A 21-year-old college student is brought to the emergency department by his roommate after he was found carving holes in the walls and ceiling of their dorm room. The patient is agitated and paces in the examination room. He says, "I had no choice. I had to locate and destroy the cameras. I refuse to answer any questions." The roommate has known him for the past year and says, "He seemed like a normal guy, but over the past several months he became withdrawn and started acting strange. He stopped seeing his friends and going to classes, and spent all his time researching government websites. I was getting annoyed with him because he stopped showering and no longer cleaned the room." The roommate does not believe the patient has any other medical problems or known psychiatric history. Temperature is 37.2 C (99 F), blood pressure is 125/85 mm Hg, pulse is 108/min, and respirations are 16/min. Examination shows normal pupils, moist mucous membranes, clear lung fields, and tachycardia. The abdomen is soft and nontender. Bowel sounds are present. There is no rebound tenderness or rigidity. Neurologic examination is within normal limits. Mental state examination is significant for poor eye contact, blank facial expression, and minimal spontaneous speech production. Which of the following would be the most useful test in the diagnostic workup of this patient?

Question

A 21-year-old college student is brought to the emergency department by his roommate after he was found carving holes in the walls and ceiling of their dorm room.  The patient is agitated and paces in the examination room.  He says, "I had no choice.  I had to locate and destroy the cameras.  I refuse to answer any questions."  The roommate has known him for the past year and says, "He seemed like a normal guy, but over the past several months he became withdrawn and started acting strange.  He stopped seeing his friends and going to classes, and spent all his time researching government websites.  I was getting annoyed with him because he stopped showering and no longer cleaned the room."  The roommate does not believe the patient has any other medical problems or known psychiatric history.  Temperature is 37.2 C (99 F), blood pressure is 125/85 mm Hg, pulse is 108/min, and respirations are 16/min.  Examination shows normal pupils, moist mucous membranes, clear lung fields, and tachycardia.  The abdomen is soft and nontender.  Bowel sounds are present.  There is no rebound tenderness or rigidity.  Neurologic examination is within normal limits.  Mental state examination is significant for poor eye contact, blank facial expression, and minimal spontaneous speech production.  Which of the following would be the most useful test in the diagnostic workup of this patient?

Quizplus · Accepted Answer

Explanation: When encountering a patient with new-onset psychosis in the emergency department, the physician must first rule out substance-induced and medical causes. This patient is at the age when primary psychotic disorders such as schizophrenia typically present. He has no known medical history and a normal physical examination with no focal neurologic findings, making medical causes less likely. However, a substance-induced psychotic disorder must be considered a possibility in this patient. Intoxication with a variety of substances including cocaine, amphetamines, and phencyclidine may mimic the symptoms of schizophrenia. It is necessary to rule out these intoxication syndromes before considering a primary psychiatric diagnosis. (Choice A) Although Wilson disease (abnormal copper excretion) can present with psychiatric symptoms, it is a rare condition that would typically be accompanied by hepatic and neurologic symptoms. Drug-induced psychosis is a much more likely possibility in this patient. (Choices B and C) Although structural brain lesions can cause psychotic symptoms, substance-induced symptoms are much more common, especially in this age group. This patient's normal neurologic examination further decreases the likelihood that imaging studies would be helpful in this case. There is no indication for an electroencephalogram at this time, as there is no seizure history and the patient does not appear postictal. (Choice D) Thyroid function tests are useful to screen for thyroid disease, which can cause depression and/or psychosis. However, in the absence of other symptoms or physical findings suggestive of thyroid disease, a urine toxicology screen takes priority. Educational objective: Diagnosis of primary psychotic disorders requires ruling out substance-induced and medical causes. Urine toxicology can be helpful in differentiating a substance-induced psychotic disorder from a primary psychiatric condition, and in guiding treatment. References: Urine drug screening: practical guide for clinicians. (http://www.ncbi.nlm.nih.gov/pubmed/18174009) Recognition and differential diagnosis of psychosis in primary care. (http://www.ncbi.nlm.nih.gov/pubmed/26131945)

A 21-Year-Old College Student Is Brought to the Emergency Department