THE EGYPTIAN SOCIETY OF PEDIATRIC ALLERGY AND IMMUNOLOGY

Asthma Therapy         

Goals of Therapy = Disease Control

- Full participation in physical activity.

- Good school attendance.

- Uninterrupted sleep.

Basic lines of therapy include:-

1. Patient education for allergen avoidance.

2. Bronchodilators (Adjuvant therapy).

3.Anti-inflammatory therapy (cornerstone of therapy)

Acute Asthma

Clinical classification of acute asthma exacerbations

Management of acute asthma exacerbation at hospital:

I. Mild to moderate exacerbations:

1.     Inhaled short acting b2-agonist by metered dose inhaler (MDI) or nebulizer up to 3 doses at 20 min. intervals then every 60 min. for 1-3 hours e.g. salbutamol (5 mg/ml solution for nebulizer). Dose: 0.15 mg/Kg i.e. 0.03 ml/Kg (max. 5 mg i.e. 1 ml) to be diluted in 2 ml normal saline. Nebulization with O2 at 6 L/min. is preferred.

       For children =6 yr of age:-

       b2 agonist by MDI or nebulizer ± ipratropium bromide 250-500 µg at 20 min intervals for 3 doses then every 2-4 hours if needed.

2.     O2 therapy at 2-3 L/min.

3.     Oral systemic corticosteroids: only if there is no response or if the patient recently took oral steroids (before the attack). Prednisone may be used (1-2 mg/Kg/day in a decreasing dose over 5-7 days).

Note: Do not rush into systemic corticosteroids in mild to moderate exacerbations unless indicated.

4. Theophylline indications:-

a)    Patients who have been receiving maintenance theophylline treatment.

b)    Patients  unable  to  tolerate  maximal  treatment  with inhaled b2  agonists.

c)    Patients with severe airway obstruction.

Dose:   20 mg/Kg/day orally in 4 divided doses or 5 mg/Kg  IV over 20 min followed by constant infusion as follows:-

0.5 mg / Kg / hr -------------------->    1-6 months of age

1  mg  / Kg / hr --------------------->    6-12 months

1.2 mg - 1.5 mg/Kg/hr ------------>    1-9 years

0.9 mg / Kg / hr -------------------->    =10 years

Theophylline level should be monitored. Peak serum concentration should not exceed 10 µg/ml.

After 3 hours of emergency room treatment (provided there is no deterioration), assessment should be repeated:

-    If still the patient has moderate attack: admit to hospital.

-    If good response sustained for one hour after the last treatment (PEFR = 70%), discharge home and  continue on inhaled or oral b2 agonist if necessary and continue the course of oral systemic corticosteroid (if started at hospital). Afterwards, start the long term management according to stage and severity of illness.

II. Acute severe asthma:

1.  Inhaled high-dose b2-agonist and anticholinergic by nebulization every 20 minutes or continually for one hour in a dose of 0.5 mg/Kg/hour (0.1 ml/Kg/hr).

2.  Oxygen therapy.

3.  Systemic steroids: Methyl prednisolone (Solu-Medrol) is preferable to hydrocortisone due to lower side effects.

4.  Theophylline: I.V.

* If poor response Admit to ICU:

1-  Baseline  investigations: chest X-ray - urine volume - arterial blood gases.

2-  Oxygen therapy.

3-  Inhaled b2 agonist.

4-  Intravenous theophylline: 0.7 mg/Kg/hr (as drip).

5-  Intravenous fluid therapy: 2/3 maintenance.

6-  Intravenous corticosteroids: hydrocortisone (15-20 mg/Kg/ day in 4 divided doses) or methyl prednisolone in a dose of 1-2 mg/Kg/24 hr for the first 48 hr followed by 1-2 mg/Kg/24 hr (maximum 60 mg) in 2 divided doses until the PEFR is 70% of the personal best or predicted.

If no improvement within 6-12 hours ---------> consider intubation and mechanical ventilation.

Note:- Because b2-agonists may produce hypokalemia, potassium should be added to the I.V. fluids after the patient voids.

III. Impending or actual respiratory arrest

- Admit to ICU.

- Intubation and mechanical ventilation with 100% O2.

- Nebulized b2-agonists and anticholinergics.

- I.V. corticosteroids.

Long Term Management of Chronic Cases

Long term management depends on the ability to characterize asthma into specific stages:-

Quick relief (rescue) therapy at any of the previous steps:

Note: If not relieved refer to previous section on acute asthma management.

Notes:

1-  â Step down :

     Review treatment every 1-6 months. If control is sustained for at least 3 months, a gradual stepwise reduction in treatment is possible.

2-  á Step up :

     If control is not maintained after reviewing the patient's compliance and environmental control.

3-  The severity of the acute attack has no relation to the disease grade i.e. patients with intermittent asthma may develop severe life threatening attacks.

4-  Antibiotics are used only if there is evidence of upper or lower respiratory tract infection.

5-  Bacterial vaccines are of no proven efficacy.

6-     Expectorants and mucolytics are not advisable during bronchospasm. They may be needed after complete bronchodilatation.

7-     Antihistamines may be needed if there is associated nasal or skin allergy.

8-     Some new adjuvant lines of treatment can be considered in mild to moderate cases like leukotriene antagonists e.g. Montelukast.

9-     Reassurance of the child and parents and discussing the prognosis with them are important.

10-  Patients are to be educated how to use inhalation therapy and should be convinced that it is the safest and preferred line of therapy.

 Normal Peak Expiratory Flow Rates

(From Sly RM: Pediatric Allergy. New Hyde Park, NY, Medical Examination Publishing Company, 1985)

Recommendations for 1ry Prevention of Asthma

(1) Non specific measures:

- Breast feeding for 2 years.

- No exposure to tobacco smoke.

- Non traumatic delivery.

- Reduce air pollution.

(2) Allergen avoidance: e.g.

- No solid foods during the first 6 months (delay weaning).

- Eggs and fish after 12 months.

- Consider maternal elimination diet during breast feeding.

- Avoid day care centers during infancy (risk of infection).

Avoidance of Provocative Agents

(1) Viral infections:

-    Avoid contact with infected subjects.

-    Non specific immunopotentiation via breast feeding, proper nutritional support.... etc.

(2) Environmental control:

-    House dust mite control.

-    Animal allergens control (pet avoidance)

-    Cockroach allergens control.

-    Avoid indoor irritants as tobacco smoke, insecticides, volatile agents and any strong odours.

Examples of Available Medications
Used in Asthma

I.     Short acting b2-agonists e.g.

 - Salbutamol 

- Terbutaline

 - Fenoterol

II.   Long acting b2-agonists e.g.

- Salmeterol inhaler (25 mg/puff):
1-2 puffs/12 hours.

 - Formoterol

III.  Anti-cholinergics:  

- Ipratropium bromide by MDI or nebulization.

IV.  Combinations e.g.

- Salbutamol + Beclomethasone DP

- Fenoterol + Ipratropium bromide

- Salbutamol + Ipratropium bromide

- Salmeterol + Fluticasone

V.   Slow release theophyllin e.g.

- Available as tablets or capsules.

- Dose: 15-20 mg/Kg/day in 2 divided doses.

VI.  Na cromoglycate or Nedocromil Na

VII. Inhaled corticosteroides e.g.

 - Beclomethasone DP:
 50 & 100 µg/puff.

 - Budesonide: 200 µg/puff.

 - Fluticasone: 50 & 125 µg/puff.

 - Triamcinolone acetonide: 100µg/puff.

VIII. Anti-leukotrienes:

- Montelukast

- Zafirlukast

IX.  Anti-histamines e.g.

- Promethazine HCl

- Loratidine

- Fexofenadine

- Mequitazine

- Terfenadine

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