Hi,

You could also try looking at a HSE publication EH40/2002 - Occupational
Exposure limits. This will list all substances with the risk phrase:

        R42 May cause sensitisation through inhalation.

The R42's have the potential to cause occupational asthma to personnel if
exposed.
I conduct annual lung function tests(spirometry)on employees at one of our
sites where the fines from a product which used to be produced there where
R42's.

Regs
Phil Kelley

-----Original Message-----
From: Stuart Cooper [mailto:[log in to unmask]]
Sent: 29 May 2002 21:15
To: [log in to unmask]
Subject: Re: Occupational Asthma


Dear Gordon,

What do you mean novice?  We are all novices really learning day by day!

I can help a little here I think, although I too have barely passed the
novice post.  Some of the more experienced list members might be able to
supplement my scribbling.

1.    Investigations

Obviously the person would need to have a history that is suggestive of
occupational asthma.  A very simple example could be asthma that develops in
adulthood where the symptoms are worse at work and better when away from
work.

Exact diagnosis can be abit hap-hazard.

The so called 'gold standard' is something known as the bronchial
provocation challenge test (also known as BPT).  This is conducted under
controlled conditions, usually in a specialist hospital unit, not least
because of the chances of severe bronchospasm.  It involves inhaling the
suspected sensitizer.  The FEV1 is then measured as well as the
responsiveness to histamine or methacholine.  The patient is usually
admitted a day or so before the test to ensure a good exposure free baseline
and is usually kept in for a few days after the test to observe late
responses.

Due to its complexity the above is usually reserved for the most troublesome
or interesting cases.

The standard test in the serial measurement of PEF, if the person if fit for
further exposure.  Readings are usually taken 3-4 times per day over a
period of several weeks and then examined to see if there is significant
changes around the time of exposure.  Reading are taken both on working and
rest days.  During the period it is clearly important to consider any other
factors that may affect PEF readings, for instance running a half marathon!
The readings are generally examined by an experienced OH physician for
patterns.

Interestingly exposure may not cause an immediate response, with some
workers experiencing the effects some hours after exposure.  This is why
occupational asthma can sometimes be diagnosed mistakenly as constitutional
asthma or put down to other causes, for instance COPD.

A few decent references that I dug out are:

Burge, P.S. (1982)  "Single and serial measurements of lung function in the
diagnosis of occupational asthma"  European Journal of Respiratory Disease
Volume 63 Pages 200-204

Bright P and Burge P.S. (1996) "The diagnosis of occupational asthma from
serial measurements of lung function at and away from work"  Thorax  Volume
51  Pages 857-863

The HSE also do a publication on occupational asthma - published in 1991 or
1992 I think??

2.    Occupational Asthma in Aviation

Having never worked in aviation I am afraid that I can't help much here.  I
can signpost you in the right direction though.

Doug Watson, who is a doctor working in aviation in New Zealand has a
website with a mailing list kind of like this one for aviation practitioners
around the world.  Many work in aviation in the armed forces and quite a few
from the UK.  I got to know about the list because I am a Captain in the
Army Medical Services and was interested in aviation medicine.  You may find
it interesting to join and then circulate a message.  Someone undoubtedly
will be able to help.  His website address is -

http://www.ozemail.com.au/~dxw/avmed.html

Alternatively a good forces contact in the UK is Colonel Malcolm Braithwaite
(RAMC).  His email address is [log in to unmask]  He is a Consultant in
Occupational and Aviation Medicine with the British Army and, so I have
heard, is always delighted to provide advice.

I hope that this helps.  Best of luck with the dissertation!!

With my best wishes,

Stuart.

----- Original Message -----
From: "Gordon Main" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, May 29, 2002 4:37 PM
Subject: Occupational Asthma


> This is my first posting here so please forgive any errors.
>
> I am currently studying for BSc in OH at Portsmouth Uni with Nancey
> Ellacott.  My dissertation is examing Occ Asthma and have two areas where
i
> need help:
>
> 1.  I am particularally interested in the investigations performed within
> the UK when OA is first suspected.
>
> 2.  I am working as a RAF nurse in a large unit of 2400 personnel and the
> unit could be compared to a airport the size of Glasgow with servicing of
> aircraft and support machinary.  In the last 19 years, in various units,
> have not seen one service person diagnosised as OA, despite the current
> rate of reported OA ranging from 800-2000 per annum.  If anyone has
> experience of what rate of OA we should be looking at within this working
> environment i would love to hear.
>
> Many thanks and i hope my first attempt has not been to novice
>
> Gordon