Chapter 11-6: Dementia with Lewy Bodies (DLB)

TEXTBOOK PRESENTATION

DLB is typically seen in a patient with Parkinson disease who has dementia. The predominant symptoms of dementia are a fluctuating course and the presence of hallucinations. In patients without a previous diagnosis of Parkinson disease, motor symptoms similar to those seen in Parkinson disease are often present.

DISEASE HIGHLIGHTS

1. DLB is among the most common types of dementia after AD.

   1. Lewy bodies are seen in the cortex of about 20% of patients with dementia.

   2. Lewy bodies may be present in some patients with a clinical diagnosis of AD thus DLB may coexist with AD.

2. The most important features of DLB are included in the Evidence-Based Diagnosis section below.

3. Patients with DLB may have a fluctuating course.

   1. Early in the disease, patients may be nearly normal at times and significantly impaired at others.

   2. Because of the fluctuation in symptoms, delirium needs to be included in the differential diagnosis.

4. Visual hallucinations are common in DLB, unlike in most other types of dementia.

5. Mild extrapyramidal motor symptoms (rigidity and bradykinesis) are often seen. These may occur late in the course of other dementias but occur early with DLB.

EVIDENCE-BASED DIAGNOSIS

The diagnostic criteria for DLB are presented below.

1. There is dementia (often mild at onset).

2. 2 of the following are essential for a diagnosis of probable DLB:

   1. Fluctuating cognition with pronounced variations in attention and alertness

   2. Recurrent visual hallucinations that are typically well-formed and detailed

   3. Spontaneous motor features of parkinsonism

3. The following features are supportive of the diagnosis of DLB:

   1. Repeated falls

   2. Syncope

   3. Transient loss of consciousness

   4. Neuroleptic sensitivity

   5. Systematized delusions and hallucinations

TREATMENT

1. Supportive treatment of patients with DLB is the same as for patients with AD.

2. Cholinesterase inhibitors have also been shown to be effective.

3. Neuroleptics can be dangerous, potentially worsening symptoms.

   Patients with dementia with parkinsonian features, a fluctuating course, and visual hallucinations should be evaluated for DLB before they are treated with neuroleptics.