# 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)

![Toxidrome recognition chart with clinical features and causative agents](illustration-toxidrome-recognition-chart.jpg)

## "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.

![Management algorithm for common pediatric toxic ingestions](illustration-pediatric-toxicology-management.jpg)

## 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.

![Antidote quick-reference table for common poisonings](illustration-antidote-reference-table.jpg)

## 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

1. Gummin DD, Mowry JB, Beuhler MC, et al. 2022 Annual Report of the National Poison Data System. *Clin Toxicol*. 2023;61(12):1-88.
2. Hendrickson RG, McKeown NJ. Acetaminophen. In: Nelson LS, et al., eds. *Goldfrank's Toxicologic Emergencies*. 11th ed. McGraw-Hill; 2019.
3. 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.
4. 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.