Prehospital Care
For patients with possible hemlock poisoning, maintain the airway, obtain IV access, and assist with ventilation as needed.
Emergency Department Care
Rapidly assess and correct any life-threatening conditions. Since no antidote exists for either toxin, gastrointestinal (GI) decontamination (if appropriate) and aggressive supportive care are mainstays of treatment for hemlock poisoning. Schep et al provide a concise review of water hemlock poisoning and management. [6]
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Secure airway.
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Decontaminate the GI tract if timing is appropriate.
If no contraindications exist, gastric lavage may be of limited benefit if performed rapidly after the ingestion.
Administer activated charcoal if the patient is able to protect the airway and presents within 1 hour of ingestion. Ipecac should not be used.
Caution should be exercised in patients exposed to water hemlock because they are at increased risk of having seizures, and can eventually aspirate the charcoal.
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Treat seizures with benzodiazepines; use barbiturates if needed.
Provide prophylaxis with water hemlock ingestion.
Benzodiazepines and barbiturates help control agitation and raise the seizure threshold.
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Aggressively administer IV fluids for dehydration or rhabdomyolysis.
Replete volume if signs of hypovolemia or hypotension are present.
Correct electrolyte abnormalities.
Administer fluids with sodium bicarbonate for urinary alkalinization if evidence of rhabdomyolysis exists. If using sodium bicarbonate, mixing it in 5% dextrose in water (D5W) is important to limit the amount of sodium load.
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Potassium levels should be monitored and corrected as needed.
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Administer antiemetics. Many antiemetics may lower the seizure threshold and should be used cautiously.
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Provide ventilatory support, if necessary.
Observe the patient closely for at least 6 hours after presentation to evaluate for symptoms and progression. Monitor all patients showing evidence of toxicity for possible seizures, dysrhythmias, or respiratory failure in an ICU setting. Consider transferring the patient to a facility with a toxicology service. Counsel pregnant patients that teratogenic effects from poison hemlock exposure have been reported in livestock.
Consultations
A regional poison center or a medical toxicologist can assist with patient treatment and potentially with plant identification. The regional poison control center should be contacted (800-222-1222) to discuss optimal management of all known or suspected hemlock poisonings.
Prevention
Educate patients about avoiding ingestions of hemlock and other unidentifiable or mistakenly identified plants.
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Hemlock. Photo by Cornell University Poisonous Plants Informational Database
