Flavorings-Related Lung Disease: Symptoms
The main respiratory symptoms experienced by workers affected by obliterative bronchiolitis include cough (usually without phlegm), wheezing, and worsening shortness of breath on exertion. The severity of the lung symptoms can range from mild cough to severe. These symptoms typically do not improve when the worker goes home at the end of the workday or on weekends or vacations. Usually these symptoms are gradual in onset and progressive, but severe symptoms can occur suddenly. Some workers may experience fever, night sweats, and weight loss. Before arriving at a final diagnosis, doctors of affected workers initially confused the symptoms with asthma, chronic bronchitis, emphysema, pneumonia, or smoking.
Medical testing may reveal several of the following findings:
- Spirometry, a type of breathing test, often shows fixed airways obstruction (i.e., difficulty blowing air out fast and no improvement
with asthma medications) and sometimes shows a restrictive pattern (i.e., decreased ability to fully expand the lungs).
- Lung volumes may show hyperinflation (i.e., too much air in the lungs due to air trapping beyond obstructed airways).
- Diffusing capacity of the lung (DLCO), a type of breathing test, is generally normal, especially early in the disease.
- Chest X-rays are usually normal but may show hyperinflation.
- High-resolution computerized tomography (HRCT) scans of the chest at full inspiration and expiration may reveal heterogeneous
air trapping on the expiratory view as well as haziness and thickened airway walls.
- Lung biopsies may reveal evidence of constrictive obliterative bronchiolitis (i.e., severe narrowing or complete obstruction of the
small airways). An open lung biopsy, such as by thoracoscopy, is typically required for a pathologic diagnosis (in contrast to a
trans-bronchial biopsy). Special processing, staining, and review of multiple tissue sections may be necessary for a diagnosis.
Workers should be promptly referred for further medical evaluation if they have persistent cough; persistent shortness of breath on exertion; frequent or persistent symptoms of eye, nose, throat, or skin irritation; abnormal lung function on spirometry testing; or accelerated decline in lung function. Physicians should advise workers on medical conditions that may be caused or aggravated by work exposures. Additionally, physicians should provide appropriate recommendations for further evaluation and treatment. To date, most cases have shown little or no response to medical treatment. Affected workers generally notice a gradual reduction or cessation of cough years after they are no longer exposed to flavoring vapors, but abnormalities on lung function tests and shortness of breath on exertion persist. Several with very severe disease were placed on lung transplant waiting lists. Workers exposed to flavorings may also experience eye, nose, throat, and skin irritation. In some cases, chemical eye burns have required medical treatment. It is possible that individuals with pre-existing asthma may experience an exacerbation of their asthma due to the irritant properties of flavoring vapors. Diacetyl and other flavoring
compounds have been reported to be sensitizers in rodents.
NIOSH is continuing to evaluate new information pertaining to the risk of obliterative bronchiolitis from occupational exposures to flavorings, in order to determine appropriate further steps to help safeguard workers’ health. We want to hear from workers who have a lung problem they suspect might be related to their work with flavorings. Workers, labor union representatives, and company management at workplaces where workers may be exposed to flavoring-related chemicals can request a NIOSH health hazard evaluation (HHE) of their facility. We also want to hear from healthcare providers who suspect flavorings-induced occupational or non-occupational obliterative bronchiolitis in a patient. NIOSH can be contacted to inquire about or provide information regarding lung disease that may be related to exposures to flavoring chemicals. Cases can also be reported to local and state public health departments.