A 19-year-old woman is brought to the emergency department following a motor vehicle collision. According to the accident report, she hit a temporary guardrail erected to redirect traffic due to construction. On arrival, the patient appears anxious and confused. She has no apparent head, neck, or body injuries. When her parents arrive, they report that she has no other medical problems but that a physician prescribed something for anxiety and insomnia during a stressful period last year. Last month, the patient had her wisdom teeth extracted and experienced a lot of postoperative pain that has since resolved. She occasionally drinks alcohol and smokes half a pack of cigarettes daily. Temperature is 37.2 C (99 F), blood pressure is 128/75 mm Hg, pulse is 110/min, and respirations are 22/min. Examination shows a thin woman with dry mouth and conjunctival injection; the pupils are equal and reactive to light and accommodation. She is oriented to person and place but not time and recalls 1 of 3 objects in 5 minutes. Which of the following substances is most likely contributing to this patient's presentation?

Question

A 19-year-old woman is brought to the emergency department following a motor vehicle collision.  According to the accident report, she hit a temporary guardrail erected to redirect traffic due to construction.  On arrival, the patient appears anxious and confused.  She has no apparent head, neck, or body injuries.  When her parents arrive, they report that she has no other medical problems but that a physician prescribed something for anxiety and insomnia during a stressful period last year.  Last month, the patient had her wisdom teeth extracted and experienced a lot of postoperative pain that has since resolved.  She occasionally drinks alcohol and smokes half a pack of cigarettes daily.  Temperature is 37.2 C (99 F), blood pressure is 128/75 mm Hg, pulse is 110/min, and respirations are 22/min.  Examination shows a thin woman with dry mouth and conjunctival injection; the pupils are equal and reactive to light and accommodation.  She is oriented to person and place but not time and recalls 1 of 3 objects in 5 minutes.  Which of the following substances is most likely contributing to this patient's presentation?

Quizplus · Accepted Answer

This patient's clinical presentation and examination findings are most consistent with acute cannabis (marijuana) intoxication. Signs of marijuana intoxication include tachycardia, tachypnea, dry mouth, conjunctival injection, and increased appetite. Marijuana slows reaction time and impairs coordination, attention, concentration, and short-term memory. Impairment of cognition, judgment, and coordination can last much longer than the acute euphoric effect, altering the ability to operate automobiles and increasing the risk of motor vehicle collisions. Patients with cannabis intoxication are managed supportively. (Choices A and B) Alcohol and benzodiazepine intoxication can present with unsteady gait, incoordination, disinhibited behavior, drowsiness, and conjunctival injection, but dry mouth would not be expected. (Choice C) Cocaine intoxication is characterized by sympathetic stimulation, with an increase in heart rate and blood pressure, diaphoresis, and dilated pupils. This response is accompanied by euphoria, a sense of self-confidence, increased arousal, and improved performance on tasks of alertness and vigilance. In contrast, this patient's pupils are not dilated, and she had a slowed reaction time while driving. (Choice E) Opioid intoxication typically presents with depressed mental status, decreased respiratory rate, bradycardia, and small, constricted pupils (miosis); tachypnea and conjunctival injection are not seen. (Choice F) Impaired judgment and tachycardia can also be seen in phencyclidine (PCP) intoxication. However, PCP intoxication is more likely to cause aggressive behavior, ataxia, mild hypertension, and multidirectional nystagmus. Educational objective: Clinical features of marijuana intoxication include increased appetite, tachycardia, tachypnea, dry mouth, and conjunctival injection. Marijuana use slows reaction time; impairs attention, concentration, and coordination; and can increase the risk of motor vehicle collisions. References: The effects of cannabis intoxication on motor vehicle collision revisited and revised. (http://www.ncbi.nlm.nih.gov/pubmed/26878835) Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/22323502)

A 19-Year-Old Woman Is Brought to the Emergency Department Following