Alzheimer disease vs Lewy body dementia
How to tell Alzheimer disease and Lewy body dementia apart when a board question makes them look alike.
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Early recurrent visual hallucinations with fluctuating attention indicates Lewy body dementia.
Side by side
Early prominent episodic memory impairment with gradual progression and no early visual hallucinations favors Alzheimer disease.
Fluctuating cognition with recurrent well-formed visual hallucinations and spontaneous parkinsonism favors Lewy body dementia.
Cortical beta-amyloid deposition and tau pathology drive progressive hippocampal and association cortex dysfunction.
Diffuse cortical alpha-synuclein Lewy bodies disrupt attention, visual processing, and motor circuits.
Neuropsychologic testing shows amnestic pattern, MRI often demonstrates hippocampal atrophy, and FDG-PET may show temporoparietal hypometabolism.
Lewy body dementia often shows occipital hypometabolism on PET or reduced dopamine transporter uptake on DaT imaging with relative memory preservation early.
The trap
Agitation in Lewy body dementia is treated with typical antipsychotics, causing severe rigidity or neuroleptic sensitivity reactions. Hallucinations should be managed cautiously, often with nonpharmacologic steps first and selective low-risk agents only if needed.
The repair move
Next best step: evaluate for Lewy body dementia features, avoid typical dopamine-blocking antipsychotics such as haloperidol, and start cognitive therapy with donepezil 5 mg nightly then titrate as tolerated for hallucination and cognition support. If severe psychosis threatens safety, use cautious low-dose quetiapine with close monitoring.
Try a free question
CoreA 74-year-old with fluctuating cognition, recurrent visual hallucinations, and mild parkinsonism is diagnosed with Lewy body dementia. What is the next best step in management?
Show answer and explanation
Answer: A. Avoid haloperidol and begin donepezil therapy. Lewy body dementia management prioritizes cholinesterase therapy and avoidance of typical antipsychotics because of neuroleptic sensitivity.
Why the other choices are tempting
- B. Wrong. Typical antipsychotics can cause severe adverse reactions in Lewy body dementia.
- C. Wrong. Supportive and pharmacologic management can improve function and safety.
- D. Wrong. There is no surgical indication.
- E. Wrong. Benzodiazepines alone may worsen confusion and falls.
Flashcards
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Which triad most strongly supports Lewy body dementia over Alzheimer disease?
Fluctuating cognition, recurrent visual hallucinations, and spontaneous parkinsonism.
What cognitive pattern is usually earliest in Alzheimer disease?
Progressive episodic memory impairment.
Quick answers
What is the fastest way to tell Alzheimer disease from Lewy body dementia?
Early recurrent visual hallucinations with fluctuating attention indicates Lewy body dementia.
What is the key clue for Alzheimer disease?
Early prominent episodic memory impairment with gradual progression and no early visual hallucinations favors Alzheimer disease.
What is the key clue for Lewy body dementia?
Fluctuating cognition with recurrent well-formed visual hallucinations and spontaneous parkinsonism favors Lewy body dementia.
What is the common trap with Alzheimer disease vs Lewy body dementia?
Agitation in Lewy body dementia is treated with typical antipsychotics, causing severe rigidity or neuroleptic sensitivity reactions. Hallucinations should be managed cautiously, often with nonpharmacologic steps first and selective low-risk agents only if needed.