Reactive Airways Dysfunction Syndrome RADS

RADS is a type of asthma that develops after exposure to a single environmental or occupational exposure to a high concentration of a single chemical or chemical mixture. Though RADS clinically simulates bronchial asthma and is associated with airways hyperactivity, it is different from OA because of its rapid onset following a single exposure, its lack of a sensitization period requirement, and its occurrence without an allergic 

It should be noted that there have been two reports in the literature of RADS apparently being induced by exposures to bromotrifluoromethane (BTM) and bromochlorodifluoromethane (BCDFM), fluorocarbons used in fire extinguishers. I86,87 Both are irritant chemicals, and the effects noted seemingly contradict the observation made above that RADS induced by irritants is always to mixtures of lipophiles and hydrophiles. Both BTM and BCDFM, however, thermally decompose and hydrolyze to haloacids (HC1, HBr, and HF) and their corresponding carbonyl halides (carbonyl chloride, bromide, and fluoride), chemicals that are corrosive to human tissue. In the two studies reported, no analysis of the air inhaled by the injured individuals was carried out. It is strongly suspected that their inju- 

The onset of symptoms following a single specific chemical exposure 

The chemical exposure is to a gas, smoke, fume, or vapor that is present in a very high concentration and has irritant qualities to its nature 

The onset of symptoms occurs within 24 h after the exposure and persists at least 3 months 

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There also are case reports of reactive airways dysfunction syndrome (RADS) associated with chlorine exposure (Alberts and do Pico 1996 Donnelly and FitzGerald 1990 Schonhofer et al. 1996). RADS is persistent hyper-reactivity of the airways that occurs after a single exposure to a high concentration of an irritant gas (Brooks et al. 1985). All reported RADS cases have resulted from accidental exposures in which exposure concentrations can be presumed to have been high. 

Persistent airway hyperreactivity after a single exposure to chemical irritant has been termed Reactive Airways Dysfunction Syndrome (RADS) (Brooks et al, 1985). There is a strong likelihood of RADS among the victims of the gas exposure at Bhopal (Nemery, 1996) however, whether or not the exposed Bhopal population suffers from RADS has not been careftilly studied. 

Brooks, S.M., Weiss, M.A., Bernstein, I.L. (1985). Reactive airways dysfunction syndrome (RADS) persistent asthma syndrome after high level irritant exposures. Chest 88 376-84. 

Most household maintenance products contain mixtures of lipophiles and hydrophiles that can produce unanticipated toxic effects. Irritant-induced asthma is an example of such an effect. Solvent-based and waterborne paints contain solvents that are nonsensitizing irritants that are individually not known to induce asthma. Despite this, exposures to both types of paints have been shown to cause the asthma-like condition reactive airways dysfunction syndrome (RADS).I13 14 RADS is discussed in detail in Chapterl8. 

Bardana EJ, Jr. Reactive airways dysfunction syndrome (RADS) Guidelines for diagnosis and treatment and insight into likely prognosis. Ann Allergy Asthma Immunol 1999 83 583 6. 

CHRONIC HEALTH RISKS reactive airways dysfunction syndrome (RADS), referring to asthma persisting after exposure to irritants persistence of respiratory symptoms and airway hyper-reactivity for at least 3 months symptoms simulating asthma, with cough, wheezing, and dyspnea prolonged exposure has been associated with allergic contact dermatitis repeated exposure to wood dust and other irritants has contributed to risk of sinonasal neoplasms (nasal cancer). 

Respiratory conditions are illnesses associated with breathing hazardous biological agents, chemicals, dust, gases, vapors, or fumes at work. Examples are silicosis, asbestosis, pneumonitis, pharyngitis, rhinitis or acute congestion farmer s lung, beryllium disease, tuberculosis, occupational asthma, reactive airways dysfunction syndrome (RADS), chronic obstructive pulmonary disease (COPD), hypersensitivity pneumonitis, toxic inhalation injury, such as metal fume fever, chronic obstructive bronchitis, and other pneumoconioses. 

Occupational reactive airways dysfunction syndrome (RADS) is defined as persistent respiratory symptoms and nonspecific airway hyperreactivity in patients with a history of acute exposure to an inhaled agent (gas or aerosol) and no prior history of allergies, smoking, or asthma (25). The definition of RADS can usefully be extended in the WTC context (Table 1) to include those with repeated irritant exposure who have developed irritant-induced asthma. RADS can progress to irreversible lower airways obstructive disease. 

Brooks et al. [22] reported several instances of reactive airways dysfunction syndrome (RADS) following exposures to mixtures of chemicals, each of which... 

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