A 26-year-old woman is brought to the emergency department by coworkers due to agitated behavior. She appears distracted by unseen stimuli during the initial interview, strikes out at a nurse taking her vital signs, and attempts to lift a hospital cart. The patient has a history of depression as well as alcohol and drug use, but she is not currently in treatment. She has no other underlying illness. Temperature is 37.2 C (99 F), blood pressure is 160/90 mm Hg, pulse is 126/min, and respirations are 18/min. The patient is confused and agitated during the examination, frequently yelling and talking to herself. Physical examination shows equal and reactive pupils, intact extraocular movements, and nystagmus. There is mild rigidity that is most prominent in the upper extremities. Upper and lower limb deep tendon reflexes are 1+. The remainder of the examination is unremarkable. Intoxication with which of the following substances is the most likely explanation in this patient?

Question

A 26-year-old woman is brought to the emergency department by coworkers due to agitated behavior.  She appears distracted by unseen stimuli during the initial interview, strikes out at a nurse taking her vital signs, and attempts to lift a hospital cart.  The patient has a history of depression as well as alcohol and drug use, but she is not currently in treatment.  She has no other underlying illness.  Temperature is 37.2 C (99 F), blood pressure is 160/90 mm Hg, pulse is 126/min, and respirations are 18/min.  The patient is confused and agitated during the examination, frequently yelling and talking to herself.  Physical examination shows equal and reactive pupils, intact extraocular movements, and nystagmus.  There is mild rigidity that is most prominent in the upper extremities.  Upper and lower limb deep tendon reflexes are 1+.  The remainder of the examination is unremarkable.  Intoxication with which of the following substances is the most likely explanation in this patient?

Quizplus · Accepted Answer

This patient is most likely under the influence of phencyclidine (PCP), a dissociative anesthetic that can cause hallucinations, dissociative feelings, agitation, confusion, tachycardia, and nystagmus (horizontal, vertical, or rotatory). In many cases, it can lead to psychotic and violent behavior, diminished pain perception, and subsequent physical injuries. The drug's onset of action is rapid, and the duration of action is generally <8 hours. High doses can cause severe hypertension, seizures, rigidity, and life-threatening hyperthermia. Benzodiazepines are used for the treatment of severe psychomotor agitation associated with PCP intoxication. (Choice A) Cocaine intoxication is characterized by elevated blood pressure and heart rate, euphoria, and increased alertness. Nystagmus and ataxia are uncommon. Violent agitation is also less common with cocaine than with PCP. (Choice B) Jimson weed (Datura stramonium) is an anticholinergic, atropine-containing plant that is abused for its hallucinatory properties. Jimson weed toxicity manifests as anticholinergic poisoning. Symptoms include hallucinations/delirium, hyperthermia, tachycardia, nonreactive mydriasis, and dry, red skin ("mad as a hatter, hot as a hare, blind as a bat, dry as a bone, and red as a beet"). Nystagmus is not commonly seen. (Choices C and H) Lysergic acid diethylamide (LSD) and psilocybin are hallucinogens that can cause visual hallucinations and illusions, euphoria (or dysphoria), and depersonalization. Orientation is often intact. Mild hypertension and tachycardia may occur. Nystagmus and combative agitation are not common and are more consistent with PCP intoxication. (Choice D) Methamphetamine intoxication can also cause severe psychomotor agitation, hallucinations, tachycardia, and hypertension, but nystagmus is less common. Methamphetamine intoxication may last up to 20 hours (longer than intoxication with PCP). (Choice E) Methylenedioxymethamphetamine (MDMA) intoxication typically presents with euphoria and increased energy, which may be accompanied by bruxism and hyperthermia. Violent agitation is not commonly seen. (Choice F) Nitrous oxide is an inhalant that induces brief euphoria and altered consciousness. This patient's presentation is not consistent with nitrous oxide intoxication. Educational objective: Phencyclidine is a dissociative anesthetic that characteristically causes nystagmus. It can also cause dissociative feelings, psychotic and violent behavior, severe hypertension, and hyperthermia. References: Phencyclidine intoxication case series study. (http://www.ncbi.nlm.nih.gov/pubmed/25502414)

A 26-Year-Old Woman Is Brought to the Emergency Department by Coworkers