common in cigarette smokers and urban dwellers, affecting 20–25% of men aged 40–65.
- A distinctive feature is hypersecretion of mucus beginning in the large airways .
- Cigarette smoking is the most important cause, along with irritants like sulfur dioxide and nitrogen dioxide.
- Irritants lead to hypertrophy of mucous glands in the trachea and bronchi, and an increase in goblet cells in smaller bronchi and bronchioles.
Read this in Lung Pathology — Must-Know
Chronic Bronchitis
- Clinical Definition: Productive cough for 3 months in 2 consecutive years
- Morphology: Hypertrophy of mucus-secreting glands ( Reid index 0.4 ) + goblet cell metaplasia
What our notes say
- Air pollution and smoking are key causes for chronic bronchitis. (Respiratory system pathology mcqs — Past Paper Questions & Answers)
- Chronic bronchitis: a clinical diagnosis: productive cough on most days for at least 3 months in each of 2 consecutive years, with other causes excluded. (Bronchitis (Acute and Chronic))
- | Amoxicillin | Penicillin | Only if systemically unwell, frail or in a purulent chronic bronchitis exacerbation | Rash, diarrhoea | (Bronchitis (Acute and Chronic))
- Chronic bronchitis: goblet cell and mucous gland hypertrophy, airway inflammation (neutrophils, macrophages, CD8 T cells), luminal narrowing. (Chronic Obstructive Pulmonary Disease (COPD))
- "Pink puffer" (emphysema: breathless, thin, no cyanosis) versus "blue bloater" (chronic bronchitis: cyanosed, oedematous): a descriptive pair, with most patients having a mixture. (Chronic Obstructive Pulmonary Disease (COPD))
- Occupational COPD and chronic bronchitis: dusts and fumes. (Occupational Lung Disease)
Study material on Chronic Bronchitis
- Lung Pathology — Must-Know
- Respiratory System Pathology 1A
- Medical MCQs: Chemical Pathology & Haematology Exam Review
- Respiratory system pathology mcqs
- Bronchitis (Acute and Chronic)
- End Sem Cat: Respiratory Pathology: Emphysema, ARDS, Pneumoconiosis
- Chronic Obstructive Pulmonary Disease (COPD)
- Examination of Respiratory system
- Dr. Irungu Notes
- Cardiovascular system examination revised 2012
Practice questions on Chronic Bronchitis
The Reid index in chronic bronchitis is
- Ratio of alveolar wall thickness to capillary diameter
- Ratio of submucosal gland thickness to bronchial wall thickness
- Ratio of FEV1 to FVC on spirometry
- Ratio of goblet cells to ciliated cells in epithelium
Answer: B. The Reid index measures submucosal gland layer thickness divided by bronchial wall thickness. Normal is ≤0.4; chronic bronchitis exceeds 0.4 due to gland hypertrophy. ---