II. Definition
III. Epidemiology
- Accounts for 20% of Dementia cases
- Second most common cause
- Mean age of onset: 75 to 80 years old
IV. Pathophysiology
- Lewy body and Lewy neurites
- Eosinophilic cytoplasmic inclusions (alpha-synuclein)
- Parkinsonism: Substantia Nigra, locus ceruleus
- Lewy Body Dementia: Frontotemporal cortex
- Eosinophilic cytoplasmic inclusions (alpha-synuclein)
- Other changes specific to Lewy Body Dementia
- Basal forebrain degeneration (CholinergicNeurons)
- Nigra degeneration (Dopaminergic Neurons)
- Serotonergic Neurons also affected
- Comparison with Alzheimer's Disease changes
- Amyloid Plaques in Alzheimer's and Lewy Body Dementia
- Neurofibrillary tangles seen in Alzheimer's only
V. Clinical features
- Dementia (cognitive function decline)
- Core features (2 features required for probable case)
- Recurrent Visual Hallucinations
- Fluctuating cognition, alertness and attention
- Normal performance in stimulating activity
- Transient periods of "blankness"
- Parkinsonism
- Rigidity, Bradykinesia and altered gait are common
- Mask-like faces are also seen
- Resting Tremor less common than Parkinson's Disease
- Manifesting signs and symptoms
- Syncope
- Recurrent falls
- Transient loss of consciousness
- Delusions
- Major Depression
- REM Sleep disorder
- Associated with Nightmares of being chased
VI. Differential Diagnosis
- See Dementia
-
Alzheimer's Disease differentiating features
- Memory Loss is more prominent than in DLB
- Visual Hallucinations less common in Alzheimer's
- Parkinsonism uncommon in Alzheimer's Disease
- Minimal cortical atrophy in Lewy Body Dementia
- Alzheimer's: MRI involves Hippocampus, Temporal Lobe
VII. Diagnostic Testing
- Rule-out other cause
- See Dementia for diagnostic testing
-
Mini-Mental State Exam (MMSE) findings
- Difficult attention and construction
- Difficult clock drawing
- Memory appears unaffected in early DLB
VIII. Management
- See Dementia Management
- Avoid Anticholinergic Medications
-
Cholinesterase Inhibitors
- Effects
- Improve apathy and anxiety
- Reduce Hallucinations and Delusions
- Improve cognition
- Agents
- Effects
- Antiparkinsonism Medications
- Levodopa-Carbidopa (Sinemet)
- Start with lowest dose of a single agent
- Goal: Improve mobility without inducing Psychosis
- Levodopa-Carbidopa (Sinemet)
-
REM Sleep Behavior Disorder
- Clonazepam 0.25 to 1 mg orally at bedtime
-
Orthostatic Hypotension
- Fluids and increase Sodium in diet
- Rise from lying or sitting slowly
- Avoid prolonged bed rest
-
Anti-Psychotic medications (Neuroleptics)
- Cholinesterase Inhibitors may reduce Psychosis
- High sensitivity to Neuroleptics in DLB
- May severely exacerbate Parkinsonism symptoms
- Rigidity
- Sedation
- Effects on Parkinsonism may be irreversible
- Effects may be life-threatening
- Example: Neuroleptic Malignant Syndrome
- Use Neuroleptics with caution and Informed Consent
- May severely exacerbate Parkinsonism symptoms
- Agents
- Risperidone 0.25 mg PO bid (maximum 1 mg bid)
- Olanzapine 2.5 mg PO daily (maximum 10 mg daily)
- Quetiapine 25 mg PO bid (maximum 150 mg/day)
- Contraindicated agents: Older, type 2 Antipsychotics
- Avoid Haloperidol, Fluphenazine, Chlorpromazine
IX. Resources
- Lewy Body Dementia Association