Environment and Toxicology Emergencies, and Communicable Diseases practice questions

Answer: A) Reversing hypoxemia by supporting the airway, ventilation, and supplemental oxygen

Hypoxia is the main life threat in drowning, so restoring airway, ventilation, and oxygenation comes first. Electrolyte correction and routine spinal immobilization are usually not the priority.

• ACorrect. Tissue hypoxia, especially cerebral hypoxia, is the main cause of illness and death in drowning. Restoring oxygenation and ventilation comes first, with SpO2 targeted at about 92-96%.
• BIncorrect. Clinically significant electrolyte disturbances are uncommon in nonfatal drowning. Freshwater and saltwater both cause hypoxemia through surfactant damage.
• CIncorrect. Routine spinal immobilization is indicated only when there is a history or signs of trauma, such as diving or a fall. Here it would delay airway management.
• DIncorrect. In drowning, airway and breathing come before compressions because the arrest is hypoxic. Resuscitation starts with rescue breaths.

Answer: D) Hydroxocobalamin

• AIncorrect. This reverses warfarin.
• BIncorrect. This reverses opioids.
• CIncorrect. This reverses benzodiazepines.
• DCorrect. It binds cyanide to form vitamin B12.

Answer: B) Time, distance and shielding

Under the CDC's ALARA principle, radiation dose is kept low by limiting time near the source, increasing distance from it, and using shielding. Measures such as decontamination, potassium iodide and decorporation agents are separate parts of radiation-incident management.

• AIncorrect. Decontamination, dosimetry badges and potassium iodide each have a place in managing a radiation incident. They are not the three ALARA protective actions. Potassium iodide protects only the thyroid, and only against radioactive iodine.
• BCorrect. The CDC's ALARA guidance tells staff to spend as little time near the source as possible, increase their distance from it, and place shielding between themselves and the source.
• CIncorrect. These are infection-control and airborne-hazard measures. They do not reduce dose from external radiation, which is what time, distance and shielding address.
• DIncorrect. Detection, triage and decorporation agents (such as Prussian blue or DTPA) are parts of radiation-incident care. They are not the ALARA protective actions for staff.

Answer: B) Place the patient in the lateral recovery position with continuous airway and respiratory monitoring.

A drowsy, vomiting intoxicated patient is at high risk of aspiration. The recovery (lateral) position with continuous monitoring keeps the airway clear. Oral intake and leaving the patient unattended are unsafe.

• AIncorrect. Lying supine lets vomit pool in the airway, and a pillow under the head flexes the neck and can block the airway. First-aid guidance says not to place a pillow under an unconscious person's head.
• BCorrect. Side-lying (recovery) position lets vomit drain from the mouth and helps keep the airway clear in a patient with a dulled gag reflex. The patient still needs close monitoring.
• CIncorrect. Giving anything by mouth to a patient with reduced consciousness raises the risk of aspiration. Caffeine does not reverse alcohol intoxication.
• DIncorrect. A patient with reduced consciousness who is vomiting should not be left unattended. Blood alcohol can keep rising, and the patient could aspirate or stop breathing without anyone noticing.

Answer: A) A synthetic cathinone acting as a CNS stimulant

'Bath salts' are synthetic cathinones, potent CNS stimulants similar to cocaine and methamphetamine that cause a sympathomimetic picture of agitation, tachycardia and hyperthermia.

• ACorrect. CDC describes synthetic cathinones, sold as 'psychoactive bath salts,' as potent central nervous system stimulants that mimic cocaine, methamphetamine and MDMA. This fits the agitation, tachycardia and hyperthermia.
• BIncorrect. Synthetic cannabinoids are a different designer-drug class, usually smoked as herbal blends. The product sold as 'bath salts' is a synthetic cathinone.
• CIncorrect. Epsom (soaking) salts are magnesium sulfate. The street-drug 'bath salts' only borrow the name to hide what they are. Magnesium toxicity causes depression, such as weakness, low blood pressure and loss of reflexes, not stimulant toxicity.
• DIncorrect. Opioids cause CNS and respiratory depression with small pupils, not combative agitation with hyperthermia. Fentanyl may be co-ingested, but it is not what 'bath salts' are.

Answer: D) Immobilize at heart level

• AIncorrect. This can worsen injury.
• BIncorrect. This can cause tissue damage.
• CIncorrect. This is harmful.
• DCorrect. Keep the limb still and mark swelling; antivenom may be needed.

Answer: A) Vinegar

• ACorrect. It's used for certain species.
• BIncorrect. That can trigger more stinging.
• CIncorrect. That isn't recommended.
• DIncorrect. That can trigger more stinging.

Answer: B) Continued fall in core temperature as cold blood from the extremities returns to the core

Afterdrop is a further fall in core temperature after rewarming starts, caused by cold peripheral blood returning to the core as the limbs vasodilate. Warming the trunk before the extremities helps reduce it.

• AIncorrect. Hypotension during rewarming is often called rewarming shock. It can happen at the same time as afterdrop, but afterdrop specifically means a further fall in core temperature.
• BCorrect. As the periphery warms and its vessels dilate, cold blood from the limbs returns to the core and core temperature keeps falling. To reduce this risk, rewarm the trunk (axillae, chest, back) before the extremities.
• CIncorrect. Potassium changes can occur with hypothermia and cell injury. Afterdrop, however, describes a change in core temperature, not an electrolyte shift.
• DIncorrect. Shivering does stop as hypothermia becomes more severe, but that is part of how hypothermia progresses. It is not the further temperature drop that happens after rewarming begins.

Answer: A) IV calcium and high-dose insulin infusion with dextrose

Shock from calcium channel blocker toxicity that persists after fluids is treated with IV calcium and high-dose insulin euglycemic therapy, adding vasopressors as needed. Hemodialysis is ineffective, and lipid emulsion is reserved for refractory arrest or periarrest.

• ACorrect. IV calcium may improve hypotension and contractility. High-dose insulin euglycemic therapy is a first-line treatment for CCB-induced cardiogenic shock. Dextrose and potassium are given and monitored, and vasopressors are added if shock persists.
• BIncorrect. CCBs are lipophilic, highly protein-bound, and have a large volume of distribution, so hemodialysis is largely ineffective. More fluid alone has already failed to correct the shock.
• CIncorrect. Lipid emulsion is reserved for cardiac arrest or periarrest after maximal conventional therapy has failed. Whole bowel irrigation is contraindicated when the patient is hemodynamically unstable.
• DIncorrect. Bicarbonate treats sodium-channel blocker toxicity (e.g., tricyclic antidepressants), and magnesium treats torsades de pointes. Neither reverses calcium channel blockade.

Answer: A) Anticholinergic toxicity

• ACorrect. Supportive care; physostigmine may be considered.
• BIncorrect. Opioids cause pinpoint pupils.
• CIncorrect. That causes secretions and small pupils.
• DIncorrect. The patient is febrile.