Which agents cause reactive airways Which agents cause reactive airways dysfunction syndrome dysfunction syndrome (RADS)?(RADS)?

M. S. Shakeri , F. D. Dick and J. G. Ayres 2008

Dr.salmaniDr.salmani

Aim: To identify agents associated with RADS.

Method: A systematic review

Keywords: Asthma; irritant-induced asthma; reactive airways dysfunction

Background:Background:• Brooks(20 years ago):

– RADS – Symptoms within 24 h of a single, massive, chemical

exposure.

• SWORD:– prevalence of asthma :• intensity and length of acute exposure• the duration of follow-up • suspected agent

Methods:Methods:

systematic review of RADS using Brooks' criteria

searching MEDLINE, EMBASE and CINAHL from 1985 to 2005

search was complemented (hand-searching) : conference abstracts published in the American

Review of Respiratory & Critical Care Medicine European Respiratory Journal and Thorax

Results:Results:

84 articles and abstracts were found but 25 of the articles were excluded:

no cases meeting RADS criteria

duplicate publications follow-up studies

Results...Results...

• 633 cases in the 59 articles: – 63 cases met Brooks' criteria – 570 had insufficient data

• 63 RADS cases:– 38 (60%) male– 12 (19%) female – 13 (21%) gender was not reported.

• mean age:– 37.8 (SD 11.6) years– age was not reported for 7 people

Results...Results...

Agents:

– chlorine (9 subjects)

– TDI (6 subjects)– oxides of nitrogen (5 subjects)– Acetic acid (4 subjects)– sulphur dioxide (4 subjects) – paint (4 subjects)

Results...Results...

location of exposure:

workplace (n = 51) environment (8 subjects), home (3 subjects) not reported (1 subject)

Results...Results...

• Atopic:

–The proportion of non-atopic patients was higher than atopic patients

– 41% of RADS group atopic status was not reported.

Results...Results...

Symptoms:– common symptoms: Dyspnoea, cough & wheeze.

• 71% dyspnoea (n = 45)• 65% cough (n = 41)• 43% wheeze (n = 31)• 43% chest tightness (n = 27)• 29% upper respiratory irritation (n = 18)• 25% eye irritation (n = 16)• 16% mucus production (n = 10)• 6% cyanosis (n = 4)

Results...Results...

• symptom duration:

The median and interquartile range (IQR) for symptom duration in patients who met Brooks' criteria was 13 (6.5–43.5) months.

Results...Results...

• In 63 RADS:

– 19 (30%): smokers

– 21 (33%) patients were non-smokers– 7 patients (11%): ex-smokers – 16 (25%): no information

Summery:Summery:

most agents: Chlorine, TDI , oxides of nitrogen

Most exposures: in the workplace and affected men (60%).

commonest symptoms: Dyspnoea (71%) and cough (65%)

Median symptom duration: 13 months