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Polycyclic Aromatic Hydrocarbons (PAHs)
Initial Check

Course: WB 1519
CE Original Date: July 1, 2009
CE Renewal Date: July 1, 2011
CE Expiration Date: July 1, 2013
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This Initial Check will help you assess your current knowledge about the toxicity of polycyclic aromatic hydrocarbons (PAH). To take the Initial Check, read the case below, and then answer the questions that follow.


Dyspnea, weight loss, and weakness in a 52-year-old male coal tar manufacturing plant worker

A 52-year-old man comes to your office for a health evaluation, his first in 3 years. While trying to assure you that he is in reasonably good health, he admits that his wife prompted this visit. She is concerned about his weight loss, lack of stamina, and weakness in the shoulders and arms. When you review his chart, you see that he has lost 30 pounds since his last visit. The patient also describes shortness of breath with moderate activity. He is a lifelong nonsmoker and drinks alcohol only occasionally. He is taking no medications. His past medical history is noncontributory. A review of systems reveals that the patient also has a chronic, intermittently productive cough, which has been ongoing for 1 month.

The patient has worked at a coal tar manufacturing plant for the past 34 years. He has been a lifelong resident of an urban industrial neighborhood that is approximately 1 mile from where he works. He has been married for 25 years. His wife and adult daughter are in good health.

A physical examination shows that his vital signs are normal. An inspection of his skin reveals multiple dry, scaly, hyperpigmented macules involving the forehead, temporoparietal areas, eyelids, and brows, and several hyperkeratotic papillomata on his face, neck, upper chest, forearms, and hands. Palpation of the right supraclavicular area reveals a firm, nontender, fixed lymph node 2 x 3 centimeters (cm) in size. Auscultation discloses intermittent, scattered, right-sided wheezes and dry bibasilar crackles. The remainder of the exam is unremarkable.

The patient’s laboratory results are remarkable for the following:

  1. hemoglobin = 12.9 grams per deciliter (g/dL) (normal = 14–18 g/dL);
  2. hematocrit = 36% (normal = 42%–52%);
  3. leukocyte count = 2.9 x 10³ per microliter (µL) (normal = 3.9–11 x 10³/µL);
  4. serum calcium = 12.9 milligrams per deciliter (mg/dL) (normal = 8.5–10.5 mg/dL);
  5. alkaline phosphatase = 483 international units per liter (IU/L) (normal = 30–125 IU/L) with concomitant elevation of GGTP (GGT);
  6. SGOT (AST) 121 IU/L (normal = 7–45);
  7. SGPT (ALT) 129 IU/L (normal = 7–35 IU/L);
  8. The chest radiograph reveals a 3.3-cm central, thick-walled, cavitating lesion with irregular, spicular margins in the right upper lobe, and atelectasis and prominence of the right hilar lymphatics.

Initial Check Questions

  1. What are likely sources of PAHs for the patient described in the case study?
  2. Besides the patient, who in the case study might be at risk for PAH exposure?
  3. The patient’s daughter, who has lived in his household all of her life, recently gave birth to a daughter. Is the newborn at risk for PAH exposure? Why or why not?
  4. How could you document that the work environment of the patient described in the case study contributed to his risk of lung cancer?
  5. Before his present employment, the patient in the case study was employed as a laborer on a farm. He says that he was not exposed to pulmonary toxic agents such as asbestos or silica. What is the problem list and the differential diagnosis for this patient?
  6. The diagnosis for the patient described in the case study is squamous cell carcinoma of the lung. In general, what can you do to decrease the risk for lung cancer among your patients?
  7. Would you consider the patient described in the case study a sentinel case requiring notification of public health agencies? Explain.

Initial Check Answers

  1. The patient may have been exposed to coal tar manufacturing pollutants at his work for more than 34 years. Moreover, if his home is in the prevailing downwind direction from the coal tar manufacturing plant, pollutants might contribute to ambient air contamination near his home. However, environmental studies related to air pollution are more complex and must separate out contaminants from indoor cooling/heating systems, environmental tobacco smoke, urban air pollution, and other sources. The patient might have been exposed to PAH mixtures by all three routes: inhalation, ingestion, and direct cutaneous contact.

    More information for this answer can be found in the “What Are Routes of Exposure to PAHs?” and “Who Is at Risk of Exposure to PAHs?” sections.

  2. Workers at the coal tar manufacturing plant and residents in the community downwind from the plant might be exposed to PAH mixtures. However, other contributors to environmental ambient air contamination should be kept in mind, including environmental tobacco smoke, indoor cooking and heating practices, and urban air pollution. The patient’s family members might be at risk for additional exposure if the patient carried these compounds home on his skin and work clothes.

    More information for this answer can be found in the “What Are Routes of Exposure to PAHs?” and “Who Is at Risk of Exposure to PAHs?” sections.

  3. The patient’s newborn granddaughter may be at risk for PAH exposure. If the patient’s daughter breathed contaminated air in and around the house, then the baby could have been exposed in utero. This exposure could have occurred while the patient’s daughter was doing various household chores, such as laundering, dusting, and general cleaning of the contaminated home or her father’s work clothing. Based on animal studies, PAH mixtures absorbed into the mother’s system might continue to be transferred to the baby via breast milk. The baby might also be breathing contaminated air, thereby increasing her exposure.

    More information for this answer can be found in the “Who Is at Risk of Exposure to PAHs?” section.

  4. The role of the workplace in the patient’s PAH mixture exposure can be determined by area sampling at the work site, individual monitoring, medical surveillance of coworkers, and air sampling within the immediate community. Industrial hygienists would typically perform these activities.  Data may be available through sources at the coal tar manufacturing plant and at local, state, or federal agencies.

    More information for this answer can be found in the ”Who Is at Risk of Exposure to PAHs” section.

  5. The patient’s problem list includes weight loss, fatigue, muscle weakness, skin lesions on exposed areas, exertional dyspnea, and a roentgenographically identified cavitating lesion in the right upper lobe with associated lymphadenopathy. The differential diagnosis includes carcinoma of the lung, tuberculosis, fungal lung infection, and lung abscess.

    More information for this answer can be found in the “What Health Effects are Associated with PAH Exposure” and “Clinical Assessment.”” sections.

  6. The main objective is to educate patients about cancer prevention. You should try to stimulate changes in their work habits and lifestyle that will decrease the risk for cancer. A risk assessment can identify elements in a person’s workplace, family history, medical history, and lifestyle that might be controllable risk factors.

    For example, between 75% and 80% of all cases of bronchogenic carcinoma are due to cigarette smoking and are therefore preventable. Of the remaining 20%–25%, many are related to occupation or the environment and could therefore be prevented by appropriate workplace or environmental controls. The incidence of lung cancer might also be decreased through education efforts that focus on

    • smoking prevention,
    • improving working conditions,
    • substitution of less-hazardous materials in work processes and building materials, and
    • increased awareness of personal risk factors.

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

  7. In view of the patient’s medical, social, occupational, and family history, the workplace and environmental factors emerge as the most likely causal factors in the development of his neoplastic disease. When the potential exists for others to be exposed, serious illness related to occupational or environmental factors should be reported to the appropriate state and federal authorities. For example, OSHA would have responsibility for PAHs in the workplace air at the coal tar manufacturing site. EPA would have responsibility for the level of emissions to the ambient air or water. Inclusion of this case in a tumor registry should also be considered.

    More information for this answer can be found in the “Clinical Assessment” and “How Should Patients Exposed to PAHs be Treated and Managed?” sections.

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