Berylliosis is chronic damage to the LUNGS, also called chronic beryllium disease, resulting from industrial exposure to beryllium, a heavy metal that has many commercial uses and applications in contemporary manufacturing processes. Inhaled beryllium fumes and dust cause irritation to the delicate alveoli that activates the body’s IMMUNE RESPONSE. In the United States berylliosis occurs primarily in people who work in the electronics, nuclear, and aerospace industries where beryllium usage is high. People who work in metal machining or alloy reclamation jobs are also at risk. The US Environmental Protection Agency (EPA) classifies beryllium dust and fumes as toxic substances, and the US Occupational Safety and Health Administration (OSHA) has established regulatory guidelines to minimize on-the-job beryllium exposure. Beryllium particles can remain in the lung tissues for six months to several years after exposure.
Berylliosis results from delayed-type hypersensitivity (DTH) in which helper T-cell lymphocytes flood the sites of exposure and encase the beryllium dust particles or the areas of INFLAMMATION, causing granulomas to form. Over time the granulomas evolve into fibromas, well-defined structures of SCAR tissue that replace normal lung tissue. As the penetration of granulomas and fibromas extends deeper into the lungs, the loss of alveolar function cripples the ability of the lungs to pass oxygen to the BLOOD.
Rarely, an individual may develop an immediate response, called acute chemical PNEUMONITIS, to beryllium exposure. Acute chemical pneumonitis requires prompt medical treatment to reduce airway irritation and INFLAMMATION.
Symptoms of Berylliosis and Diagnostic Path
Symptoms of berylliosis are similar to symptoms of other chronic inflammatory diseases affecting the lungs, though employment in an occupation involving beryllium use is a key indication of the cause and nature of disease. Symptoms typically include
- chronic, nonproductive (dry) COUGH
- chest tightness or PAIN
- unintended weight loss
- shortness of breath (DYSPNEA), particularly with exertion
The diagnostic path includes chest X-RAY, BRONCHOALVEOLAR LAVAGE, and a specialized test called the beryllium lymphocyte proliferation test (BeLPT). The pulmonologist may also choose to perform high-resolution COMPUTED TOMOGRAPHY (CT) SCAN, which reveals small lesions within the lungs, and bronchial biopsy via BRONCHOSCOPY to further evaluate lesions that imaging procedures show. Pulmonary function tests and sometimes cardiopulmonary exercise testing can help assess the status of lung capacity and the ability of the lungs to oxygenate the blood. Conclusive diagnosis may require varied and numerous tests as well as thorough medical and personal histories, as berylliosis is similar to other interstitial lung diseases including sarcoidosis.
Berylliosis Treatment Options and Outlook
The first line of treatment is removal from the source of beryllium, which for most people means leaving the jobs that require exposure to beryllium. CORTICOSTEROID MEDICATIONS may help suppress the immune response and subdue the inflammation. However, there is no known medical therapy to treat damage that has occurred to the lungs. Damage that does occur to the lungs is permanent and berylliosis is usually progressive, tending to continue even after exposure to beryllium ends. The resulting damage to the lungs may lead to HEART FAILURE and other cardiovascular health conditions because the HEART cannot pump enough BLOOD to oxygenate the body’s tissues. LUNG TRANSPLANTATION may become a viable treatment option for people who develop complete pulmonary failure.
Risk Factors and Preventive Measures
Recent research suggests GENETIC PREDISPOSITION underlies most cases of berylliosis, with mutations or defects affecting the MAJOR HISTOCOMPATABILITY COMPLEX (MHC), which encodes aspects of immune response. The role of genetic predisposition is not entirely clear, though likely explains why some people who have limited exposure develop serious disease whereas others who have prolonged exposure seem to experience no adverse effects. However, berylliosis occurs only in people exposed to beryllium and nearly all such exposure is occupational, though beryllium is a natural mineral present in the environment. Reducing this exposure through appropriate occupational hygiene and protective measures can significantly reduce the risk of disease development.
|MANUFACTURING JOBS WITH HIGH RISK FOR BERYLLIOSIS|
|aerospace alloys||computer electronics|
|dental alloys (bridges and crowns)||electrode welding|
|electronic resistors||heat sinks|
|jet brake pads||jet turbine blades|
|laser tubes||metal alloy bicycle frames|
|metal working||nuclear weapons|
People who work in industries in which beryllium use is common should be alert to the early symptoms of berylliosis. Contact with or use of products containing beryllium after their production or manufacture does not convey beryllium exposure, however. Screening blood BeLPT tests among people who work with beryllium can identify early indications of immune reactivity, allowing medical intervention to avert extensive damage to the lungs. OSHA recommends the use of powered respirators with high-efficiency particulate air (HEPA) filters and protective clothing in the workplace, as well as safeguards, such as showering and changing into complete street clothes (including shoes) before leaving the workplace.