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A 67-year-old man is evaluated for several months of visual hallucinations that tend to occur at night or when he is short on sleep. He frequently falls asleep in the daytime. Two years ago, he had an episode of delirium and visual hallucinations after taking meclizine for vestibular neuronitis. He recovered 2 weeks after the meclizine therapy was discontinued. Neurologic examination reveals impairment of recent memory and attention, mild rigidity and resting tremor in the left arm, and a shuffling gait without postural instability.
Which of the following treatments is most appropriate in this patient?
] A Donepezil
]] B Pergolide
] C Carbidopa-levodopa
D Haloperidol
E Risperidone
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Correct Answer = A)
Key Points
* The three specific criteria for dementia with Lewy bodies are fluctuating encephalopathy, parkinsonism, and visual hallucinations.
* A centrally acting anticholinesterase agent may alleviate the inattention, hallucinations, and fluctuating encephalopathy of dementia with Lewy bodies.
This patient has the three specific inclusion criteria for probable dementia with Lewy bodies (fluctuating encephalopathy, parkinsonism, visual hallucinations). Affected patients have a central cholinergic deficiency. Cholinergic augmentation with a centrally acting anticholinesterase agent such as donepezil, galantamine, or rivastigmine is likely to alleviate the inattention, hallucinations, and fluctuating encephalopathy. Since this patient has a history of inordinate sensitivity to anticholinergic medication (meclizine), there is specific evidence of cholinergic deficiency, and cholinergic augmentation is the treatment of choice.
This patient has only mild, functionally insignificant parkinsonism, and antiparkinson therapy is probably not necessary at this time. A dopamine agonist would likely exacerbate the encephalopathy.
Patients with dementia with Lewy bodies may develop a severe parkinsonian reaction to standard neuroleptic agents (for example, haloperidol). In this setting, neuroleptic therapy carries an increased risk of neuroleptic malignant syndrome and mortality. Hallucinations, delusions, and agitation are appropriately treated with cholinergic augmentation and/or an atypical neuroleptic.
Therapy with an atypical neuroleptic agent (risperidone, quetiapine) usually alleviates the psychiatric symptoms in patients with dementia with Lewy bodies; however, neuroleptic therapy does not improve cognitive symptoms and sometimes exacerbates parkinsonism.
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