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Asthma is the most common chronic disease among children. At least 75 percent of asthmatic patients demonstrate immediate hypersensitivity to common aeroallergens. Asthma triggers include viral infections; environmental pollutants, such as tobacco smoke; certain medications, (aspirin, nonsteroidal anti-inflammatory drugs), and sustained exercise, particularly in cold environments asthma, asma
Diagnosis
History
Symptoms of episodic complaints of breathing difficulties, seasonal or nighttime cough, prolonged shortness of breath after a respiratory infection, or
Reversible airways disease does not always represent asthma. Wheezing may persist for weeks after an acute bronchitis episode. Patients with chronic obstructive pulmonary disease may have a
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Asthma Triggers |
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Sources of inhaled allergens House dust mites Animal danders from house pets Pollen Fungal spores Cockroaches Animal urine from laboratory animals Infections Viral respiratory infections Sinusitis Gastroesophageal reflux Sulfites (used as preservatives in food, beer and wine) |
Environmental irritants/precipitants Tobacco smoke Cold air Exercise Particulates from wood stoves Air pollution Chemical gases or fumes Drugs Aspirin Nonsteroidal anti-inflammatory drugs Angiotensin converting enzyme inhibitors Beta blockers |
Physical examination. Hyperventilation, use of accessory muscles of respiration, audible wheezing, and a prolonged expiratory phase are common. Increased nasal secretions or congestion, polyps, and
Measurement of lung function. An increase in the forced expiratory volume in one second (FEV1) of 12 percent after treatment with an inhaled beta2 agonist is sufficient to make the diagnosis of
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Asthma Classification |
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Symptoms |
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Classification |
Daytime |
Nighttime |
Lung function |
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Mild intermittent |
Symptoms occur up to 2 times/week; exacerbations are brief (hours to days), with normal PEFR and no symptoms between exacerbations |
Symptoms occur up to 2 times/month |
PEFR or FEV1 $80% of predicted; <20% variability in PEFR |
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Mild persistent |
Symptoms occur more than 2 times/week but less than one time/day; exacerbations may affect normal activity |
Symptoms occur more than 2 times/month |
PEFR or FEV, $80% of predicted; PEFR variability 20-30% |
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Moderate persistent |
Symptoms occur daily; daily need for inhaled short-acting beta2 agonist; exacerbations affect normal activity; exacerbations occur more than 2 times/week and may last for days |
Symptoms occur more than one time/week |
PEFR or FEV1 >60 but <80% of predicted; PEFR variability >30% |
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Severe persistent |
Symptoms are continual; physical activity is limited; exacerbations are frequent |
Symptoms are frequent |
PEFR or FEV1 <60% of predicted; PEFR variability >30% |
Treatment
Allergen avoidance. Patients should avoid opening windows and using unfiltered window fans. Elimination of allergens from house dust mites and
Long-term control medications
Corticosteroids
Glucocorticoids provide anti-inflammatory effects and reduce bronchial hyperactivity. Inhaled corticosteroids are first-line agents in patients who require daily asthma therapy. No specific inhaled
Prednisone, prednisolone or methylprednisolone ( Solu-Medrol), 40 to 60 mg qd; for children, 1 to
Cromolyn sodium (Intal, Nasalcrom) and nedocromil sodium (Tilade) are anti-inflammatory
Leukotriene modifiers
Zafirlukast ( Accolate), montelukast ( Zyflo) interfere with the actions of leukotriene inflammatory mediators, preventing bronchoconstriction. Zileuton is a 5-lipoxygenase inhibitor. Zafirlukast is a leukotriene receptor antagonist. Montelukast is similar to zafirlukast but is taken only once per day at night. Zafirlukast must be taken on an empty stomach.
Zafirlukast and zileuton may interfere with the metabolism of warfarin (Coumadin).
Zileuton has been associated with elevated levels of liver enzymes; thus, periodic monitoring of alanine transaminase is required. Zafirlukast (Accolate, 20 mg bid, on an empty stomach), montelukast (Singular, 10 mg PO qhs) and zileuton (Zyflo, 600 mg PO qid) are alternatives for patients with mild
Long-acting beta2 agonists. If inhaled anti-inflammatory medications do not prevent asthma symptoms, an inhaled long-acting beta2 agonist may be added. Long-acting beta2 agonists relax bronchial smooth muscle. Salmeterol (Serevent, 2 puffs bid), a long-acting beta2 agonist, has a slower onset of action (up to 30 minutes) but a longer duration (at least 12 hours) than short-acting beta2
Methylxanthines use has declined with the arrival of safer and more effective medications. However, they still have a role in asthma therapy when newer anti-inflammatory medications fail to provide relief. Theophylline produces smooth muscle relaxation resulting in bronchodilation but also improves
Management of acute exacerbations
High-dose, short-acting beta2 agonists delivered by a metered-dose inhaler with a volume spacer or via a nebulizer remain the mainstays of urgent treatment. Nebulized ipratropium bromide