Case: A 14-year-old with altered mental status

You walk over to the clinic to meet your new patient. He is lying on the bed, staring at the ceiling accompanied by his two concerned parents. With minimal prompting, the parents begin to describe their son's recent puzzling behavior.

A sudden and dramatic change

They first noticed that he was not himself two nights prior while they were preparing to leave for the movies. Their son brought a fully packed suitcase with him to the car. Later that same night, the father awoke at 2 a.m. and found his son fully dressed, standing in the back doorway. He said that people had been yelling at him through his bedroom window to come outside. His unusual behavior continued throughout the next day. He stepped into the shower fully dressed and couldn't remember how to work the faucet-a task he normally performs with ease. He repeatedly appeared to be hearing and seeing people who were not present.

Alarmed by this sudden and dramatic change in behavior, the family sought care at an emergency department (ED) the night prior to admission. A head computed tomography (CT) scan, complete metabolic panel, urine analysis, and basic urine drug screen were all within normal limits. They diagnosed him with a urinary tract infection, and discharged him home with a prescription for trimethoprim/sulfamethoxazole. When his hallucinations and confusion continued through this morning, his parents decided to bring him into your walk-in clinic for further evaluation.

Patient history

The patient's past medical history is significant for mild CP/MR. He was the thirty-nine week product of a cesarean delivery complicated by placental abruption. He has a history of seizures in his first month of life but has been seizure-free since then. He is not currently taking any medications, and has no known allergies. He lives with his parents and 8-year-old brother and is highly functioning at baseline. He is in the 9th grade, and attends resource classes. His review of systems is negative except for the pertinent positives mentioned previously. His family medical history is non-contributory.

On physical exam, his vitals are as follows: temperature 98.2° F, pulse 90 bpm, respirations 20 bpm, blood pressure 120/68 mmHg, oxygen saturation 100% on room air. He is awake and alert but will only follow simple commands, and answer questions with repeated prompting. He appears confused and begins to have a conversation with a person who is not present. He is oriented to person and place but not time. His neurological exam is as follows: cranial nerves intact; muscle strength 5/5 on the left and 4/5 on the right (baseline), reflexes 3+ and symmetric, sensation intact, mild tremor present in both upper and lower extremities. The remainder of his examination was within normal limits.