Toxicology DDx

Match the patient's vitals, pupils, skin, and mental status to the toxidrome below. Always check glucose, temperature, and an ECG. Consider co-ingestants — especially acetaminophen and salicylate.

• Sympathomimetic

  Adrenergic overdrive — agitated, hot, tachy, dilated, diaphoretic.

  Vitals

  ↑ HR, ↑ BP, ↑ T, ↑ RR

  Pupils

  Mydriasis (reactive)

  Skin

  Diaphoretic

  Mental

  Agitation, paranoia, psychosis

  Other clues

  • Hyperreflexia
  • Seizures
  • Chest pain (vasospasm)

  Classic agents

  CocaineMethamphetamine / amphetaminesMDMACathinones (bath salts)Pseudoephedrine

  Bedside

  • ECG (QRS, QTc, ischemia)
  • Glucose, temp
  • Pregnancy test

  Initial mgmt

  • Benzodiazepines (titrate to calm)
  • Aggressive cooling if T >39°C
  • IV fluids; treat rhabdo
  • Avoid β-blocker monotherapy in cocaine (unopposed α)

  Pearls

  • Hard to distinguish from anticholinergic — sympathomimetic SWEATS, anticholinergic is DRY.

• Anticholinergic

  “Hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat.”

  Vitals

  ↑ HR, ↑ T, ± ↑ BP

  Pupils

  Mydriasis (poorly reactive)

  Skin

  Dry, flushed

  Mental

  Delirium, mumbling, picking

  Other clues

  • Urinary retention
  • Absent bowel sounds
  • Seizures

  Classic agents

  DiphenhydramineTCAsAtropine / scopolamineJimson weedAntipsychoticsAntispasmodics

  Bedside

  • ECG (QRS >100 → bicarb for TCA)
  • Bladder scan
  • Glucose

  Initial mgmt

  • Benzodiazepines for agitation/seizures
  • Sodium bicarb if QRS >100 ms (TCA-type)
  • Physostigmine ONLY for pure anticholinergic (NOT TCA, NOT wide QRS)
  • Cooling, foley if retention

• Cholinergic

  SLUDGE / DUMBELS — wet everywhere, bradycardic, miotic.

  Vitals

  ↓ HR, ↓ BP, ± ↑ RR (bronchorrhea)

  Pupils

  Miosis (pinpoint)

  Skin

  Diaphoretic

  Mental

  Confusion → coma

  Other clues

  • Salivation, Lacrimation, Urination, Defecation, GI cramps, Emesis
  • Bronchospasm + bronchorrhea
  • Fasciculations, weakness

  Classic agents

  Organophosphates (insecticides)CarbamatesNerve agents (sarin, VX)Pilocarpine, physostigmine

  Bedside

  • RBC cholinesterase if available
  • ECG
  • Decontaminate (PPE!)

  Initial mgmt

  • Atropine — titrate to dry secretions (not HR)
  • Pralidoxime (2-PAM) for organophosphates
  • Benzos for seizures
  • Aggressive airway / suction

  Pearls

  • Patients can off-gas — staff must wear PPE.

• Opioid

  Triad: CNS depression + miosis + hypoventilation.

  Vitals

  ↓ RR, ↓ HR, ↓ BP, ± ↓ T

  Pupils

  Miosis (pinpoint)

  Skin

  Normal / cool

  Mental

  Sedation → coma

  Other clues

  • Hyporeflexia
  • Hypoactive bowel sounds
  • Track marks

  Classic agents

  HeroinFentanyl / analogsOxycodone, hydrocodoneMethadone (long QT)Tramadol (seizures, serotonin)

  Bedside

  • Pulse ox + capnography
  • ECG (methadone → QT)
  • Glucose

  Initial mgmt

  • Naloxone 0.04–0.4 mg IV/IM/IN — titrate to RR, not consciousness
  • BVM ventilation while waiting
  • Observe for re-sedation (fentanyl, methadone, sustained-release)

• Sedative-Hypnotic

  CNS depression with NORMAL pupils and preserved respirations early.

  Vitals

  ± ↓ RR, ± ↓ BP, ± ↓ T

  Pupils

  Normal or small (variable)

  Skin

  Normal

  Mental

  Sedation, slurred speech, ataxia

  Other clues

  • Nystagmus
  • Hyporeflexia

  Classic agents

  BenzodiazepinesBarbituratesEthanolGHBZ-drugs (zolpidem)

  Bedside

  • Glucose
  • ECG
  • ETOH level if available

  Initial mgmt

  • Supportive: airway, IV fluids
  • Flumazenil — generally AVOID (seizure risk in chronic use / co-ingestants)
  • Consider co-ingestants (acetaminophen, salicylate)

• Serotonin Syndrome

  AMS + autonomic instability + neuromuscular excitation (clonus, hyperreflexia — LOWER > upper).

  Vitals

  ↑ HR, ↑ BP, ↑ T

  Pupils

  Mydriasis

  Skin

  Diaphoretic, flushed

  Mental

  Agitation, confusion

  Other clues

  • Inducible/spontaneous clonus (esp. ankles)
  • Hyperreflexia
  • Tremor
  • Onset hours after med change

  Classic agents

  SSRIs / SNRIsMAOIsTramadol, meperidineLinezolidTriptansMDMA, dextromethorphan

  Bedside

  • Hunter criteria (clonus + agent)
  • ECG, temp, CK

  Initial mgmt

  • Stop offending agent
  • Benzodiazepines
  • Aggressive cooling if T >38.5°C; paralyze + intubate if T >41°C
  • Cyproheptadine (PO) for refractory cases
  • AVOID antipsychotics with intrinsic anticholinergic load

  Pearls

  • Vs NMS: serotonin = rapid onset, hyperreflexia/clonus. NMS = days, lead-pipe rigidity.

• Neuroleptic Malignant Syndrome

  Lead-pipe rigidity + hyperthermia + AMS + autonomic instability after antipsychotic.

  Vitals

  ↑ T (often >40°C), labile BP/HR

  Pupils

  Normal

  Skin

  Diaphoretic, pale

  Mental

  Stupor, mutism, catatonia

  Other clues

  • Diffuse 'lead-pipe' rigidity (no clonus)
  • ↑↑ CK, rhabdo, AKI
  • Onset over days

  Classic agents

  Haloperidol, other typical antipsychoticsAtypicals (less commonly)Antiemetics (metoclopramide, prochlorperazine)Abrupt withdrawal of dopaminergics (Parkinson meds)

  Bedside

  • CK, BMP, CK
  • ECG, temp
  • UA for myoglobin

  Initial mgmt

  • Stop offending agent / restart dopaminergic if withdrawal-triggered
  • Aggressive cooling + IV fluids
  • Benzodiazepines
  • Bromocriptine or dantrolene for severe / refractory

Educational reference only. Call your regional Poison Control for case-specific guidance.