A 3-year-old boy is brought to the emergency department 2 hours after ingesting an unknown substance found in his grandfather's medicine cabinet. On examination, he is drowsy but arousable, with pinpoint pupils (2 mm), slow respiratory rate of 16/min, and oxygen saturation of 88% on room air. Blood pressure is 95/60 mmHg. His mother reports he was playful 30 minutes before arrival but has become progressively unresponsive. What is the most appropriate immediate intervention?

Explanation

## Clinical Diagnosis: Opioid Poisoning The clinical presentation is pathognomonic for acute opioid toxicity: - **Pinpoint pupils** (miosis) — hallmark sign of opioid overdose - **Respiratory depression** (RR 16/min, SpO₂ 88%) — life-threatening - **Altered consciousness** — progressive CNS depression - **Timeline** — rapid onset within 30 minutes of ingestion ## Immediate Management **Key Point:** Naloxone is a competitive opioid receptor antagonist and is the definitive antidote for opioid poisoning. It must be given immediately in any child with suspected opioid overdose, regardless of diagnostic certainty. ### Naloxone Administration Protocol | Parameter | Details | |-----------|----------| | **Drug** | Naloxone (Narcan) | | **Dose (pediatric)** | 0.01 mg/kg IV bolus (max 0.4 mg) | | **Route** | IV preferred; IM/IN if IV access unavailable | | **Onset** | 1–2 minutes IV | | **Duration** | 30–60 minutes (shorter than most opioids) | | **Repeat dosing** | May repeat every 2–3 minutes if no response | **Clinical Pearl:** Naloxone has a shorter half-life than most opioids (especially long-acting formulations like methadone). After initial reversal, the child may relapse into respiratory depression — continuous monitoring and repeat doses are essential. **High-Yield:** In pediatric opioid poisoning, the priority is **airway protection and reversal**, not decontamination. Gastric lavage is contraindicated in drowsy/comatose children without airway protection. ## Why This Answer Is Correct 1. **Immediate life threat:** Respiratory depression (SpO₂ 88%, RR 16) requires urgent reversal. 2. **Specific antidote:** Naloxone directly antagonizes opioid effects at the receptor. 3. **Rapid onset:** IV naloxone works within 1–2 minutes, providing immediate clinical improvement. 4. **Safety:** Naloxone is safe even if the diagnosis is wrong (no harm if not opioid poisoning). ## Concurrent Management - Secure airway (bag-mask ventilation if needed while awaiting naloxone effect) - Establish IV access - Continuous cardiac and SpO₂ monitoring - Prepare for repeat naloxone doses (shorter duration than opioid) - Do NOT delay naloxone for diagnostic confirmation [cite:Park 26e Ch 10]