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. Pathogenesis
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, CD+4 T-lymphocytes and plasma cells aggregate together to form the noncaseating granulomas. 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. Eventually, the outcome is fibrosis of the lung.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 CBD. The HLA-DPB1 gene is important for MHC class II molecule function on antigen presenting cells.According to the International Agency for Research on Cancer (IARC), beryllium and beryllium compounds are Category 1 carcinogens; they are carcinogenic to both animals and humans. Diagnosis
The differential diagnosis for berylliosis includes:
Sarcoidosis
Granulomatous lung diseases
Tuberculosis
Fungal infections (e.g., histoplasmosis)
Granulomatosis with polyangiitis
Idiopathic pulmonary fibrosis
Hypersensitivity pneumonitis
AsthmaOf these possibilities, berylliosis presents most similarly to sarcoidosis. Some studies suggest that up to 6% of all cases of sarcoidosis are actually berylliosis.Definitive diagnosis of berylliosis is based on history of beryllium exposures, documented beryllium sensitivity and granulomatous inflammation on lung biopsy.
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). Beryllia was used in lamp manufacture because of ceramics obvious virtues for insulation and heat resistance, and also because beryllia could be made transparent. 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. Prevention
Typical levels of beryllium that industries may release into the air are of the order of 0.01 µg/m3, averaged over a 30-day period, or 2 µg/m3 of workroom air for an 8-hour work shift. Compliance with the current U.S. Occupational Safety and Health Administration (OSHA) permissible exposure limit for beryllium of 2 µg/m3 has been determined to be inadequate to protect workers from developing beryllium sensitization and CBD. The American Conference of Governmental Industrial Hygienists (ACGIH), which is an independent organization of experts in the field of occupational health, has proposed a threshold limit value (TLV) of 0.05 µg/m3 in a 2006 Notice of Intended Change (NIC).