Introduction
Bronchial asthma is a chronic inflammatory disease of the airways that is characterized by hyper responsiveness of the tracheo-bronchial tree to a multiplicity of stimuli.
Manifests physiologically by wide-spread
airway narrowing and clinically by
paroxysmal attacks of dyspnoea, cough and wheezing.
Acute episodes are interspersed with
symptom-free periods.
Clinical features of bronchial asthma
- Episodic dyspno
- Cough: unproductive, or productive of scanty sputum
- Wheezing
- Tachycardia
- Tachypnoea
- Mildly raised blood pressure
- Pulsus paradoxus in severe attacks
- Rhonchi: inspiratory and expiratory
- Prolonged expiration
- Silent chest (an ominous sign)
Differential diagnoses
- Chronic bronchitis
- Left ventricular failure
- Glottic dysfunction with respiratory obstruction
- Recurrent pulmonary emboli
- Eosinophilic pneumonia
- Carcinoid tumour
Complications of bronchial asthma
- Spontaneous pneumothorax
- Pneumo-mediastinum
- Atelectasis
Investigations
Diagnosis of bronchial asthma is based on:
- Airway reversibility to inhaled ß-adrenergic agonist
- Isocapnoeic response to hyperventilation of cold air
- Chest radiograph: hyperinflation
- Sputum eosinophilia
Treatment for bronchial asthma
Treatment objectives
The following are the treatment objectives of bronchial asthma:
- Arrest and reverse acute episodes
- Prevent (or at least reduce) frequencies of asthmatic attacks
- Achieve a stable asymptomatic state
- Maintain the best pulmonary function possible.
Drug treatment
A. Acute asthma episodes:
1. Nebulised salbutamol
Adult and child over 18 months:
- 2.5 mg repeated up to 4 times daily; may be increased to 5 mg if necessary
Child under 18 months:
- 1.25 2.5 mg up to 4 times daily
More frequent administration may be
needed in severe cases
2. Intravenous aminophylline
In patients not previously treated with theophyilline and without contraindications.
Adult:
- 250 – 500 mg slowly (with close monitoring) over 20 minutes
Child 1 month-18 years:
- by intravenous injection 5mg/kg (maximum 500 mg), and then by intravenous infusion
3. Intravenous steroids
4. Adequate hydration
5. Oxygen
B. Chronic management
This is based on severity:
1. Intermittent symptoms
- Inhaled salbutamol on as-needed basis
2. Mild persistent asthma
Inhaled salbutamol
Adult:
- 100-200 μg for persistent symptoms up to 4 times daily
Child 1 month – 18 years:
- 100 – 200 μg (1-2 puffs) up to 4 times daily (for occasional use only)
Plus:
Inhaled corticosteroid
- Beclomethasone dipropionate 100 μg 3-4 times daily.
3. Moderate persistent asthma
Inhaled salbutamol
Adult:
- 100 – 200 μg for persistent symptoms up to 4 times daily
Child 1 month – 18 years:
- 100-200 μg (1-2 puffs) up to 4 times daily (for occasional use only)
Plus:
Inhaled corticosteroid
Beclomethasone dipropionate
Adult:
- 100 μg 3-4 times daily
Child
- under 2 years: 50 μg every 12 hours;
- 2-5 years: 100-200 μg every 12 hours;
- 5-12 years: 100-200 μg every 12 hours;
- 12 – 18 years: 100 – 400 μg every 12 hours
Plus:
Long-acting β₂ agonist
Salmeterol
Adult:
- 50 μg twice daily, up to 100 μg
Child
- 2-4 years: 25 μg (1 puff) every 12 hours;
- 4-12 years: 50 μg (2 puffs) every 12 hours;
- 12 18 years: 50 – 100 μg (2-4 puffs) every 12 hours
4. Severe persistent asthma
Inhaled salbutamol
Adult and child up over 18 months:
- nebulizer 2.5 mg repeated up to 4 times daily; may be
increased to 5 mg if necessary
Child under 18 months:
- 1.25 2.5 mg up to 4 times daily
Repeated administration may be required in severe cases
Long-acting β₂ agonist
Adult:
- 50 μg twice daily up to 100 μg
Child
- 2-4 years: 25μg (1 puff) every 12 hours;
- 4-12 years: 50 μg (2 puffs) every 12 hours;
- 12-18 years: 50 – 100 μg (2-4 puffs) every 12 hours
Oral corticosteroid
Prednisolone
Adult:
40 – 50 mg orally daily for a few days, and then reduce gradually
Child:
- 1-2mg/kg orally once daily for 3-5days
Supportive measures
- Supplemental oxygen
- Hydration
- Education on care and precipitating factors
Caution
In all cases, prescribers/dispensers should consult product literature to confirm the strengths of various aerosol preparations
Aminophylline
- Do not exceed 500 mg in 24 hours because of the risk of cardiac arrhythmias
- Avoid in elderly or in patients with arrhythmias and hyperthyroidism
- Exercise caution in hypertensive patients
- May cause CNS stimulation with
insomnia and convulsions
Steroids
- Immuno suppression, metabolic derangements, etc
- Care should be taken in withdrawing steroids
Prevention of bronchial asthma
How to prevent bronchial asthma include the following:
- Avoid precipitating factors
- Appropriate use of medicines
- Training of patients in the techniques of the proper use of aerosols/spacer devices is important