Pediatricians and other child health care providers should continue to expand their skills in taking an environmental history, delivering anticipatory guidance, and conducting appropriate risk-based laboratory tests for environmental illnesses (in consultation with pediatric environmental specialists as necessary). Table 5 is a basic environmental database form that can be used in an office setting to keep a baseline environmental record handy in the patient's chart and update it as necessary. Portions of this tool could be self-administered in the waiting room, as is done with medical history questionnaires. The practitioner can review the form with the patient as necessary. Appendix C, taken from the work of Sophie Balk, MD (Balk 1996), provides a summary of environmental health questions for an environmental history. Appendix C also includes a table describing when to introduce specific environmental health questions appropriate to age. Other pediatric environmental health history tools are also available (e.g., Goldman et al. 1999).
To determine whether an environmental factor plays a role in a child's illness, a high index of suspicion should be maintained. Most investigations that require the help of a specialist in environmental medicine begin in the primary care provider's office. Further probing can be done when a clinical presentation warrants. (See ATSDR's Case Studies in Environmental Medicine: Taking an Exposure History [ATSDR 2001c].)
Clinicians rarely see a child with a disease pathognomonic for environmental exposure, such as fetal alcohol syndrome or
acrodynia (a manifestation of chronic mercury poisoning). Instead, a child generally will have a complex of signs and symptoms for which there is an extensive differential diagnosis and the possibility of multiple causes. Some common conditions might be caused by one of several environmental contaminants; for example
seizures can occur as the result of lead poisoning or carbon monoxide intoxication;
learning disabilities can have multiple contributing environmental factors, such as intrauterine alcohol exposure and lead intoxication; or
eczema and other preexisting diseases can be aggravated by environmental factors (e.g., if an adolescent begins working with solvents in an auto mechanics class at a trade school).
Preconception and prenatal counseling present opportunities to prevent exposures that might have devastating and lifelong effects. The March of Dimes and the U.S. Surgeon General recommend that preconception counseling be done by all primary care physicians. When providing preconception and prenatal counseling, a primary health care provider should include a screening environmental exposure history to assess basic environmental information about the home, occupations, and hazardous hobbies of both parents and of other adults living in the home (Table 5).
Child health care providers should
Provide parents with an environmental hazards checklist to be used to prepare the home for the arrival of their baby (Table 6).
Discuss the hazards associated with remodeling (e.g., lead poisoning) and furnishing a nursery (e.g., what items are considered safe).
Warn parents about the intake of certain potentially contaminated foods, such as fish that might be contaminated with mercury. Health care providers can use local public health advisories or those provided by the U.S. Food and Drug Administration, ATSDR, or the U.S. Environmental Protection Agency (EPA).
Counsel parents and caregivers about the use of prescribed and over-the-counter medications (e.g., Tylenol, aspirin, and cough suppressants that contain alcohol), nutritional supplements, alternative remedies, and other "natural" treatments.
Review and discuss at length the hazards of alcohol and controlled substance use and abuse while pregnant. It is important to emphasize that environmental tobacco smoke, marijuana smoke, and cocaine smoke can adversely affect fetal health (Etzel and Balk 1999) (Appendix D provides resources for further information) and that these are all preventable causes of potential adverse fetal health effects.
For the well child, a developmentally appropriate environmental
checklist should be used to identify the child's potential exposure risks.
Age-appropriate, environmental, anticipatory guidance should be provided (Table 2), and risk-based screening tests for lead poisoning should be performed (Centers for Disease Control and Prevention 1997 and Appendix E). This is another opportunity to provide parents and caregivers with educational materials on how to prevent exposure to hazardous substances and what to do if exposure occurs. The reality of a general pediatrician or primary health care provider's practice is that there is little time to do an extensive environmental exposure history. At a minimum, the following questions taken from the AAP Handbook of Pediatric Environmental Health (Etzel and Balk 1999) should be integrated into the well-child visit:
Where does the child live or spend time?
Does anyone in the home smoke?
Do you use well water? Tap water?
Is the child protected from excessive exposure to the sun?
What do parents/teenagers do for a living?
Appendix C and Table 5 include information about taking an environmental history; Appendix D includes additional information and resources for environmental health concerns. Responses to the questions in Appendix C and Table 5 can guide the child health care provider in providing anticipatory guidance about preventing or stopping harmful environmental exposures. Additional questions can be added as necessary when trying to determine if specific community environmental health risks might be a problem for the child.
For the sick child whose illness might be environmentally related, the physician should consider an environmental agent as potentially related to a child's current illness, particularly when the illness in question does not follow a usual pattern, or when more than one family member or schoolmate is affected.
For the child with a history of a known or suspected specific exposure (with or without symptoms), concerned parents might visit a child's health care provider with worries that their child might become sick in the future as a result of a suspected exposure. The parents might inquire about signs and symptoms associated with such exposures. This inquiry will help raise suspicion for a possible environmental etiology and thus guide the history and subsequent differential diagnosis.
Because most environmental or occupational illnesses manifest as common medical problems or have nonspecific symptoms, an environmental etiology might be missed. Therefore, it is important to take an exposure history, especially if an illness has been unresponsive to therapy or has an atypical presentation. In a practical sense, an extensive environmental exposure history is beyond the scope of a primary child health care provider's practice. However, asking a few screening questions that would alert the provider to a possible environmental cause would then allow the general provider to contact experts in pediatric environmental medicine for further guidance in the diagnosis, treatment, and management of such cases. Following is the evaluation process in its entirety, with emphasis on what is generally feasible within the clinical generalist's practice and what would probably be referred to a pediatric environmental specialist.
Questions that might help in discerning whether an illness is related to the environment (in addition to the screening exposure history questions taken at the well child visit) follow. [Questions taken from the AAP Handbook of Pediatric Environmental Health (Etzel and Balk 1999).]
Do symptoms subside or worsen in a particular location (e.g., home, child care, school, or room)?
Do symptoms subside or worsen on weekdays or weekends? At a particular time of day?
Do symptoms worsen during hobby activities, such as working with arts and crafts?
Are other children that your child spends time with experiencing symptoms similar to your child's?
Using the traditional tools of interviewing, physical examination, and problem-specific laboratory tests, the child health care provider should attempt to objectify complaints and establish a problem list and a differential diagnosis. The evaluation might identify a specific organ disorder such as eczematous changes in the skin,
asthma, or hepatitis, or broad abnormalities such as developmental delays. In other situations, the initial problem list might only include signs, symptoms, and laboratory test results. The child health care provider who has experience with environmental toxicants might be quick to suspect a disease or a syndrome that has been associated with hazardous environmental exposures, such as asthma or acute lead toxicity. However, the problem list should still be used to keep the differential diagnosis broad in the beginning. Any and all specific exposures identified by the child's parents or caregiver(s) or suspected by the child health care provider should also be listed. Clinicians should be trained to seek sophisticated environmental etiologies when dealing with possible hazardous environmental exposures. In most cases, these etiologies will involve consultation and/or referral to a pediatric environmental medicine specialist. Appendix D includes information on the Pediatric Environmental Health Specialty Units.
Every clinical evaluation of a sick child should include an exposure history that is developmentally appropriate and relevant to the problem list (Table 5, Appendix C, Appendix D, and ATSDR's Case Studies in Environmental Medicine: Taking an Exposure History [ATSDR 2001c]). If certain responses to a few screening questions point to a possible environmental etiology, a more detailed environmental history should be taken. In some cases, consultation with a specialist in pediatric environmental medicine might be indicated. The child health care provider should also be alert to clusters of cases that come into the office that would prompt further investigations. Augment the basic environmental history that might already be part of the patient's chart with problem-specific questions. Even if a parent is focused on a specific exposure, collect information about all possible sources of exposure to environmental hazards. For example, when assessing a 4-year-old child with asthma, focus questions on sources of allergens at home, at preschool, or at the child care center, as well as exposure to outdoor or indoor irritating pollutants (e.g., cat hair, mold, ETS, home pesticides, cockroaches, and periodic high ozone levels). Health care providers must specifically identify chemicals and the routes by which a child might be exposed.
No matter how toxic, no chemical will harm anyone unless exposure (biologic uptake) with subsequent target organ contact occurs, thus causing biologic changes that can lead to disease (Figure 1).
When parental occupations might result in take-home exposures, the child health care provider should request copies of the material safety data sheets (MSDSs) from the parent's employer about hazardous substances at work (see box). MSDSs can also be obtained from other sources. To obtain more reliable information on substance-specific health effects, see Appendix D.
An MSDS describes harmful routes of exposure for specific hazardous substances. The particular route of exposure often determines whether an environmental contaminant will cause harm. For example, a child might bite and break a thermometer and swallow its liquid contents. Fortunately, elemental mercury is relatively nontoxic when ingested because it is not well absorbed by the intestinal route. However, because of its high absorption rate by the respiratory route, elemental mercury is highly toxic when it volatilizes and is inhaled.
The Occupational Safety and Health Administration (OSHA) requires employers to maintain MSDSs on all chemical products used in their facilities. OSHA regulations require employers, if asked, to provide relevant MSDSs to their employees, their representatives, and their health care providers. The Superfund Reauthorization Act also requires businesses to provide MSDSs to concerned community members when the products in question might be released into the community.
After identifying the relevant environmental contaminants, their properties need to be researched. If the primary child health care provider is not familiar with the contaminant or if the case is complex, consultation with a pediatric environmental specialist, poison control center, and/or toxicologist is indicated (Appendix D). Physical and chemical properties of a contaminant help to determine the likelihood of exposure and absorption and how a chemical will be metabolized and excreted if exposure or absorption occur.
For example, knowing that metallic (elemental) mercury volatilizes at room temperature helps predict the occurrence of respiratory exposure if a rug is contaminated with mercury. Air monitoring can contribute to an understanding of the extent of exposure. Because mercury vapor layers close to the floor, this situation leads to greater concern for exposure of young children.
Details about a substance's metabolism and excretion (toxicokinetic) characteristics help to predict the type of biologic monitoring that would be useful in measuring exposure. With information about the half-life of a substance, the clinician can better interpret the results of biologic testing for exposure. Finally, information about animal and human toxicities helps focus laboratory testing on organs known to be affected.
Dose response refers to the extent of a biologic effect in relation to the received dose of an agent. Although variations exist, generally, the higher the dose, the greater the effect. One exception, as discussed previously, is that low doses at critical periods of organ development might have a greater effect than higher doses at other times. An environmental medical evaluation must characterize the extent of exposure with the goal of estimating as closely as possible the absorbed dose (Figure 1). This is usually done in consultation with or referral to a pediatric environmental medicine specialist. Exposure intensity, duration, and frequency all contribute to dose considerations. The exposure assessment relies on three tools: the exposure history; the environmental monitoring performed on environmental samples; and the biologic monitoring performed on samples of blood, urine, or other body fluids or tissues from the exposed person.
Even though more detailed information regarding environmental history, environmental monitoring, biologic monitoring, risk communication, and risk assessment goes beyond what a primary health care provider will realistically know and do in the midst of a busy practice setting, this information is provided in Appendix F to help with understanding the role of others and communication with others (e.g., staff at the state or local health department, poison control center, ATSDR, Association of Occupational and Environmental Clinics' Pediatric Environmental Health Specialty Units [ PEHSUs], and experts at other organizations). Appendix F also provides a better understanding of what is involved in doing a comprehensive pediatric environmental medical evaluation.
