Introduction

Because most environmental or occupational illnesses manifest as common medical problems or have non-specific symptoms, an environmental etiology for a sign, symptom, or disease may 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 general pediatrician’s expertise. However, asking a few screening questions will alert the pediatrician to a possible environmental cause. The pediatrician can then contact experts in pediatric environmental medicine for further guidance for diagnosis, treatment, and management of complicated or unusual cases (see Pediatric Environmental Health Speciality Units (PEHSU) and Poison Control Center in the “For More Information” section later is this CSEM).

Purpose of the Pediatric Exposure History

The purpose of taking a pediatric exposure history is to detect environmental toxicants that can be risk factors for pre-clinical changes before overt toxicity occurs. In addition, pediatricians should include screening questions directed toward identifying and preventing common childhood adverse environmental exposures on the well child visit. Typical environmental exposure questions focus on environmental sources of

• carbon monoxide (CO),
• lead,
• methyl mercury in fish(diet),
• pesticides, and
• second-hand smoke (SHS).

When there are symptoms or an illness, taking a careful exposure history may allow the pediatrician to identify the specific agent causing the toxicity or poisoning.

What can a pediatrician do to improve his/her ability to recognize diseases related to current or past environmental exposures?

• First, pediatricians must think about the possibility of environmental factors in the etiology of disease by adding environmental causes to a list of differential diagnoses.
• Additional questions will be prompted according to the child’s life stage (e.g., asking about water used to make up formula is relevant for an infant; school-based exposures are relevant for an older child; occupational exposures may be relevant to working teenagers or to toxicants a parent unknowingly brings home from work).

Conducting an Environmental Medicine Evaluation

In cases in which an environmental exposure is strongly suspected, there is a step-wise process to the pediatric environmental medicine evaluation:

1. Taking a full exposure history to define possible exposures.
2. Conducting appropriate laboratory testing (after consulting with experts in pediatric environmental medicine and toxicology).
3. Performing a thorough risk assessment regarding possible sources of exposure.
4. Obtaining guidance and consultation regarding ending ongoing exposure and appropriately treating toxicity.

Pediatricians should continue to expand their skills in

• taking a pediatric exposure history,
• delivering anticipatory guidance,
• conducting appropriate risk-based laboratory tests (in consultation with pediatric environmental specialists as necessary) according to the specific toxicant, exposure status, and clinical presentation of the child, and
• treating or managing patients with environmentally related illness in consultation with pediatric environmental health specialists.

The general pediatrician is frequently the person who initially suspects the role of environmental factors in disease. Investigations that require the help of an environmental medicine specialist often begin in the primary care provider’s office. Help is available from specialists in Pediatric Environmental Health Specialty Units (PEHSUs) or from other sources (see the “For More Information” section later in this CSEM).

Including Environmental Etiologies in the Differential Diagnosis

Clinicians rarely see a child with a symptom or disease that is pathognomonic for environmental exposure—such as fetal alcohol spectrum disorder or acrodynia (a manifestation of chronic elemental mercury poisoning). As illustrated by the child in this case study, an environmental exposure case can present with non-specific signs and symptoms for which there is an extensive differential diagnosis.

The key to making an accurate diagnosis is to include environmentally related possibilities when one is thinking about the differential diagnosis.

Examples of common conditions that may result from exposure to environmental contaminants include

• Headaches caused by mild CO intoxication or solvent exposure.
• Seizures as the result of severe lead poisoning or severe CO intoxication.
• Learning disabilities from one factor or multiple contributing environmental factors, such as intrauterine alcohol exposure and lead or mercury intoxication.
• Asthma exacerbated by exposure to
  • allergens (such as animal dander, mites, cockroaches),
  • irritants (such as SHS, indoor air fresheners, or cleaners),
  • outdoor air pollutants (such as ozone, polycyclic aromatic hydrocarbons and other particulates), and
  • exposures from hazardous substances in the nearby environment (e.g., an industrial emission or waste processing sites).
• Eczema and other skin conditions exacerbated by environmental factors (e.g., an adolescent works with solvents in an auto mechanics class at a trade school).

Etiology distinguishes a disorder as an environmental illness. Unless the clinician pursues an exposure history, the environmental etiology may be missed, treatment may be inappropriate, and exposure can continue.

When to Take an Environmental Exposure History

Opportunities for the pediatrician to ask exposure-related questions.

• Pre-conception. The purpose of a preconception history is to
  • identify hazards in the environment to which a child may be exposed,
  • educate and counsel regarding how to avoid exposure risks during pregnancy, and
  • educate the prospective parents about how to provide a healthy environment for their future children.

  Important examples include advising future parents to stop smoking and counseling a future mother to avoid consuming mercury-containing fish.

• Pediatric prenatal visit. Pediatricians may see mothers before a baby is born. An environmental exposure history includes asking the expectant mother if she
  • smokes cigarettes,
  • is exposed to SHS,
  • consumes mercury-containing fish, and
  • is planning renovations (possibly releasing lead or asbestos from renovation debris) to prepare for the baby.
• Initial well child visit. This is an opportunity to take a screening history to identify potential environmental exposures.
• Periodic well child visits. Pediatricians see children for routine well child visits at least 6 times in the 1st year of life, 3–4 times in the 2nd year, twice in the 3rd year, and every year thereafter. These visits provide opportunities to update information about the child’s surroundings and exposures.
• Adolescent well visits. Many teenagers work after school and on weekends, potentially resulting in environmental exposures. Well visits also provide the opportunity for the pediatrician to inquire about active smoking and SHS exposure. Preconception counseling is relevant to some teens.
• Sick child visits. These visits provide opportunities for pediatricians to ask exposure-related questions to determine if environmental hazards could play a role in the child’s illness. A full exposure history should follow if exposure is suspected.
• Follow-up visits for symptoms or illness. Pediatricians should consider an environmental etiology if there
  • is an unusual presentation of a common disease,
  • are persistent or puzzling symptoms unresponsive to treatment modalities, or
  • are multiple people in the immediate environment with the same symptoms.

Progress Check