General Approach
- ABCs first — airway, breathing, circulation take priority over identifying the specific substance
- Identify the substance, amount, time of exposure, and route where possible (from the patient, witnesses, or pill bottles/packaging)
- Check the anion gap and osmolar gap — both can narrow the differential in an unknown ingestion
- Involve a poison control center or toxicology service early for guidance specific to the substance involved
Common Toxidromes
| Toxidrome | Key features | Example causes |
|---|---|---|
| Opioid | Miosis, respiratory depression, decreased consciousness | Heroin, fentanyl, prescription opioids |
| Sedative-hypnotic | CNS depression, slurred speech, ataxia | Benzodiazepines, alcohol, barbiturates |
| Anticholinergic | Mydriasis, dry flushed skin, urinary retention, delirium | Antihistamines, tricyclic antidepressants |
| Cholinergic | Salivation, lacrimation, urination, diarrhea, miosis | Organophosphates, some pesticides |
| Sympathomimetic | Tachycardia, hypertension, agitation, mydriasis, diaphoresis | Cocaine, amphetamines |
General Supportive Care Principles
- Continuous monitoring of airway, breathing, and circulation
- Activated charcoal may be considered in selected early presentations — timing and substance both matter, and it's not appropriate for every ingestion
- Specific antidotes exist for some toxins (e.g. naloxone for opioids, N-acetylcysteine for acetaminophen) — use per current protocol and toxicology guidance
- Correct any metabolic derangements identified on labs (electrolytes, acid-base status)
When the Gaps Matter
An elevated osmolar gap raises suspicion for toxic alcohol ingestion. As the toxic alcohol is metabolized over time, the osmolar gap narrows while the anion gap widens — so the pattern over time, not just a single value, helps build the clinical picture.