DRG Category: 202

Mean LOS: 4.3 days

Description MEDICAL: Bronchitis and Asthma with CC or Major CC

classification section:



Asthma is classified as an intermittent, reversible, obstructive disease of the lungs. It is a growing health problem in the United States, with approximately 20 to 25 million people affected. In the past 20 years, the number of children with asthma has increased markedly, and it is now the leading serious chronic illness in children. Unfortunately, approximately 75% of children with asthma continue to have chronic problems in adulthood. The total deaths annually from asthma has increased by over 100% since 1979 in the United States.

Asthma is a disease of the airways characterized by airway inflammation and hyperreactivity (increased responsiveness to a wide variety of triggers). Hyperreactivity leads to airway obstruction due to acute onset of muscle spasm in the smooth muscle of the tracheobronchial tree, thereby leading to a narrowed lumen. In addition to muscle spasm, there is swelling of the mucosa, which leads to edema. Lastly, the mucous glands increase in number, hypertrophy, and secrete thick mucus.

In asthma, the total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV) increase, but the hallmark of airway obstruction is a reduction in ratio of the forced expiratory volume in 1 second (FEV1) and the FEV1 to the forced vital capacity (FVC).

Although asthma can result from infections (especially viral) and inhaled irritants, it often is the result of an allergic response. An allergen (antigen) is introduced to the body, and sensitizing antibodies such as immunoglobulin E (IgE) are formed. IgE antibodies bind to tissue mast cells and basophils in the mucosa of the bronchioles, lung tissue, and nasopharynx. An antigen–antibody reaction releases primary mediator substances such as histamine and slow-reacting substance of anaphylaxis (SRS-A) and others. These mediators cause contraction of the smooth muscle and tissue edema. In addition, goblet cells secrete a thick mucus into the airways that causes obstruction. Intrinsic asthma results from all other causes except allergies, such as infections (especially viral), inhaled irritants, and other causes or etiologies. The parasympathetic nervous system becomes stimulated, which increases bronchomotor tone, resulting in bronchoconstriction. The classification for asthma is described in Table 9.

Classification of Asthma