If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 3 exam, you might want to know which questions are most often missed by test-prep takers. Check out this example from Kaplan Medical, and read an expert explanation of the answer. Also check out all posts in this series.
A 22-year-old man is brought to the emergency department by a police officer who says that he "picked this guy up on the street after a violent outburst." People at the scene told the officer that it appeared as if this man was "out of his mind." The patient's father comes to the hospital and states that his son has been increasingly aggressive and has been stumbling and tripping around the house for several weeks. He is especially concerned about this "uncharacteristic violent behavior."
The patient's temperature is 38.1ºC (100.6ºF), blood pressure is 130/80 mm Hg, pulse is 75/min, and respirations are 20/min. He is diaphoretic and has vertical nystagmus. He begins to have convulsions in the emergency department, making the remainder of the examination impossible.
Which of the following is the most likely cause of these findings?
A. Cocaine withdrawal
B. Heroin intoxication
C. Heroin withdrawal
D. Marijuana intoxication
E. Phencyclidine intoxication
The correct answer is E.
Kaplan Medical explains why
Kaplan Medical explains why
This patient displays the signs and symptoms of PCP intoxication. PCP causes aggression, distortion of body image, disorganized thoughts, ataxia, nystagmus, myoclonus, fever, hypersalivation and hyperacusis. It can lead to seizures, coma and death. It can also lead to an acute psychosis with a high risk of violent behavior and suicide. Haloperidol is the treatment for the violent behavior.
Why the other answers are wrong
Why the other answers are wrong
Choice A. Cocaine withdrawal causes severe depression, hypersomnolence, nightmares, headaches and sweating. The symptoms peak 2-4 days after the last dose. Aggression, ataxia, and nystagmus are not present.
Choice B. Heroin is an opioid that produces euphoria, hypoactivity, and impaired concentration. Physical signs of intoxication include needle "track-marks", miosis, respiratory depression, hypotension, bradycardia, and decreased body temperature. Constipation is very common. Nausea, vomiting, shock, coma, and pulmonary edema may occur. Overdoses are treated with naloxone. Methadone maintenance is used for individuals with demonstrated physiologic dependence and is found to reduce drug-seeking behavior.
