Asthma

Asthma is a chronic inflammatory condition of the lung airways that is characterized by (1) airway obstruction which is usually reversible; (2) airway hyper-responsiveness; (3) inflammation of the bronchi with epithelial damage, smooth muscle hypertrophy and mucus plugging. It is useful for epidemiologic and clinical purposes to classify asthma by the principal stimuli that incite or are associated with acute episodes. In that sense asthma can be classified as allergic and idiosyncratic asthma (asthma that is not caused by an allergic reaction to a allergic stimulus). 

Clinical suspicion

Clinical picture is highly suggestive with episodic bouts of wheezing, shortness of breath, cough, sense of chest tightness and choking in the neck. The attacks usually occur at night time or on waking up but can occur at any time of the day.

Diagnosis

Confirmation by spirometry is required and is defined as the improvement of obstructive pattern after bronchodilator therapy. Improvement is defined as an increase in FEV(1) by 12% or Forced expiratory flow (FEF) {flow of expiration at midlung volumes} by 35% after 2/3 puffs of a short acting bronchodilator.  

Treatment

Stepwise approach:

Step 1 Mild Intermittent

Patients do not have daily attacks & do not awaken at night.

1. Quick relief: use a beta agonist or anticholinergic bronchodilator as required.
2. No long term therapy needed.

Step 2 Mild Persistent

The administration of a disease-modifying agent is required for patients with daily symptoms or daily use of a bronchodilator.

1. Quick relief: use a beta agonist or anticholinergic bronchodilator as required.
2. Long term therapy: (disease modifying agents) use anti-inflammatory drugs e.g. sodium cromoglycate inhalation or daily inhaled steroids. Sustained-release theophylline to serum concentration of 5-15 �g/mL is an alternative, but not preferred, therapy. Leukotriene modifiers zafirlukast or zileuton may also be considered for patients >/=12 years of age, and montelukast for patients >/=6 years of age, although their position in therapy is not fully established.
3. Nocturnal symptoms: These symptoms may necessitate the addition at night of either a long-acting inhaled beta-adrenergic agonist (e.g., salmeterol, two puffs qhs) or theophylline. Also consider increasing the dose of the disease modifying drug.

Step 3 Severe Persistent

Patients have severe symptoms and control is inadequate despite the use of high-dose inhaled corticosteroids (>20 puffs per day of beclomethasone, triamcinolone, or flunisolide)

1. Quick relief: use a beta agonist or anticholinergic bronchodilator as required.
2. Long term therapy: these patients may require regular use of oral steroids to control symptoms. Fluticasone, 220 mug per puff, is approximately four times more potent per puff than is beclomethasone, triamcinolone, or flunisolide. In patients requiring high-dose inhaled corticosteroids or regular use of oral corticosteroid, fluticasone is very effective in reducing symptoms and in minimizing the effects of oral corticosteroid use. Medications to reduce the need for oral corticosteroids have been studied. Methotrexate or troleandomycin may be useful in some patients. Many of these patients require regular doses of bronchodilators and may benefit from the addition of a long-acting beta₂ -adrenergic agonist (e.g., salmeterol, two puffs bid).

Modifying chronic therapy

Review treatment every 1 to 6 months; a gradual stepwise reduction in treatment may be possible. Evaluate possible signs, symptoms of corticosteroid withdrawal when weaning patient of inhaled steroids.
If control is not maintained, review patient medication technique, adherence, and environmental control (avoidance of allergens or other factors that contribute to asthma severity). May need to increase controller (anti-inflammatory) therapy vs addition of long-acting �-agonist.