Asthma Overview

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This article presents our current understanding of the biological heterogeneity of asthma and reviews some of the key features of the latest proposed recommendations of the National Asthma Education and Prevention Program Guidelines. The diagnosis of asthma is based on such clinical features as variable airflow obstruction that is partially if not fully reversible and airway hyperresponsiveness that predisposes to episodic bronchospasm following exposure to a variety of triggers. The underlying inflammation and airway biology of asthma is heterogeneous and is part of the explanation for the variable response to therapy. New biologics that help to characterize patients according to their underlying biology will aid in making better choices for treatment. New asthma guidelines emphasize the importance of regular monitoring.

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Burden of illness

Asthma is one of the most common chronic medical conditions in the developed world and is increasing in its prevalence in less developed countries as well. In the United States, over 22.2 million people are diagnosed with asthma [3]. Over 12.2 million people suffer asthma exacerbations (requiring increased asthma therapy and/or additional interventions) each year [3]. The total annual costs of asthma in the United States in 2002 were estimated to be $16.1 billion of which $11.5 billion were

What is asthma?

The clinical presentation of asthma includes typical symptoms of episodic dyspnea variably associated with other symptoms, such as chest tightness, wheezing, and coughing. Typical triggers for asthma symptoms include allergens, exertion, cold air, irritant exposures, and strong odors. The hallmark features of asthma include reversible airflow obstruction (>12% improvement in forced expiratory volume in 1 second [FEV1] with a minimum of 200-mL improvement postbronchodilator), bronchial

Pathogenesis/pathophysiology of asthma

As previously stated, the pathogenesis of asthma is varied and there are several biological pathways, inflammatory cells, and mediators that play varying roles in different patient phenotypes (Fig. 1) [19]. While several inflammatory cell types may play important roles in asthma, eosinophils have classically been identified as part of the most common histological pattern. However, the exact role of eosinophils and their importance remain controversial. Mast cells and basophils, when stimulated

Assessing for the presence of asthma

As noted above, patients suspected of having asthma typically present with a history of episodic shortness of breath associated with chest tightness and variable wheezing and coughing. Typically there are a number of triggers, such as extremes of air temperature and humidity; air pollution; strong odors, such as from perfume and cleaning agents; dust; and smoke. If individuals are known to be atopic, then exposure to common environmental allergens, such as trees, weeds, grasses, animal dander,

Asthma management for infants to age 11

For children from infancy through to the age of 4 (Box 6), there is A-level evidence that inhaled corticosteroids for patients with persistent asthma are safe and effective first-line therapy. Because few drugs are ever studied in this patient population, the level of evidence for use of long-acting beta-agonists, montelukast, and oral steroids at higher severity stages is no higher than D. For children between ages of 5 to 11, studies have shown the benefit of inhaled corticosteroids at all

Asthma treatment for those 12 years or older

For patients 12 years old and older, inhaled corticosteroids are the mainstay of therapy for all steps of asthma care with increasing doses through steps 2 to 6 (level A evidence) (Box 8). For patients with mild moderate asthma (stage 3) long-acting beta-agonists can be added to low-dose corticosteroids if moderate-dose corticosteroids cause too many side effects or are poorly tolerated (level A evidence). When patients have more severe disease, long-acting beta-agonists are considered for

Long-acting beta-agonists

There has been concern recently regarding the safety of such long-acting beta-agonists as salmeterol and formoterol. SMART [5] examined the safety of salmeterol compared with placebo in over 26,000 patients. Patients who stated they had a diagnosis of asthma and were on at least one medication used for asthma (even a short-acting beta-agonist) could be entered into the trial. Patients who had never been on a long-acting beta-agonist were excluded. Patients were given medication for the study

Setting up patients with asthma action plans

In devising asthma action plans for patients, perhaps the first question to ask is: Which asthma patients need such a plan? There has been some debate as to whether plans make a difference and some studies have suggested that outcomes were not significantly altered in groups given action plans compared with those that were not [46], [47], [48]. Nonetheless, it is likely that there are at least some patients for whom action plans are helpful, such as those who have frequent exacerbations and

Summary

The diagnosis of asthma is based on such clinical features as variable airflow obstruction that is partially if not fully reversible and airway hyperresponsiveness that predisposes to episodic bronchospasm following exposure to a variety of triggers, which differ from patient to patient. The underlying inflammation and airway biology of asthma is heterogeneous and is part of the explanation for the variable response to therapy. New biologics, such as anti-IgE agents, and other new techniques

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