Dementia with Lewy bodies

Clinical vignette
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By Ann Marie Hake MD

A 68-year-old man presented for further evaluation of recent confusion during a hospitalization for a urologic procedure 1 month earlier. On review, the patient’s family stated that he had been somewhat more forgetful in the past year and had shown signs of visual-spatial difficulties, for example, having difficulty parallel parking his car. The changes, however, had been too subtle to prompt them to seek medical attention. He had also been slower in his walking speed; for instance, the family had recently taken a trip, during which he had not walked as fast as the others in the group, which was atypical for him.

The hospitalization had been for an elective transurethral resection of the prostate. It was supposed to be a same-day procedure, but when the man awoke from anesthesia, he was agitated, disoriented, and hallucinating. He received haloperidol and developed significant somnolence and rigidity that lasted 24 hours. The family stated that since his hospitalization, he had gradually improved, returning close to his baseline functioning.

On examination, the Mini-Mental State Examination (MMSE) was administered, yielding a score of 26 out of 30. He had difficulties with attention and constructional apraxia in his ability to draw intersecting pentagons and a clock face. He had intact delayed recall. On examination there were very subtle signs of parkinsonism: specifically, mild decreases in facial expression and volume of voice, traces of postural tremor but no resting tremor, and mild bilateral arm rigidity. His gait was abnormal, secondary to a stooped posture and decreased arm swing with walking. Stride length and gait speed were also decreased.

On further review of the history, the man’s family described symptoms consistent with REM sleep behavior disorder, with yelling and intermittent acting out of his dreams, which had been present for the past several years. These episodes had been becoming more frequent and severe. Since his hospital stay, he had had several occasions of visual hallucinations that had continued despite his otherwise overall improvement. He typically saw people, especially in the evenings or when he awoke from a daytime nap. He had also had some intermittent visual misperceptions since his hospital stay, where he would see things differently from others – for example, looking out the window and stating that it was raining when it was not.

Re-evaluation 6 months later showed continuing evidence of parkinsonism and increasing cognitive impairment on repeat testing (new MMSE score of 24). He was having increasing functional impairment in his everyday activities and still had intermittent visual hallucinations, especially in the evening hours. Diagnostic testing included MR imaging of the brain, which showed mild generalized atrophy but no other structural cause of his symptoms. Laboratory tests included B12 and TSH, which were normal. Formal neuropsychological testing showed evidence of mild dementia with difficulty with executive cognitive functions and attention, and significant visual-spatial impairment. There were mild memory deficits, especially memory retrieval, but overall memory was relatively spared.

This patient’s presentation and work-up is consistent with the diagnosis of dementia with Lewy bodies. The onset of his cognitive impairment and parkinsonism were approximately at the same time. He had evidence of dementia associated with parkinsonism and frequent visual hallucinations. By history, he had also had cognitive fluctuations. Other supportive features include REM sleep behavior disorder, significant adverse effects with an antipsychotic medication (haloperidol), and susceptibility to delirium.

For management, the patient was placed on a cholinesterase inhibitor. This stabilized his cognitive function, and his hallucinations were less frequent. There appeared to be less frequent fluctuations in his symptoms. An antipsychotic medication was not needed. He was not having symptoms of depression. He was placed on a low dose of clonazepam at nighttime to suppress REM sleep behavior disorder symptoms and to improve his overall sleep.

In This Article

Historical note and nomenclature
Clinical manifestations
Clinical vignette
Pathogenesis and pathophysiology
Differential diagnosis
Diagnostic workup
Prognosis and complications
References cited