Chronic obstructive pulmonary disease COPD
الدكتور خلدون ذنون- كلية طب نينوى- المرحلة الرابعObjectives of COPD
The student should know the following:1. COPD includes chronic bronchitis and emphysema.
2. COPD is a chronic disease, the risk factor is smoking.
3. Obstructive rather than restrictive i.e FEV1/FVC <70%
4. Mild disease: no signs, more severe disease results in cough and
dyspnea with recurrent chest infections.
5. Haemoptysis may herald cancer.
6. CXR and lung functions are important in the diagnosis.
7. Management: Stop smoking, bronchodilators, antibiotics, O2 for
respiratory failure, and may be given at home in advanced state,
ventilators for critical cases, surgery is exceptional. 8. Complications: chest infection, respiratory failure, cor pulmonale.
Definition airway obstruction over several months and is not fully reversible like asthma. It includes:
( Chronic bronchitis
( Emphysema ( Chronic bronchiolitis- small airway disease
Epidemiology
- UK prevalence 1-2%
- 30.000 deaths/year, 6th most common cause of death.
- Causes a lot of morbidity and mortality in developing countries.
Risk factors
- Smoking: the main factor, >10 pack/year i.e 20 cigarette/day/10 years.- Solid fuel fires
- Occupation: coal miners, cadmium
- Air pollution
- Infections
- Genetics: (1 antitrypsin deficiency, airway hyper- reactivity
Pathophysiology
PulmonaryHypertrophy and increase number of goblet cells.
Loss of elastic tissue
Airway inflammation and fibrosis with mucus accumulation.
Airway closure and gas trapping
Proteases and oxidants destruct alveoli ( emphysema
Bullae form in emphysema- impair gas exchange.
Pulmonary hypertension leading to right sided heart failure i.e cor pulmonale.
Flattening of diaphragm and intercostal muscle misalignment.
B. Systemic
Muscle weakness, increase inflammatory markers, salt and water
retention with oedema, weight loss and osteoporosis.
Clinical features
Cough: the earliest symptom, age usually over 40 years, mucoid sputum that changes in colour during chest infection. Chronic bronchitis: cough and sputum on most days for 3 consecutive months for at least 2 years. Haemoptysis may occur but might be due to cancer.
Breathlessness: grade 0- 4 according to severity.
Blue bloaters and pink puffers.
Physical signs occur in advanced COPD
- Pursed lip breathing
- Central cyanosis
- Prolonged expiration
- Reduced cricosternal distance
- Use of accessory muscles
- Intercostal indrawing during inspiration
- Hyperinflated barrel chest
- Cardiac apex is not palpable with loss of cardiac dullness
- Low flat diaphragm
- Warm hands, flapping tremor and drowsiness due to respiratory
failure. - - Raised JVP, hepatomegaly and leg oedema
- Weight loss
- - Increase in resonant percussion note in emphysema.
- Diminished air entry, wheezes and crackles may be heard.
Acute exacerbation of COPD
- Worsening respiratory symptoms and health status due to deteriorationin lung function.
- Causes: bacterial or viral infection, change in air quality.
- It may lead to respiratory failure, fluid retention and death. - Cyanosis, edema and disturbed consciousness: need hospital admission.
Investigation of COPD
1. Chest X-ray: may be normal or show increased bronchovascular
markings, signs of infection, cardiomegaly, signs of emphysema and
bullae also may detect abnormal tumor mass.
2. High resolution CT scan is more sensitive than CXR for diagnosis of
emphysema.
3. Full blood count: increased WBC, anaemia, polycythaemia.
4. (1 antitrypsin: young with emphysema and positive family history.
5. Spirometry - Post bronchodilator FEV1 <80% of predicted value - FEV1/FVC <70% - Increase in lung volumes and residual volume in emphysema. - Decrease gas transfer kco especially in emphysema. - Decrease PEFR
6. Blood gas analysis: may show hypoxia and hypercapnoea in advanced
disease.
Management of COPD
1. Smoking cessation: it is the only method proven to decrease the declinein FEV1, improve lung function and decrease symptoms.
2. Bronchodilators: - Relieves dyspnoea - Inhaled route is advisable - Start inhaled short acting bronchodilators p.r.n (B2 agonist or
anticholinergic sometimes combined). - If still symptomatic use inhaled long acting bronchodilators. - Moderate and severe COPD: add inhaled corticosteroid, discontinue if
no benefit after 4 weeks. - Oral theophylline: added if still symptomatic and for those who can
not use inhalers properly.
3. Corticosteroids - Reduce frequency and severity of acute exacerbations, indicated for
severe disease FEV1<50%, start with inhalers. - Oral steroids are useful during exacerbations, 30mg prednisolone for
10days.
4. Mucolytic therapy for chronic productive cough e.g acetyl cysteine
200 mg oral 8-hourly for 8 weeks, continue if patient improves.
5. Antibiotics: to treat chest infections e.g aminopenicillins, macrolides,
co-amoxiclav.
6. Oxygen therapy - used for exacerbation of severe COPD. - Avoid high concentration of O2, use controlled 02 23-28% =
2-4L/min. to maintain paO2>8Kpa=60mm Hg or 02 saturation >90%.
- Long term domiciliary O2 therapy: * Used via nasal prongs * Used for >15 hours/day in patients with COPD and severe chronic
hypoxia FEV1<1.5L, PO2<7.3kpa =55mm Hg and for those who
desaturate on exercise. * Improves survival, reduce polycythaemia and pulmonary hypertension. * Patient should stop smoking.
7. Diuretics for oedema in cor pulmonale.
8. Venesection for polycythaemia if PCV >0.6, aiming 0.5
9. Non invasive ventilation
- Used to treat acute exacerbation if the patient remains tachypnoeic
and acidotic despite usual measures.
- Reduces the need for endotracheal intubation, hospital stay, and
mortality. - - It is not useful for drowsy and comatosed patients who can not
protect their airways.
10. Doxapram: respiratory stimulant for those with low respiratory rate.
11. Vaccination: influenza and pneumocccal.
12. Manage obesity, loss of weight and improve nutrition.
13. Treat social isolation, depression and anxiety.
14. Pulmonary rehabilitation - Encourage suitable exercise and increase physical fitness. - Patient education.
15. Surgery - Done for selected patients - Bullectomy, lung volume reduction surgery, and lung transplant.
Prognosis - Depends on: degree of airway obstruction, severity of dypnoea,
exercise capacity and body mass index.
- Poor prognosis: increasing age, little increase in FEV1 after
bronchodilators, weight loss, pulmonary hypertension.