Clinical Reasoning:A 28-year-old IV drug user with bilateral basal ganglia and brainstem lesions

A 28-year-old man presented with progressive lethargy and confusion over 2 days. He has a longstanding history of IV heroin use. His last use was 2 weeks ago, and he completed inpatient detoxification 2 days before admission. After he returned home from rehabilitation, his roommate noticed that he became increasingly confused. On the day of admission, he was febrile, unable to get out of bed, or speak, although he was able to nod yes and no to simple questions. He also lost urinary control.