An 81-year-old man with imbalance and memory impairment

An 81-year-old man presented for evaluation of balance difficulties and nocturia. From January 1994 through February 1995, he developed progressive dizziness, which he described as a feeling of imbalance or unsteadiness when walking. This sensation occurred independently of changes in position and was not associated with true vertigo. His symptoms were identified shortly after he underwent knee surgery that was complicated by a gastrointestinal bleed requiring a blood transfusion. Over the year, his symptoms progressively worsened; he required a cane due to frequent falls and he lost interest in hunting, fishing, and reading. He developed increased rumination and anxiety with obsessive/compulsive behaviors that included the need to draw blinds, lock doors, or take out the trash immediately upon thinking of these actions. On a daily basis, he would sit at the window waiting for the mail to arrive and had to be the first one to retrieve and open it once it arrived. From March 1995 through February 1996, the patient’s wife noted he was becoming more forgetful and impatient. She took over the household finances by this time. Local evaluation included a head CT scan that by report demonstrated diffuse atrophy and he was diagnosed with Alzheimer disease (AD). A 4-week trial of tacrine hydrochloride was not beneficial. He continued to drive a motor vehicle and reported no traffic violations or motor vehicle accidents. His medical history was remarkable for atrial fibrillation, hypertension, and benign prostatic hyperplasia. His medications included fluoxetine, probenecid, and terazosin, the last of which was discontinued in March 1996. His social history was remarkable for moderate alcohol intake. He did not use tobacco. His family history was negative for gait, cognitive, or other neurologic disorders. Review of symptoms was remarkable for recent complaints of lightheadedness, which was non-positional, and nocturia (three times nightly). He denied …