Bardana E J
Department of Medicine, Oregon Health Sciences University, Portland.
Dis Mon. 1995 Mar;41(3):143-99.
Occupational rhinitis is a common but generally underreported entity. Although it may occur alone, it is frequently associated with occupational asthma. Occupational asthma may have one of several presentations that are difficult to distinguish from non-work conditions. The respiratory tract acts as the final common pathway for all inhaled environmental pollutants, whether encountered in the home or at work. More than 200 chemicals have been incriminated as a cause of work-related asthma. It is said that about 2% of the 10 million Americans who have asthma acquired it as a result of some chemical irritant or immunogen in their work environment. A number of predisposing factors facilitate the development of work-related asthma. These include industrial conditions, climatic factors, atopic predisposition, smoking, recreational drug use, viral infection, nonspecific bronchial hyperreactivity, and a variety of miscellaneous factors. Pathogenetically, occupational asthma may be immunologic or nonimmunologic in nature. The immunologic variants involve sensitization to a variety of large-molecular-weight constituents. The major nonimmune variant is referred to as inflammatory bronchoconstriction or reactive airways dysfunction syndrome (RADS). There are well-defined criteria for the diagnosis of immunologic and nonimmunologic asthma. The several clinical variations of occupational asthma can be difficult to distinguish from nonindustrial disorders. The most common presentation in practice involves the worker with preexistent asthma who has been adversely affected by work exposures. Occasionally these industrial exposures precipitate permanent impairment. It is clear, however, that occupational asthma is not a single, simple, or homogeneous entity, even when a single specific causal factor can be identified in the workplace. Therefore the physician must be aware of the patient's entire medical history and the precise occupational exposures and must have convincing physiologic evidence that demonstrates a cause-and-effect relationship before making a definitive diagnosis of work-related asthma. Once the diagnosis is established, the worker should be removed from the work-place. If the diagnosis is made in a timely fashion, the patient should experience a significant improvement. The major factor in determining a poor prognosis in occupational asthma is the duration of exposure before the diagnosis is established. Prevention of the disorder is the best therapeutic intervention.
职业性鼻炎是一种常见但普遍报告不足的疾病。虽然它可能单独发生，但常与职业性哮喘相关。职业性哮喘可能有几种表现形式，难以与非工作相关情况区分开来。呼吸道是所有吸入性环境污染物的最终共同通道，无论是在家中还是在工作场所接触到的污染物。超过200种化学物质被认为是导致工作相关哮喘的原因。据说，1000万患哮喘的美国人中约有2%是由于工作环境中的某种化学刺激物或免疫原而患上哮喘的。一些易感因素促进了工作相关哮喘的发展。这些因素包括工业条件、气候因素、特应性易感性、吸烟、使用消遣性药物、病毒感染、非特异性支气管高反应性以及各种其他因素。从发病机制上讲，职业性哮喘在性质上可能是免疫性的或非免疫性的。免疫性变体涉及对多种大分子成分的致敏。主要的非免疫性变体被称为炎症性支气管收缩或反应性气道功能障碍综合征（RADS）。对于免疫性和非免疫性哮喘的诊断有明确的标准。职业性哮喘的几种临床变异可能难以与非工业性疾病区分开来。在实际情况中，最常见的表现是已有哮喘的工人因工作接触而受到不利影响。偶尔，这些工业接触会导致永久性损伤。然而，很明显，即使在工作场所能够确定单一的特定因果因素，职业性哮喘也不是一个单一、简单或同质的疾病实体。因此，医生必须了解患者的完整病史和精确的职业接触情况，并且在做出工作相关哮喘的明确诊断之前，必须有令人信服的生理学证据来证明因果关系。一旦确诊，应将工人调离工作场所。如果诊断及时，患者的病情应会有显著改善。决定职业性哮喘预后不良的主要因素是确诊前的接触持续时间。预防该疾病是最佳的治疗干预措施。
