Residency · Residency · Medicine Pediatrics
Toxicology Across Ages
Introduction
Poisoning and toxic exposures represent a significant cause of morbidity and mortality across the lifespan. In children, unintentional ingestions predominate, typically in toddlers aged 1-5 years exploring their environment. In adolescents and adults, intentional ingestions (self-harm, substance abuse) and occupational exposures are more common. Med-peds physicians must master the systematic approach to the poisoned patient, recognize toxidromes, and apply age-appropriate decontamination and treatment strategies.
Epidemiology
U.S. poison control centers receive over 2 million calls annually; ~50% involve children under age 6. Most pediatric exposures are single-agent, unintentional, and result in minimal toxicity. Leading causes of pediatric poisoning deaths: opioids, cardiovascular medications, and acetaminophen. Adult poisoning deaths are most commonly from opioids, sedative-hypnotics, and stimulants. The opioid epidemic has dramatically increased poisoning mortality across all age groups.
Approach to the Poisoned Patient
Initial Stabilization
ABCs take priority: secure airway, ensure adequate ventilation, establish IV access. Dextrose (D10W 5 mL/kg in children, D50W 50 mL in adults) for altered mental status with hypoglycemia. Naloxone 0.1 mg/kg (pediatric, max 2 mg) or 0.4-2 mg IV (adult) for suspected opioid toxicity; titrate to respiratory effort. Flumazenil: Generally avoided due to seizure risk in chronic benzodiazepine users or mixed ingestions. Continuous cardiac monitoring and 12-lead ECG for all significant ingestions.
Toxidrome Recognition
| Toxidrome | Vital Signs | Pupils | Key Features | Common Causes |
|---|---|---|---|---|
| Sympathomimetic | Tachy, HTN, hyperthermia | Mydriasis | Diaphoresis, agitation | Cocaine, amphetamines |
| Anticholinergic | Tachy, HTN, hyperthermia | Mydriasis | Dry skin, urinary retention, delirium | TCAs, antihistamines, jimsonweed |
| Cholinergic | Brady, hypotension | Miosis | SLUDGE/BBB (salivation, lacrimation, bronchospasm) | Organophosphates, carbamates |
| Opioid | Brady, hypotension, bradypnea | Miosis | Respiratory depression, decreased AMS | Morphine, fentanyl, methadone |
| Serotonin syndrome | Tachy, HTN, hyperthermia | Mydriasis | Clonus, hyperreflexia, agitation | SSRIs + MAOIs, tramadol |
Sympathomimetic: Tachycardia, hypertension, hyperthermia, mydriasis, diaphoresis (cocaine, amphetamines) Anticholinergic: "Hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat" (antihistamines, TCAs, jimsonweed) Cholinergic: SLUDGE/BBB - Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis, Bradycardia, Bronchospasm, Bronchorrhea (organophosphates, carbamates) Opioid: Miosis, respiratory depression, decreased mental status. Serotonin syndrome: Clonus, hyperreflexia, hyperthermia, agitation (SSRIs, MAOIs, tramadol combinations)
"One-Pill Killers" in Pediatrics
Certain medications can cause life-threatening toxicity in toddlers from a single pill or small dose:
Calcium channel blockers: Hypotension, bradycardia, hyperglycemia; treat with high-dose insulin-euglycemia therapy, calcium, vasopressors. Sulfonylureas: Profound hypoglycemia lasting 12-24 hours; requires prolonged glucose monitoring and octreotide. Opioids (methadone, buprenorphine): Respiratory depression; extended observation needed for long-acting formulations. Tricyclic antidepressants: Seizures, wide QRS, arrhythmias; sodium bicarbonate for QRS >100 ms. Beta-blockers: Bradycardia, hypotension, hypoglycemia; glucagon is the specific antidote. Clonidine: Altered mental status, bradycardia, respiratory depression, miosis mimicking opioid toxicity.
Specific Toxicologic Emergencies
Acetaminophen
Most common cause of acute liver failure in the U.S. and UK. Toxic dose: >150 mg/kg in children; >7.5 g in adults (or >150 mg/kg) Rumack-Matthew nomogram: Plot 4-hour serum level to guide treatment (only valid for acute single ingestions) N-acetylcysteine (NAC): Antidote; most effective within 8 hours but beneficial up to 24+ hours; IV protocol preferred for fulminant cases.
Salicylates
Causes mixed respiratory alkalosis and metabolic acidosis. Tinnitus, hyperpnea, altered mental status, hyperthermia. Treatment: IV sodium bicarbonate for urine alkalinization (target urine pH 7.5-8.0), dextrose supplementation, hemodialysis for severe cases (level >90 mg/dL, end-organ dysfunction, refractory acidosis)
Iron
Particularly dangerous in pediatric ingestions; elemental iron >60 mg/kg is potentially lethal. Phases: GI toxicity (0-6 hr), latent period (6-24 hr), systemic toxicity and shock (12-48 hr), hepatotoxicity (48-96 hr) Deferoxamine chelation for symptomatic patients with serum iron >500 mcg/dL or metabolic acidosis.
Carbon Monoxide
Headache, nausea, confusion progressing to coma and death. Carboxyhemoglobin (COHb) levels guide severity; pulse oximetry is unreliable. Treatment: 100% oxygen via non-rebreather; hyperbaric oxygen considered for COHb >25%, loss of consciousness, or pregnancy.
Decontamination
Activated charcoal: Most effective within 1-2 hours of ingestion; dose 1 g/kg (max 50 g); contraindicated if unprotected airway, caustic ingestion, or hydrocarbons. Whole bowel irrigation: For sustained-release preparations, iron, lithium, and body-packing; polyethylene glycol solution at 500 mL/hr (children) or 1-2 L/hr (adults) Gastric lavage: Rarely indicated; considered only for life-threatening ingestions within 1 hour. Syrup of ipecac: No longer recommended in any setting.
Substance Use Considerations
Adolescents: Screen for intentional ingestions; psychiatric evaluation mandatory for all intentional overdoses. Adults: Consider polypharmacy, illicit substances, and alcohol co-ingestion. Fentanyl: Increasing presence in counterfeit pills and illicit drug supply; ultra-potent requiring higher and repeated naloxone doses. Vaping-related illness: EVALI presents with respiratory distress, bilateral infiltrates; often vitamin E acetate exposure.
Clinical Pearls
In toddlers, even a single pill of a calcium channel blocker, sulfonylurea, or opioid can be fatal; these require mandatory observation. Acetaminophen levels should be obtained in all intentional ingestions regardless of reported substances taken. The Rumack-Matthew nomogram is only valid for acute single-time ingestions of immediate-release acetaminophen. Activated charcoal is most effective within one hour but should not delay definitive antidote administration. All intentional overdoses in adolescents and adults require psychiatric evaluation before discharge.
References
- Gummin DD, Mowry JB, Beuhler MC, et al. 2022 Annual Report of the National Poison Data System. Clin Toxicol. 2023;61(12):1-88.
- Hendrickson RG, McKeown NJ. Acetaminophen. In: Nelson LS, et al., eds. Goldfrank's Toxicologic Emergencies. 11th ed. McGraw-Hill; 2019.
- Beauchamp GA, Hendrickson RG. The one-pill killers: A review of the toxic medications that can cause death in toddlers. Pediatr Emerg Med Rep. 2020;25(1):1-12.
- Mowry JB, Spyker DA, Brooks DE, et al. Annual Report of the American Association of Poison Control Centers. Clin Toxicol. 2016;54(10):924-1109.