Pediatric Toxicology: Part 1

     Although pediatric exposure to toxic substances has undergone a significant decline since the 1960s, it remains a common emergency in children in the United States. Ingestions account for a small but significant number of emergency department visits. This three-part series will discuss epidemiology and treatment principles, plus review common exposure medications and their ensuing effects.

     The most common unintentional ingestion that occurs in the home in children under the age of 6 is of toxic substances. Common contributors of accidental ingestions include improper storage of medications, poor supervision or distracted caretakers. Most episodes have a favorable outcome, as the ingestion is generally secondary to curiosity and does not involve large amounts of toxic substances. However, toxicological emergencies continue to be a significant, yet preventable, cause of morbidity and mortality. One particularly dangerous situation occurs with ingestion of sustained-release medications that can have prolonged and deleterious effects on children. EMS personnel must recognize and be prepared for those situations, which can cause rapid deterioration, serious illness or death.

EPIDEMIOLOGY
     In 2006, more than 2.4 million exposures to toxic agents in the general population were reported to poison control centers, although it is estimated there were many more unreported exposures. Fifty-one percent of total exposures—1.2 million—occurred in children under age 6 (see Table I). In this age group, the most common exposures were to cosmetics and personal products (see Table II).

     The peak incidence in all children occurs between ages 1–3, which accounts for 38% of the total exposures. This is due to developmental milestones, such as increased mobility, curiosity and oral exploration, as well as the attraction to brightly colored objects. There is a male predominance for ingestion in children younger than 13, and a female predominance in teenagers and adults.

     Most toxic exposures in 2006 were unintentional, accounting for just over 2 million (83%) episodes, while intentional ingestions accounted for just over 300,000 cases (13%). The majority of exposures in children under age 13 were unintentional; the majority of exposures in 13–19-year- olds were intentional.

     Of the reported exposures, there were 1,200 fatalities, of which 673 (55%) involved two or more toxic agents. Although children under 6 years accounted for most of the exposures, there were only 29 fatalities in this age group; there were no fatalities from intentional exposure in children under age 13 (see Table III). Toxic substances associated with the largest number of fatalities included sedatives, hypnotics, antipsychotics, opioids and cardiac medications.

GENERAL PRINCIPLES
     Most ingestions in the pediatric population require only supportive care. The clinical condition of the patient dictates care; the goal of treatment is to treat the patient, not the poison. Only a few toxic agents have specific antidotes, and many of these are not available in the prehospital setting. Specific antidotes should not be given blindly in an unknown overdose, as several of these can have toxic side effects if they are not indicated. For example, administering sodium bicarbonate, glucophage or calcium when not indicated can cause metabolic alkalosis, hyperglycemia and hypercalcemia, respectively. Supportive care and determining the ingested substance must always precede the administration of specific antidotes.