Berylliosis | |
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Other names | Chronic beryllium disease (CBD) |
Peribronchal non-necrotizing granuloma from berylliosis | |
Specialty | Pulmonology |
Berylliosis, or chronic beryllium disease (CBD), is a chronic allergic-type lung response and chronic lung disease caused by exposure to beryllium and its compounds, a form of beryllium poisoning. It is distinct from acute beryllium poisoning, which became rare following occupational exposure limits established around 1950. [1] Berylliosis is an occupational lung disease.
While there is no cure, symptoms can be treated. [2]
With single or prolonged exposure by inhalation the lungs may become sensitized to beryllium. Berylliosis has a slow onset and progression. Some people who are sensitized to beryllium may not have symptoms. [1] Continued exposure causes the development of small inflammatory nodules, called granulomas. [3] Of note, the authors of a 2006 study suggested that beryllium inhalation was not the only form of exposure and perhaps skin exposure was also a cause, as they found that a reduction in beryllium inhalation did not result in a reduction in chronic beryllium disease or beryllium sensitization. [4]
Granuloma formation is seen in other diseases such as tuberculosis and sarcoidosis. Sarcoidosis, like berylliosis, also produces granulomas without a necrotic core, and so distinction between the two processes can be difficult.
Ultimately, this process leads to restrictive lung disease (a decrease in diffusion capacity).
The earliest symptoms are typically cough and shortness of breath. [5] Other symptoms include chest pain, joint aches, weight loss, and fever.
Rarely, one can get granulomas in other organs including the liver.
The onset of symptoms can range from weeks up to tens of years from the initial exposure. In some individuals, a single exposure to beryllium can cause berylliosis.
In susceptible persons, beryllium exposure can lead to a cell-mediated immune response. The T-cells become sensitized to beryllium. Each subsequent exposure leads to an immune response involving CD4+ helper T-lymphocytes and macrophages accumulating in the lungs. As this response continues macrophages, CD4+ T-lymphocytes and plasma cells aggregate together to form the noncaseating granulomas. [6] [7] When beryllium is phagocytized by macrophages, the beryllium triggers macrophage apoptosis, thereby reducing beryllium clearance from the lungs and eventually resulting in secondary necrosis and lysis. [8] Eventually, the outcome is fibrosis of the lung. [9] [10]
Several studies have shown that there is a genetic component to beryllium sensitivity. Specifically, those beryllium-exposed workers with a mutation at the HLA-DPB1 Glu69 position have increased prevalence of beryllium sensitization and chronic beryllium disease. [11] The HLA-DPB1 gene is important for MHC class II molecule function on antigen presenting cells. [11] A study of the immune response to beryllium in individuals who express the HLA-DP2 allele found that CD4 T-cells do not detect the Be+ cation itself, but instead detect surface changes in the HLA-DP2/peptide complex in which Be+ is embedded. Those researchers concluded that chronic beryllium disease is a predisposition that lies between "allergic hypersensitivity and autoimmunity." [12]
According to the International Agency for Research on Cancer, beryllium and beryllium compounds are Category 1 carcinogens; they are carcinogenic to both animals and humans. [13]
The differential diagnosis for berylliosis includes: [14]
Diagnosis of berylliosis is based on history of beryllium exposures, documented beryllium sensitivity, and granulomatous inflammation on lung biopsy. Given the invasive nature of a lung biopsy, diagnosis can also be based on clinical history consistent with berylliosis, abnormal chest x-ray or CT scan findings, and abnormalities in pulmonary function tests. [15]
The radiologic and pathologic features of berylliosis are very similar to sarcoidosis. Due to the strong clinical and histopathological resemblance of sarcoidosis and berylliosis, patients are sometimes misdiagnosed with sarcoidosis until the history of exposure to beryllium is elicited and beryllium hypersensitivity demonstrated with specific testing. Some studies suggest that up to 6% of all cases of sarcoidosis are actually berylliosis. [16] [17]
The beryllium lymphocyte proliferation test (BeLPT) is the standard way of determining sensitivity to beryllium. [15] The test is performed by acquiring either peripheral blood or fluid from a bronchial alveolar lavage, and lymphocytes are cultured with beryllium sulfate. Cells are then counted and those with elevated number of cells are considered abnormal. [18] Those exposed persons with two abnormal BeLPT tested with peripheral blood, or one abnormal and one borderline result, are considered beryllium sensitized. Also, those with one abnormal BeLPT tested with fluid from a bronchial alveolar lavage are considered sensitized. [15]
Chest radiography findings of berylliosis are non-specific. Early in the disease radiography findings are usually normal. In later stages interstitial fibrosis, pleural irregularities, hilar lymphadenopathy and ground-glass opacities have been reported. [19] [20] Findings on CT are also not specific to berylliosis. Findings that are common in CT scans of people with berylliosis include parenchymal nodules in early stages. One study found that ground-glass opacities were more commonly seen on CT scan in berylliosis than in sarcoidosis. In later stages hilar lymphadenopathy, interstitial pulmonary fibrosis and pleural thickening. [20]
Berylliosis is an occupational disease. [1] Relevant occupations are those where beryllium is mined, processed or converted into metal alloys, or where machining of metals containing beryllium and recycling of scrap alloys occurs. [21] It is associated with aerospace manufacturing, microwave semiconductor electronics, beryllium mining or manufacturing of fluorescent light bulbs (which once contained beryllium compounds in their internal phosphor coating). [22] [23] [24] Beryllia was used in lamp manufacture because of ceramic's obvious virtues for insulation and heat resistance, and also because beryllia could be made transparent. [25] Certain welding anodes along with other electrical contacts and even non-sparking tools are made of beryllium copper alloy and the subsequent machining of such materials would cause the disease as well.
Because it can be difficult to control industrial exposures to beryllium, it is advisable to use any methods possible to reduce airborne and surface contamination by beryllium, to minimize the use of beryllium and beryllium-containing alloys whenever possible, and to educate people about the potential hazards if they are likely to encounter beryllium dust or fumes. [26] It is important to damp wipe metallographic preparation equipment to prevent accumulation of dry particles. Sectioning, grinding, and polishing must be performed under sufficiently vented hoods equipped with special filters. [27]
On 29 January 2009, the Los Alamos National Laboratory announced it was notifying nearly 2,000 current and former employees and visitors that they may have been exposed to beryllium in the lab and may be at risk of disease. Concern over possible exposure to the material was first raised in November 2008, when a box containing beryllium was received at the laboratory's short-term storage facility. [28]
There is no cure for berylliosis; the goals of treatment are to reduce symptoms and slow the progression of disease. [10] [29]
Although the evidence that stopping exposure to beryllium decreases progression of the disease is limited, [30] it is still considered to be an accepted approach to treatment in any stage of disease. [31]
People with early stages of disease, without lung function abnormalities or clinical symptoms, are periodically monitored with physical exams, pulmonary function testing and radiography. [29]
Once clinical symptoms or significant abnormalities in pulmonary function testing appear, treatments include oxygen and oral corticosteroids and whatever supportive therapy is required. [1] [15] [29]
Overall mortality rates are 5–38%. [32]
The number of workers in the United States exposed to beryllium vary but has been estimated to be as high as 800,000 during the 1960s and 1970s. [33] A more recent study from 2004 estimated the number of exposed workers in the United States to be around 134,000. [34]
The rate of workers becoming sensitized to beryllium varies based on genetics and exposure levels. In one study researchers found the prevalence of beryllium sensitization to range from 9–19% depending on the industry. [35] Many workers who are found to be sensitive to beryllium also meet the diagnostic criteria for chronic beryllium disease. [35] In one study of nuclear workers, among those who were sensitized to beryllium, 66% were found to have chronic beryllium disease as well. [36] The rate of progression from beryllium sensitization to chronic beryllium disease has been estimated to be approximately 6–8% per year. [30] [37] Stopping exposure to beryllium in those sensitized has not been definitively shown to stop the progression to chronic beryllium disease. [30]
The overall prevalence of chronic beryllium disease among workers exposed to beryllium has ranged from 1–5% depending on industry and time period of study. [35] [36] [38]
The general population is unlikely to develop acute or chronic beryllium disease because ambient air levels of beryllium are normally very low (<0.03 ng/m3). [39] However, a study found 1% of people living within 3/4 of a mile of a beryllium plant in Lorain, Ohio, had berylliosis after exposure to concentrations estimated to be less than 1 milligram per cubic metre of air. In the United States the Beryllium Case Registry contained 900 records, early cases relating to extraction and fluorescent lamp manufacture, later ones coming from the aerospace, ceramics and metallurgical industries. [40] [41]
Since the 1920s, beryllium has been used in electronics, ceramics, research and development labs, aircraft, and the atomic energy and defense industry. [26] Cases of bronchitis and pneumonia-like symptoms were reported in Germany and Russia in the 1930s among workers mining and refining beryllium. By 1946, a cluster of cases associated with fluorescent lamp manufacturers were apparent in the United States, and the lamp industry stopped using beryllium in 1949. [31] At that time, most construction trades and industries were unaware of the potential risks associated with beryllium exposure. [42]
It occasionally killed early workers in nuclear weapons design, such as Herbert L. Anderson. [43]
Beryllium sensitivity testing was first performed as a cutaneous beryllium patch test in the early 1950s, but was discontinued due to the test stimulating sensitization or aggravating existing chronic beryllium disease. [44] : 115
In the 1990s, the DOE began screening employees using the BeLPT test in facilities where beryllium was used, to take preventive measures against beryllium exposure. Somewhat alarmingly, clerical staff who were never involved in handling the material had developed asymptomatic sensitivities. [45]
Sarcoidosis is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly affected are the eyes, liver, heart, and brain, though any organ can be affected. The signs and symptoms depend on the organ involved. Often, no symptoms or only mild symptoms are seen. When it affects the lungs, wheezing, coughing, shortness of breath, or chest pain may occur. Some may have Löfgren syndrome with fever, large lymph nodes, arthritis, and a rash known as erythema nodosum.
Pneumoconiosis is the general term for a class of interstitial lung disease where inhalation of dust has caused interstitial fibrosis. The three most common types are asbestosis, silicosis, and coal miner's lung. Pneumoconiosis often causes restrictive impairment, although diagnosable pneumoconiosis can occur without measurable impairment of lung function. Depending on extent and severity, it may cause death within months or years, or it may never produce symptoms. It is usually an occupational lung disease, typically from years of dust exposure during work in mining; textile milling; shipbuilding, ship repairing, and/or shipbreaking; sandblasting; industrial tasks; rock drilling ; or agriculture. It is one of the most common occupational diseases in the world.
Asbestosis is long-term inflammation and scarring of the lungs due to asbestos fibers. Symptoms may include shortness of breath, cough, wheezing, and chest tightness. Complications may include lung cancer, mesothelioma, and pulmonary heart disease.
A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments.
Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis. Silicosis, particularly the acute form, is characterized by shortness of breath, cough, fever, and cyanosis. It may often be misdiagnosed as pulmonary edema, pneumonia, or tuberculosis. Using workplace controls, silicosis is almost always a preventable disease.
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium and space around the alveoli of the lungs. It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage, but in interstitial lung disease, the repair process is disrupted, and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The disease presents itself with the following symptoms: shortness of breath, nonproductive coughing, fatigue, and weight loss, which tend to develop slowly, over several months. The average rate of survival for someone with this disease is between three and five years. The term ILD is used to distinguish these diseases from obstructive airways diseases.
Hypersensitivity pneumonitis (HP) or extrinsic allergic alveolitis (EAA) is a syndrome caused by the repetitive inhalation of antigens from the environment in susceptible or sensitized people. Common antigens include molds, bacteria, bird droppings, bird feathers, agricultural dusts, bioaerosols and chemicals from paints or plastics. People affected by this type of lung inflammation (pneumonitis) are commonly exposed to the antigens by their occupations, hobbies, the environment and animals. The inhaled antigens produce a hypersensitivity immune reaction causing inflammation of the airspaces (alveoli) and small airways (bronchioles) within the lung. Hypersensitivity pneumonitis may eventually lead to interstitial lung disease.
Byssinosis is an occupational lung disease caused by inhalation of cotton or jute dust in inadequately ventilated working environments and can develop over time with repeated exposure. Byssinosis commonly occurs in textile workers who are employed in yarn and fabric manufacture industries. It is now thought that the cotton dust directly causes the disease and some believe that the causative agents are endotoxins that come from the cell walls of gram-negative bacteria that grow on the cotton. Although bacterial endotoxin is a likely cause, the absence of similar symptoms in workers in other industries exposed to endotoxins makes this uncertain. Current smokers are also at risk for developing byssinosis or having complications relating to byssinosis.
Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo-therapy, the inhalation of debris, aspiration, herbicides or fluorocarbons and some systemic diseases. If unresolved, continued inflammation can result in irreparable damage such as pulmonary fibrosis.
Eosinophilic pneumonia is a disease in which an eosinophil, a type of white blood cell, accumulates in the lungs. These cells cause disruption of the normal air spaces (alveoli) where oxygen is extracted from the atmosphere. Several different kinds of eosinophilic pneumonia exist and can occur in any age group. The most common symptoms include cough, fever, difficulty breathing, and sweating at night. Eosinophilic pneumonia is diagnosed by a combination of characteristic symptoms, findings on a physical examination by a health provider, and the results of blood tests and X-rays. Prognosis is excellent once most eosinophilic pneumonia is recognized and treatment with corticosteroids is begun.
Bronchiolitis obliterans (BO), also known as obliterative bronchiolitis, constrictive bronchiolitis and popcorn lung, is a disease that results in obstruction of the smallest airways of the lungs (bronchioles) due to inflammation. Symptoms include a dry cough, shortness of breath, wheezing and feeling tired. These symptoms generally get worse over weeks to months. It is not related to cryptogenic organizing pneumonia, previously known as bronchiolitis obliterans organizing pneumonia.
Occupational lung diseases comprise a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases, infections, lung cancer and mesothelioma. These can be caused directly or due to immunological response to an exposure to a variety of dusts, chemicals, proteins or organisms. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.
Bird fancier's lung (BFL), also known as bird breeder's lung, is a type of hypersensitivity pneumonitis. It can cause shortness of breath, fever, dry cough, chest pain, anorexia and weight loss, fatigue, and progressive pulmonary fibrosis. It is triggered by exposure to avian proteins present in the dry dust of droppings or feathers of a variety of birds. The lungs become inflamed, with granuloma formation. It mostly affects people who work with birds or own many birds.
The Kveim test, Nickerson-Kveim or Kveim-Siltzbach test is a skin test used to detect sarcoidosis, where part of a spleen from a patient with known sarcoidosis is injected into the skin of a patient suspected to have the disease. If non caseating granulomas are found, the test is positive. If the patient has been on treatment, the test may return a false negative result. The test is not commonly performed, and in the UK no substrate has been available since 1996. There is a concern that certain infections, such as bovine spongiform encephalopathy, could be transferred through a Kveim test.
Occupational asthma is new onset asthma or the recurrence of previously quiescent asthma directly caused by exposure to an agent at workplace. It is an occupational lung disease and a type of work-related asthma. Agents that can induce occupational asthma can be grouped into sensitizers and irritants.
Desquamative interstitial pneumonia (DIP) is a type of idiopathic interstitial pneumonia featuring elevated numbers of macrophages within the alveoli of the lung. DIP is a chronic disorder with an insidious onset. Its common symptoms include shortness of breath, coughing, fever, weakness, weight loss, and fatigue. In more severe cases, it may lead to respiratory failure, chest pain, digital clubbing, cyanosis, and hemoptysis. Asymptomatic cases are rare.
Beryllium granulomas is a skin condition caused by granulomatous inflammation of the skin which may follow accident laceration, usually in the occupational setting.
Acute beryllium poisoning is acute chemical pneumonitis resulting from the toxic effect of beryllium in its elemental form or in various chemical compounds, and is distinct from berylliosis. After occupational safety procedures were put into place following the realization that the metal caused berylliosis around 1950, acute beryllium poisoning became extremely rare.
Flock worker's lung is an occupational lung disease caused by exposure to flock, small fibers that are glued to a backing in order to create a specific texture. People who work in flocking are at risk of inhaling small pieces of the flock fibers, which causes interstitial lung disease. The disease was initially described in 1998, when a group of workers at a flocking plant developed interstitial lung disease of unknown cause.
Indium lung is a rare occupational lung disease caused by exposure to respirable indium in the form of indium tin oxide. It is classified as an interstitial lung disease.
Individuals carrying the MHCII allele, HLA-DP2, are at risk for chronic beryllium disease (CBD), a debilitating inflammatory lung condition caused by the reaction of CD4 T cells to inhaled beryllium.