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Dementia with Lewy Bodies

Overview

Dementia with Lewy Bodies, or DLB, is a gradually progressive dementia with features that overlap with Parkinson disease. It is the second most common neurodegenerative dementia after Alzheimer ’s disease (AD), but it has distinct symptoms and a different treatment approach. Therefore, it is important to obtain the most accurate diagnosis as early as possible.

First and foremost, DLB is a type of dementia, meaning that impaired cognition is required for diagnosis. Unlike the memory impairment that is seen early in the course of Alzheimer’s Disease, DLB patients often present with impaired attention, visuospatial and executive function. These deficits cause symptoms such as driving difficulty (getting lost, missing signs), trouble concentrating, and impaired job performance. Memory problems can occur, but are typically seen later in the course of the illness compared with AD.

If cognitive decline occurs within the first year of the onset of motor symptoms, or if motor symptoms appear within one year of cognitive decline, then a diagnosis of DLB is made.

Core Clinical Features

In addition to the dementia, there are core clinical features that point to a diagnosis of DLB. These include fluctuations in cognition and alertness, parkinsonism, and visual hallucinations.

Fluctuations

Up to 80% of patients with DLB have fluctuations. These fluctuations can vary quite a bit, even for the individual patient. Episodes may range from brief lapses in lucidity or clarity of speech, lasting seconds to minutes, to taking prolonged naps or having staring spells. Sometimes the fluctuations can be confused with seizures. In between these episodes, patients may have near normal cognitive function. When patients with DLB are admitted to the hospital, the fluctuations can mimic delirium, sometimes prolonging hospital stays.

Parkinsonism

The term parkinsonism implies slowness of movement (bradykinesia), combined with muscle rigidity, rest tremor, and/or postural instability. The parkinsonism of DLB occurs in 70-90% of patients and is difficult to distinguish clinically from idiopathic Parkinson disease (PD). As a group, patients with DLB tend to have less tremor and more symmetric symptoms compared with PD patients. DLB, as opposed to PD, should be suspected if cognitive symptoms are prominent either before onset or within one year of motor symptoms (see below).

Visual Hallucinations

Visual hallucinations or misperceptions occur in about two-thirds of patients with DLB. Although they can also occur in PD, in PD they are typically triggered by medications that the patient is taking to address his or her PD symptoms, and will resolve with adjusting or discontinuing the offending drug. Medications can certainly exacerbate hallucinations in DLB, but the hallucinations are often present in the absence of culprit medication or before the patient has even sought treatment. The hallucinations can take on the form of people or animals, but can also be fairly subtle, such as perceiving a shadow or something moving in one’s peripheral vision.

Suggestive Clinical Features

Rapid Eye Movement (REM) Sleep Behavior Disorder

REM Sleep Behavior Disorder, or RBD, is a type of parasomnia that can occur in up to 85% of DLB patients. (RBD can also occur outside the context of DLB. It affects about 15% of PD patients, for example.) Symptoms consist of acting out dreams, sometimes in a violent manner, and talking and shouting in one’s sleep. Patients often do not remember these episodes. Because RBD can interfere with the quality of sleep, and can occasionally cause injury to the patient or bed partner, treatment with clonazepam or melatonin is typically recommended.

Neuroleptic Sensitivity

Another key feature of DLB is that patients are very sensitive to the class of medications called neuroleptics. These are drugs that are used to treat psychosis or extreme agitation, and are sometimes given in a hospital setting when a patient is agitated enough to be a risk to him or herself. Patients with DLB can become very rigid and “frozen” as a result of being given this type of medication. In some cases, DLB patients may even develop a life-threatening high fever and blood pressure instability in response to these medications. Two safer exceptions when DLB patients require treatment for their hallucinations or psychosis are the medications quetiapine (Seroquel) and clozapine (Clozaril).

Treatment

Treatment of DLB poses a dilemma to the clinician and patient, because trying to address the motor symptoms, or parkinsonism, can worsen the cognitive symptoms, and treatment of cognitive symptoms can often worsen the parkinsonism. It becomes a careful balancing act that requires good communication among the treatment team, patient and caregivers. In general, non-levodopa treatments for parkinsonism (such as dopamine agonists or other adjunctive PD medications) should be avoided and carbidopa-levodopa (Sinemet) should be used sparingly.

Cognitive symptoms can be treated with cholinesterase inhibiting medications, such as donepezil (Aricept) and rivastigmine (Exelon). Many patients with DLB respond well to these medications and sometimes even have reduction in hallucinations as a result.

Behavioral and psychotic symptoms should be managed without medication to the extent possible. When antipsychotic medications are required, low doses of quetiapine or clozapine can be started cautiously with careful monitoring.

Summary

DLB can be a challenging condition to diagnose and treat due to the overlap of symptoms with regular Parkinson disease and Alzheimer’s disease. Proper diagnosis is important to guide the treatment approach. The observation and documentation of core and suggestive clinical features are the mainstays of diagnosis. Working closely with a movement disorders or dementia specialist can be quite helpful for avoiding some of the pitfalls of DLB management.

Publications

Dementia with Lewy Bodies

Parkinson Disease Dementia

Additional Resources

Lewy Body Dementia Association www.lbda.org 404-935-6444

LBD Caregiver Link: 800-539-9767

Alzheimer’s Association http://www.alz.org/dementia/dementia-with-lewy-bodies-symptoms.asp