Hemlock Poisoning: Treatment & Supportive Care

Poison hemlock (Conium maculatum) ingestion is life-threatening. There is no specific antidote. The toxin coniine (and γ-coniceine) is a nicotinic acetylcholine receptor antagonist causing neuromuscular blockade. Death results from respiratory paralysis.

Immediate Actions

1. Call 911 / Emergency Services immediately.
2. Call Poison Control: 1-800-222-1222 (US).
3. Do NOT induce vomiting. Aspiration risk; seizures can occur suddenly.
4. Remove plant material from mouth; rinse with water.
5. If unconscious: recovery position, monitor airway.

Hospital Supportive Care

• Airway Management: Early intubation & mechanical ventilation for respiratory failure (may be needed for days).
• Gastrointestinal Decontamination: Activated charcoal (50–100g) if within 1h of ingestion and airway protected.
• Seizure Control: Benzodiazepines (lorazepam, midazolam). Avoid phenytoin (may worsen conduction).
• Hemodynamic Support: IV fluids, vasopressors for hypotension.
• Atropine: For bradycardia/hypersalivation (muscarinic effects); does not reverse neuromuscular blockade.
• Renal Replacement: Hemodialysis/hemoperfusion — limited evidence; coniine has large Vd, not efficiently dialyzed.
• Monitoring: Continuous ECG, SpO₂, EtCO₂, neuromuscular transmission (train-of-four), ABGs, CK, renal function.

Prognosis

• Mortality: 5–10% with modern ICU care; higher if delayed presentation.
• Recovery: Usually complete if ventilatory support sustained through acute phase (24–72h).
• Rhabdomyolysis & AKI possible from prolonged paralysis.

Identification

• Purple-spotted hollow stem, fern-like leaves, white umbel flowers, mouse-like odor.
• Often mistaken for wild carrot (Queen Anne's lace), parsley, anise, fennel.

Prevention is paramount. Teach plant identification. Never forage without expert certainty.