This patient presents to the Emergency Department with altered mental status, difficulty breathing, vomiting, and hypersalivation after an unknown ingestion. His exam shows an ill patient with constricted pupils (miosis), wet skin (diaphoresis), bradycardia, and tachypnea. Altered mental status has a broad differential diagnosis, including intracranial bleeding, stroke, post-ictal state, hypoglycemia, electrolyte abnormalities, other metabolic causes, infectious etiologies, toxicological causes, and many other conditions. This patient’s constellation of signs and symptoms support the presence of a cholinergic toxidrome due to organophosphate poisoning. See the chart below for a review of the most common toxidromes (toxic syndromes).
Cholinergic toxidromes can be caused by organophosphate or carbamate pesticides, as well as nerve gas agents (i.e., sarin gas). These agents cause poisoning by increasing the amount of acetylcholine at the neuromuscular junction, causing stimulation at muscarinic and nicotinic acetylcholine receptors. This causes a dramatic increase in bodily secretions with increased respiratory secretions and airway compromise as the most common cause of death in this population. The cholinergic toxidrome can be remembered with the mnemonic “DUMBBELLS” (diarrhea/diaphoresis, urination, miosis, bradycardia, bronchorrhea, emesis, lacrimation, low BP, salivation).
The first step in treating any patient who has the potential cause to harm or expose staff members to the poisoning agent is patient decontamination (Choice C). This patient should be undressed and adequately decontaminated by staff members who are wearing personal protective equipment (PPE). Once the patient is decontaminated, the airway should be established with endotracheal tube placement (Choice A) and IV atropine (Choice B) should be given to reverse the toxidrome. Atropine can be started at 2-4mg IV and repeated every 5-10 minutes until respiratory secretions are cleared. Pralidoxime (Choice D) should also be given as soon as possible to prevent irreversible changes (“aging”) to the acetylcholinesterase at the neuromuscular junction. This timeframe varies from minutes to hours after exposure, depending on the agent. All choices provided in this question are important actions to take, but patient decontamination (Choice C) is the most important initial next step. Correct Answer: C
- Kitchen, L. (2015). The Approach to the Poisoned Patient. EMDocs. http://www.emdocs.net/the-approach-to-the-poisoned-patient/
- Sahi, N. (2018). TOXCard: Nerve agents. EM Docs. http://www.emdocs.net/toxcard-nerve-agents/