Organophosphate and carbamate poisoning
Encounter flow
12/12 authoredCanonical 12-phase frame with authored status for this dossier.
Frame
Recognize anticholinesterase poisoning from the cholinergic toxidrome in a plausible exposure context; identify the killers early (bronchorrhea + bronchospasm + bradycardia, respiratory-muscle failure) (WHO/IPCS; Eddleston Lancet 2008)
Cholinergic poisoning suspected and exposure context framed
Patient inputs (12)
Pediatric atropine/pralidoxime dosing is weight-based; children present atypically (more CNS, less classic muscarinic) (WHO/IPCS)
All antidote dosing (atropine titration ceiling, pralidoxime WHO bolus/infusion) and ventilator settings are weight-based (WHO/IPCS)
OP vs carbamate (oximes usually deferred in carbamate — spontaneous reversal) and ingestion vs dermal vs inhalational drives decontamination + oxime decision (Eddleston Lancet 2008)
Oxime efficacy falls after enzyme "aging" — give pralidoxime EARLY; informs intermediate-syndrome surveillance window (24–96 h) (WHO/IPCS)
Bronchorrhea/salivation/sweat are the atropine titration endpoint (titrate to DRYING, NOT to pupils or HR) (Eddleston Lancet 2008)
Hypoxemia from bronchorrhea + bronchospasm + respiratory-muscle weakness is the leading cause of death (WHO/IPCS)
Muscarinic bradycardia (a killer) vs nicotinic tachycardia; do NOT titrate atropine to HR alone (Eddleston Lancet 2008)
Respiratory failure / hypoventilation from nicotinic paralysis + intermediate syndrome drives intubation decision (WHO/IPCS)
Fasciculations → flaccid weakness/paralysis (nicotinic) and delayed proximal/respiratory weakness (intermediate syndrome 24–96 h) (critical-care tox review)
Miosis supports cholinergic dx and is the OPPOSITE of anticholinergic mydriasis — but is NOT the atropine endpoint (Eddleston Lancet 2008)
RBC AChE is more specific than plasma/pseudocholinesterase for severity/recovery — but is CONFIRMATORY ONLY; never delay treatment for it (Eddleston Lancet 2008)
CNS toxicity (seizures, coma) — atropine does NOT treat CNS; needs benzodiazepines (WHO/IPCS)
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Severity triggers (6)
- informationallife_threateningbronchorrhea_respiratory_failureBronchorrhea + bronchospasm with hypoxemia / impending respiratory failure (the primary muscarinic killer) (Eddleston Lancet 2008)Trigger could not be auto-evaluated — needs clinician judgement.
- informationallife_threateningcholinergic_seizure_or_comaSeizure or coma from CNS cholinergic toxicity (Eddleston Lancet 2008)Trigger could not be auto-evaluated — needs clinician judgement.
- informationallife_threateningintermediate_syndrome_weaknessNew proximal limb / neck-flexor / respiratory / cranial-nerve weakness 24–96 h after exposure (intermediate syndrome) (critical-care tox review)Trigger could not be auto-evaluated — needs clinician judgement.
- informationalsevererefractory_bradycardia_hypotensionMuscarinic bradycardia / AV block with hypotension refractory to volume (Eddleston Lancet 2008)Trigger could not be auto-evaluated — needs clinician judgement.
- informationalsevereinadequate_atropinizationPersistent secretions / wet chest / hypoxemia despite initial atropine (under-atropinized) (Eddleston Lancet 2008)Trigger could not be auto-evaluated — needs clinician judgement.
- informationalseverestaff_secondary_contamination_riskDermal/clothing contamination with a lipophilic agent — risk to rescuers/ED staff (Eddleston Lancet 2008)Trigger could not be auto-evaluated — needs clinician judgement.
Workflow calculators
Run this disease's risk and dosing calculators inline.
Recommended regimen
Cholinergic crisis — decontaminate → atropinize → oxime → control seizures → airway/ventilate (incl. intermediate syndrome)- skin and clothing decontamination + RPE/PPEfirst linedecontaminationRemove ALL clothing (double-bag), copious soap-and-water / water irrigation of skin, eye irrigation if ocular; staff in chemical-resistant gloves/gown + respiratory protection • topical/physical • once, repeat irrigation until decontaminatedtriggers: dermal_or_clothing_contamination, lipophilic_agent, nerve_agent_attackSecondary contamination of rescuers/ED staff is a real hazard — lipophilic OPs penetrate skin and off-gas; decontaminate at the door, never in a closed treatment bay (WHO/IPCS; Eddleston Lancet 2008)
ed playbook — drug actions (4)
- 1. skin/clothing decontamination + staff PPERemove all clothing, copious water/soap irrigation; staff chemical-resistant gloves/gown + respiratory protection • physical • at the door, in parallel with resuscitationtrigger: Any dermal/clothing contamination (decontaminate before closed-bay care) (Eddleston Lancet 2008)Prevents secondary contamination of ED staff (WHO/IPCS)
- 2. atropine (escalating-doubling)1–3 mg IV (peds 0.02 mg/kg), DOUBLE q~5 min until atropinized, then infusion ~10–20% of loading dose/h • IV • q5min doubling then infusiontrigger: Any muscarinic feature (do not wait for labs) (Eddleston Lancet 2008)Endpoint = dry chest + adequate oxygenation, NOT pupils/HR (WHO/IPCS)
- 3. pralidoximeWHO: ≥30 mg/kg IV load over 20–30 min then ≥8 mg/kg/h infusion • IV • load then continuous infusiontrigger: OP confirmed/suspected — give EARLY before aging (defer for pure carbamate) (Eddleston Lancet 2008)Reactivates AChE; targets nicotinic features atropine does not treat (WHO/IPCS)
- 4. diazepam/lorazepamDiazepam 5–10 mg IV (peds 0.1–0.3 mg/kg) PRN • IV • PRN seizurestrigger: Seizure or severe agitation (atropine does not treat CNS) (WHO/IPCS)First-line anticonvulsant + neuroprotective in OP (critical-care tox review)
Auto-drafted A&P note
edSubjective
- Possible entry pathways: Cholinergic toxidrome — diaphoresis, miosis, salivation, bronchorrhea, vomiting, diarrhea, fasciculations (WHO/IPCS; Eddleston Lancet 2008); Known or suspected organophosphate/carbamate pesticide ingestion, dermal exposure, or nerve-agent attack (WHO/IPCS); Unexplained copious secretions + bronchospasm + bradycardia + pinpoint pupils + AMS cluster (Eddleston Lancet 2008).
Objective
- No vitals, labs, or imaging entered for this encounter.
Assessment
**Organophosphate and carbamate poisoning** (tox.organophosphate-poisoning.core.v1). Phenotype framing: Rule in cholinergic toxidrome; exclude/contrast anticholinergic toxidrome (DRY skin, mydriasis, tachycardia — the OPPOSITE), sympathomimetic, opioid, sedative-hypnotic, CNS infection/sepsis, hypoglycemia, status epilepticus, GBS/botulism (descending weakness) (WHO/IPCS) Scope: Recognize anticholinesterase poisoning from the cholinergic toxidrome in a plausible exposure context; identify the killers early (bronchorrhea + bronchospasm + bradycardia, respiratory-muscle failure) (WHO/IPCS; Eddleston Lancet 2008) No severity triggers fired against current inputs.
Plan
Regimen axis: **Cholinergic crisis — decontaminate → atropinize → oxime → control seizures → airway/ventilate (incl. intermediate syndrome)** — step "Step 1 — Decontamination + staff PPE (secondary-contamination control)". 1. skin and clothing decontamination + RPE/PPE Remove ALL clothing (double-bag), copious soap-and-water / water irrigation of skin, eye irrigation if ocular; staff in chemical-resistant gloves/gown + respiratory protection topical/physical once, repeat irrigation until decontaminated (decontamination, first line) — Secondary contamination of rescuers/ED staff is a real hazard — lipophilic OPs penetrate skin and off-gas; decontaminate at the door, never in a closed treatment bay (WHO/IPCS; Eddleston Lancet 2008) Setting playbook (ed) — Decontaminate safely (protect staff), recognize cholinergic crisis clinically, atropinize to dry chest, start pralidoxime early, control seizures, secure airway WITHOUT succinylcholine, triage to ICU (WHO/IPCS; Eddleston Lancet 2008) 2. skin/clothing decontamination + staff PPE Remove all clothing, copious water/soap irrigation; staff chemical-resistant gloves/gown + respiratory protection physical at the door, in parallel with resuscitation — Any dermal/clothing contamination (decontaminate before closed-bay care) (Eddleston Lancet 2008) (Prevents secondary contamination of ED staff (WHO/IPCS)) 3. atropine (escalating-doubling) 1–3 mg IV (peds 0.02 mg/kg), DOUBLE q~5 min until atropinized, then infusion ~10–20% of loading dose/h IV q5min doubling then infusion — Any muscarinic feature (do not wait for labs) (Eddleston Lancet 2008) (Endpoint = dry chest + adequate oxygenation, NOT pupils/HR (WHO/IPCS)) 4. pralidoxime WHO: ≥30 mg/kg IV load over 20–30 min then ≥8 mg/kg/h infusion IV load then continuous infusion — OP confirmed/suspected — give EARLY before aging (defer for pure carbamate) (Eddleston Lancet 2008) (Reactivates AChE; targets nicotinic features atropine does not treat (WHO/IPCS)) 5. diazepam/lorazepam Diazepam 5–10 mg IV (peds 0.1–0.3 mg/kg) PRN IV PRN seizures — Seizure or severe agitation (atropine does not treat CNS) (WHO/IPCS) (First-line anticonvulsant + neuroprotective in OP (critical-care tox review)) Non-pharmacologic actions: - High-flow O2 + aggressive airway suctioning for bronchorrhea (WHO/IPCS) - Intubate for hypoxemia/secretion burden/paralysis/coma — AVOID succinylcholine; use higher-dose non-depolarizing NMB if paralytic needed (Eddleston Lancet 2008) - Continuous cardiac monitoring + QTc (WHO/IPCS) - IV crystalloid for GI-loss volume depletion / hypotension (critical-care tox review) - Poison-centre / medical-toxicology consult; psychiatry flag if intentional (WHO/IPCS) AVOID / contraindication checks: - AVOID succinylcholine — pseudocholinesterase inhibition causes grossly prolonged paralysis; use non depolarizing NMB at higher dose (Eddleston Lancet 2008) - AVOID morphine/opioids — respiratory depression compounds cholinergic respiratory failure (WHO/IPCS) - AVOID aminophylline/theophylline — lowers seizure threshold and worsens dysrhythmia in cholinergic crisis (WHO/IPCS) - AVOID phenothiazines and other anticholinergic/CNS depressant antiemetics/sedatives — confound the toxidrome and lower seizure threshold (critical care tox review) - Do NOT titrate atropine to pupils or to heart rate — endpoint is drying of secretions + clear chest + adequate oxygenation (Eddleston Lancet 2008) - Do NOT delay atropine/pralidoxime to await cholinesterase assays — diagnosis is clinical (Eddleston Lancet 2008) - Oximes usually unnecessary / often deferred in pure carbamate poisoning (spontaneously reversible) (WHO/IPCS)
Monitoring
Regimen monitoring: - continuous secretion burden + chest auscultation + SpO2 (atropine titration endpoint) (Eddleston Lancet 2008) - continuous HR/BP + telemetry + QTc (WHO/IPCS) - atropine total dose log + maintenance infusion titration (Eddleston Lancet 2008) - pralidoxime infusion continuity until clinically improved (WHO/IPCS) - serial RBC acetylcholinesterase + plasma/pseudocholinesterase trend (confirmatory only) (Eddleston Lancet 2008) - daily neuromuscular exam for intermediate syndrome 24–96 h (critical-care tox review) - watch for recrudescent toxicity from lipophilic-agent redistribution + need to re-escalate atropine (Eddleston Lancet 2008) Setting (ed) monitoring: - Secretions + chest + SpO2 continuously (atropine endpoint) (Eddleston Lancet 2008) - HR/BP/telemetry/QTc continuous (WHO/IPCS) - Atropine cumulative dose + response q5–15 min (Eddleston Lancet 2008) - Neuromuscular strength baseline (intermediate-syndrome reference) (critical-care tox review) Follow-up plan: Watch for OPIDN delayed neuropathy (1–3 wk) and chronic neuropsychiatric sequelae; psychiatry referral if intentional self-poisoning; occupational/agricultural exposure source remediation + PPE education; outpatient neuro follow-up (WHO/IPCS; critical-care tox review) - Close-out criterion: Discharge plan + OPIDN counseling + psych (if intentional) + source remediation arranged Monitoring phase: Continuous secretions/chest/SpO2/HR/BP, atropine-infusion titration, oxime infusion, serial RBC/plasma cholinesterase trend, daily neuromuscular exam for intermediate syndrome (24–96 h), telemetry/QTc, recurrent toxicity from lipophilic agents redistributing (Eddleston Lancet 2008)
Disposition
Current setting: ed — Decontaminate safely (protect staff), recognize cholinergic crisis clinically, atropinize to dry chest, start pralidoxime early, control seizures, secure airway WITHOUT succinylcholine, triage to ICU (WHO/IPCS; Eddleston Lancet 2008) Disposition criteria: - ICU: any significant cholinergic features, atropine/oxime infusion, intubation, or intermediate-syndrome risk (almost all symptomatic OP) (WHO/IPCS) - Observation/ward: trivial carbamate exposure, asymptomatic after an adequate monitored watch with normal exam (WHO/IPCS) - Psychiatry hold + medical clearance pathway if intentional self-poisoning (critical-care tox review) Escalation triggers (move to higher acuity): - Bronchorrhea/bronchospasm with hypoxemia → aggressive atropine + intubation + ICU (Eddleston Lancet 2008) - Seizure / coma → benzodiazepine + airway + ICU (WHO/IPCS) - Nicotinic weakness/paralysis or rising oxime/atropine need → ICU (critical-care tox review) - Refractory bradycardia/hypotension → escalate atropine, ICU (Eddleston Lancet 2008)
Earlier-Return Triggers
Return-precaution thresholds (watch for): - [LIFE_THREATENING] Bronchorrhea + bronchospasm with hypoxemia / impending respiratory failure (the primary muscarinic killer) (Eddleston Lancet 2008) - [LIFE_THREATENING] Seizure or coma from CNS cholinergic toxicity (Eddleston Lancet 2008) - [LIFE_THREATENING] New proximal limb / neck-flexor / respiratory / cranial-nerve weakness 24–96 h after exposure (intermediate syndrome) (critical-care tox review)
Citations
- WHO/IPCS organophosphate management; 2024-2025 critical-care tox reviews; Eddleston Lancet OP poisoning [PMID:18242601](https://pubmed.ncbi.nlm.nih.gov/18242601/) - Cited evidence (PMID 17961051) [PMID:17961051](https://pubmed.ncbi.nlm.nih.gov/17961051/) - Cited evidence (PMID 15555635) [PMID:15555635](https://pubmed.ncbi.nlm.nih.gov/15555635/) - Cited evidence (PMID 16039337) [PMID:16039337](https://pubmed.ncbi.nlm.nih.gov/16039337/) - Cited evidence (PMID 24050627) [PMID:24050627](https://pubmed.ncbi.nlm.nih.gov/24050627/) Last reconciled with current guidelines: 2026-05-16.
- WHO/IPCS organophosphate management; 2024-2025 critical-care tox reviews; Eddleston Lancet OP poisoning — PMID:18242601
- Cited evidence (PMID 17961051) — PMID:17961051
- Cited evidence (PMID 15555635) — PMID:15555635
- Cited evidence (PMID 16039337) — PMID:16039337
- Cited evidence (PMID 24050627) — PMID:24050627