"The concept of asthma as an inflammatory disease has led to very effective treatments for most asthma patients," said Dr. Spahn, a pediatric pharmacologist at National Jewish. "But something more is happening in the lungs of children with very severe asthma. We need to learn what else is making these kids sick so that we can find medications to help them."
In recent years scientists have come to believe that asthma is a disease caused primarily by long-term inflammation of the airways, which leads to "twitchy" airways and permanent, harmful changes in lung tissue. As a result, anti-inflammatory medications, primarily corticosteroids, have become the cornerstone of asthma treatment. Bronchodilators, which relax airway muscles, are also an important component of asthma treatment, but are not generally believed to treat root causes or to change the course of the disease.
Many severe asthma patients from around the country come to National Jewish for treatment. National Jewish physicians often perform bronchoscopies to obtain tissue from deep in the lungs of their patients. The tissue can provide a clearer picture of the state of the lungs, but, because it is such an invasive procedure, it is not often done to children. The severe nature of the cases seen at National Jewish, however, occasionally warrants these procedures even on children.
Dr. Spahn and his colleagues use results of the bronchoscopies as well as other historical, clinical and pulmonary data to describe six children ages 6 to 17 with severe asthma. Despite aggressive anti-inflammatory treatment with oral corticosteroids, all the patients had uncontrolled asthma. All had been to hospital emergency rooms several times for severe asthma episodes, and four of the six had breathing tubes put down their throats at least once because they had stopped breathing. One patient has died from an asthma exacerbation since being seen at National Jewish.
"These patients have very twitchy, abnormal airways," said Dr. Spahn.
These severely asthmatic patients did not fit the standard inflammation-driven model of asthma. For one, five of the six showed little to no evidence of ongoing inflammation in their lungs. Second, all the patients showed evidence of permanent changes to lung tissue, called remodeling, despite long-term anti-inflammatory therapy. Third, in spite of the apparent remodeling of lung tissue, after treatment at National Jewish, the majority of the patients were able to achieve nearly normal airflow in and out of their lungs.
"These patients clearly do not fit the standard model of asthma," said Dr. Spahn. "They suggest that severe asthma may be a distinct disease, different from mild or moderate asthma. Anti-inflammatory medications are a vital part of treatment for these patients, but they are not enough to control the disease and prevent permanent changes to the lungs."
National Jewish Medical and Research Center is a nonprofit, non-sectarian institution devoted entirely to treating and researching respiratory, allergic and immune-system diseases, including asthma, allergies, turberculosis, emphysema, lupus and other autoimmune diseases.