Berylliosis

Berylliosis, or beryllium disease, is a lung condition caused by inhalation of the metallic element beryllium (Be). The term “berylliosis” most often refers to chronic beryllium disease (CBD), a painful scarring of the lung tissue. Acute or short-term berylliosis, also called beryllium disease, is a nonspecific inflammatory reaction of the lung tissue in response to direct contact with Be, and can lead to CBD. Berylliosis is almost always caused by workplace exposure to Be. Improved industrial hygiene has almost completely eliminated the acute form of the disease, although CBD remains a problem.

Beryllium occurs naturally in rocks, coal and oil, soil, and volcanic dust. The element has been used in metallurgy at least since the times of the ancient Egyptians. However, Be toxicity was not recognized until the twentieth century, when beryllium began to be widely used in manufacturing and other industrial processes. During the 1930s, beryllium was used to extend the life of fluorescent lights. Acute berylliosis was first reported in England in 1933 and in the United States in 1943. By 1946, chronic berylliosis was described as affecting workers manufacturing fluorescent lamps in Salem, Massachusetts.

Although the use of beryllium compounds in fluorescent lighting was discontinued in 1949, the numbers of other products and processes using beryllium continues to grow. Safety regulations and improved industrial hygiene have almost eliminated acute berylliosis in the United States and other developed countries. However, CBD remains a serious threat for workers in some industries and in some parts of the world.

Beryllium dust and fumes are classified as toxic air pollutants by the U.S. Environmental Protection Agency (EPA). Beryllium and various beryllium compounds are also classified as carcinogens or possible carcinogens, meaning that they may have the potential to cause cancer. Any workplace or industrial process that involves pure Be, beryllium compounds such as beryllium oxide, or beryllium alloys, and that generates beryllium fumes, gases, dust, or other airborne particles poses an occupational exposure risk for berylliosis. Industries and occupations that utilize beryllium include:

Although berylliosis is primarily an occupational disease, other people may be at risk. Family members of beryllium workers may be at risk for Be exposure from dust brought home on a worker's shoes, clothing, hair, or body. There have even been reports of acute berylliosis in janitors and secretaries who may have been exposed to very low levels of beryllium in the workplace. In the United States, beryllium concentrations in the air are generally extremely low; however, Be is released into the air during the burning of coal and oil, and Be concentrations in the outside air can be almost ten times higher than normal in some American cities. People living near industries that process or utilize beryllium or near hazardous landfills with high beryllium concentrations also may be exposed to higher than normal levels. A genetic factor has been identified that appears to increase the risk of developing beryllium sensitization (BeS) and berylliosis after exposure to beryllium.

Berylliosis is classified as a rare disease in the United States, and acute berylliosis has been almost completely eliminated. Berylliosis may be far more widespread in developing countries, where occupational safety standards may be lower and manufacturing processes less regulated. It is estimated that 1–10% of individuals exposed to beryllium develop Be hypersensitivity and that an estimated 2–6% of workers exposed to beryllium dust and fumes eventually develop chronic berylliosis. Among workers who are exposed to the highest levels of inhaled beryllium, such as machinists in beryllium operations, 10–14% have developed chronic berylliosis.

Acute berylliosis is caused by even a brief exposure to a high level of beryllium in the atmosphere that inflames the airways and respiratory tract and causes the lungs redden and swell. Symptoms may begin abruptly, with coughing, shortness of breath, chest pain, and difficulty breathing. Acute berylliosis usually causes severe illness and can lead to weight loss. The eyes and skin may be affected. Although berylliosis usually occurs within months of the exposure, longer exposure to lower concentrations of beryllium can cause acute berylliosis that progresses slowly and that resembles pneumonia or bronchitis.

CBD results from the formation of abnormal lung tissue and enlargement of the lymph nodes. Early-stage berylliosis can have symptoms similar to asthma or acute berylliosis, although symptoms develop more slowly and can vary a great deal. Some patients with CBD have no symptoms, and their cases are detected only through blood tests performed during workplace surveillance. Symptoms of chronic berylliosis may include:

CBD only rarely involves organs other than the lungs, although exposure to beryllium can also cause skin disease. In later stages of berylliosis, there is scarring of the lung tissue. Severe cases may strain the right side of the heart due to increased pressure from lung damage.

Berylliosis may be suspected from the symptoms in patients with a history of beryllium exposure. In such cases, complete occupational, environmental, and medical histories are required. In addition, further testing is necessary, since berylliosis can mimic various other lung diseases. In particular, berylliosis is often misdiagnosed as sarcoidosis, a chronic disease of unknown cause that often affects the lungs. The beryllium lymphocyte proliferation test (BeLPT) is the most definitive diagnostic test for berylliosis. It detects BeS or a hypersensitive allergic-type reaction to beryllium by measuring a beryllium-specific immune response. The BeLPT can also detect early-stage berylliosis. The BeLPT is performed by only a small number of laboratories in the United States. If a BeLPT blood test reveals sensitivity, the test is performed again on cells that are washed from the lungs by a procedure called a bronchoalveolar lavage (BAL).

Diagnosis of berylliosis also includes bronchoscopy—examination of the bronchial tubes—and and pulmonary function tests to evaluate the severity and progression of the disease. A chest x ray may show lung changes that are characteristic of berylliosis. Patients with a positive blood BeLPT, but no lung pathology are considered to be sensitized to Be but without berylliosis.

Chronic berylliosis is treatable but not curable. Management is based on suppressing the hypersensitivity reaction to prevent the development of lung fibrosis, which represents irreversible damage to the lungs. When berylliosis is detected at an early stage, it may be years before any specific treatment is necessary. Corticosteroids, usually prednisone, are often prescribed for berylliosis. Following initial prednisone treatment, the lowest dose that prevents disease progression is maintained, often for life. Corticosteroids have no effect on the scarring of lung tissue and may not alter the progression of the disease. Treatment of severe berylliosis may require supplemental oxygen or bronchodilators, as well as pulmonary rehabilitation.

In the United States, the Occupational Health and Safety Administration (OSHA) is responsible for enforcing workplace regulations on beryllium exposure and for ensuring that employers institute safe-handling procedures and that workers are adequately trained. Concerns about beryllium exposure have increased in recent years, since epidemiological studies have indicated an increased risk for lung cancer among workers exposed to beryllium or those with acute or chronic berylliosis. Development of the BeLPT has allowed at-risk workers to be screened with blood tests for BeS and early-stage CBD. A positive BeLPT is considered evidence of prior exposure to beryllium. In developing countries with relatively unregulated manufacturing industries, berylliosis is presumed to be a serious problem that is both under-recognized and underreported.

Although acute berylliosis can be fatal, most patients recover fully within 7–10 days of the initiation of treatment, and the disease usually causes no permanent aftereffects. Chronic berylliosis ranges from asymptomatic disease to a debilitating and sometimes fatal illness marked by pulmonary failure. Severe lung damage from CBD can place strain on the heart, leading to heart failure. Inhaled beryllium can be solubilized in the lungs and transported to the bone, liver, and kidneys. It may affect other organs as well. Thus, chronic berylliosis often requires lifelong treatment with corticosteroids, and any reduction in the corticosteroid dose may cause the disease to progress.

Eliminating exposure to beryllium is the surest way to prevent berylliosis. Primary preventive measures include skin and respiratory protection and minimizing airborne beryllium dust and particles to prevent sensitization. However, unlike most other occupationally related lung diseases, early detection of berylliosis, prior to the appearance of symptoms, can not only prevent further exposure, it can lead to treatment that may reduce symptoms and prevent disease progression. Screening susceptible workers with the BeLPT is an important preventative measure.

See also Fibrosis ; Industrial hygiene .