Introduction

Pediatricians play an important role in preventing environmental exposures by asking the right questions and providing anticipatory guidance.

Pediatricians treating a sick child must be aware that most diseases related to hazardous exposures in adults and children manifest as common medical problems or have nonspecific symptoms. Because environmental causes may not enter into the differential diagnosis, pediatricians may miss opportunities to make correct diagnoses or prevent disease.

Spectrum of Harm

A spectrum of harm to those exposed can be caused by hazardous substances in the environment. These substances include

• allergens,
• ionizing radiation,
• toxicants, or
• ultraviolet (UV) radiation.

Effects of exposure can range from no effects or sub-clinical effects to frank poisonings. These levels of harm are usually related to the amount or dose of the substance to which the child or group has been exposed [Guidotti and Ragain 2007]. For example, a rise of 10 micrograms per deciliter (µg/dL) in blood lead results in the loss of 2 IQ points in a child [Sattler et al. 2003]. Exposure can also lead to frank poisoning with obvious clinical symptoms (i.e., such as results from a blood lead level of >60/dL of lead) [Centers for Disease Control 2005; AAP 2005].

At a population level, very low levels of toxic chemicals may increase an exposed population’s probability that a certain number of people will develop an illness.

The Exposure-Disease Model

No matter how toxic, no chemical can harm a person unless exposure occurs.

The exposure disease model outlines actions that must occur for exposure to an environmental toxicant to eventually cause disease.

• Environmental contamination: This is the physical source of the contaminant within the environment that creates the potential for exposure.
• Biologic uptake: This occurs at the point of contact between the person and the physical source of contamination in the environment. The uptake creates a completed exposure pathway.
• Absorbed dose: The amount of the toxicant absorbed after an exposure occurs.
• Biologic changes: Toxic mechanisms that cause damage to tissues following an exposure and an absorbed dose. For example, hypoxia is caused by carbon monoxide (CO) exposure.
• Target organ: An organ affected by exposure to the toxicant. The “critical organ” is the organ that is the most sensitive to the exposure.
• Clinical disease: Overt symptoms that result, given a sufficient absorbed dose of a toxicant.

Roles of the Pediatrician in Environmental Health

Pediatricians have several important roles in environmental health.

1. Primary prevention—preventing the development of risk factors that may lead to the onset of a negative health condition. The major role of pediatricians is to provide advice to families on how to prevent, reduce, or mitigate potential exposures to hazardous substances in order to prevent an adverse health effect. Examples include

   • giving advice about maintaining fuel-burning appliances on a regular basis to prevent CO poisoning,
   • counseling parents to have paint in older homes tested for lead before a child is exposed, and
   • counseling parents to stop smoking to prevent a child’s asthma exacerbations due to second-hand smoke (SHS) exposure.

   Pediatricians may also provide pre-conception counseling on avoiding environmental exposures, such as second-hand smoke (SHS), to couples considering having children. Counseling during pregnancy and lactation may also be part of the pediatrician’s role.

2. Secondary prevention—identifying and treating asymptomatic children who have already developed risk factors or preclinical disease but in whom the condition is not clinically apparent. One example is screening asymptomatic children for lead poisoning before the onset of symptoms, as outlined by the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP).

3. Tertiary prevention—activities involving the care of established disease, with attempts made to restore to highest function, minimize the negative effects of disease, and prevent disease-related complications. Such prevention includes giving oxygen to a child with symptomatic CO poisoning.

In order to prevent, reduce, or mitigate exposures and diagnose and manage environmentally related health effects, pediatricians need to hone certain skills.

• Developing expertise in screening for possible environmental exposures commonly found in pediatric practice.
• Knowing how to take a full pediatric exposure history in cases of suspected exposures.
• Creating a complete differential diagnosis, including possible environmental factors as causes of signs and symptoms.
• Developing the ability to conduct a medical evaluation and an environmental risk assessment in cases where a frank poisoning or an environmentally mediated disease such as asthma is strongly suspected.
• Learning how to identify and work with consultants during an environmental workup. Consultants may include industrial hygienists, environmental medicine specialists, and pediatric toxicologists.
• Accessing expert consultants in pediatric environmental medicine to help with the medical management of more complicated cases.

Progress Check