Occupational Medicine 2005 55(8):635-637; doi:10.1093/occmed/kqi146
© The Author 2005. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org
Saved by a material safety data sheet
Ching-Hua Lin1,
Chung-Li Du1,2,
Chang-Chuan Chan1 and
Jung-Der Wang1,2
1 Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan
2 Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
Correspondence to: Jung-Der Wang, Institute of Occupational Medicine and Industrial Hygiene, College of Public health, National Taiwan University, Taipei, Taiwan. e-mail: jdwang{at}ha.mc.ntu.edu.tw
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Abstract
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Background We present the case of a young female laboratory
worker who developed acute hepatic encephalopathy.
Objective To show that knowledge of occupational exposures to causative agents can alter therapeutic management.
Methods Although the patient was in a deep coma, her family members examined the workplace material safety data sheet, revealing exposure to chloroform. Since most chemical-induced hepatitis is self-limiting, a scheduled liver transplantation was postponed.
Results The patient recovered. Subsequent air sampling suggested that the patient had been exposed to chloroform at a concentration of more than 15 ppm for 2 weeks.
Conclusion Our case report demonstrates the importance of obtaining an occupational history and how the patient's family can be important in this process.
Keywords Chloroform; hepatic failure; material safety data sheet
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Introduction
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Although the prevalence of viral hepatitis is high in Taiwan
[
1], cases of chemically induced hepatitis do occur but may
be difficult to diagnose, especially when hazard communication
guidelines are not carefully followed. We report a case involving
a young woman who suffered from acute hepatic encephalopathy
after being exposed to chemicals for 2 weeks in a laboratory
where the chemical extraction hood was out of service.
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Case report
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In June 2003, a recently employed 24-year-old female laboratory
worker in a meat processing plant was transferred in a coma
from a local hospital to the National Taiwan University Hospital
(NTUH) with a diagnosis of acute hepatitis complicated by encephalopathy.
Because the patient's condition and state of consciousness was
deteriorating rapidly, her local physician had suggested liver
transplantation. The laboratory tests at NTUH found her blood
samples to be serum negative for hepatitis A, B or C virus.
Her autoimmune profile results were not remarkable. Alanine
aminotransferase and aspartate aminotransferase, which showed
spiking elevation on admission, dropped after hospitalization
(
Table 1). The patient had no previous history of alcohol or
drug abuse, though she had taken some weight control medication
for several weeks in January 2003. Finally, with the help of
the patient's family we took a further history and reviewed
her workplace's chemical inventory and material safety data
sheets (MSDS) [
2]. Together, we concluded that the patient's
acute hepatitis was caused by exposure to chloroform in the
laboratory. Because most chemically induced hepatic failures
are self-limiting in nature and often subside if exposure is
discontinued, we postponed liver transplantation and instituted
plasmapheresis. After several treatments, her condition improved.
On 17 July 2003 we visited the patient's laboratory at the meat
processing plant, where she had worked for 2 weeks. A walkthrough
revealed that chloroform was used to extract residual antibiotics
in the meats. Usually, 25 ml of 90% chloroform solution was
used in each of the three to five tests performed per day. The
chloroform was first mixed with the homogenized chicken meat,
which was connected to a condenser and bathed with 42°C
water in an attempt to recycle the chloroform. Due to a leak
in the suction machine, none was reclaimed. The whole procedure
was usually performed in a relatively enclosed chemical extraction
hood where the chloroform vapour would be collected and expelled.
However, the hood had malfunctioned and was not in service for
2 weeks while our patient, a new employee, continued performing
the tests without effective protection. The windows of the laboratory
were always kept closed and the air was refiltered conditioned
air. We did a series of routine tests to simulate our patient's
working environment, but with the windows fully opened. An air
sample was collected in a stainless steel canister for 15 min.
Using Method TO-14A [
3] and Method NIEA A715.11B approved by
the Environmental Protection Agency, Executive Yuan, Taiwan
[
4], we measured the concentration of volatile organic compounds
(VOCs) in the air sample. We also performed three area samples
using Method 1105 of Council of Labor Affairs, Executive Yuan,
Taiwan [
5] which are derived from National Institute of Occupational
Safety and Health (NIOSH) 1003 [
6].
The workplace layout can be seen in Figure 1. Gas chromatography showed ambient air VOC consisting mostly of chloroform at a concentration of 14.9 ppm during the 15 min that the recycling procedure was being conducted. Other organic compounds with possible hepatotoxicity, e.g. ethanol, were found in the ambient air, but at very low concentrations. The three area samples showed air chloroform to be 10.5, 6.1 and 2.5 ppm, indicating the lower concentration of actual exposures as the windows were open when these samples were taken. Basing our estimates on the law of conservation of mass, the average chloroform concentration would have been about 17.7 ppm in that environment, as most of the 25-ml solution containing 90% chloroform was being vapourized into the ambient air during the recycling process. It is also reasonable to assume that both the peak and average concentrations would be much higher, because three to five tests were performed consecutively each day with the windows closed.
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Discussion
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Our patient developed acute hepatitis after being exposed to
chloroform at high concentrations for 2 weeks. Other possible
hepatotoxic agents, including viral hepatitis, alcohol, and
hepatotoxic medications were all ruled out and we concluded
that our patient's hepatitis was work related. Unnecessary intervention
was avoided when a history of occupational exposure to hepatotoxic
chemicals was obtained from the patient's family.
When confronted with acute hepatitis, a physician should keep in mind the possibility that the disease might be chemically induced. This can be clarified by taking a careful and complete history and reviewing an employer's chemical processes and MSDS. In some instances, however, the MSDS may not always be kept up to date and the agents listed on MSDS should be double checked against large databases, such as those posted on the websites of NIOSH, World Health Organization, and International Agency for Research of Cancer.
The patient in this case report was transferred from a local hospital to NTUH for a liver transplant. Had we and the patient's family not taken a careful employment history and reviewed the chemical inventory and MSDS, the chemical cause of her disease may not have been discovered and she may very well have received a transplant with its risk of complications and the consequent need to take immunosuppressive medications for the rest of her life. Our case report demonstrates the importance of an occupational history and how this can be obtained from the patient's family if necessary.
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Conflicts of interest
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None declared.
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Acknowledgements
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The procedures of air sampling and the further analysis mentioned
above were performed by staff members of the Center for Environmental
Safety and Health Technology, the Industrial Technology Research
Institute, regularly monitored and certified by the Council
of Labor Affairs, Executive Yuan, Taiwan. The work was supported
by a grant for the Center of Management of Occupational Injuries
and Diseases from the Council of Labor Affairs and a grant from
the National Health Research Institutes (NHRI-EX93-9204PP).
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References
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- DS Chen. Viral hepatitis: from A to E, and beyond? J Formos Med Assoc 2003;102:671–679.[Medline]
- Wang JD, Cheng TJ, Guo YLL. Occupational health in Taiwan. In: LaDou J, ed. Occupational Medicine. Philadelphia, PA: Hanley & Belfus, Inc, 2002; 427–435.
- U.S. Environmental Protection Agency. Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method TO-14A, Second Edition, EPA 600/625/R-96/010b. http://www.epa.gov/ttn/amtic/airtox.html (28 January 2004, date last accessed).
- Environmental Protection Agency. Environmental Protection Agency, Executive Yuan, Taiwan, R.O.C.: NIEA A715.11B. http://www.niea.gov.tw/niea/AIR/A71511B.htm (27 August 2003, date last accessed).
- Council of Labor Affairs. Council of Labor Affairs, Executive Yuan, Taiwan, R.O.C.: Standard Analytic Methods, 1105, Chloroform. http://www.iosh.gov.tw/data/f10/old1105.htm (27 August 2003, date last accessed).
- The National Institute of Occupational Safety and Health. Manual of Analytic Methods (NMAM). 4th edn. http://www.cdc.gov/niosh/nmam/pdfs/1003.pdf (27 August 2003, date last accessed).
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Abstract
Introduction