(See also Overview of Environmental Pulmonary Disease.)
Beryllium exposure is a common but underrecognized cause of illness in many industries, including beryllium mining and extraction, alloy production, metal alloy machining, electronics, telecommunications, nuclear weapon manufacture, defense industries, aircraft, automotive, aerospace, metal scrap, jewelry making, dental/alloy appliance, computer, and electronics recycling. Because small amounts of beryllium are toxic and are added to many copper, aluminum, nickel, and magnesium alloys, workers are often unaware of their exposure and its risks.
Acute beryllium disease is a chemical pneumonitis causing diffuse parenchymal inflammatory infiltrates and nonspecific intra-alveolar edema. Other tissues (eg, skin, conjunctivae) may be affected. Acute beryllium disease is now rare because most industries have reduced exposure levels, but cases were common between 1940 and 1970, and many cases progressed from acute to chronic beryllium disease.
Chronic beryllium disease remains a common illness in industries that use beryllium and beryllium alloy. It differs from most pneumoconioses in that it is a cell-mediated hypersensitivity disease. Beryllium is presented to CD4+ T cells by antigen-presenting cells, principally in HLA-DP molecules. T cells in the blood, lungs, or other organs, in turn, recognize the beryllium, proliferate, and form T-cell clones. These clones then release proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-2, and interferon-gamma. These cytokines amplify the immune response, resulting in formation of mononuclear cell infiltrates and noncaseating granulomas in target organs where beryllium has deposited.
On average, about 2% to 6% of beryllium-exposed people develop beryllium sensitization (defined by positive blood lymphocyte proliferation to beryllium salts in vitro), with most sensitized people progressing to disease. In certain high-risk groups, such as beryllium metal and alloy machinists, chronic beryllium disease prevalence is > 17%. Workers with bystander exposures, such as administrative assistants and security guards, also develop sensitization and disease but at lower rates.
The typical pathologic consequence is
Diffuse pulmonary, hilar, and mediastinal lymph node granulomatous reaction that is histologically indistinguishable from sarcoidosis
Early granuloma formation with mononuclear and giant cells can also occur.
Many lymphocytes are found when cells are washed from the lungs (bronchoalveolar lavage) during bronchoscopy. These T cells proliferate when exposed to beryllium in vitro, much as the blood cells do (a test called beryllium lymphocyte proliferation test [BeLPT]).
Patients with chronic beryllium disease often have dyspnea, cough, night sweats, fatigue, weight loss, and a variable chest x-ray pattern, typically showing nodular opacities in the mid and upper lung zones, frequently with hilar and mediastinal adenopathy. Patients complain of insidious and progressive exertional dyspnea, cough, chest pain, weight loss, night sweats, and fatigue. Symptoms may develop within months of first exposure or > 30 years after exposure has ceased. Some people remain asymptomatic.
Diagnosis of beryllium disease depends on a history of exposure, the appropriate clinical manifestations, and an abnormal beryllium lymphocyte proliferation test (BeLPT, in which lymphocytes are cultured with beryllium sulfate) done on blood, bronchoalveolar lavage fluid, or both. Diagnosis of beryllium disease requires 2 abnormal BeLPT results or one abnormal and one borderline result from peripheral blood, or a single abnormal BeLPT result from bronchoalveolar lavage cells.
Acute beryllium disease is distinguished from chronic disease based on history of a very high level of exposure followed by acute onset of dry cough and progressive dyspnea on exertion in addition to systematic signs and symptoms (conjunctivitis, dermatitis, pharyngitis, laryngotracheobronchitis). Further, radiographic findings occur within 1 to 3 weeks of exposure.
In chronic beryllium disease, the signs and symptoms are present for at least a year and the clinical presentation can be varied from asymptomatic to dry cough, progressive dyspnea, fatigue, and night sweats (1). BeLPT done on bronchoalveolar lavage cells is highly sensitive and specific, helping to distinguish chronic beryllium disease from sarcoidosis and other forms of diffuse pulmonary disease. Because serum angiotensin converting enzyme levels are not sensitive and, when positive, fail to distinguish between exposure and disease, these levels are not routinely measured (2).
Chest x-ray may be normal or show diffuse infiltrates that can be nodular, reticular, or have a hazy ground-glass appearance, often with hilar adenopathy resembling the pattern seen in sarcoidosis. A miliary pattern also occurs. High-resolution (thin-section) CT is more sensitive than x-ray, although cases of biopsy-proven disease occur even in people with normal imaging test results.
1. Stoeckle JD, Hardy HL, Weber AL: Chronic beryllium disease: Long-term follow-up of sixty cases and selective review of the literature. Am J Med 46 (4):545–561, 1969.
2. Newman LS, Orton R, Kreiss K: Serum angiotensin converting enzyme activity in chronic beryllium disease. Am Rev Respir Dis 146 (1):39–42, 1992.
Acute beryllium disease can be fatal, but prognosis is usually excellent unless progression to chronic beryllium disease occurs. Chronic beryllium disease often results in progressive loss of respiratory function. Early abnormalities include air flow obstruction and decreased oxygenation on arterial blood gas (ABG) at rest and during exercise testing. Decreased diffusing capacity for carbon monoxide (DLCO) and restriction appear later. Pulmonary hypertension and right ventricular failure develop in about 10% of cases, with death due to cor pulmonale.
Beryllium sensitization progresses to chronic beryllium disease at a rate of about 6% per year after initial detection through workplace medical surveillance programs. Subcutaneous granulomatous nodules caused by inoculation with beryllium splinters or dust usually persist until excised.
In acute beryllium disease, the lungs often become edematous and hemorrhagic. Mechanical ventilation is necessary in severely affected patients.
In chronic beryllium disease, some patients never require treatment because the disease progresses relatively slowly. When needed, treatment is with corticosteroids, which decrease symptoms and improve oxygenation. Treatment is generally started only in patients with significant symptoms and evidence of abnormal gas exchange or evidence of an accelerated decline in lung function or oxygenation. The overall mortality rates reported are between 5 and 38% (1).
In symptomatic patients with abnormal pulmonary function, prednisone 40 to 60 mg orally once a day or every other day is given for 3 to 6 months. Then, measures of pulmonary physiology and gas exchange are repeated to document a response to therapy, and the dose is gradually tapered to the lowest dose that maintains symptomatic and objective improvement (usually about 5 to 10 mg orally once a day or every other day). Lifelong treatment with corticosteroids is usually required. Inhaled corticosteroids do not appear to improve lung function but can be considered for symptomatic relief of cough and dyspnea for patients who are not taking systemic corticosteroids (2). There is anecdotal evidence that the addition of methotrexate (10 to 25 mg orally once a week) reduces the need for corticosteroids as it does in sarcoidosis. Azathioprine, which is also used in sarcoidosis, has not been recommended in chronic beryllium disease.
Spontaneous remission of chronic beryllium disease is rare. In patients with end-stage disease, lung transplantation can be lifesaving. Other supportive measures, such as supplemental oxygen therapy, pulmonary rehabilitation, and drugs for treatment of right ventricular failure, are used as needed.
1. Newman LS, Lloyd J, Daniloff E: The natural history of beryllium sensitization and chronic beryllium disease. Environ Health Perspect 104 (Suppl 5):937–943, 1996.
2. Mroz MM, Ferguson JH, Faino AV, et al: Effect of inhaled corticosteroids on lung function in chronic beryllium disease. Respir Med 138S: S14–S19, 2018. doi: 10.1016/j.rmed.2018.01.009
Industrial dust suppression is the basis for preventing beryllium exposure. Exposure must be limited to levels that are as low as reasonably achievable; 0.2 micrograms per cubic meter of air, averaged over 8 hours and limited short-term exposure to 2.0 micrograms per cubic meter of air, over a 15-minute sampling period (see OSHA Final Rule to Protect Workers from Beryllium Exposure).
Medical surveillance, using blood BeLPT and chest x-ray, is recommended for all exposed workers, including those with indirect contact. Both acute and chronic disease must be promptly recognized and affected workers removed from further beryllium exposure. High-risk individuals should be screened for lung cancer using low-dose CT (1).
1. Markowitz SB, Manowitz A, Miller JA, et al: Yield of low-dose computerized tomography screening for lung cancer in high-risk workers: The case of 7189 US nuclear weapons workers. Am J Public Health 108(10): 1296–1302, 2018.
Beryllium disease is under recognized and affects workers in many industries.
Consider high-resolution CT and beryllium lymphocyte proliferation test (using blood or bronchoalveolar lavage cells) to confirm the diagnosis.
Treat symptomatic patients with corticosteroids.
Prevention involves suppression of beryllium dust and surveillance of exposed workers.
Balmes JR, Abraham JL, Dwiek RA, et al: An official American Thoracic Society statement: Diagnosis and management of beryllium sensitivity and chronic beryllium disease. Am J Respir Crit Care Med 190(10):e34–e59, 2014. doi: 10.1164/rccm.201409-1722ST