Poisoning
Michael A. Nares
G. Patricia Cantwell
Richard S. Weisman
KEY POINTS
Childhood poisoning requires a continuum of care from the prehospital environment to the emergency department and the ICU that can quickly distinguish ingestions that pose significant risk from those that are inconsequential.
A comprehensive history, focused physical examination, and thoughtful laboratory evaluation provide an excellent template for assessing risk of toxicity and enabling the practitioner to avail of the use of a multitude of poisoning resources.
Identification of toxidromes (sympathomimetic/adrenergic, cholinergic, anticholinergic, and opioid) requires meticulous attention to clinical signs and symptoms.
The laboratory evaluation generally serves to confirm a toxicologic diagnosis, but a negative screen does not exclude the possibility of toxic exposure. Targeted determination of electrolytes, osmolality, glucose, electrocardiogram, urinalysis, and radiographic imaging may be particularly helpful in eliciting the etiology of a suspected toxin.
Familiarity with specific toxins and their antidotes enables immediate initiation of therapy, as well as the ability to definitively identify certain toxins.
Toxicokinetic principles focus on the processes of absorption, distribution, metabolism, and elimination of drugs or toxins and provide the mainstay of specific management of the poisoned child.
Supportive care remains the crux of therapy and requires aggressive airway management with attention to airway reflexes, careful evaluation and maintenance of ventilation, recognition and correction of hemodynamic compromise, and anticipation of aberrations in the cardiopulmonary and neurologic systems.
Childhood poisoning remains a common occurrence despite widespread educational efforts by healthcare providers and the utilization of childproof medication dispensers. The challenge to the pediatric intensivist can be daunting in determining which ingestions are potentially high risk and which are inconsequential. Yearly data collection reveals that more than 2 million exposures to toxic substances are reported to poison centers throughout the United States. The overwhelming majority of toxic exposures cause minimal to no effect; morbidity and mortality associated with these exposures are extremely uncommon (1). Poisoning that occurs in children less than 5 years of age is generally accidental and accounts for ~85%-90% of pediatric poisoning. Poisoning in a child older than 5 years is generally considered intentional and comprises the remaining 10%-15% of childhood poisonings (2). Unintentional overdoses may occasionally occur in teenagers who take alcohol and street drugs. Teenagers are also subject to hospitalization following suicide attempts or suicide gestures. The Toxic Exposure Surveillance System of the American Association of Poison Control Centers reports ingestion to be the primary route of exposure to toxic substances (1). Risk factors for childhood exposure include exploratory behavior, child abuse, the possibility of environmental exposures, suicide attempts in children, and neonates exposed to toxins in utero.
EPIDEMIOLOGY
Poisoning may occur with differing modes of exposure. Exposures may occur via ingestion, ocular exposure, topical exposure, envenomation, inhalation, and transplacental exposure. The ingestion of poisonous plants is common in children and may account for ~5%-10% of calls to poison control centers. It is difficult to establish a clear-cut list of problem plants, as many plants have both edible and toxic parts, are difficult for nonbotanists to identify accurately, and have variable plant names, and for many plants, the quantity necessary to produce toxicity is unclear.
Management of childhood poisoning is challenging owing to the large variety of prescription medications, household chemicals, stings, envenomations, illicit drugs and designer drugs, as well as an increase in the use of nonprescription and herbal medications. Pediatric fatalities are most often associated with the following agents: analgesics, hydrocarbons, antidepressants, gases and fumes, stimulants, street drugs, cardiovascular drugs, anticonvulsants, sedative/hypnotics, antipsychotics, and chemicals. The agents that most frequently prompt calls to poison control centers are cosmetics and personal care products, cleaning substances, analgesics, foreign bodies, topical agents, and plants.
CLINICAL APPROACH TO THE POISONED CHILD
The acute management of the poisoned child generally begins in the emergency department. Recommendations for the management of the poisoned child have been challenging owing to limited research based upon small-case series, animal studies, and case reports. Initial evaluation involves the process of triage and the determination of appropriate decontamination
and treatment regimens. The intensivist may be immediately involved, as aggressive interventions are often required before it is possible to determine a comprehensive history, physical examination, and diagnostic testing. Urgent priorities include the focus on a primary survey that involves attention to the patient’s airway, breathing, and circulation (ABC). Following the establishment of life-saving supportive care, a detailed evaluation can be meticulously performed. Toxins may cause respiratory failure by depression of the respiratory drive, hypoperfusion of the central nervous system (CNS
and treatment regimens. The intensivist may be immediately involved, as aggressive interventions are often required before it is possible to determine a comprehensive history, physical examination, and diagnostic testing. Urgent priorities include the focus on a primary survey that involves attention to the patient’s airway, breathing, and circulation (ABC). Following the establishment of life-saving supportive care, a detailed evaluation can be meticulously performed. Toxins may cause respiratory failure by depression of the respiratory drive, hypoperfusion of the central nervous system (CNS