Physicians Sharpen Focus on Little-Known Lung Disease
Bronchiectasis is an under-diagnosed disease -- with the potential to cause devastating lung damage.
It affects the walls of the large airways of the lung, slowly destroying the muscles and the elastic tissues that line the bronchial tubes. Normal airways are built to contract and funnel mucus out of the lungs. But when the airways become distorted and scarred by repeated infections, they can no longer clear out normal secretions. Mucus accumulates, forming a breeding ground for bacteria and inflammation, causing further damage. As the disease progresses, it creates irregularly shaped pockets in the airways, a home for still more infections.
"This is a cumulative process, one that develops over a long time, so early diagnosis can make a huge difference," said lung specialist Pamela McShane, MD. "The sooner we can intervene, before serious damage is done, the better we can control the process. We can't reverse the damage that has been done, but we can slow it down and often hold it in check."
"Unfortunately," said McShane, who has developed a large registry of patients with bronchiectasis to study the natural history of this disease and provide the opportunity for patients to participate in research trials, "the disease is often misdiagnosed. Despite growing awareness of this problem, we often see patients who have been struggling for years."
Such patients have been mislabeled as having chronic bronchitis, or asthma, or they blame their nagging cough on smoking. "But this is a different disease with a different natural history," she added. "Effective treatment begins with a correct diagnosis."
Bronchiectasis increases with age. Fewer than 1 out of 20,000 people age 18 to 34 have the disease but that rises to about one in 350 people by age 75. A 2005 study estimated that 110,000 persons in the United States receive treatment for bronchiectasis each year, resulting in additional medical-care expenditures of $630 million annually. Another study found that hospitalization for bronchiectasis has been increasing by more than five percent a year since 2001.
Classic symptoms include a cough that never goes away and increased sputum production. Some patients have frequent bouts of pneumonia. Shortness of breath and increasing fatigue follow as lung function decreases. Advanced disease can lead to heart failure.
Although a patient's history can indicate probable bronchiectasis, definitive diagnosis often comes from a high-resolution CT scan. These detailed images can reveal the thickening of the walls of the bronchial tubes and the misshapen, damaged or collapsed airways. Pulmonary function studies can assess the type and severity of the disease and measure the benefits of treatment.
Bronchiectasis can't be cured. Treatment is based on clearing mucus from the lungs, preventing infections and reducing inflammation. With proper treatment, most people with this disease can live a normal life. The sooner the disease is detected and treated, however, the better the chance of preventing serious damage to the lungs.
Living with this disease process requires diligence and commitment. One mainstay of treatment, clearing mucus out of the lungs, is often compared to "forcefully emptying the last remnants from a ketchup bottle." It combines postural drainage (placing the head lower than the chest) with chest percussion (thumping over the lungs to dislodge pooled secretions).
Patients are also encouraged to drink lots of fluids to keep secretions flowing and to exercise frequently to help clear the lungs and maintain cardiovascular health. Many patients also benefit from frequent, even constant, antibiotic use, often delivered directly to the lungs with a nebulizer, as well as medications to dilute mucus, dilate the airways and decrease inflammation.
For some patients, surgery is another option. Cutting out a damaged airway can help, or removing part of the lung that acts as a reservoir for frequent infections. A lung transplant may be considered in severe cases.
Bronchiectasis can develop at any age, said McShane, who is working to clarify the role that immune deficiency, autoimmunity, and ethnicity may play in the cause and natural history of bronchiectasis. It begins most often in childhood, but symptoms may not appear until much later.
There is usually an underlying medical condition, an inherited disease such as cystic fibrosis, or an environmental trigger such as exposure to caustic fumes, a major lung infection, or a blocked airway. Although physicians historically could connect fewer than half of all cases to a probable cause, McShane and colleagues were able, in a recent study, to determine an etiology -- most often to an immune deficiency or an autoimmune process -- in 93 percent of their cases.
"There are many possible causes and we have more and more treatment options," said McShane. Many patients, if caught early enough and treated aggressively, can lead a fairly normal life -- depending on the underlying cause. But in all cases, “the sooner the disease is detected and diagnosed, the better the prognosis."