Clinical Reasoning: A 66-Year-Old Woman With Progressive Encephalopathy and Bilateral Hearing Loss

A 66-year-old woman with no medical history presented to an outside hospital for an acute alteration in cognition described as wandering aimlessly, combative behavior, and incomprehensible speech that progressed over 3 days. On arrival, she had altered cognition, psychomotor agitation, and inability to follow commands, but no weakness, dysarthria, sensation loss, vision loss, or meningismus. Vital signs and laboratory studies including complete blood count, comprehensive metabolic panel, urinalysis, and urine drug screen were normal.