A 3-year-old boy is brought to the emergency department by his mother for the evaluation of abdominal pain for one hour after drinking a bottle of toilet bowl cleaner. The mother reports that he vomited once on the way to the hospital and his vomit was non-bloody. The patient has pain with swallowing. He appears uncomfortable. Pulse oximetry shows an oxygen saturation of 82%. Examination shows heavy salivation. Oral examination shows mild oral erythema in the area of the epiglottis, but no burns. An x-ray of the chest shows no abnormalities. The patient is admitted to the intensive care unit. He is intubated and oxygenation and intravenous fluid resuscitation are begun. All contaminated clothes are removed. Which of the following is the most appropriate next step in the management of this patient?

Obtain barium upper gastrointestinal series

A 6-year-old boy is brought to the emergency department 12 hours after ingesting multiple pills. The patient complains of noise in both his ears for the past 10 hours. The patient’s vital signs are as follows: pulse rate, 136/min; respirations, 39/min; and blood pressure, 108/72 mm Hg. The physical examination reveals diaphoresis. The serum laboratory parameters are as follows: Na+ 136 mEq/L Cl- 99 mEq/L Arterial blood gas analysis under room air indicates the following results: pH 7.39 PaCO2 25 mm HG HCO3- 15 mEq/L Which of the following is the most appropriate first step in the management of this patient?

Gastrointestinal decontamination

Multiple-dose activated charcoal

Toxic ingestions and overdoses for USMLE Step 2 CK: High-Yield Management Lessons

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 Vital Signs, Pupils, Skin, and Mental Status

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

Antidote Chart: Common Toxins & Stocking Levels

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.

ECG: TCA overdose with wide QRS and prominent R in aVR

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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