Home                   

Introduction            

Project Aims           

What is involved? (including coding of cases)

Register to Notify      

Notification form      

SABRE Results         

SABRE Case Studies and Information    

Diseases                

Occupational Asthma   

Links                   

Contact Us            

A worker with reactive airways dysfunction syndrome

A 39 year old male smoker has worked for the last four years at a chemical plant in Sydney, as a process worker. In January of this year he was told to clean a mixing tank, a task he’d never done before. An accident whilst cleaning the tank resulted in the patient being covered in a mixture of toluene, xylene and dimethyl benzene.  He fell ill immediately with eye irritation, skin irritation, dyspnoea and in general felt unwell. He was taken to the local hospital and discharged six hours later.  Four days after the accident he went back to work.  His dyspnoea has persisted and he has developed episodic wheezing.  He has no prior history of asthma or respiratory problems and was on no regular medications prior to the incident.   On examination his chest was clear.  His FEV₁/FVC was 2.7/3.45L, with a predicted of 3.65/4.54L. After bronchodilator there was a 17% improvement in his FEV1 to 3.15L.  He was commenced on p.r.n. Ventolin and underwent a methacholine challenge, which showed a PD20 of 3.18 mg/ml.  He then commenced Flixotide 500 mcg bd then Seretide due to frequent symptoms. When last seen, two months after the accident, he still displayed daily symptoms.

Diagnosis
Reactive airways dysfunction syndrome (RADS) or irritant induced asthma.

Discussion
The term reactive airways dysfunction syndrome (RADs) was first coined by Brooks et al (1985), who reported on 10 individuals with asthma-like illness after a single exposure to high levels of an irritating vapour, fume, or smoke. The high level exposure was generally 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 within minutes after exposure.  None of the subjects had a documented pre-existing respiratory illness and all showed positive methacholine challenge tests.  In the majority of cases there was persistence of respiratory symptoms and continuation of airways hyper-reactivity for more than one year.  The incriminated etiologic agent varied but was irritant in nature.  In two cases, bronchial biopsy specimens were available, and an airways inflammatory response was noted.

Main Points
1. Acute high level, uncontrolled irritant exposures may cause an asthma-like syndrome.
2. Different from typical occupational asthma (no latency period or time lag between commencement of exposure and development of symptoms).
3. Can lead to long-term sequelae and chronic airways disease.
4. Subjects are not usually sensitised to the offending agent so they can return to work and be re-exposed, although obviously not at high levels.

Reference:
Brooks, S. M., M. A. Weiss, et al. 1985. Reactive airways dysfunction syndrome (RADS). Persistent asthma syndrome after high level irritant exposures." Chest 88(3): 376-84.