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Tetrachloroethylene Toxicity
Initial Check

Course: WB 1110
CE Original Date: May 23, 2008
CE Renewal Date: May 23, 2011
CE Expiration Date: May 23, 2013
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This Initial Check will help you assess your current knowledge about tetrachloroethylene toxicity. To take the Initial Check, read the case below and then answer the questions that follow.


A 37-year-old female clerical worker has headache, decreased concentration, and irritability

A 37-year-old woman who is four months postpartum is seen at your office with complaints of headache, increasing irritability, and difficulty concentrating. She says she has become impatient and short-tempered with her husband and new child; minor things make her angry. These feelings began about one month ago. She is most aware of them in the evenings, when they are sometimes accompanied by a throbbing frontal headache. She has no psychiatric history. She has been drinking three ounces of alcohol a day since her marriage four years ago. She did not drink during the pregnancy and does not use other drugs or medications. She has had no trouble sleeping.

Two weeks ago the patient and her family visited her parents for a week. During that time she felt well; the irritability and headaches subsided. Since she returned home last week, however, the symptoms have returned.

The patient is worried that something in the home is causing her symptoms. She reports that the house was sprayed for termites two years ago, but she does not remember the name of the pesticide used. Her husband feels fine and has not been ill. Her infant daughter's delivery was uneventful and the baby appears to be developing normally, but has been “very fussy” lately. The infant, whom you saw five weeks ago for otitis media, is still breast-feeding.

One month ago the patient returned to her job as a word processor. She works mornings and relaxes with her hobby, silk screening, in the afternoons. She gets along well with her employer and fellow employees, and the job is not generally stressful. However, she is concerned that a loss in typing accuracy and a decreased ability to concentrate may lead to conflict with her supervisor. The patient has no symptoms of postpartum depression and had no history of headaches before she resumed these activities.

Physical Examination

On physical examination, you find that the woman is slightly overweight. Her nail beds are pale. She has no skin rashes, lesions, or stigmata of liver disease. The conjunctiva are mildly injected, but the nares and oral mucosa are not swollen or injected. The thyroid is not enlarged, and no lymphadenopathy is present. She has no focal muscle tension or tenderness. Her liver is not enlarged and examination of the abdomen is unremarkable. Neurological examination results are within normal limits. Recent and distant memory are intact. Proverb interpretation and Mini-Mental State Examination results are normal. Sensory and motor functions are normal, as are Romberg test results and gait. Deep tendon reflexes are normal and symmetrical.

  • Blood pressure: 125/85 mmHg
  • Pulse: 68 beats/minute and regular
  • Temperature: normal

Initial Check Questions

  1. What should be included in this patient's problem list?
  2. What further information would assist in establishing a diagnosis?
  3. What laboratory tests would you order for this patient?
  4. On questioning, your patient explains that silk screening involves stretching a large piece of cloth across a form, like a picture frame, masking it to create a pattern, then dying the unmasked areas. Before masking the cloth, it must be cleaned. The patient mentions that she just started using a new fabric cleaner about five weeks ago. Her cousin, who also enjoys silk screening, assured her it was harmless and the best available. The product is called “Clean Cloth*,” but the patient can remember little else about it.

    Assuming the label on the container does not list the contents, how will you determine the ingredients of this consumer product?

    It is fictional and not to be assumed to represent any actual product.

  5. The poison control center in your region informs you that Clean Cloth is 90% tetrachloroethylene and 10% Freon-12 (dichlorodifluoromethane). Might the infant described in the case study be at increased risk? Explain.

  6. How could you determine if a patient has been exposed to tetrachloroethylene?
  7. What will you tell your patient regarding the hazards of tetrachloroethylene?
  8. What other history will help in determining if the neurological symptoms of the patient described in the case study are due to Clean Cloth?

  9. The patient asks why her cousin, who uses Clean Cloth for the same purpose, has not been ill. What can you tell her?

  10. The patient's laboratory tests show urinary trichloroacetic acid of 4.2 mg/L immediately after a 1-week exposure and a slightly elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT). How do you interpret these results?

  11. What recommendations can you make if the patient wishes to continue using Clean Cloth?
  12. What authorities should be notified if you believe a product is being used improperly in an industrial setting? By a large number of hobbyists?

Initial Check Answers

  1. Your patient is four months postpartum, has transient headaches, irritability, decreased ability to concentrate, slightly impaired coordination, and possible alcoholism.

  2. More information about the history of her headaches and her silk-screening hobby would help in diagnosing her symptoms. An accurate history of her current drinking pattern using a specific questionnaire for alcohol or other drug-related problems would also be helpful (Ewing 1984).

    More information for this answer can be found in the section “What Are the Routes of Exposure for Tetrachloroethylene?

  3. Because the patient is postpartum and possibly consumes alcohol in excess, you should rule out anemia and check renal and hepatic functions. A complete blood count, urinalysis, blood urea nitrogen (BUN), serum creatinine, and liver function tests would be appropriate.

    More information for this answer can be found in the section “Clinical Assessment - Laboratory Tests”.

  4. The quickest way to identify the ingredients in Clean Cloth may be to call your regional poison control center (In the U.S. call 1-800-222-1222 or check for an updated list of U.S. Poison Control Centers. The World Health Organization and the International Program on Chemical Safety maintain an international list of poison control centers on the internet at: ). If this is unsuccessful, ask the patient to obtain a Material Data Safety Sheet (MSDS) for the product from the store that sells it or the manufacturer's sales representative or chemist. The MSDS ( will list ingredients in the product and describe their toxicity.

    More information for this answer can be found in the section “Sources of Additional Information”.

  5. Yes. Maternal exposure to tetrachloroethylene could result in the chemical being transmitted to the nursing infant, because the solvent selectively concentrates in breast milk. In addition, the infant may be exposed through inhalation if she is nearby when the fabric is being cleaned.

    More information for this answer can be found in section “What Are the Routes of Exposure for Tetrachloroethylene?”.

  6. Perhaps a first step would be to halt the exposure and determine if the symptoms resolve. Direct biologic indicators of tetrachloroethylene exposure may be obtained by measuring levels in breath or blood, or metabolites in urine. A laboratory that performs these tests may be located by calling your local poison control center or by searching the internet. Consultation with a certified industrial hygienist may be helpful in locating a reputable laboratory and interpreting the results of biological indicators of exposure.

    More information for this answer can be found in the section “Clinical Assessment – History, Signs and Symptoms”.

  7. You should inform your patient of the adverse effects of acute and chronic exposure to tetrachloroethylene. Advise her and her cousin to use a well-ventilated area when cleaning cloth during silk-screening. You should also review with her the potential long-term risks, particularly to nursing infants.

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

  8. Questions about symptoms and temporal association of the use of Clean Cloth may reveal a direct connection. The type and amount of ventilation also may have an effect. (Your questioning reveals that the patient sprays the cloth in late afternoon in a small garage and keeps the door closed to prevent dust from entering. She recalls that one day last week, when it was hot, she felt particularly ill after spraying the cloth.)

    More information for this answer can be found in the section “What Are the Routes of Exposure for Tetrachloroethylene?”.

  9. You should review the factors that may reduce the cousin's actual exposure. For example, the cousin may work outdoors or in a better ventilated area, or she may not leave rags soaked with the compound lying around, follow directions on product, and so forth. You could also discuss individual variability ( e.g., breathing rate; effects of other exposures such as smoking, drugs, and alcohol on metabolic function; genetic differences in metabolic function) as a reason why some people become ill and others do not after similar exposures.

    More information for this answer can be found in the section “What Are the Routes of Exposure for Tetrachloroethylene?”.

  10. The urinary trichloroacetic acid level indicates an average ambient air exposure of about 30 ppm tetrachloroethylene (calculated using the occupationally based ratio in the “Direct Biologic Indicators” section within the laboratory evaluation discussion). Although this level indicates definite exposure, it may not be high enough to cause her symptoms. However, the patient could have been periodically exposed to short-term levels much higher than this average level, which could have caused her symptoms.

    Although not relevant here, the linear correlation between urinary trichloroacetic acid and tetrachloroethylene exposure levels breaks down when the exposure is above 100 ppm tetrachloroethylene. The plateau effect resulting from saturation of the tetrachloroethylene metabolic pathway limits the effectiveness of the assay when the ambient level is above 100 ppm.

    The slightly elevated levels of AST and ALT are inconclusive for tetrachloroethylene exposure because of the confounding factor of alcohol consumption. An AST:ALT ratio greater than 1 (i.e., AST greater than ALT) tends to support an alcoholic etiology; a ratio less than 1 (i.e., AST less than ALT) supports toxic, infectious, or other etiologies. The patient should be advised to reduce alcohol consumption and should possibly be counseled regarding alcoholism. Liver function tests should be repeated in several months.

    More information for this answer can be found in the section “Clinical Assessment - Laboratory Tests”.

  11. It would be preferable for your patient to use a less toxic cleaner. However, if the patient insists on continuing to use Clean Cloth, you should advise her to get proper industrial hygiene consultation or other professional assistance. The local or state health department may be able to provide some information.

    Tetrachloroethylene crosses the placenta and can be found in breast milk; therefore, the fetus and nursing newborn may be at increased risk of adverse effects from maternal exposure. Women regularly exposed to tetrachloroethylene should carefully weigh the benefits of breast-feeding against possible risks, and reduce exposure to the extent feasible. If your patient starts using a Clean Cloth alternative that has no chlorinated solvents, the tetrachloroethylene presently in her milk can be eliminated in several days if she continues to pump her breasts.

    More information for this answer can be found in the section “What Instructions Should Be Given to Patients?”.

  12. OSHA has regulatory responsibility for the workplace and should be notified if employees may be dangerously exposed. You could also request that the National Institute for Occupational Safety and Health (NIOSH) initiate a health hazard evaluation of the workplace. A product with hazardous potential used by a number of hobbyists would be reported to the local or state health department.

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

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