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Trichloroethylene Toxicity
Initial Check

Course: WB1112
CE Original Date: November 8, 2007
CE Renewal Date: November 8, 2010
CE Expiration Date: November 8, 2012
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This Initial Check will help you assess your current knowledge about trichloroethylene toxicity. To take the Initial Check, read the case below and then answer the questions that follow.

Case Study

Concerns of a young family exposed to TCE-contaminated drinking water

Your practice is in a suburban community with a number of high-technology industries. A couple for whom you have been the family physician asks for an appointment to discuss their daughter's illnesses and a matter of concern to them.

During the initial consultation, the mother reports that they are living in an area supplied by municipal well water. They have recently received a notice from the municipal water district stating that their drinking water contains 100 parts per billion (ppb) trichloroethylene (TCE), and as a precaution, they are being supplied with bottled drinking water until an alternative well can be put into service. The notice indicates that the well water is suitable for bathing and laundering. The father interjects that he is familiar with TCE; it is used in the electronics plant where he works.

The daughter, aged four has had a number of ear infections during her first two years, culminating in a myringotomy at age three. Follow-up by an Ear, Nose, and Throat (ENT) specialist has shown normal hearing. Although there have been no further infections, the mother stresses that her daughter seems to have a greater number of colds than her classmates and "has not seemed as healthy as she should be." However, the daughter's chart does not reflect an unusual number of office visits or calls. The mother also notes that the child's day-care center is next to "some kind of machine shop" where a chemical odor has been noticed recently. Several of the children and one of the teachers have complained of eye and throat irritation in association with the odor.

The mother, who is 33 years old, then reveals that she might be pregnant and she has had mild nausea for one week. It has been eight weeks since her last menstrual period. Both parents are concerned about the possibility that the TCE in the drinking water might have affected the fetus. Although this pregnancy was planned, they might consider terminating the pregnancy if the fetus was likely to be "damaged." They are also concerned that the entire family might suffer from cancer or other diseases in the future.

Before receiving bottled water, the family drank tap water when thirsty and made coffee with tap water. Tap water also was used for cooking and brushing teeth, and is still used for bathing. They have never noticed discoloration or an off-taste to the tap water. They encourage their child to drink water instead of sodas during the summer and estimate the amount of water each of them drinks is two to three glasses a day.

You schedule each parent and the child for an individual office visit.

Initial Check Questions

  1. What would you include in the mother's and daughter's problem list?

  2. What additional information would you seek before seeing the family again?

  3. What reassurances might you provide at the end of this initial visit?

  4. What are the possible sources of exposure to TCE for the family described in the case study?

  5. Which members of the family described in the case study are at increased risk for adverse effects from TCE? Explain.

  6. On the next visit to your office, the mother states that some families in their neighborhood are being seen by another practitioner, who has sent specimens to a laboratory for measurement of indicators of TCE exposure. What biologic indicators of TCE exposure are likely being measured?

  7. If biologic measurements are performed, what considerations should be taken into account to properly interpret the results?

  8. The father says that he has felt increasingly tired and easily fatigued for the past few months. Results of his physical examination are entirely within normal limits. What tests, if any, would you order?

  9. The mother's obstetrician calls one month later. Examination, including sonogram, is normal for her stage of pregnancy. The obstetrician asks you about the potential fetotoxicity of TCE and whether a more invasive evaluation (amniocentesis or chorionic villus biopsy) is indicated. What is your response?

  10. You evaluate the 4-year-old child. A review of her history reveals three to four episodes of otitis media, which were treated with ampicillin, in each of the last three years. The child was placed on continuous prophylactic antibiotics during the last two cold seasons. Last year, the child developed additional infections despite the antibiotic regimen, and you referred her to an otolaryngologist, who performed a myringotomy and tympanostomy without incident. The mother estimates the child has had four episodes of coryza or mild influenza last year, with about seven days of illness that merited staying home from day care.

    Does this pattern reflect compromise of the child's immune system?

  11. The mother asks about immune system tests. A health care practitioner evaluating other families has performed such tests. Is the assessment of immunocompetence appropriate in this case?

  12. TCE has been identified as the irritant at the day-care center. The mother described in the case study is concerned and wishes to take action to get the level reduced. What can you recommend to her?

Initial Check Answers

  1. The mother's problem list includes pregnancy and anxiety; the child's, frequent otitis media (status post myringotomy and tympanostomy tube placement) and frequent upper respiratory infections.

  2. You will need information on TCE toxicity, including reproductive and developmental effects; information on TCE contamination of the family's drinking water, including duration and level of contamination; copies of information provided to the family by the municipal water company; and responses, if any, from local and state health agencies.

    More information for this answer can be found in the sections “How Are People Exposed to Trichloroethylene?” and “What Are the Physiological Effects of Trichloroethylene?”

  3. None of the symptoms described in the case indicate serious illness. However, you should reassure the family that you will perform a complete physical examination with appropriate testing at the next visit. In response to concern about the child's infections, you should indicate that you will collect information about possible TCE effects on the immune system. Explain to the parents that tests of immune function are often difficult to interpret and might not be appropriate. You might indicate that you will consult sources of information on TCE's effects on pregnancy. It is important to maintain a balance between reassurance that the unborn child is probably not affected by the water contamination and concern for the possible risk to the fetus. Reassurance should not, however, appear to trivialize the family's fears. It would also be appropriate to discuss that no evaluation, however thorough, can totally exclude the possibility that a person might develop an illness, including cancer.

    More information for this answer can be found in the section “What Are the Physiological Effects of Trichloroethylene?”

  4. Possible sources of the family's TCE exposure include home drinking water (ingestion and dermal and inhalation exposure during bathing), the father's workplace (inhalation), and the daughter's day-care center (inhalation). Other sources would be washing dishes, laundry, or any other use of hot water in the home; the use of TCE-containing consumer products such as correction fluid, spot removers, and so forth.

    More information for this answer can be found in the section “How Are People Exposed to Trichloroethylene?”

  5. All members of the family described in the case study are at increased risk for adverse effects from TCE exposure.

    More information for this answer can be found in the section “How Are People Exposed to Trichloroethylene?”

  6. The most convenient biologic indicators of TCE exposure are the urinary metabolites, trichloroethanol and trichloroacetic acid. These metabolites are not specific to TCE, however, because they are also metabolites of tetrachloroethylene (perchloroethylene), 1,1,1-trichloroethane (methyl chloroform), and certain medications. TCE itself can be measured directly in blood or exhaled air, but because of the difficulty of obtaining samples, such measurements are not indicated here.

    More information for this answer can be found in the section “What Laboratory Tests Can Assist in the Evaluation of Patients Exposed to Trichloroethylene?”

  7. To properly interpret any of the tests mentioned in answer 6, knowledge of the time lapse between exposure and collection is necessary. To prevent contamination or sample loss (evaporation or adsorption), the proper collection, handling, storage, and transportation procedures must be followed. It is likely that members of this family would have elevated levels of TCE or its metabolites, above background levels, for a few hours after exposure, for instance, after they shower. However, there are no appropriate reference values currently available for a health risk assessment.

    More information for this answer can be found in the section “What Laboratory Tests Can Assist in the Evaluation of Patients Exposed to Trichloroethylene?”

  8. No further studies are indicated for TCE exposure. A workup for fatigue can indicate additional tests.

  9. Evidence from animal and epidemiologic studies suggests that several reproductive and developmental toxicity end points may be associated with TCE exposure, including infertility in males and females, impaired fetal growth, and cardiac teratogenesis. Invasive procedures are therefore justified in this case.

    More information for this answer can be found in the section “What Are the Physiological Effects of Trichloroethylene?”

  10. No. A survey of infections in children under three years of age over a September-to-March period found an average of 2.5 total infections and more than one episode of otitis media per child (1.4 episodes per child for those in day care). More than 3% of the children in day care were hospitalized for tympanostomies (Bell, Gleiber et al. 1989). The child described in the case study appears to have an above-average rate of infections, but they are not frequent enough to suggest immunologic impairment.

  11. No. Immunocompetence tests are not appropriate because no evidence of immune function abnormalities has been found in this case. It is uncertain about TCE drinking water exposures and immune system abnormalities given the lack of quality studies on this question. Primary immunodeficiency is suspected in an infant who has repeated upper respiratory tract or other infections. It is also suspected if repeated infection occurs in a child who has had little exposure to infectious agents, or any child with unusual infections, incomplete clearing of infections, growth failure, hepatosplenomegaly, or features associated with specific immunodeficiency disorders, such as ataxia or telangiectasia. The child described in the case study has none of these indications.

    More information for this answer can be found in the section “What Are the Physiological Effects of Trichloroethylene?”

  12. Although EPA has not issued an emission standard for TCE, New York State has set a guideline for TCE air emission of 5 µg/m³. Assuming discussions with the owner or operator of the shop adjacent to the day-care center have not been effective in reducing the level of ambient TCE, the community's air pollution control center should be notified. States might allow this control under the jurisdiction of local air pollution control districts, county health departments, or other local agencies. The agency responsible for enforcement of air standards should be contacted to investigate possible release of TCE onto the day-care center property.

    More information for this answer can be found in the section “What Are the U.S. Standards for Trichloroethylene Exposure?”

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