Tintinalli's Summary โ Treat the Patient, Not the Poison
"The overwhelming majority of poisoned patients do well with meticulous supportive care alone โ airway, breathing, circulation, and correction of the metabolic consequences. Specific antidotes exist for only a minority of toxins. The initial approach is therefore generic: resuscitate, identify a toxidrome to narrow the agent, decontaminate when appropriate, give an antidote if one is available and indicated, and consider enhanced elimination for the few toxins it benefits."
Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th Ed. McGraw-Hill 2020. Section: Toxicology โ General Approach.The Core Message (Tintinalli's)
- Resuscitation first โ ABC, glucose, oxygen; most deaths are from airway loss, hypoventilation, arrhythmia or seizures, not from lack of an antidote.
- The "coma cocktail" thoughtfully: check glucose (give dextrose if low), consider thiamine, naloxone for opioid hypoventilation; flumazenil is rarely used (seizure risk).
- Identify a toxidrome from vitals + pupils + skin + mental state to narrow a vast differential to a manageable one.
- Risk-assess and consult the poisons centre; observe for delayed toxicity (sustained-release drugs, paracetamol, toxic alcohols).
๐งช Two Bedside Tests in Every Overdose
Glucose (instant, reversible cause of coma) and a 12-lead ECG (QRS widening โ sodium-channel blockade e.g. TCA โ needs bicarbonate; QTc prolongation โ torsades risk). Add a paracetamol level in any deliberate self-poisoning โ it is common, silent early, and lethal but treatable.
Rosen's โ The Classic Toxidromes
"A toxidrome is a constellation of signs โ vital signs, pupil size, skin, bowel sounds, and mental status โ that points to a class of poison. Recognising the pattern allows the clinician to begin specific treatment before any laboratory confirmation, and to avoid being misled by an unreliable history. The pupils, the skin (wet versus dry), and the bowel sounds are the great discriminators between the cholinergic and anticholinergic states that are so often confused."
Rosen's Emergency Medicine: Concepts and Clinical Practice, 10th Ed. Elsevier 2023. Chapter: General Approach to the Poisoned Patient.| Toxidrome | Key features | Pupils | Examples | Treatment |
|---|---|---|---|---|
| Cholinergic | SLUDGE/DUMBELS, wet, bradycardia, bronchorrhoea, fasciculations | Miosis | Organophosphates, carbamates, nerve agents | Atropine (to dry chest) + pralidoxime |
| Anticholinergic | "Mad, hot, dry, red, blind" โ delirium, dry skin, โHR, urinary retention, mydriasis | Mydriasis | TCAs, antihistamines, atropine, datura | Supportive; benzodiazepines; physostigmine (selected) |
| Sympathomimetic | Agitation, โHR, โBP, โtemp, sweaty (vs dry anticholinergic) | Mydriasis | Cocaine, amphetamines, cathinones | Benzodiazepines; cooling; avoid ฮฒ-blockers (cocaine) |
| Opioid | โRR (hallmark), โGCS, โBP | Miosis (pinpoint) | Heroin, morphine, fentanyl, tramadol | Naloxone; ventilatory support |
| Sedative-hypnotic | โGCS, normal/โvitals, RR relatively preserved | Variable | Benzodiazepines, barbiturates, alcohol | Supportive; flumazenil rarely (seizure risk) |
These two are the most dangerous to confuse. Cholinergic = WET (salivation, lacrimation, bronchorrhoea, sweating), miosis, bradycardia โ the killer is the airway drowning in secretions (organophosphate). Anticholinergic = DRY (dry skin/mouth, urinary retention, ileus), mydriasis, tachycardia, delirium with picking movements. Mnemonic for anticholinergic: "hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat."
An unexplained high anion-gap metabolic acidosis in a poisoned patient should trigger thoughts of toxic alcohols (methanol, ethylene glycol), salicylates, metformin (lactate), and iron. A raised osmolar gap early supports toxic alcohol (before it is metabolised to acid). See the AcidโBase Disorders topic โ these are time-critical (fomepizole/ethanol + dialysis).
What Actually Helps (and What Doesn't)
Gastric lavage is rarely indicated (only very recent, life-threatening ingestion, protected airway). Ipecac is obsolete. Whole-bowel irrigation (PEG) for sustained-release/enteric-coated drugs, iron, lithium, body packers.
Haemodialysis for dialysable toxins โ remember "I-STUMBLE": Isopropanol, Salicylates, Theophylline, Uraemia, Methanol, Barbiturates, Lithium, Ethylene glycol (also metformin-associated lactic acidosis, valproate, severe).
Multi-dose activated charcoal โ carbamazepine, dapsone, phenobarbital, quinine, theophylline (drugs with enterohepatic recirculation).
Antidotes Every ED Should Stock
| Poison | Antidote | Dose |
|---|---|---|
| Paracetamol | N-acetylcysteine (NAC) | IV regimen (e.g. 150 mg/kg โ 50 โ 100, or 2-bag); per nomogram/timing |
| Opioids | Naloxone | 0.4 mg IV q2โ3 min (titrate to ventilation); infusion if needed |
| Organophosphate / carbamate | Atropine + Pralidoxime | Atropine 2โ4 mg IV, double q5 min to atropinisation; pralidoxime 30 mg/kg |
| Benzodiazepines | Flumazenil (rare) | 0.2 mg IV โ avoid if dependence/co-ingestion (seizures) |
| TCA (wide QRS) | Sodium bicarbonate | 1โ2 mEq/kg IV bolus for QRS >100 ms / arrhythmia / hypotension |
| Beta-blocker / Ca-channel blocker | Glucagon; high-dose insulin euglycaemia (HIET); calcium | Glucagon 5โ10 mg IV; HIET 1 U/kg bolus โ 0.5โ1 U/kg/h + glucose |
| Methanol / ethylene glycol | Fomepizole (or ethanol) + dialysis | Fomepizole 15 mg/kg IV load; haemodialysis |
| Iron | Desferrioxamine | 15 mg/kg/h IV infusion for severe toxicity |
| Digoxin | Digoxin-specific Fab | Per level/ingested dose; empirically for life-threatening arrhythmia/hyperK |
| Methaemoglobinaemia | Methylene blue | 1โ2 mg/kg IV over 5 min |
| Local anaesthetic / lipophilic drug toxicity | IV lipid emulsion (Intralipid 20%) | 1.5 mL/kg bolus โ 0.25 mL/kg/min |
| Cyanide | Hydroxocobalamin (or Na thiosulfate) | 5 g IV |
| Snake envenomation | Anti-snake venom | See the Snakebite topic |
The Poisoned Patient โ Step by Step
Resuscitate (ABC) + glucose + ECG
- Airway/ventilation (intubate for airway loss/hypoventilation), circulation, seizures (benzodiazepines).
- Capillary glucose; 12-lead ECG (QRS, QTc); consider naloxone/thiamine.
Identify a toxidrome & risk-assess
- Vitals + pupils + skin (wet/dry) + mental state + bowel sounds โ toxidrome.
- Bloods: paracetamol & salicylate level, VBG + lactate, U&E, anion & osmolar gap, drug levels as relevant; call the poisons centre.
Decontaminate & give antidote
- Activated charcoal if <1 h, suitable toxin, protected airway.
- Specific antidote if indicated (table above); sodium bicarbonate for wide-QRS TCA, etc.
Enhanced elimination, observe & psych
- Haemodialysis / urinary alkalinisation / MDAC for the few toxins that benefit.
- Observe for delayed/sustained-release toxicity; risk-assess for self-harm and arrange psychiatric review before discharge.
High-Burden Indian Poisonings
- Organophosphate / carbamate (pesticides) โ the classic cholinergic crisis; atropine titrated to a dry chest (huge doses), pralidoxime, intubation for respiratory failure / intermediate syndrome. (See ICU Toxicology for detail.)
- Aluminium phosphide ("rice tablet"/Celphos) โ releases phosphine; profound, often refractory cardiogenic shock and metabolic acidosis; no antidote โ supportive care, intensive haemodynamic support; very high mortality. Avoid contact aspiration; consider IV lipid/magnesium per local protocols.
- Paraquat โ corrosive; delayed pulmonary fibrosis; avoid supplemental oxygen unless SpOโ low (oxygen worsens free-radical lung injury); early charcoal/Fuller's earth; poor prognosis with significant ingestion.
- Yellow oleander / cardiac glycoside plants โ brady-arrhythmias/hyperkalaemia like digoxin; Fab fragments where available.
- Corrosives (acids/alkalis) โ do NOT induce vomiting or give charcoal; endoscopy assessment; airway protection.
- Snakebite, alcohol, sedative overdoses โ common; see relevant topics.
Common Mistakes in Poisoning
Most poisoned patients survive on supportive care alone; few toxins have antidotes. Secure the airway, support ventilation and circulation, treat seizures, and correct glucose first โ the antidote is secondary.
Paracetamol is common in deliberate self-poisoning, asymptomatic early, and lethal but eminently treatable with NAC. Check a paracetamol level in every deliberate overdose regardless of the stated agent.
Wet + miosis + bradycardia = cholinergic (organophosphate) needing atropine; dry + mydriasis + tachycardia + delirium = anticholinergic. Mixing them up leads to dangerously wrong treatment โ read the skin and pupils.
Activated charcoal in an obtunded, unprotected airway causes aspiration; it doesn't bind alcohols, metals, hydrocarbons or caustics. Give it only to alert patients within ~1 h of a charcoal-binding toxin.
Flumazenil can precipitate seizures (in dependence or with pro-convulsant co-ingestions like TCAs) and refractory status. Benzodiazepine overdose is usually managed with supportive airway/ventilation, not reversal.
Supplemental oxygen accelerates paraquat's free-radical pulmonary injury. Withhold oxygen unless the patient is genuinely hypoxic, and target the lowest SpOโ acceptable โ the opposite of the usual instinct.
References
- Tintinalli JE, Ma OJ, Yealy DM et al. Tintinalli's Emergency Medicine, 9th Ed. Section: Toxicology. McGraw-Hill; 2020.
- Walls RM, Hockberger RS, Gausche-Hill M et al. Rosen's Emergency Medicine, 10th Ed. General Approach to the Poisoned Patient. Elsevier; 2023.
- Chyka PA, Seger D, Krenzelok EP, Vale JA (AACT/EAPCCT). Position paper: Single-dose activated charcoal. Clin Toxicol 2005;43:61โ87.
- Eddleston M, Buckley NA, Eyer P, Dawson AH. Management of acute organophosphorus pesticide poisoning. Lancet 2008;371:597โ607.
- Goldfrank's Toxicologic Emergencies, 11th Ed. McGraw-Hill; 2019 (antidotes & toxidromes reference).
- National Poisons Information Centre (NPIC), AIIMS New Delhi. Indian poisoning management guidance.