Your doctor will use your medical history, imaging pattern, symptoms, family history, and test results to investigate the cause. Finding the underlying cause matters: in some cases, treating the root cause can slow or even halt disease progression. More recent guidelines provide a framework for the testing clinicians should consider when evaluating a new bronchiectasis diagnosis.
No Known Cause (Idiopathic) For almost half of BE patients, there is no known cause for why they developed BE, even after extensive testing and evaluation. This is called
idiopathic bronchiectasis.
Previous Serious Lung Infections (Post-Infectious BE) Another common reason for developing BE is lung damage caused by an infection such as pneumonia or nontuberculous mycobacteria. These infections can scar and widen the airways, making it harder to clear mucus.
There is a “chicken-or-the-egg” question about post-infectious BE. In some people, an infection causes airway damage that leads to BE. In others, it may have already been developing, for reasons known or unknown, and the infection simply made symptoms noticeable enough for the diagnosis to be made. Because most people don’t have lung scans prior to becoming sick, it is often impossible to know which came first.
Asthma or Chronic Obstructive Lung Disease (COPD) Asthma or COPD and BE can occur together. In some individuals, long-
standing asthma or COPD may contribute to airway damage that leads to BE. In others, these conditions simply coexist without one causing the other. When asthma or COPD and BE are present, they must be managed together as part of a comprehensive treatment plan.
It’s important to note that while COPD is typically caused by smoking, bronchiectasis is not. Many people are incorrectly diagnosed with COPD for months or years before receiving a proper diagnosis of BE, which can delay appropriate treatment. Poorly controlled COPD can worsen airway inflammation, increase the risk of infections, and make BE symptoms harder to manage. While smoking does not cause BE, quitting smoking is an essential part of treating both COPD and BE.
Aspiration and Gastroesophageal Reflux Disease (GERD) Aspiration and GERD (also called acid reflux) are associated with BE because
they involve stomach contents entering the airways and lungs. Aspiration occurs when food, liquid, saliva, or stomach contents accidentally go into the lungs while swallowing or breathing. GERD is a digestive condition in which stomach contents repeatedly flow backward into the esophagus and throat, especially when lying down or asleep. When stomach contents reach the airways, they can irritate and injure the
airway lining and introduce bacteria. Over time, this repeated exposure can lead to chronic inflammation, recurrent infections, and permanent airway damage. Aspiration and GERD are common in people with BE. Though they commonly coexist with BE, they may not be a primary risk factor for everyone. In some individuals, reflux or aspiration may contribute to the development of BE. In others, BE may already be present, and reflux increases symptoms or the risk of infection. Ongoing management of your GERD may help mitigate this risk.
Autoimmune or Inflammatory Conditions Certain autoimmune diseases, such as rheumatoid arthritis (RA), Sjögren’s disease, Crohn’s disease, and ulcerative colitis, can cause inflammation throughout the body, including the airways. Over time, this inflammation can cause damage and lead to BE. While these causes are less common, identifying and treating the underlying autoimmune condition may help reduce further progression of BE.
Immune System Problems Some people have immune system disorders that make them more likely to develop frequent or severe lung infections. One example is hypogammaglobulinemia, a condition where the body does not produce enough immunoglobulins, which are antibodies that help fight infections. Repeated infections over many years can gradually damage the airways and result in BE. If you have an immune system disorder, it is important to treat it to reduce the risk of BE progression. Your provider may check your immunoglobulin levels as part of the diagnostic workup.
Genetic Conditions Some inherited conditions can lead to BE, with cystic fibrosis (CF) being one of the most well-known. This condition is the result of mutations in the CFTR gene. Although CF is commonly thought of as a severe childhood disease, some adults are now being diagnosed with CFTR gene mutations that cause milder disease. This condition is called CFTR-related BE. Identifying harmful mutations in the CFTR gene as the underlying cause of BE is important because it can help guide treatment and provide information about disease risk
for family members, and ensure care is tailored to your specific cause of BE. Another inherited condition that can lead to BE is primary ciliary dyskinesia (PCD), where the tiny hair-like cilia in the lungs do not work properly. Cilia normally help move mucus out of the airways; when they do not function properly, mucus builds up and repeated infections can occur, eventually leading to BE. Alpha-1 antitrypsin (A1A) deficiency is an inherited genetic disorder causing low levels of a protective protein (AAT) in the blood, leading to early-onset lung disease
(COPD/emphysema, BE) and liver damage. Research is currently being conducted to better understand the role of A1A deficiency in the development of BE.
BE in the Context of Other Conditions In addition to being caused by other conditions or infections, BE often occurs alongside other medical conditions. Recognizing these associations is crucial for comprehensive treatment. Chronic or recurring sinus disease (chronic rhinosinusitis) is another common co-existing condition. The sinuses and lungs are part of the same airway system, and inflammation or infection in one area can affect the other. At the same time, BE makes it harder to clear mucus, which can increase the risk of chronic
sinus infections. Managing sinus disease is therefore an important part of bronchiectasis care. Swallowing problems, other airway diseases, and gastrointestinal issues also warrant attention as part of a holistic care approach. Regardless of the cause, BE should be monitored and you should follow up regularly with your recommended care team.