What is berylliosis?
Berylliosis is type of lung disease caused by inhaling beryllium. It only affects a small proportion of people exposed to beryllium and is mainly seen among beryllium workers. Beryllium is a metal that is not commonly encountered in everyday life . Therefore berylliosis is primarily an occupational lung disease. It can be inhaled as a dust or vapor. Beryllium inhalation can cause two types of lung conditions – one is an acute pneumonitis and the other is a chronic granulomatous lung disease. It is the chronic form which is known as berylliosis but the term is often loosely used even for the acute form of beryllium lung diseae.
Beryllium exposure mainly occurs in workers handling the metal or items containing beryllium. The metal enters the body mainly through the lungs during inhalation but can also enter through contact with broken skin. Beryllium on its own can be eliminated from the body over time as it passed out through the urine over weeks and months. However, different compounds containing beryllium (where beryllium is bonded to other substances) may not be eliminated as easily and could be retained permanently in the body.
Workers dealing with beryllium processing and production, metal works and scrap metal processing are at the highest risk of exposure. People exposed to end products containing beryllium are not at risk of developing berylliosis. Therefore consumers can rest assured in purchasing and utilizing products beryllium-containing products. However, sanding or drilling these products can be dangerous as beryllium dust may become airborne and then inhaled.
Types of Lung Disease
Beryllium inhalation can lead to either acute or chronic lung disease.
Acute Beryllium Disease
The acute form of beryllium lung disease is a form of chemical pneumonitis. This means that the lung tissue is inflamed because it is irritated by beryllium. It has become a rare form of beryllium lung disease as modern occupational health practices has virtually eradicated it from the workplace in developed nations.
Chronic Beryllium Disease
The chronic form of beryllium lung disease is known as berylliosis. People who develop this type of beryllium lung disease have a genetic susceptibility. It is type of granulomatous pulmonary disease that causes destruction of the lung tissue over a prolonged period of time. There is a gradual decline in lung function and it may eventually lead to respiratory failure.
Lung Damage with Beryllium
In acute beryllium disease, there is non-specific inflammation. If the the exposure is not persistent and once the beryllium is eliminated, inflammation should subside and the lung tissue should heal shortly thereafter. Permanent lung damage and scarring is unlikely to occur. With chronic beryllium disease (berylliosis), the scenario is different. People who develop berylliosis are usually exposed to beryllium on a very regular basis, typically within the workplace. However, in some instances even a single episode of beryllium exposure can lead to berylliosis.
Berylliosis patients are usually hypersensitive to beryllium, possibly as a result of a genetic predisposition. Furthermore the disease may only be detected later in its progression as it is largely asymptomatic in the early stages. All of these factors can lead to severe lung damage in the chronic form of the disease. Berylliosis is a granulomatous lung disease. This means that the immune cells aggregate at the site of beryllium deposition in the lung tissue.
It attempts to wall off the site if the beryllium cannot be eliminated. This aggregation of immune cells is known as a granuloma. It is marked by the presence of large amounts of macrophages, the body’s scavenger cells, which may fuse to form giant cells in a granuloma. Over time scar tissue develops at the site of the granulomas forming nodules that can impair lung function if large or widespread.
Picture of beryllium from Wikimedia Commons
Patients with berylliosis may not have any symptoms for long periods of time. Even when symptoms become evident, it is often vague and non-specific. Without a medical history indicating beryllium exposure, particularly in the work setting, berylliosis may not be suspected at the outset.
The respiratory symptoms are the most prominent :
- Dyspnea (difficulty breathing) is the most common symptom.
- Coughing may develop after some time.
- Chest pain may be present and tends to be worse with deep breathing and coughing.
- Abnormal breathing sounds.
Other symptoms that may also be present with berylliosis includes :
- Swollen lymph nodes.
- Joint pain.
- Skin rashes.
- Enlarged spleen and liver.
- Weight loss.
Causes of Beryllium Lung Disease
Both acute and chronic beryllium lung disease arise with exposure to beryllium dust or vapor. The main route of entry into the body is through the airways when it is inhaled. Chemical pneumonitis, the acute form of beryllium lung disease, can occur in any person who is exposed to the noxious substance. Pneumonitis is inflammation of lung tissue with injury and in this case more specifically due to chemical injury. It is not the same as pneumonia which is primarily an infection.
Chronic beryllium disease (CBD) or berylliosis is an immune mediated reaction that is more likely to occur in genetically predisposed individuals. Susceptible people have the allelic substitution of Glu69 in th HLA-DPB1 gene. It has been found in about 97% of patients with chronic beryllium disease (CBD). However, genetic susceptibility on its own does not mean a person will develop the condition without a certain degree of beryllium exposure, usually seen only in the occupational setting. Some 30% of the general population also have this genetic susceptibility but are not at risk of berylliosis without beryllium exposure.
Tests and Diagnosis for Berylliosis
Berylliosis should be suspected in patients with respiratory symptoms who are known to work in industries dealing with beryllium-containing products. At times there may be abnormalities detected in the lung upon conducting a chest x-ray. However, only about half of all berylliosis patients will have any findings on chest x-ray. A blood BeLPT (beryllium lymphocyte proliferation test) is the preferred method for diagnosing beryllium sensitivity among workers in high risk occupations for developing berylliosis. It can confirm if a patient is sensitized to beryllium.
Other important diagnostic investigations in the evaluation and monitoring of chronic beryllium disease includes :
- High-resolution computed tomography (HRCT) scan of the chest.
- Pulmonary function tests.
- Lung biopsy (not always necessary unless a definitive diagnosis has not been reached or other pulmonary conditions need to be excluded).
Treatment for Chronic Beryllium Lung Disease
Beryllium lung disease should be treated immediately once diagnosed. Rapid intervention may help reduce inflammation and limit scarring in acute cases and at least slow the progression of the disease in chronic cases. Severe cases where there is extensive destruction of the lung tissue may require surgical intervention. The key in the management of beryllium lung disease is to avoid further exposure to the metal.
- Corticosteroids are the drug of choice for treating both acute and chronic beryllium disease. It may be continued indefinitely in low doses for chronic cases.
- Methotrexate reduces immune activity and is only considered for cases that do not respond to corticosteroids.
The only surgical option for chronic cases with extensive lung destruction and poor pulmonary function is lung transplantation.