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NREMT — EMT & Paramedic
NREMT Toxicology & Environmental Emergencies Practice Questions
Toxicology and environmental items reward syndrome recognition: a handful of toxidromes (opioid, sympathomimetic, anticholinergic, cholinergic) and a handful of thermal patterns (heat exhaustion vs heat stroke; mild vs severe hypothermia) cover nearly the entire question bank. As always, scene safety carries extra weight here — poisoned scenes poison rescuers.
Frame every answer with: protect yourself, support ABCs (most poisoned patients die of airway/ventilation failure, not the poison directly), identify the syndrome, apply the few specific fixes you carry (naloxone, glucose, oxygen, cooling, warming), and transport with the product/container information when safe to bring.
The toxidromes that matter
Opioid: respiratory depression, pinpoint pupils, decreased mentation — the triad. Management: ventilate first (BVM beats everything), then naloxone per protocol titrated to adequate breathing, anticipating withdrawal agitation and re-sedation (naloxone is often shorter-acting than the opioid). Sympathomimetic (cocaine, methamphetamine): agitation, tachycardia, hypertension, hyperthermia, dilated pupils, diaphoresis — manage with calm handling, cooling, and safety; hyperthermia is the lethal element. Anticholinergic (antihistamine ODs, certain plants): 'hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter' — looks sympathomimetic but the skin is dry. Cholinergic (organophosphates/nerve agents): SLUDGE/DUMBELS — salivation, lacrimation, urination, defecation, GI distress, emesis, plus killer B's: bradycardia, bronchorrhea, bronchospasm — decontamination and scene safety dominate; the drowning airway needs aggressive suction; antidotes (atropine-based kits) per ALS protocol.
Carbon monoxide deserves its own line: vague flu-like symptoms in groups sharing a building, winter heating sources, headache/nausea/confusion — with reliable pulse oximetry false reassurance (standard SpO2 can't distinguish carboxyhemoglobin). Action: remove from the environment, high-flow oxygen regardless of the oximeter, transport (hyperbaric per local criteria). 'The whole family has the flu' is the tell.
Heat, cold, and water
Heat exhaustion: heavy sweating, weakness, nausea, headache — mentation essentially intact; cool environment, oral rehydration if fully alert, rest. Heat stroke: altered mental status with severe hyperthermia (skin may be dry or sweaty — mentation, not moisture, is the discriminator): a true emergency where aggressive, immediate cooling is the treatment — ice-water immersion where feasible per protocol, otherwise ice packs to neck/axilla/groin, evaporative cooling, cold IV fluids at ALS level — begun on scene because neurological outcome tracks cooling speed.
Hypothermia: mild (shivering, clumsy, withdrawn) → passive/active external rewarming, dry insulation, warm sweet drinks if fully alert; severe (shivering stops, lethargy → coma, slow irregular pulse) → gentle handling (rough movement can trigger VF), horizontal positioning, careful pulse checks for up to 30–45 seconds, ventilation support, core rewarming in hospital — and the resuscitation maxim 'not dead until warm and dead' applied through medical direction. Drowning: ventilation-first resuscitation (the arrest is hypoxic — rescue breaths matter; the compression-only shortcut is the planted error), spinal precautions only with suspicious mechanism, and every symptomatic submersion transported (delayed pulmonary deterioration). Frostbite: no rubbing, no rewarming if refreezing is possible, dry dressings, hospital rewarming.
Practice questions with answers & rationales
Q1. An unresponsive man breathes 5 times a minute with pinpoint pupils. Order your first three actions.
Answer: (1) Open the airway and begin BVM ventilation — hypoxic injury and arrest are the actual killers; (2) naloxone per protocol, titrated to adequate respirations rather than full wakefulness; (3) reassess continuously, prepared for withdrawal agitation, vomiting (suction ready), and re-sedation as naloxone wears off — with transport regardless of response. Any answer giving naloxone before ventilating an apneic/near-apneic patient inverts the tested priority.
Q2. A family of four reports headaches, dizziness and nausea that improve when they leave the house. SpO2 reads 98% on everyone. What's your leading suspicion and action?
Answer: Carbon monoxide poisoning — clustered, environment-linked flu-like symptoms are the classic tell, and standard pulse oximetry reads carboxyhemoglobin as if it were oxygen, so 98% is false reassurance. Actions: evacuate everyone, high-flow oxygen via NRB regardless of the oximeter, assess for severe features (altered mentation, chest pain, pregnancy — hyperbaric considerations), notify the fire department for the source, transport. Trusting the oximeter is the planted error.
Q3. Differentiate anticholinergic from sympathomimetic toxidromes at the bedside.
Answer: Both produce agitation, tachycardia, hypertension, hyperthermia and dilated pupils. The skin decides: sympathomimetic patients are diaphoretic (the sympathetic system sweats); anticholinergic patients are hot, red and bone-dry (muscarinic blockade stops sweating), often with urinary retention and absent bowel sounds. Same vital-sign storm, different moisture — and the distinction matters for cause identification and anticipated course.
Q4. A farm worker collapses near a sprayer: drooling, tearing, vomiting, incontinent, pulse 44, audible wheeze. What's the syndrome, and what's different about this scene?
Answer: Cholinergic crisis (organophosphate exposure) — SLUDGE plus the killer B's: bradycardia, bronchorrhea, bronchospasm. The scene is the difference: the agent contaminates by contact, so PPE, distance, and decontamination (remove clothing, irrigate) come before hands-on care; the airway needs aggressive suction (he's drowning in secretions), ventilation support, and ALS antidote therapy per protocol. Rescuer contamination is exactly what this stem is probing.
Q5. Two outdoor workers: one is sweaty, weak and nauseated but answers questions normally; the other is confused and stumbling with hot skin. Triage and treat.
Answer: Worker one: heat exhaustion — cool environment, rest, oral fluids if fully alert, monitor. Worker two: heat stroke — altered mentation is the discriminator regardless of whether skin is wet or dry — begin immediate aggressive cooling (immersion if available per protocol; otherwise ice to neck/axillae/groin plus evaporative cooling), airway protection, rapid transport with cooling continuing. Minutes of hyperthermia cost neurons; cooling on scene is the credited choice over 'load and go warm.'
Q6. Why is a severely hypothermic patient handled 'like glass,' and what's different about pulse checks?
Answer: A cold myocardium is electrically irritable — rough handling or sudden movement can precipitate ventricular fibrillation that won't defibrillate well until rewarmed. Handle gently, keep horizontal, cut clothes rather than wrestling them off. Pulse checks extend to 30–45 seconds because profound bradycardia and vasoconstriction hide pulses; starting compressions on a beating cold heart can cause the arrest you feared. Resuscitation decisions defer to 'warm and dead' doctrine via medical direction.
Q7. Why does drowning resuscitation start with ventilations when bystander CPR teaching emphasizes compressions?
Answer: Compression-only CPR was designed for sudden cardiac arrest with oxygenated blood still in circulation. Drowning is a hypoxic arrest: the blood is desaturated, so circulating it without restoring oxygen accomplishes little — rescue breaths/BVM ventilation are the priority, with full CPR integrated per guidelines. Add airway readiness (water and vomitus — suction), spinal precautions only for diving/trauma mechanisms, and transport for every symptomatic submersion because pulmonary injury blooms hours later.
Common mistakes to avoid
- Giving naloxone before ventilating, or titrating it to wakefulness instead of breathing.
- Trusting pulse oximetry in carbon monoxide and smoke-inhalation patients.
- Confusing the wet (sympathomimetic) and dry (anticholinergic) hot-agitated toxidromes.
- Touching contaminated patients (organophosphate, hazmat) before decontamination and PPE.
- Using mentation-free criteria for heat stroke — altered mental status plus heat is heat stroke, sweaty or not.
- Rough handling, premature compressions, or early death pronouncement in severe hypothermia.