What is involved? (including coding of cases)
SABRE Case Studies and Information
Case Study: Occupational Asthma
A
30 year old male with asthma and exposure to Western Red Cedar. He had no past
history of asthma. He commenced work in 1986 as a glazier in a firm
manufacturing windows and doors. His workplace was one open factory; wood
machining, wood joinery and glazing were carried out in adjoining areas. His job
involved cutting glass and placing glass in windows and doors. Almost all of the
wood used in the factory was Western Red Cedar.
Within
12 months of commencing work he developed rhinitis and dermatitis. During 1994
he noticed the gradual onset of cough and chest tightness. His GP diagnosed
asthma and commenced him on beclomethasone and salbutamol. In 1995 he left his
job as he felt his asthma was work related. Between 1995 and 1997 he worked as a
courier. During this time he ceased all asthma medications and had no asthma
symptoms. In October 1997 he recommenced work as a glazier in the same factory
as previously. Within one month he recommenced asthma medications because his
symptoms had recurred. His asthma has persisted since and has become worse in
the last year. He has had had two exacerbations of asthma during the last year
requiring courses of prednisone. Triggers to his wheezing episodes include
exercise and upper respiratory tract infections. He doesn’t recall any spills
or accidents at work. He had a 5 pack year history of cigarette smoking and has
not smoked for 10 years.
His
examination was unremarkable and his baseline spirometry was normal. He had
evidence of non specific bronchial hyper responsiveness with a positive
methacholine challenge. He monitored his serial peak flows and the results are
shown in Fig 1. There is a significant deterioration in his peak flows at the
start of the working week with an improvement on the weekends.
Figure
1. Serial Peak Flow Measurements
A
diagnosis of occupational asthma due to Western Red Cedar was made. He was moved
to another part of the factory with no exposure to western red cedar and now has
no asthma symptoms, is on no medications and normal methacholine challenge.
Important
Points
-
New asthma in a working person means a careful occupational history needs to be taken.
-
Occupational exposure to a known cause of occupational asthma increases the likelihood of the diagnosis of occupational asthma.
-
Work related symptoms including rhinitis and dermatitis followed by asthma symptoms are suggestive of occupational sensitisation.
-
Evidence of non specific bronchial hyper responsiveness confirms the diagnosis of asthma.
-
Evidence of work relationship documented with serial peak flows confirms the diagnosis of occupational asthma and should be done before advising worker to cease exposure.
-
Exposure ceased and symptoms and non specific bronchial hyper responsiveness has resolved.
-
Further exposure to Western Red Cedar needs to be avoided.