Initial Management - Get The Bad Stuff Out
Primary goal: Prevent absorption of ingested toxins. Time is critical; efficacy ↓ rapidly after ingestion.
- Activated Charcoal (AC):
- Standard dose: 1 g/kg.
- Most effective within 1 hour of ingestion.
- Ineffective for: 📌 Pesticides, Hydrocarbons, Acids/Alkalis, Iron, Lithium/Lead, Solvents (PHAILS).
- Urinary Alkalinization:
- Enhances elimination of weak acids (e.g., Aspirin, Phenobarbital).
- Achieved with IV sodium bicarbonate to maintain urine pH > 7.5.
⭐ Activated charcoal should not be given to patients with a compromised airway, risk of aspiration, or GI obstruction unless the airway is protected by intubation.
Toxidromes - What's The Vibe?
Recognizing patterns in vital signs & physical exam is key to identifying the toxin class.
| Toxidrome | Vitals (HR, BP, T) | Pupils | Skin | Other Key Signs |
|---|---|---|---|---|
| Sympathomimetic | ↑↑↑ | Mydriasis | Diaphoretic | Agitation, seizures |
| Anticholinergic | ↑↑↑ | Mydriasis | Dry, flushed | Delirium, urinary retention |
| Cholinergic | ↓↓↓ (or ↑) | Miosis | Diaphoretic | 📌 DUMBBELS |
| Opioid | ↓↓↓ | Miosis (pinpoint) | Normal | ↓ Respiratory drive, CNS depression |
| Sedative-Hypnotic | ↓↓↓ | Normal | Normal | CNS depression, slurred speech |
📌 Anticholinergic Mnemonic:
- Blind as a bat (mydriasis)
- Mad as a hatter (delirium)
- Red as a beet (flushing)
- Hot as a hare (hyperthermia)
- Dry as a bone (anhidrosis)
Specific Antidotes - The Magic Bullets
- Acetaminophen: N-acetylcysteine (NAC)
- Replenishes glutathione stores.
- Opioids: Naloxone
- Competitive opioid receptor antagonist.
- Benzodiazepines: Flumazenil
- ⚠️ Use with caution in chronic users; can precipitate seizures.
- Organophosphates/Nerve Agents: Atropine (muscarinic antagonist) + Pralidoxime (regenerates acetylcholinesterase)
- Methanol/Ethylene Glycol: Fomepizole
- Inhibits alcohol dehydrogenase.
- Warfarin: Vitamin K (slow) / Fresh Frozen Plasma (FFP) (fast)
- Heparin: Protamine Sulfate
- Digoxin: Digoxin immune Fab (DigiFab)
- Iron: Deferoxamine
- Lead: Succimer (oral), Dimercaprol/EDTA (IV)
⭐ High-Yield: Fomepizole is the preferred treatment for methanol or ethylene glycol poisoning, as it has fewer side effects than the older ethanol infusion therapy.
Lab & ECG Clues - Diagnostic Detective Work
- Anion & Osmolal Gaps:
- ↑ Anion Gap: 📌 MUDPILES (Methanol, Uremia, DKA, Propylene glycol, Iron, Lactic acidosis, Ethylene glycol, Salicylates).
- ↑ Osmolal Gap: Methanol, Ethylene glycol.
- Key Drug Levels: Check acetaminophen, salicylates, digoxin, lithium.
- ECG Clues:
- TCA: Wide QRS >100ms, tall R in aVR.
- Digoxin: Scooped ST segments, AV block.
- QT Prolongation: Antipsychotics, antiarrhythmics.
⭐ In suspected TCA overdose, a QRS duration >100 ms predicts seizures, and >160 ms predicts ventricular arrhythmias.
High‑Yield Points - ⚡ Biggest Takeaways
- Always prioritize the ABCs (Airway, Breathing, Circulation) before specific antidotes.
- Activated charcoal is used for GI decontamination but is ineffective for alcohols, lithium, and iron.
- Recognize key toxidromes: opioids (miosis, respiratory depression) vs. anticholinergics (mydriasis, flushed, dry skin).
- For acetaminophen toxicity, use the Rumack-Matthew nomogram to guide N-acetylcysteine (NAC) therapy.
- TCA overdose causes QRS widening; the antidote is sodium bicarbonate.
- Salicylate toxicity classically presents with a mixed respiratory alkalosis and anion gap metabolic acidosis.
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