Medline ® Abstracts for References 1,7,8
of 'Reactive airways dysfunction syndrome and irritant-induced asthma'
Reactive airways dysfunction syndrome (RADS). Persistent asthma syndrome after high level irritant exposures.
Brooks SM, Weiss MA, Bernstein IL
Ten individuals developed an asthma-like illness after a single exposure to high levels of an irritating vapor, fume, or smoke. In most instances, the high level exposure was the result of an accident occurring in the workplace or a situation where there was poor ventilation and limited air exchange in the area. In all cases, symptoms developed within a few hours and often minutes after exposure. We have designated the illness as reactive airway dysfunction syndrome (RADS) because a consistent physiologic accompaniment was airways hyperreactivity. When tested, all subjects showed positive methacholine challenge tests. No documented preexisting respiratory illness was identified nor did subjects relate past respiratory complaints. In two subjects, atopy was documented, but in all others, no evidence of allergy was identified. In the majority of the cases, there was persistence of respiratory symptoms and continuation of airways hyperreactivity for more than one year and often several years after the incident. The incriminated etiologic agent varied, but all shared a common characteristic of being irritant in nature. In two cases, bronchial biopsy specimens were available, and an airways inflammatory response was noted. This investigation suggests acute high level, uncontrolled irritant exposures may cause an asthma-like syndrome in some individuals which is different from typical occupational asthma. It can lead to long-term sequelae and chronic airways disease. Nonimmunologic mechanisms seem operative in the pathogenesis of this syndrome.
Long-term effects of exposure to sulfur dioxide. Lung function four years after a pyrite dust explosion.
Härkönen H, Nordman H, Korhonen O, Winblad I
Am Rev Respir Dis. 1983;128(5):890.
The lung function of 7 men accidentally exposed to sulfur dioxide (SO2) in a pyrite dust explosion was followed for 4 yr. The greatest decrease in forced vital capacity, forced expiratory volume in one second, and maximal midexpiratory flow was observed 1 wk after the accident. After about 3 months no further decrement occurred. The pattern of spirometric findings was obstructive in 6 and restrictive in 1 of the patients. Four years after the accident a reversible obstruction of the bronchi was still observable in 3. Four patients reacted positively to the histamine challenge test. Two patients either did not respond to bronchodilator or did not react to histamine. The results suggest that bronchial hyperreactivity is a frequent sequela after exposure to high concentrations of SO2. The hyperreactivity may persist for several years.
Cough and bronchial responsiveness in firefighters at the World Trade Center site.
Prezant DJ, Weiden M, Banauch GI, McGuinness G, Rom WN, Aldrich TK, Kelly KJ
N Engl J Med. 2002;347(11):806.
BACKGROUND: Workers from the Fire Department of New York City were exposed to a variety of inhaled materials during and after the collapse of the World Trade Center. We evaluated clinical features in a series of 332 firefighters in whom severe cough developed after exposure and the prevalence and severity of bronchial hyperreactivity in firefighters without severe cough classified according to the level of exposure.
METHODS: "World Trade Center cough" was defined as a persistent cough that developed after exposure to the site and was accompanied by respiratory symptoms severe enough to require medical leave for at least four weeks. Evaluation of exposed firefighters included completion of a standard questionnaire, spirometry, airway-responsiveness testing, and chest imaging.
RESULTS: In the first six months after September 11, 2001, World Trade Center cough occurred in 128 of 1636 firefighters with a high level of exposure (8 percent), 187 of 6958 with a moderate level of exposure (3 percent), and 17 of 1320 with a low level of exposure (1 percent). In addition, 95 percent had symptoms of dyspnea, 87 percent hadgastroesophageal reflux disease, and 54 percent had nasal congestion. Of those tested before treatment of World Trade Center cough, 63 percent of firefighters (149 of 237) had a response to a bronchodilator and 24 percent (9 of 37) had bronchial hyperreactivity. Chest radiographs were unchanged from precollapse findings in 319 of the 332 with World Trade Center cough. Among the cohort without severe cough, bronchial hyperreactivity was present in 77 firefighters with a high level of exposure (23 percent) and 26 with a moderate level of exposure (8 percent).
CONCLUSIONS: Intense, short-term exposure to materials generated during the collapse of the World Trade Center was associated with bronchial responsiveness and the development of cough. Clinical and physiological severity was related to the intensity of exposure.
Bureau of Health Services, Fire Department of New York City, New York, USA. email@example.com