Question 1:
A 23-year-old man is brought to the emergency department after being found obtunded on the
street. The history suggests that he may have ingested 180 mg of his friend's methadone during
a suicide attempt. On arrival he has a Glasgow Coma Scale (GCS) score of 6, with hypoactive
bowel sounds and pinpoint pupils. His initial vital signs are temperature 36C, heart rate 56/min,
blood pressure 103/70 mm Hg, respiratory rate 6, and oxygen saturation 84% on room air.
Blood glucose is 4.6 mmol/L. Initially, his ventilation was supported through bag-valve-mask
(BVM) apparatus but after three doses of 0.4 mg IV naloxone there is improvement in his
respiratory effort. He is transferred to the ICU. What is the most appropriate management?
Intubation for airway protection
Naloxone boluses as needed plus activated charcoal
Naloxone infusion at 0.4 mg/h
Naloxone infusion at 0.8 mg/h
Answer:
The correct answer is D.
Rationale:
This patient's presentation is consistent with opioid toxicity. Immediate resuscitation and
administration of antidotal therapy are the most important initial steps in management. Given
the hypoxia and bradypnea, supplemental oxygen without assisted ventilation is of minimal
benefit. As a disease of hypoventilation, opioid toxicity requires ventilation. This is achieved
through BVM and administration of opioid antagonists. Methadone is a long- acting opioid, with
expected clinical toxicity to last beyond 24 hours. The proper dosing of a naloxone infusion per
hour is 2/3 the dose required to adequately reverse the patient. This patient responded to 1.2
mg IV naloxone, so the infusion dose should start at 0.8 mg/h (choice D is correct). If naloxone
was not available, intubation would be an option, but there is no need to do so at this time
(choice A is incorrect).
Methadone is a liquid product with rapid absorption, so activated charcoal would be of no
benefit and potentially harmful as the fluctuating level of consciousness may result in
aspiration, and lower doses of naloxone would be insufficient (choices B and C are incorrect).
,Question 2:
A 48-year-old woman is brought in after being found unconscious in a house fire. She was
intubated in the emergency department and transferred to the ICU for further management.
She received 2L IV Ringer lactate and is now on a norepinephrine infusion. Her Glasgow Coma
Scale (GCS) score has remained at 3 since arrival. Her vitals are temperature 37.2 C, HR
120/min, BP 70/50 mm Hg, respiratory rate 18 set by ventilator, and oxygen saturation 95% on
100% FiO2. Blood glucose is 8.5 mmol/L. Initial laboratory testing reveals pH 6.98,
pCO2 34 mm Hg, bicarbonate 6 mmol/L, and lactate 17 mmol/L. What is the most appropriate
next step in management?
Dantrolene
Hydroxocobalamin
Hyperbaric oxygenation
Methylene Blue
Answer:
The correct answer is B.
Rationale:
This clinical presentation is highly suggestive of cyanide toxicity.
,Question 3:
A 48-year-old woman is brought in after being found unconscious in a house fire. She was
intubated in the emergency department and transferred to the ICU for further management.
She received 2L IV Ringer lactate and is now on a norepinephrine infusion. Her Glasgow Coma
Scale (GCS) score has remained at 3 since arrival. Her vitals are temperature 37.2 C, HR
120/min, BP 70/50 mm Hg, respiratory rate 18 set by ventilator, and oxygen saturation 95% on
100% FiO2. Blood glucose is 8.5 mmol/L. Initial laboratory testing reveals pH 6.98,
pCO2 34 mm Hg, bicarbonate 6 mmol/L, and lactate 17 mmol/L. What is the most appropriate
next step in management?
Dantrolene
Hydroxocobalamin
Hyperbaric oxygenation
Methylene Blue
Answer:
The correct answer is B.
Rationale:
This clinical presentation is highly suggestive of cyanide toxicity.
Patients with hyperlactatemia after a fire should be assumed to have inhaled cyanide.
Obtundation, hypotension, and tachycardia all support the diagnosis. Treatment of cyanide
toxicity is prompt administration of hydroxocobalamin (choice B is correct). Dantrolene would
be used in patients with significant hyperthermia and muscle rigidity secondary to malignant
hyperthermia (choice A is incorrect). Carbon monoxide toxicity is also a concern after a fire, and
a carboxyhemoglobin level should certainly be obtained. However, given the elevated lactate
and hemodynamic instability, management of suspected cyanidetakes precedence over
transfer to a hyperbaric chamber for carbon monoxide toxicity (choice C is incorrect).
Methylene blue is therapy for methemoglobinemia (choice D is incorrect).Patients with
hyperlactatemia after a fire should be assumed to have inhaled cyanide. Obtundation,
hypotension, and tachycardia all support the diagnosis. Treatment of cyanide toxicity is prompt
administration of hydroxocobalamin (choice B is correct). Dantrolene would be used in patients
with significant hyperthermia and muscle rigidity secondary to malignant hyperthermia (choice
A is incorrect). Carbon monoxide toxicity is also a concern after a fire, and a carboxyhemoglobin
level should certainly be obtained. However, given the elevated lactate and hemodynamic
instability, management of suspected cyanidetakes precedence over transfer to a hyperbaric
chamber for carbon monoxide toxicity (choice C is incorrect). Methylene blue is therapy for
methemoglobinemia (choice D is incorrect).
Patients with hyperlactatemia after a fire should be assumed to have inhaled cyanide.
Obtundation, hypotension, and tachycardia all support the diagnosis. Treatment of cyanide
toxicity is prompt administration of hydroxocobalamin (choice B is correct). Dantrolene would
be used in patients with significant hyperthermia and muscle rigidity secondary to malignant
hyperthermia (choice A is incorrect). Carbon monoxide toxicity is also a concern after a fire, and
a carboxyhemoglobin level should certainly be obtained. However, given the elevated lactate
and hemodynamic instability, management of suspected cyanide
takes precedence over transfer to a hyperbaric chamber for carbon monoxide toxicity (choice C
is incorrect). Methylene blue is therapy for methemoglobinemia (choice D is incorrect).
Patients with hyperlactatemia after a fire should be assumed to have inhaled cyanide.
Obtundation, hypotension, and tachycardia all support the diagnosis. Treatment of cyanide
toxicity is prompt administration of hydroxocobalamin (choice B is correct). Dantrolene would
be used in patients with significant hyperthermia and muscle rigidity secondary to malignant
hyperthermia (choice A is incorrect). Carbon monoxide toxicity is also a concern after a fire, and
a carboxyhemoglobin level should certainly be obtained. However, given the elevated lactate
and hemodynamic instability, management of suspected cyanide
, Question 4:
A 38-year-old man is admitted to the ICU after being intubated for severe agitation. He was
brought to the emergency department after being detained at an international airport for
aggressive behavior. He required prehospital sedation with intramuscular midazolam to
facilitate transport. On arrival, his vital signs were temperature 40.2 C, HR 165/min, BP 180/100
mm Hg, respiratory rate 24, and oxygen saturation 96% on room air. Blood glucose 10.5 mmol/L
(189 mg/dL). He was intubated using rocuronium and was started on a propofol infusion at 4
mg/kg/hr. Vitals signs have not significantly changed. What is the most appropriate
management?
Active cooling
Active cooling, increased sedation
Active cooling, increased sedation, and β-blockade
Active cooling, increased sedation, and paralysis
Answer:
The correct answer is D.
Rationale:
This patient's presentation is consistent with significant toxicity
from sympathomimetic agents (such as cocaine or amphetamines). His most immediate
life-threatening problem is his hyperthermia, and goal is to cool the patient, which will be
facilitated by a neuromuscular blocker (choice D is correct). Cooling with sedation alone are
insufficient (choices A and B are incorrect) and β-Blockade is not indicated (choice C is
incorrect).
Sympathomimetic toxicity is a centrally driven disease (symptoms are due to an increase in
excitation in the central nervous system). β-Blockade does not address this, as it only targets
the peripheral symptoms of that centrally mediated process. Furthermore, β-blockers
pharmacologically result in unopposed alpha stimulation, though the clinical significance of this
has been recently debated.