Bronchial Asthma

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:

  1. Arrest and reverse acute episodes
  2. Prevent (or at least reduce) frequencies of asthmatic attacks
  3. Achieve a stable asymptomatic state
  4. 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:

  1. Avoid precipitating factors
  2. Appropriate use of medicines
  3. Training of patients in the techniques of the proper use of aerosols/spacer devices is important